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1
Greenstreet, Simon P. R., Helen M. Fraser et Gerjan J. Piet. « Using MPAs to address regional-scale ecological objectives in the North Sea : modelling the effects of fishing effort displacement ». ICES Journal of Marine Science 66, no 1 (1 janvier 2009) : 90–100. http://dx.doi.org/10.1093/icesjms/fsn214.
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Abstract Greenstreet, S. P. R., Fraser, H. M., and Piet, G. J. 2009. Using MPAs to address regional-scale ecological objectives in the North Sea: modelling the effects of fishing effort displacement. – ICES Journal of Marine Science, 66: 90–100. The use of Marine Protected Areas (MPAs) to address regional-scale objectives as part of an ecosystem approach to management in the North Sea is examined. Ensuring that displacement of fishing activity does not negate the ecological benefits gained from MPAs is a major concern. Two scenarios are considered: using MPAs to safeguard important areas for groundfish species diversity and using them to reduce fishing impacts on benthic invertebrates. Appropriate MPAs were identified using benthic invertebrate and fish abundance data. Fishing effort redistribution was modelled using international landings and fishing effort data. Closing 7.7% of the North Sea to protect groundfish species diversity increased the fishing impact on benthic invertebrates. Closing 7.3% of the North Sea specifically to protect benthic invertebrates reduced fishing mortality by just 1.7–3.8%, but when combined with appropriate reductions in total allowable catch (TAC), 16.2–17.4% reductions in fishing mortality were achieved. MPAs on their own are unlikely to achieve significant regional-scale ecosystem benefits, because local gains are largely negated by fishing effort displacement into the remainder of the North Sea. However, in combination with appropriate TAC reductions, the effectiveness of MPAs may be enhanced.
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Bourgeois-Roy, Andréanne, Hugo Crites, Pascal Bernatchez, Denis Lacelle et André Martel. « Abrupt mortality of marine invertebrates at the Younger Dryas-Holocene transition in a shallow inlet of the Goldthwait Sea ». Holocene 28, no 12 (10 septembre 2018) : 1894–908. http://dx.doi.org/10.1177/0959683618798130.
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The late Pleistocene–early Holocene transition period was characterized by rapid environmental change. Here, we investigate the impact of these changes on the marine invertebrates living in a shallow inlet of the post-glacial Goldthwait Sea. The site is located near Baie-Comeau (QC, Canada), where a number of remarkably well-preserved shell deposits are found along the Rivière aux Anglais Valley on the north shore of the St. Lawrence maritime estuary. Seven phyla of marine invertebrates with a minimum of 25 species or taxa were inventoried in a shell deposit, dominated by a community of Hiatella arctica with Mytilus edulis and barnacles composing the subcommunity. The majority of taxa identified in the shell deposit are boreal and sub-Arctic species; however, temperate species that exist today in the St. Lawrence maritime estuary have not been found. Based on marine invertebrate diversity and δ18O(CaCO3) of Mytilus edulis, the water in the shallow inlet of the Goldthwait Sea must have been cold and saline. The range of AMS 14C ages from 15 Mytilus edulis, constrained to 10,900 and 10,690 cal. yr BP, and exceptional state of preservation of adult and juvenile molluscan specimens suggest the abrupt mortality of entire invertebrate communities due to changing hydrodynamic conditions that included the combined effect of freshwater discharge from the receding Laurentide Ice Sheet and rapid isostatic uplift.
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Robinson, L. A., S. P. R. Greenstreet, H. Reiss, R. Callaway, J. Craeymeersch, I. de Boois, S. Degraer et al. « Length–weight relationships of 216 North Sea benthic invertebrates and fish ». Journal of the Marine Biological Association of the United Kingdom 90, no 1 (14 janvier 2010) : 95–104. http://dx.doi.org/10.1017/s0025315409991408.
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Size-based analyses of marine animals are increasingly used to improve understanding of community structure and function. However, the resources required to record individual body weights for benthic animals, where the number of individuals can reach several thousand in a square metre, are often prohibitive. Here we present morphometric (length–weight) relationships for 216 benthic species from the North Sea to permit weight estimation from length measurements. These relationships were calculated using data collected over two years from 283 stations. For ten abundant and widely dispersed species we tested for significant spatial and temporal differences in morphometric relationships. Some were found, but the magnitude of differences was small in relation to the size-ranges of animals that are usually present and we recommend that the regression relationships given here, based on pooled data, are appropriate for most types of population and community analyses. Our hope is that the availability of these morphometric relationships will encourage the more frequent application of size-based analyses to benthic survey data, and so enhance understanding of the ecology of the benthic/demersal component of marine ecosystems and food webs.
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Antoniadou, Chryssanthi, Martha Pantelidou, Maria Skoularikou et Chariton Charles Chintiroglou. « Mass Mortality of Shallow-Water Temperate Corals in Marine Protected Areas of the North Aegean Sea (Eastern Mediterranean) ». Hydrobiology 2, no 2 (30 avril 2023) : 311–25. http://dx.doi.org/10.3390/hydrobiology2020020.
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Coral mortality is a global phenomenon of increasing magnitude, correlated with climate change. Prolonged marine heatwaves have particularly affected the north Aegean Sea in summer 2021, threatening shallow-water stony corals, such as Balanophyllia europaea and Cladocora caespitosa. To assess their population status, ten coastal, rocky-bottom stations dispersed in Natura 2000 sites of Chalkidiki (north Aegean) were surveyed using non-destructive techniques in autumn 2021. At each station, corals’ abundance was estimated in situ, by counting the number of B. europaea polyps within randomly placed 50 × 50 cm quadrats, and the number of C. caespitosa colonies along three replicate belt transects 1 × 10 m. The status of corals was qualitatively assigned as healthy, bleached (partially or complete), or in necrosis (partial or complete). B. europaea was found in 80% of stations; in total, 58.17% of the coral specimens were affected by necrosis. C. caespitosa was found in 30% of stations; in total, 27.49% of the coral colonies were partially bleached and 11.32% in necrosis. Another nine sessile invertebrates (sponges, bivalves, and ascidians) were observed in necrosis. These results highlight the need to establish monitoring programs on vulnerable sessile invertebrate populations along the Aegean Sea to assess climate change impacts.
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Dyer, M. F. « The Distribution of Hyas Araneus (L.) and Hyas Coarctatus Leach (Crustacea : Decapoda : Brachyura) in the North Sea and the Svalbard Region ». Journal of the Marine Biological Association of the United Kingdom 65, no 1 (février 1985) : 195–201. http://dx.doi.org/10.1017/s0025315400060902.
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The distribution patterns of many marine benthic invertebrates are not well known, and when records exist they are usually in the form of presence and absence data with little or no information on the relative density of populations from area to area.
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Ivanova, Elena P., Olga I. Nedashkovskaya, Tomoo Sawabe, Natalia V. Zhukova, Galina M. Frolova, Dan V. Nicolau, Valery V. Mikhailov et John P. Bowman. « Shewanella affinis sp. nov., isolated from marine invertebrates ». International Journal of Systematic and Evolutionary Microbiology 54, no 4 (1 juillet 2004) : 1089–93. http://dx.doi.org/10.1099/ijs.0.02992-0.
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Four marine bacterial strains, designated KMM 3587T, KMM 3586, KMM 3821 and KMM 3822, were isolated from the sipuncula Phascolosoma japonicum, a common inhabitant of Troitza Bay in the Gulf of Peter the Great (Sea of Japan region), and from an unidentified hydrocoral species collected in Makarov Bay (Iturup Islands), Kuril Islands, North-West Pacific Ocean. The strains were characterized to clarify their taxonomic position. 16S rRNA gene sequences of KMM 3587T and KMM 3586 indicated 99 % similarity to Shewanella colwelliana. Despite such a high level of 16S rRNA gene sequence similarity, DNA–DNA hybridization experiments demonstrated only 45–52 % binding with DNA of S. colwelliana ATCC 39565T. The DNA G+C contents of the novel strains were 45 mol% and the shared level of DNA hybridization was conspecific (81–97 %), indicating that they represent a single genospecies. The novel strains were mesophilic (able to grow at 10–34 °C), neutrophilic and haemolytic, and able to degrade gelatin, casein and Tween 20, 40 and 80, but not starch, agar, elastin, alginate or chitin. The major fatty acids were i13 : 0, i15 : 0, 16 : 0, 16 : 1ω7 and 17 : 1ω8 (68·9 % of total). The major isoprenoid quinones were Q7 (47–62 %) and Q8 (26–47 %). Eicosapentaenoic acid was produced in minor amounts. Based on these data, the strains are assigned to a novel species, Shewanella affinis sp. nov. (type strain KMM 3587T=CIP 107703T=ATCC BAA-642T).
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Moss, Madonna L. « Did Tlingit Ancestors Eat Sea Otters ? Addressing Intellectual Property and Cultural Heritage through Zooarchaeology ». American Antiquity 85, no 2 (11 février 2020) : 202–21. http://dx.doi.org/10.1017/aaq.2019.101.
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The maritime fur trade caused the extirpation of sea otters from southeast Alaska. In the 1960s, sea otters were reintroduced, and their numbers have increased. Now, sea otters are competing with people for what have become commercially important invertebrates. After having been absent for more than a century, the reentry of this keystone species has unsettled people. Although some communities perceive sea otters as a threat to their livelihoods, others view their return as restoration of the marine ecosystem. The federal Marine Mammal Protection Act authorizes any Alaska Native to harvest sea otters for subsistence provided that the harvest is not wasteful. Some people are seeking to define “traditional” Tlingit use of sea otters as not only using their pelts but consuming them as food, but some Tlingit maintain they never ate sea otters. This project analyzes the largest precontact archaeological assemblage of sea otter bones in southeast Alaska, with the benefit of insights gained from observing a Tlingit hunter skin a sea otter to infer that Tlingit ancestors hunted sea otters primarily for pelts. The extent to which other Indigenous peoples of the North Pacific consumed sea otters as food deserves investigation, especially as sea otters recolonize their historic range.
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Rueda, José L., Ana Mena-Torres, Marina Gallardo-Núñez, Emilio González-García, Alejandro Martín-Arjona, Javier Valenzuela, Cristina García-Ruiz et al. « Spatial Distribution and Potential Impact of Drifted Thalli of the Invasive Alga Rugulopteryx okamurae in Circalittoral and Bathyal Habitats of the Northern Strait of Gibraltar and the Alboran Sea ». Diversity 15, no 12 (7 décembre 2023) : 1206. http://dx.doi.org/10.3390/d15121206.
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The arrival of a new invasive alga, Rugulopteryx okamurae, in the Strait of Gibraltar (SoG) in 2015 marked an unprecedented milestone in the North African and, later, in the European marine ecosystems. Nowadays, it is colonising vast infralittoral areas and significantly modifying some habitats and associated communities of the southern Iberian Peninsula. In recent expeditions, a high amount of free drifted thalli of this alga has been detected in different circalittoral and bathyal habitats of the northern SoG and the Alboran Sea. The present study combines quantitative data of this alga obtained with the use of a remotely operated vehicle (ROV) and a bottom otter trawl. The coverage–entanglement level of the drifted thalli on circalittoral and bathyal benthic invertebrates (e.g., not covering, covering only the basal part, covering one-third of the invertebrate, etc.) was also annotated from picture frames taken in locations with abundant drifted thalli. In underwater images, drifted thalli were mainly detected in circalittoral and bathyal bottoms of the northern SoG and the north-western Alboran Sea, between 50 to ca. 450 m depth. Nevertheless, abundant drifted thalli were also detected in bottom otter trawl samples from circalittoral bottoms of the north-central and north-eastern Alboran Sea. Small benthic organisms (e.g., encrusting sponges, hydrozoans, etc.) generally displayed low coverage–entanglement levels of drifted thalli. Nevertheless, large sessile and colonial benthic organisms with a complex three-dimensional morphology (e.g., gorgonians, colonial scleractinians) reached high levels of R. okamurae thalli entangled in different parts of their colonies. The drifted R. okamurae thalli entangled in these colonial suspension feeding organisms may hinder their feeding capability in the long term, resulting in habitat deterioration in the near future.
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Scinto, Alice, Giorgio Bavestrello, Massimo Boyer, Monica Previati et Carlo Cerrano. « Gorgonian mortality related to a massive attack by caprellids in the Bunaken Marine Park (North Sulawesi, Indonesia) ». Journal of the Marine Biological Association of the United Kingdom 88, no 4 (25 juin 2008) : 723–27. http://dx.doi.org/10.1017/s002531540800129x.
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A massive attack of caprellids is reported here, that is related to a local mortality event of gorgonians in North Sulawesi. Three species of sea fans were affected by the presence of Metaprotella sandalensis, a caprellid widely distributed in the Indo-Pacific. The degree of damage here documented was in relation to the skeletal features of the gorgonian species. The amphipod gut contents were analysed, highlighting an unusual trophic source for caprellids and a new predator for gorgonians. This phenomenon is discussed also evidencing parallels between colonial marine invertebrates and their predators and terrestrial plant–herbivore interactions.
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Petrescu, Iorgu, et Ana–Maria Petrescu. « Invertebrate Collection Donated by Professor Dr. Ion Cantacuzino to “Grigore Antipa” National Museum of Natural History from Bucharest ». Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” 59, no 1 (1 juin 2016) : 7–30. http://dx.doi.org/10.1515/travmu-2016-0013.
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AbstractThe catalogue of the invertebrate collection donated by Prof. Dr. Ion Cantacuzino represents the first detailed description of this historical act. The early years of Prof. Dr. Ion Cantacuzino’s career are dedicated to natural sciences, collecting and drawing of marine invertebrates followed by experimental studies. The present paper represents gathered data from Grigore Antipa 1931 inventory, also from the original handwritten labels. The specimens were classified by current nomenclature. The present donation comprises 70 species of Protozoa, Porifera, Coelenterata, Mollusca, Annelida, Bryozoa, Sipuncula, Arthropoda, Chaetognatha, Echinodermata, Tunicata and Chordata.. The specimens were collected from the North West of the Mediterranean Sea (Villefranche–sur–Mer) and in 1899 were donated to the Museum of Natural History from Bucharest. The original catalogue of the donation was lost and along other 27 specimens. This contribution represents an homage to Professor’s Dr. Cantacuzino generosity and withal restoring this donation to its proper position on cultural heritage hallway.
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Marco-Herrero, Elena, Montserrat Ramón, Sergio Ramírez-Amaro, Olga Sánchez-Guillamón, Francesc Ordines, Carmina López-Rodríguez, María Teresa Farriols, Juan Tomás Vázquez et Enric Massutí. « New Deep-Sea Molluscan Records from Mallorca Channel Seamounts (North-Western Mediterranean) ». Diversity 14, no 11 (29 octobre 2022) : 928. http://dx.doi.org/10.3390/d14110928.
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Seamounts are globally important and essential ecosystems for supporting and maintaining marine biodiversity. In the Mallorca Channel, three prominent seamounts are present: Ausias March, Ses Olives and Emile Baudot. Currently, this area is being evaluated for inclusion in the Natura 2000 network. For this objective three surveys were conducted in the seamounts of the Mallorca Channel during July 2018 and July 2020. Samples of macro-invertebrates obtained in the deep sea revealed a rich fauna of Mollusca (68 species belonging to 40 families). New Mollusca occurrences included: four species of Gastropoda: Colus jeffreysianus, Cantrainea peloritana, Fusiturris similis, Gymnobela abyssorum, and seven species of Bivalvia: Pododesmus squama, Allogramma formosa, Asperarca nodulosa, Cetomya neaeroides, Spondylus gussonii, Haliris granulata and Policordia gemma. Where possible, the identification of these species was confirmed using the DNA barcoding method (sequencing of the cytochrome c oxidase subunit I). This study contributes towards filling the gap in knowledge of deep-sea mollusc fauna of the north-western Mediterranean.
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Alekseev, Victor, et Natalia Sukhikh. « Ust-Luga Seaport of Russia : Biological Invasions and Resting Stages Accumulation ». Life 13, no 1 (31 décembre 2022) : 117. http://dx.doi.org/10.3390/life13010117.
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This article describes the results of a three-year study of invasive species of aquatic ecosystems in the vicinity of Ust-Luga, the largest Russian seaport in the Baltic. Taking into account the great importance of the participation of marine vessels in the dispersal of invasive species, an experimental study of the seasonality of accumulation of resting stages of aquatic invertebrates in the ballast compartments of a vessel located in the Baltic Sea of the Gulf of Finland was carried out. Experiments show that the time of filling the ballast compartments in late summer and autumn poses the greatest risk for the spread of aquatic invertebrates with ship ballast water. In the Baltic Russian port, 11 invasive species of zooplankton and zoobenthos were found, which comprises 15% of the biodiversity in the samples. Copepoda demonstrated the highest presence of invasive species in class among zooplankton groups (14%) and Malacostraca among benthos groups (80%). Alien species findings correspond to the main vectors of invasive species dispersal for the Baltic Sea: North America, Indochina, and the Ponto-Caspian region.
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Gerdes, Gisela, et Wolgang E. Krumbein. « Burrowing and tube-building marine invertebrates controlled by potential siliciclastic stromatolites of the supratidal (Southern North Sea Coast) ». Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 172, no 2 (16 juin 1986) : 163–91. http://dx.doi.org/10.1127/njgpa/172/1986/163.
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Bezhenar, Roman, Kyung Tae Jung, Vladimir Maderich, Stefan Willemsen, Govert de With et Fangli Qiao. « Transfer of radiocaesium from contaminated bottom sediments to marine organisms through benthic food chains in post-Fukushima and post-Chernobyl periods ». Biogeosciences 13, no 10 (23 mai 2016) : 3021–34. http://dx.doi.org/10.5194/bg-13-3021-2016.
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Abstract. After the earthquake and tsunami on 11 March 2011 damaged the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), an accidental release of a large amount of radioactive isotopes into both the air and the ocean occurred. Measurements provided by the Japanese agencies over the past 5 years show that elevated concentrations of 137Cs still remain in sediments, benthic organisms, and demersal fishes in the coastal zone around the FDNPP. These observations indicate that there are 137Cs transfer pathways from bottom sediments to the marine organisms. To describe the transfer quantitatively, the dynamic food chain biological uptake model of radionuclides (BURN) has been extended to include benthic marine organisms. The extended model takes into account both pelagic and benthic marine organisms grouped into several classes based on their trophic level and type of species: phytoplankton, zooplankton, and fishes (two types: piscivorous and non-piscivorous) for the pelagic food chain; deposit-feeding invertebrates, demersal fishes fed by benthic invertebrates, and bottom omnivorous predators for the benthic food chain; crustaceans, mollusks, and coastal predators feeding on both pelagic and benthic organisms. Bottom invertebrates ingest organic parts of bottom sediments with adsorbed radionuclides which then migrate up through the food chain. All organisms take radionuclides directly from water as well as food. The model was implemented into the compartment model POSEIDON-R and applied to the north-western Pacific for the period of 1945–2010, and then for the period of 2011–2020 to assess the radiological consequences of 137Cs released due to the FDNPP accident. The model simulations for activity concentrations of 137Cs in both pelagic and benthic organisms in the coastal area around the FDNPP agree well with measurements for the period of 2011–2015. The decrease constant in the fitted exponential function of simulated concentration for the deposit-feeding invertebrates (0.45 yr−1) is close to the observed decrease constant in sediments (0.44 yr−1). These results strongly indicate that the gradual decrease of activity in demersal fish (decrease constant is 0.46 yr−1) is caused by the transfer of activity from organic matter deposited in bottom sediment through the deposit-feeding invertebrates. The estimated model transfer coefficient from bulk sediment to demersal fish in the model for 2012–2020 (0.13) is larger than that to the deposit-feeding invertebrates (0.07). In addition, the transfer of 137Cs through food webs for the period of 1945–2020 has been modelled for the Baltic Sea contaminated due to global fallout and from the Chernobyl accident. The model simulation results obtained with generic parameters are also in good agreement with available measurements in the Baltic Sea. Unlike the open coastal system where the FDNPP is located, the dynamics of radionuclide transfer in the Baltic Sea reach a quasi-steady state due to the slow rate in water mass exchange in this semi-enclosed basin. Obtained results indicate a substantial contribution of the benthic food chain in the long-term transfer of 137Cs from contaminated bottom sediments to marine organisms and the potential application of a generic model in different regions of the world's oceans.
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Chacón-Monge, José-Leonardo, Arturo Angulo et Jorge Cortés. « New hosts and morphological data for the Star pearlfish Carapus mourlani (Ophidiiformes : Carapidae) from collections made in the North Pacific coast of Costa Rica ». Revista de Biología Tropical 69, Suppl.2 (6 septembre 2021) : S219—S233. http://dx.doi.org/10.15517/rbt.v69isuppl.2.48319.
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Introduction: The family Carapidae includes about 40 species of marine fishes distributed in coastal habitats worldwide. The family includes some free-living species, however, most of them are found as commensal inquilines or parasites of marine invertebrates, including several echinoderm species. In the Eastern Tropical Pacific, the biology and host use of the representatives of the Carapidae is relatively poorly known.
Objective: The present study reports the occurrence of the Star pearlfish Carapus mourlani within three previously unknown hosts in the region: the sea stars Nidorellia armata, Phataria unifascialis, and the sea cucumber Stichopus horrens. Some ecological implications and considerations regarding such symbiotic relationships are raised and discussed. Additional morphometric and meristic data for the fish and the echinoderms are also provided and discussed.
Methods: Echinoderms were collected, from 25 localities along the North Pacific coast of Costa Rica, and were carefully examined searching for commensal/parasitic fishes. Echinoderms and fishes were identified and characterized in accordance with the specialized literature.
Results: A total of 497 echinoderms, including about 60 species, were collected and examined. Commensal/parasitic fish (a single species represented by 13 specimens) were found in three echinoderm specimens/species.
Conclusions: The list of echinoderm hosts for this carapid fish, through its whole distribution range, rises to 12 species (six sea stars and six sea cucumbers) and that could be a consequence of its wide geographic distribution, its generalist feeding habits and opportunistic commensal behavior.
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Eisenbarth, Jan-Hendrik, Nani Undap, Adelfia Papu, Dorothee Schillo, Jobel Dialao, Sven Reumschüssel, Fontje Kaligis et al. « Marine Heterobranchia (Gastropoda, Mollusca) in Bunaken National Park, North Sulawesi, Indonesia—A Follow-Up Diversity Study ». Diversity 10, no 4 (4 décembre 2018) : 127. http://dx.doi.org/10.3390/d10040127.
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Bunaken National Park has been surveyed for a fourth time in 14 years, in an attempt to establish the species composition of heterobranch sea slugs in a baseline study for monitoring programs and protection of this special park. These molluscs are potentially good indicators of the health of an ecosystem, as many are species-specific predators on a huge variety of marine benthic and sessile invertebrates from almost every taxonomic group. Additionally, they are known to contain bio-compounds of significance in the pharmaceutical industry. It is therefore of paramount importance not only to document the species composition from a zoogeographic point of view, but to assist in their protection for the future, both in terms of economics and aesthetics. These four surveys have documented more than 200 species, with an approximate 50% of each collection found only on that survey and not re-collected. Many species new to science have also been documented, highlighting the lack of knowledge in this field.
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EL LAKHRACH, H., A. HATTOUR, O. JARBOUI, K. ELHASNI et A. A. RAMOS-ESPLA. « Spatial distribution and abundance of the megabenthic fauna community in Gabes gulf (Tunisia, eastern Mediterranean Sea) ». Mediterranean Marine Science 13, no 1 (28 février 2012) : 12. http://dx.doi.org/10.12681/mms.19.
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The aim of this paper is to bring to light the knowledge of marine diversity of invertebrates in Gabes gulf. The spatial distribution of the megabenthic fauna community in Gabes gulf (Tunisia, Eastern Mediterranean Sea), together with the bottom type and vegetation cover, were studied. The abundance of the megabenthic fauna was represented by eight groups: Echinodermata (38%), Crustacea (21%), Tunicata (19%), Mollusca (13%), Porifera (4%), Cnidaria (3%), Bryozoa, and Annelida (2%). It was spatially more concentrated in the coast area of the gulf than in the offshore waters. This area, especially, in Southern Kerkennah, North-est of Gabes and North-east of Djerba appeared to be in a good ecological condition hosting a variety of species like the paguridsPaguristes eremita and Pagurus cuanensis, the brachyura Medorippe lanata, Inachus doresttensis, the Gastropoda Hexaplex trunculus, Bolinus brandaris, Aporrhais pespelecani, andErosaria turdus, the Bivalvia Fulvia fragilis, the Echinoidea Psammechinus microtuberculatus, Holothuria polii,Ophiothrix fragilis and Antedon mediterranea, and the AscidiaceaAplidium cf. conicum, Didemnum spp, and Microcosmus exasperatus.The species’ compositions of the megabentic fauna community showed clearly that the spatial analysis represented the differences between the community of these two regions (inshore waters and offshore waters). These differences were closely related to peculiar characters of the fauna and biotopes (depth, bottom type and vegetation cover community). The results of the present study should be considered as a necessary starting point for a further analysis of priceless benthic fauna contribution to the marine environment and its organisms.
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DENIS, JEREMY, RYM BOUAZIZ, BRAHIM DRAREDJA, JEAN MARIE MUNARON, ABDELLAH BORHANE DJEBAR, RACHID AMARA, FRANÇOIS LE LOC’H et FRIDA BEN RAIS LASRAM. « Fish food-web structure of a southern Mediterranean lagoon (El Mellah Lagoon, Algeria) : what we can learn from stable isotope analysis ». Mediterranean Marine Science 24, no 2 (12 mai 2023) : 211–28. http://dx.doi.org/10.12681/mms.30180.
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The structure of a fish food-web was described for the first time in a coastal lagoon in the southern Mediterranean Sea by analysing stable carbon and nitrogen isotopes of fish species and their potential food sources. The El Mellah Lagoon (EML) located in extreme north-eastern Algeria, is the only coastal lagoon in the southern Mediterranean with low human pressure due to few human activities and its protected status under the Ramsar Convention. We investigated the structure of the fish food-web in the spring at four stations in the lagoon that differed in their proximity to rivers and the channel, which connects to the sea. The results provided insight into ecological functions of EML as a feeding area for all fish species caught in the lagoon, in particular marine migrant juveniles and resident species. The δ13C results highlighted the importance of marine organic matter on the functioning of the EML fish food-web, to which organic matter in marine sediments and likely microphytobenthos contribute most. Our study also revealed the importance of seagrass (Ruppia sp.) for detritivorous fish (i.e., Mugilidae species) and for their potential to shelter a wide variety of benthic invertebrates that are potential food sources for benthivorous fish. Our study revealed the small influence of freshwater inputs on the functioning of the EML food-web and that juvenile marine fish may use the lagoon for reasons other than feeding, most likely to avoid predation and obtain physiological advantages.
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Marina, Pablo, José L. Rueda, Javier Urra, Carmen Salas, Serge Gofas, J. Enrique García Raso, Francina Moya et al. « Sublittoral soft bottom assemblages within a Marine Protected Area of the northern Alboran Sea ». Journal of the Marine Biological Association of the United Kingdom 95, no 5 (11 février 2015) : 871–84. http://dx.doi.org/10.1017/s0025315414002082.
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The composition and structure of sublittoral faunal assemblages inhabiting soft bottoms (15–72 m depth) within the Marine Protected Area ‘Acantilados y Fondos Marinos de Calahonda-Castell de Ferro’ in southern Spain (North Alboran Sea, Mediterranean) have been studied in relation to sediment and water column variables. Three assemblages were identified and corresponded to mixed bottom, unstable bottom and coastal detritic bottom assemblages, based on Pérès & Picard's (1964) benthic classification. A total of 14,318 individuals were collected and 218 species identified, molluscs being the best represented group (141 species). Species richness displayed significant differences with depth and transect, with the highest values observed in the medium to very fine sand and muddy bottoms with bioclasts located at the shallowest sampling stations. The presence of some rare and poorly known invertebrates that are scarce in other areas of the Mediterranean Sea is remarkable, such as the crustacean decapods Bythocaris cosmetops and Pagurus mbizi, Atlantic species with no records in the Mediterranean Sea, and the bathyal molluscs Poromya granulata and Alvania testae, collected at shallow depths. The spatial distribution of faunal assemblages was mainly related to depth and percentage of gravel and clay according to the canonical correspondence analysis. The geographic location of the area, the heterogeneity of soft bottoms and the presence of upwellings in the area may favour the high biodiversity found in the studied soft bottoms. This study increases the scarce knowledge of the circalittoral fauna of sedimentary habitats of the Alboran Sea, providing a baseline for the management of this interesting SCI and for the EU Marine Strategy Framework Directive.
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Chernova, Natalia V. « Amphiboreality and Distribution of Snailfishes (Cottiformes : Liparidae) in the Arctic and the North Atlantic ». Diversity 14, no 12 (11 décembre 2022) : 1097. http://dx.doi.org/10.3390/d14121097.
Texte intégralRésumé :
The marine ichthyofauna of the Arctic Ocean has an ancestral origin from the Pacific Ocean and, to a lesser extent, from the Atlantic Ocean, which is explained by the amphiboreal concept, developed on groups of fish and invertebrates. Snailfishes (Liparidae) of the Arctic and the North Atlantic are analyzed in the context of this amphiboreal concept. The review is based on the data of many years of research on their taxonomy using various material of morphological differences/similarities of the taxa and patterns of species distribution against the background of biogeographic representations. For the Arctic area, 33 species of the family are known: Liparis (5), Careproctus (21), Paraliparis (2), Rhodichthys (2), and Psednos (3). For the Atlantic fauna, with the same number of species, their composition differs: Liparis (6), Careproctus (3), Paraliparis (12), Psednos (11), and Eutelichthys (1). The amphiboreal concept explains the speciation of Liparis and the majority of Careproctus as the result of trans-Arctic preglacial migrations. For other (deep-sea) species, the hypothesis of a transoceanic dispersal route is applicable; it passed from the North Pacific through the Southern Ocean and then north across the Atlantic.
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Hiddink, Jan Geert, Adriaan D. Rijnsdorp et Gerjan Piet. « Can bottom trawling disturbance increase food production for a commercial fish species ? » Canadian Journal of Fisheries and Aquatic Sciences 65, no 7 (juillet 2008) : 1393–401. http://dx.doi.org/10.1139/f08-064.
Texte intégralRésumé :
Fishery closures and marine protected areas are increasingly being used as tools to achieve sustainable fisheries. The “plaice box”, a gear restriction area in the North Sea that was established to reduce the bycatch of undersized plaice ( Pleuronectes platessa ), is considered ineffective because there has been a shift in the distribution of juvenile plaice to the waters that remained open to bottom trawlers. Here we examine the hypothesis that bottom trawling benefits the small benthic invertebrates that form the food source for plaice and that the plaice box had a negative impact on food production for plaice. A size-based model of benthic communities indicates that the production of prey was low without trawling and maximal in areas that are trawled once to twice a year. Therefore, bottom disturbance may improve the feeding conditions for species that feed on small invertebrates. As plaice aggregate at the locations with the highest benthic biomass, this may explain the observed redistribution to areas outside the plaice box. We conclude that the plaice box may not have been the most appropriate measure to protect plaice from discarding and that the species’ ecology should be considered when choosing the most appropriate management measure to achieve an objective.
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Estes, James A., et Peter D. Steinberg. « Predation, herbivory, and kelp evolution ». Paleobiology 14, no 1 (1988) : 19–36. http://dx.doi.org/10.1017/s0094837300011775.
Texte intégralRésumé :
We propose that the kelps (Laminariales) radiated in the North Pacific following the onset of late Cenozoic polar cooling. The evidence is that (1) extant kelps occur exclusively in cold-water habitats; (2) all but one of 27 kelp genera occur in the North Pacific, 19 of these exclusively; and (3) limpets and herbivorous marine mammals obligately associated with kelps or other stipitate brown algae appeared late in the Cenozoic, even though more generalized forms of both groups are much older. We propose, further, that sea otters and perhaps other groups of benthic-feeding predatory mammals, whose late Cenozoic distributions all were limited to the North Pacific, created an environment for the evolution of kelps in which the intensity of herbivory was unusually low. We hypothesize that this interaction created predictable differences among habitats in the intensity of herbivory on several spatial scales, with resulting trade-offs between anti-herbivore defenses and plant competitive abilities in their respective floras. Sea otters incur time and energy costs for diving, resulting in depth-related reductions to foraging efficiency and thus increased sizes and densities of herbivorous sea urchins. Thus, the deep-water flora is well defended, but competitively subordinate, compared with the shallow-water flora. Similarly, we argue that during the same period of earth history, predation had less of a limiting influence on herbivorous invertebrates in the temperate southwestern Pacific. We hypothesize that (1) consequent biogeographical differences in the intensity of herbivory may have selected the phenolic-rich brown algal flora in temperate Australia/New Zealand; and (2) tightly coevolved plant/herbivore interactions may explain why Australian and New Zealand herbivores are undeterred by phenolics and why other classes of secondary compounds in the Australian/New Zealand flora significantly deter herbivores.
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Pogoda, Bernadette. « Current Status of European Oyster Decline and Restoration in Germany ». Humanities 8, no 1 (11 janvier 2019) : 9. http://dx.doi.org/10.3390/h8010009.
Texte intégralRésumé :
Marine ecosystems of temperate regions are highly modified by human activity and far from their original natural status. The North Sea, known as an intensively used area, has lost its offshore oyster grounds due to overexploitation in a relatively short time. Native oyster beds as a once abundant and ecologically highly important biogenic reef-type have vanished from the North Sea ecosystem in most areas of both their former distribution and magnitude. Worldwide, oyster stocks have been severely exploited over the past centuries. According to estimates, about 85% of the worldwide oyster reef habitats have been destroyed over the course of the last century. This loss of oyster populations has meant far more than just the loss of a valuable food resource. Oyster reefs represent a characteristic benthic community which offers a variety of valuable ecosystem services: better water quality, local decrease of toxic algal blooms, increase in nutrient uptake, increase of bentho-pelagic coupling, increase in species richness, increase of multidimensional biogenic structures which provide habitat, food, and protection for numerous invertebrate and fish species. The aim of oyster restoration is to promote redevelopment of this valuable missing habitat. The development of strategies, methods, and procedures for a sustainable restoration of the European oyster Ostrea edulis in the German North Sea is currently a focus of marine nature conservation. Main drivers for restoring this ecological key species are the enhancement of biodiversity and ecosystem services in the marine environment. Results of these investigations will support the future development and implementation of a large-scale and long-term German native oyster restoration programme to re-establish a healthy population of this once-abundant species now absent from the region.
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Bettinelli, Maurizio, Sandro Spezia et Claudio Minoia. « Analysis of uranium and isotopic ratio measurement in fish and marine invertebrates from the North Adriatic Sea by inductively coupled plasma mass spectrometry ». Rapid Communications in Mass Spectrometry 18, no 4 (9 février 2004) : 465–68. http://dx.doi.org/10.1002/rcm.1346.
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Goddard, Jeffrey H. R. « Developmental mode in benthic opisthobranch molluscs from the northeast Pacific Ocean : feeding in a sea of plenty ». Canadian Journal of Zoology 82, no 12 (1 décembre 2004) : 1954–68. http://dx.doi.org/10.1139/z05-008.
Texte intégralRésumé :
Mode of development was determined for 130 of the nearly 250 species of shallow-water, benthic opisthobranchs known from the northeast Pacific Ocean. Excluding four introduced or cryptogenic species, 91% of the species have planktotrophic development, 5% have lecithotrophic development, and 5% have direct development. Of the 12 native species with non-feeding (i.e., lecithotrophic or direct) modes of development, 5 occur largely or entirely south of Point Conception, California, where surface waters are warmer, lower in nutrients, and less productive than those to the north; 4 are known from habitats, mainly estuaries, that are small and sparsely distributed along the Pacific coast of North America; and 1 is Arctic and circumboreal in distribution. The nudibranchs Doto amyra Marcus, 1961 and Phidiana hiltoni (O'Donoghue, 1927) were the only species with non-feeding development that were widespread along the outer coast. This pattern of distribution of developmental mode is consistent with the prediction that planktotrophy should be maintained at high prevalence in regions safe for larval feeding and growth and should tend to be selected against where the risks of larval mortality (from low- or poor-quality food, predation, and transport away from favorable adult habitat) are higher. However, direct development, which includes the most derived mode of non-feeding development, was also correlated with small adult size, reflecting an association common in marine invertebrates. Planktotrophic development also predominates in decapod Crustacea from the northeast Pacific, but is less common in echinoderms and prosobranch gastropods from this region owing to the presence of lineages constrained by phylogeny to non-feeding modes of development.
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Montañez-Rivera, Irene, et Oliver Hampe. « An unfamiliar physeteroid periotic (Cetacea : Odontoceti) from the German middle–late Miocene North Sea basin at Groß Pampau ». Fossil Record 23, no 2 (6 août 2020) : 151–68. http://dx.doi.org/10.5194/fr-23-151-2020.
Texte intégralRésumé :
Abstract. The Miocene mica clay locality of Groß Pampau, known for numerous and partly spectacular finds of marine mammals is becoming more and more a prominent site that bears the potential to resolve questions regarding taphonomic relationships and to interpret life communities of the ancient North Sea because of its rich faunal assemblage including invertebrates and other remains of various vertebrate organisms. In the present work we describe a right periotic of Physeteroidea with morphological characters so far unknown from other sperm whales. The periotics of the middle Miocene Aulophyseter morricei demonstrate the closest resemblance to the Groß Pampau specimen in their overall appearance and in the general arrangement and proportions of single structures, particularly of the anterior process and pars cochlearis. A great similarity is also documented with periotics of the living sperm whale, Physeter macrocephalus, especially regarding the shape and disposition of the anterior process and the bony element located dorsally to the accessory ossicle. Kogiid periotics differ strongly from that of the Groß Pampau specimen by having an inflated and short anterior process and, typically, three well-defined spines on it. A new taxonomic naming of the Groß Pampau periotic is not appropriate at this stage, although it might demonstrate the existence of a so-far undescribed physeteroid species. Additionally, its systematic position remains yet unclear and it is unknown at this point if it could belong to Hoplocetus ritzi, another physeterid, whose fragments were discovered in the same locality, or to another, already-described taxon, of which the periotic is still unknown.
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Dean, Karl J., Robert G. Hatfield, Vanessa Lee, Ryan P. Alexander, Adam M. Lewis, Benjamin H. Maskrey, Mickael Teixeira Alves et al. « Multiple New Paralytic Shellfish Toxin Vectors in Offshore North Sea Benthos, a Deep Secret Exposed ». Marine Drugs 18, no 8 (29 juillet 2020) : 400. http://dx.doi.org/10.3390/md18080400.
Texte intégralRésumé :
In early 2018, a large easterly storm hit the East Anglian coast of the UK, colloquially known as the ‘Beast from the East’, which also resulted in mass strandings of benthic organisms. There were subsequent instances of dogs consuming such organisms, leading to illness and, in some cases, fatalities. Epidemiological investigations identified paralytic shellfish toxins (PSTs) as the cause, with toxins present in a range of species and concentrations exceeding 14,000 µg STX eq./kg in the sunstar Crossaster papposus. This study sought to better elucidate the geographic spread of any toxicity and identify any key organisms of concern. During the summers of 2018 and 2019, various species of benthic invertebrates were collected from demersal trawl surveys conducted across a variety of locations in the North Sea. An analysis of the benthic epifauna using two independent PST testing methods identified a ‘hot spot’ of toxic organisms in the Southern Bight, with a mean toxicity of 449 µg STX eq./kg. PSTs were quantified in sea chervil (Alcyonidium diaphanum), the first known detection in the phylum bryozoan, as well as eleven other new vectors (>50 µg STX eq./kg), namely the opisthobranch Scaphander lignarius, the starfish Anseropoda placenta, Asterias rubens, Luidia ciliaris, Astropecten irregularis and Stichastrella rosea, the brittlestar Ophiura ophiura, the crustaceans Atelecyclus rotundatus and Munida rugosa, the sea mouse Aphrodita aculeata, and the sea urchin Psammechinus miliaris. The two species that showed consistently high PST concentrations were C. papposus and A. diaphanum. Two toxic profiles were identified, with one dominated by dcSTX (decarbamoylsaxitoxin) associated with the majority of samples across the whole sampling region. The second profile occurred only in North-Eastern England and consisted of mostly STX (Saxitoxin) and GTX2 (gonyautoxin 2). Consequently, this study highlights widespread and variable levels of PSTs in the marine benthos, together with the first evidence for toxicity in a large number of new species. These findings highlight impacts to ‘One Health’, with the unexpected sources of toxins potentially creating risks to animal, human and environmental health, with further work required to assess the severity and geographical/temporal extent of these impacts.
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Reiss, Henning, Steven Degraer, Gerard C. A. Duineveld, Ingrid Kröncke, John Aldridge, Johan A. Craeymeersch, Jacqueline D. Eggleton et al. « Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea ». ICES Journal of Marine Science 67, no 2 (29 novembre 2009) : 278–93. http://dx.doi.org/10.1093/icesjms/fsp253.
Texte intégralRésumé :
Abstract Reiss, H., Degraer, S., Duineveld, G. C. A., Kröncke, I., Aldridge, J., Craeymeersch, J., Eggleton, J. D., Hillewaert, H., Lavaleye, M. S. S., Moll, A., Pohlmann, T., Rachor, E., Robertson, M., vanden Berghe, E., van Hoey, G., and Rees, H. L. 2010. Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea. – ICES Journal of Marine Science, 67: 278–293. Understanding the structure and interrelationships of North Sea benthic invertebrate and fish communities and their underlying environmental drivers is an important prerequisite for conservation and spatial ecosystem management on scales relevant to ecological processes. Datasets of North Sea infauna, epifauna, and demersal fish (1999–2002) were compiled and analysed to (i) identify and compare spatial patterns in community structure, and (ii) relate these to environmental variables. The multivariate analyses revealed significantly similar large-scale patterns in all three components with major distinctions between a southern community (Oyster Ground and German Bight), an eastern Channel and southern coastal community, and at least one northern community (>50 m deep). In contrast, species diversity patterns differed between the components with a diversity gradient for infauna and epifauna decreasing from north to south, and diversity hotspots of demersal fish, e.g. near the major inflows of Atlantic water. The large-scale hydrodynamic variables were the main drivers for the structuring of communities, whereas sediment characteristics appeared to be less influential, even for the infauna communities. The delineation of ecologically meaningful ecosystem management units in the North Sea might be based on the structure of the main faunal ecosystem components.
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Tsiamis, Konstantinos, Maria Salomidi, Vasilis Gerakaris, Andrew O. M. Mogg, Elizabeth S. Porter, Martin D. J. Sayer et Frithjof C. Küpper. « Macroalgal vegetation on a north European artificial reef (Loch Linnhe, Scotland) : biodiversity, community types and role of abiotic factors ». Journal of Applied Phycology 32, no 2 (3 janvier 2020) : 1353–63. http://dx.doi.org/10.1007/s10811-019-01918-2.
Texte intégralRésumé :
AbstractVery little is known about the marine macroalgae of artificial reefs—especially in the North Atlantic—despite the growing number and extent of man-made structures in the sea, and even though seaweed communities have paramount importance as primary producers, but also as feeding, reproductive and nursery grounds in coastal ecosystems. This paper explores the macroalgal diversity of a large system of artificial reefs in Loch Linnhe, on the west coast of Scotland, in a quantitative and qualitative study based on diving surveys and correlates the observations with the prevalent abiotic factors. The study was conducted in order to test the hypothesis that artificial reefs can enhance seaweed habitats—in particular, for kelps—and that there is a clear correlation with substrate type. While the reef is home to a large range of biota and abundance of early-successional species of turf and bushy macroalgae, totalling 56 taxa and with Delesseria sanguinea as the dominant species, canopy-forming perennial kelp species are conspicuously relatively rare. Macroalgal vegetation is explored in correlation with reef geometry/geography and depth. Statistical analysis shows benthic communities were strongly affected by substrate type, with turf algae and invertebrates dominating the artificial reefs, while bushy algae dominate the natural ones. Common macroinvertebrates associated with the phytobenthic communities are assessed qualitatively.
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Palmer, Hannah M., Veronica Padilla Vriesman, Roxanne M. W. Banker et Jessica R. Bean. « Compilation of a database of Holocene nearshore marine mollusk shell geochemistry from the California Current System ». Earth System Science Data 14, no 4 (12 avril 2022) : 1695–705. http://dx.doi.org/10.5194/essd-14-1695-2022.
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Abstract. The shells of marine invertebrates can serve as high-resolution records of oceanographic and atmospheric change through time. In particular, oxygen and carbon isotope analyses of nearshore marine calcifiers that grow by accretion over their lifespans provide seasonal records of environmental and oceanographic conditions. Archaeological shell middens generated by Indigenous communities along the northwest coast of North America contain shells harvested over multiple seasons for millennia. These shell middens, as well as analyses of archival and modern shells, have the potential to provide multi-site, seasonal archives of nearshore conditions throughout the Holocene. A significant volume of oxygen and carbon isotope data from archaeological shells exist, yet they are separately published in archaeological, geochemical, and paleoceanographic journals and have not been comprehensively analyzed to examine oceanographic change over time. Here, we compiled a database of previously published oxygen and carbon isotope data from archaeological, archival, and modern marine mollusks from the California Current System (North American coast of the northeast Pacific, 32 to 55∘ N). This database includes oxygen and carbon isotope data from 598 modern, archaeological, and sub-fossil shells from 8880 years before present (BP) to the present, from which there are 4917 total δ13C and 7366 total δ18O measurements. Shell dating and sampling strategies vary among studies (1–345 samples per shell, mean 44.7 samples per shell) and vary significantly by journal discipline. Data are from various bivalves and gastropod species, with Mytilus spp. being the most commonly analyzed taxon. This novel database can be used to investigate changes in nearshore sea surface conditions including warm–cool oscillations, heat waves, and upwelling intensity, and it provides nearshore calcium carbonate δ13C and δ18O values that can be compared to the vast collections of offshore foraminiferal calcium carbonate δ13C and δ18O data from marine sediment cores. By utilizing previously published geochemical data from midden and museum shells rather than sampling new specimens, future scientific research can reduce or omit the alteration or destruction of culturally valued specimens and sites. The dataset is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.941373 (Palmer et al., 2021).
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Harvey, Ben P., Sylvain Agostini, Koetsu Kon, Shigeki Wada et Jason M. Hall-Spencer. « Diatoms Dominate and Alter Marine Food-Webs When CO2 Rises ». Diversity 11, no 12 (16 décembre 2019) : 242. http://dx.doi.org/10.3390/d11120242.
Texte intégralRésumé :
Diatoms are so important in ocean food-webs that any human induced changes in their abundance could have major effects on the ecology of our seas. The large chain-forming diatom Biddulphia biddulphiana greatly increases in abundance as pCO2 increases along natural seawater CO2 gradients in the north Pacific Ocean. In areas with reference levels of pCO2, it was hard to find, but as seawater carbon dioxide levels rose, it replaced seaweeds and became the main habitat-forming species on the seabed. This diatom algal turf supported a marine invertebrate community that was much less diverse and completely differed from the benthic communities found at present-day levels of pCO2. Seawater CO2 enrichment stimulated the growth and photosynthetic efficiency of benthic diatoms, but reduced the abundance of calcified grazers such as gastropods and sea urchins. These observations suggest that ocean acidification will shift photic zone community composition so that coastal food-web structure and ecosystem function are homogenised, simplified, and more strongly affected by seasonal algal blooms.
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Todd, Victoria L. G., Laura D. Williamson, Sophie E. Cox, Ian B. Todd et Peter I. Macreadie. « Characterizing the first wave of fish and invertebrate colonization on a new offshore petroleum platform ». ICES Journal of Marine Science 77, no 3 (5 mai 2019) : 1127–36. http://dx.doi.org/10.1093/icesjms/fsz077.
Texte intégralRésumé :
Abstract Offshore Oil & Gas (O&G) infrastructure creates artificial reef complexes that support marine communities in oceans. No studies have characterized the first wave of colonization, which can reveal information about habitat attraction and ecological connectivity. Here we used opportunistically-collected industrial Remotely Operated Vehicles (ROVs) to investigate fish and invertebrate colonization on a new North Sea O&G platform and trenching of an associated pipeline. We observed rapid colonization of fish communities, with increases in species richness (S), abundance (N), and diversity (H′) over the first four days (the entire study period). By contrast, there was minimal change in motile invertebrate communities over the survey period. After trenching, invertebrate S, N and H′ decreased significantly, whilst fish S, N and H′ increased. This study is the first to report on the pioneer wave of fish and invertebrate colonization on O&G infrastructure, thereby providing rare insight into formation of new reef communities in the sea. These short and opportunistic data are valuable in terms of showing what can be discovered from analysis of ‘pre-installation’ ROV footage of O&G structures, of which there are terabytes of data held by O&G companies waiting to be analyzed by environmental scientists.
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Vasquez, Ignacio, Trung Cao, Setu Chakraborty, Hajarooba Gnanagobal, Nicole O’Brien, Jennifer Monk, Danny Boyce, Jillian D. Westcott et Javier Santander. « Comparative Genomics Analysis of Vibrio anguillarum Isolated from Lumpfish (Cyclopterus lumpus) in Newfoundland Reveal Novel Chromosomal Organizations ». Microorganisms 8, no 11 (27 octobre 2020) : 1666. http://dx.doi.org/10.3390/microorganisms8111666.
Texte intégralRésumé :
Vibrio anguillarum is a Gram-negative marine pathogen causative agent of vibriosis in a wide range of hosts, including invertebrates and teleosts. Lumpfish (Cyclopterus lumpus), a native fish of the North Atlantic Ocean, is utilized as cleaner fish to control sea lice (Lepeophtheirus salmonis) infestations in the Atlantic salmon (Salmo salar) aquaculture industry. V. anguillarum is one of the most frequent bacterial pathogens affecting lumpfish. Here, we described the phenotype and genomic characteristics of V. anguillarum strain J360 isolated from infected cultured lumpfish in Newfoundland, Canada. Koch’s postulates determined in naïve lumpfish showed lethal acute vibriosis in lumpfish. The V. anguillarum J360 genome was shown to be composed of two chromosomes and two plasmids with a total genome size of 4.56 Mb with 44.85% G + C content. Phylogenetic and comparative analyses showed that V. anguillarum J360 is closely related to V. anguillarum strain VIB43, isolated in Scotland, with a 99.8% genome identity. Differences in the genomic organization were identified and associated with insertion sequence elements (ISs). Additionally, V. anguillarum J360 does not possess a pJM1-like plasmid, typically present in virulent isolates from the Pacific Ocean, suggesting that acquisition of this extrachromosomal element and the virulence of V. anguillarum J360 or other Atlantic isolates could increase.
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Muñoz, CC, T. Saito et P. Vermeiren. « Cohort structure and individual resource specialization in loggerhead turtles, long-lived marine species with ontogenetic migrations ». Marine Ecology Progress Series 671 (5 août 2021) : 175–90. http://dx.doi.org/10.3354/meps13767.
Texte intégralRésumé :
Cohort structure and degree of individual resource specialization affect individual- and population-level fitness and ecosystem interactions. These 2 characteristics are difficult to establish for long-lived marine species such as sea turtles. Both characteristics were approached by applying a novel Broken-Stick analysis of Stable isotope Time series (BS-SiTs) framework to longitudinal data series derived from metabolically inert carapace scute tissue of 13 loggerhead turtles Caretta caretta near the coast of Kochi prefecture, Japan. During the subadult stage, δ15N signatures decreased 1.29‰ per 50 µm scute slice away from values associated with neritic habitats and a diet of benthic invertebrates. Following a breakpoint, δ15N signatures stabilized in the range of 10-15‰, corresponding with planktonic feeding adults with an oceanic foraging strategy in the North Pacific. Ontogenetic shifts in δ15N occurred at different chronological points for each individual, implying the presence of a diverse cohort structure within the local coastal population. During the adult stage, within-individual variation in δ15N was <6.1% of the total δ15N variation among sampled individuals. To offer effective protection, management actions should account for this potentially high individual resource specialization at the scale of local coastal populations. Nesting numbers of loggerhead turtles in Japan have been declining since the 1990s. The BS-SiTs framework provides ecological baseline information on ontogenetic shifts in resource use of individuals suitable to support management plans. Specifically, when applied across multiple individuals, the BS-SiTs framework offers a low-cost, non-invasive solution to monitor and compare trends in cohort structure among local coastal populations.
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Kopytina, N. I. « Fungi of the Black Sea basin : Directions and perspectives of research ». Marine Biological Journal 4, no 4 (30 décembre 2019) : 15–33. http://dx.doi.org/10.21072/mbj.2019.04.4.02.
Texte intégralRésumé :
Totally 71 literature source focused on the study of the Black Sea fungi (micromycetes) for the period from 1867 to 2018 was analyzed. In the 1860s and 1930s Zostera marina sea grass epidemics were recorded caused by fungi-like organisms of the genus Labyrinthula. In the late 19th and early 20th centuries, several cases of seagrass local mycosis were also identified. In the 1960s–2000s invertebrate epizootics caused by fungi were recorded: Hyphochytrium peniliae species parasitized on the Cladocera Penilia avirostris and caused its mass death; fungus Leptolegnia pontica infected eggs of Cirripedia Balanus improvisus and significantly reduced the population fecundity; the invasion of the fungus Ostracoblabe implexa led to the destruction of the Ostrea edulis oyster populations. Currently, single cases of the lesions on the cultivated oyster Crassostrea gigas (its spat is brought from other countries) by O. edulis are noted. Fungi-epibionts were isolated from the shells of C. gigas and Mytilus galloprovincialis. Microsporidia Steinhausia mytilovum was identified in mature oocytes of M. galloprovincialis. On the surface of fish and in their internal organs, filamentous fungi and intracellular parasites (microsporidia) were found. Fungi were revealed on the surface of bottlenose dolphins. The study of pelagial, benthal, cellulose-containing substrates’, foams’, periphyton, micro- and macroalgae, seagrasses mycobiota was carried out. Currently, 435 species of fungi were found in the Black Sea basin. They belong to 212 genera, 84 families, 50 orders, 19 classes, and 3 kingdoms. Totally 372 species were recorded in the marine environment, 196 were found in the freshwaters, and 31 species was recorded in the hypersaline waters. In the water column, 230 species of fungi were identified (in the hydrogen sulfide zone – 21); in the bottom sediments – 202 (in the hydrogen sulfide zone – 31); 70 species were recorded on wood; 30 – in periphyton on glasses and artificial stony supralittoral (berths, traverses); 46 – in marine foam; 50 – on/in molluscs; 18 – on the skin of dolphins; 116 – on macroalgae; 2 – on microalgae; 38 – on seagrasses; 69 – on/in fish; 14 – on/in crustaceans. The number of species found in the coastal waters of different regions is: Georgia – 8; Gelendzhik (Russia) – 56; Crimean Peninsula – 276; the north-western part of the Black Sea – 177; Romania – 112; Bulgaria – 44; Turkey – 9; Danube River – 238; Snake Island – 30. This review reflects individual studies on the fungi ability to utilize cellulose, petroleum and its products, phenol, and sulfur and to cause corrosion of metals. The first results in the study of antimicrobial activity of facultative and obligatory marine fungi of the Black Sea, as well as the ability of fungi to luminescence, are considered. This article lists directions of research in marine mycology that are perspective for the further study.
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van Deurs, Mikael, Nicholas P. Moran, Kristian Schreiber Plet-Hansen, Grete E. Dinesen, Farivar Azour, Henrik Carl, Peter R. Møller et Jane W. Behrens. « Impacts of the invasive round goby (Neogobius melanostomus) on benthic invertebrate fauna : a case study from the Baltic Sea ». NeoBiota 68 (19 août 2021) : 19–30. http://dx.doi.org/10.3897/neobiota.68.67340.
Texte intégralRésumé :
The round goby (Neogobius melanostomus) was first observed in the Baltic Sea in 1990 and has since displayed substantial secondary dispersal, establishing numerous dense populations where they may outcompete native fish and negatively impact prey species. There have been multiple round goby diet studies from both the Baltic Sea and the North American Great Lakes where they are similarly invasive. However, studies that quantify their effects on recipient ecosystems and, specifically, their impacts on the benthic invertebrate macrofauna are rare, particularly from European waters. In this study, we conducted the first before-after study of the potential effects of round goby on benthic invertebrate macrofauna taxa in marine-brackish habitats in Europe, focusing of two sites in the Western Baltic Sea, Denmark. Results were in line with those from the Great Lakes, indicating negative impacts on specific molluscan taxa (e.g. Cardiidae bivalves and Neritidae gastropods, which both showed a fall in detected densities of approximately 98% within the Guldborgsund Strait). In contrast, many other groups appeared to be largely unaffected or even show positive trends following invasion. Round goby gut content data were available at one of our study sites from the period immediately after the invasion. These data confirmed that round goby had in fact been preying on the subset of taxa displaying negative trends.
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Hossain, Abul, Deepika Dave et Fereidoon Shahidi. « Northern Sea Cucumber (Cucumaria frondosa) : A Potential Candidate for Functional Food, Nutraceutical, and Pharmaceutical Sector ». Marine Drugs 18, no 5 (22 mai 2020) : 274. http://dx.doi.org/10.3390/md18050274.
Texte intégralRésumé :
Sea cucumber (Cucumaria frondosa) is the most abundant and widely distributed species in the cold waters of North Atlantic Ocean. C. frondosa contains a wide range of bioactive compounds, mainly collagen, cerebrosides, glycosaminoglycan, chondroitin sulfate, saponins, phenols, and mucopolysaccharides, which demonstrate unique biological and pharmacological properties. In particular, the body wall of this marine invertebrate is the major edible part and contains most of the active constituents, mainly polysaccharides and collagen, which exhibit numerous biological activities, including anticancer, anti-hypertensive, anti-angiogenic, anti-inflammatory, antidiabetic, anti-coagulation, antimicrobial, antioxidation, and anti- osteoclastogenic properties. In particular, triterpene glycosides (frondoside A and other) are the most researched group of compounds due to their potential anticancer activity. This review summarizes the latest information on C. frondosa, mainly geographical distribution, landings specific to Canadian coastlines, processing, commercial products, trade market, bioactive compounds, and potential health benefits in the context of functional foods and nutraceuticals.
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Archer, Allen W., John H. Calder, Martin R. Gibling, Robert D. Naylor, Donald R. Reid et Winton G. Wightman. « Invertebrate trace fossils and agglutinated foraminifera as indicators of marine influence within the classic Carboniferous section at Joggins, Nova Scotia, Canada ». Canadian Journal of Earth Sciences 32, no 12 (1 décembre 1995) : 2027–39. http://dx.doi.org/10.1139/e95-156.
Texte intégralRésumé :
The sea cliffs at Joggins, Nova Scotia, are the most extensive and continuous Carboniferous section in eastern North America. Although the section has been considered to have formed within a nonmarine depositional basin, paleobiological information indicates that parts of the section were deposited in brackish water. The occurrence of a trace-fossil assemblage, which includes Cochlichnus, Kouphichnium, and Treptichnus, is part of an assemblage of biogenic structures that apparently reflects paleodeposition within fluvial systems that may have experienced distal marine influences. Presence of agglutinated foraminifera characteristic of brackish-water environments supports this interpretation. This information provides new evidence of brackish-water conditions at Joggins such as those now being widely recognized in other Carboniferous coal-bearing sections.
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Ershova, Tatiana, Vladimir Chaplygin, Vyacheslav Zaitsev, Alisher Khursanov et Natalia Shaboyants. « The content of mercury and lead in the feed base of valuable fish species of the Caspian Sea ». Fisheries 2021, no 4 (28 juillet 2021) : 10–14. http://dx.doi.org/10.37663/0131-6184-2021-4-10-14.
Texte intégralRésumé :
Mercury and lead are not essential elements and have a high degree of toxicity to all groups of living organisms, including hydrobionts. In turn, the accumulation of dangerous chemical elements in the primary trophic units of marine ecosystems is also reflected in the high level of accumulation and toxication of fish-valuable objects of fishing. As part of the study of the ecological state of the biota of the Volga-Caspian basin, there is a need to study the concentrations of heavy metals such as mercury and lead. The aim of the work is to study the content of mercury and lead in some invertebrate species of the Caspian Sea. The main source of mercury and lead in the body of the studied species is the water of the north-western part of the Caspian Sea. Among the studied taxonomic groups of organisms, mercury accumulators were all species of mollusks, as well as Balanus improvises and Rhithropanopeus harrisii. The lead concentrating organisms were Cerastoderma lamarcki and Mytilaster lineatus, Rhithropanopeus harrisii, and Balanus improvises.
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Gaudin, François, Nicolas Desroy, Stanislas F. Dubois, Caroline Broudin, Louis Cabioch, Jérôme Fournier, Franck Gentil et al. « Marine sublittoral benthos fails to track temperature in response to climate change in a biogeographical transition zone ». ICES Journal of Marine Science 75, no 6 (23 août 2018) : 1894–907. http://dx.doi.org/10.1093/icesjms/fsy095.
Texte intégralRésumé :
Abstract Species ranges are shifting globally to track temperature changes in response to climate warming, with substantial variability among taxa. In the English Channel, a biogeographical transition zone between the cold temperate and warm temperate provinces of the North-East Atlantic, distribution shifts have been relatively well documented for plankton, fish and intertidal benthic organisms, but little information is available on sublittoral benthos. Following a description of the magnitude of the sea bottom temperature (SBT) rise, the changes in the distribution and occupancy of 65 benthic invertebrate species were analysed by comparing data collected throughout the English Channel at more than 200 stations sampled during a cool period in the 1960s–1970s and at present in 2012–2014. A non-uniform rise in SBT for the last three decades was observed at the regional scale, varying from 0.07 to 0.54°C per decade. This rise differs from that reported for sea surface temperature (SST) in stratified areas suggesting that SBT should be used rather than SST to analyse responses of subtidal organisms to climate change. Despite shifts in both minimum and maximum sea bottom isotherms (2.5 and 3.2 km.year−1, respectively), the distribution centroid shift of most species remained <1.0 km.year−1, regardless of the average temperatures they usually experience. Conversely, decreases were observed in the occurrence of most cold-water species and increases were found in the occurrence of most warm-water species. These results suggest that ongoing climate change could lead to a decrease in benthic biodiversity at range limits, especially where connection routes are lacking for new migrants.
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Smith, J. W., A. E. Elarifi, R. Wootten, A. W. Pike et M. D. B. Burt. « Experimental Infection of Rainbow Trout, Oncorhynchus mykiss, with Contracaecum osculatum (Rudolphi, 1802) and Pseudoterranova decipiens (Krabbe, 1878) (Nematoda ; Ascaridoidea) ». Canadian Journal of Fisheries and Aquatic Sciences 47, no 12 (1 décembre 1990) : 2293–96. http://dx.doi.org/10.1139/f90-255.
Texte intégralRésumé :
The fate of freshly hatched larvae of the marine ascaridoid nematodes Contracaecum osculatum and Pseudoterranova decipiens (from grey seals, Halichoerus grypus, from Scotland and the Canadian Atlantic) was investigated following oral or intraperitoneal introduction into rainbow trout, Oncorhynchus mykiss, maintained at 7–13 °C in fresh water. Neither species appeared to survive for long in the trout alimentary tract following oral introduction; a few larvae were found alive after 2 d but none after 21 d. intraperitoneally, P. decipiens did not survive beyond 21 d, but some C. osculatum exsheathed and developed over several months to lengths over 13 mm, and morphologically and morphometrically resembled third-stage larvae from naturally infected whiting, Merlangius merlangus, from the northern North Sea; no moult was detected. Thus, freshly hatched free-living larvae of C. osculatum are able to develop directly to the third stage in the body cavity of a fish without earlier passage through a crustacean or other invertebrate host.
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Schultze, Hans-Peter. « The Upper Devonian fish locality of Miguasha, Quebec, Canada ». Paleontological Society Special Publications 6 (1992) : 262. http://dx.doi.org/10.1017/s2475262200008224.
Texte intégralRésumé :
At Miguasha, Québec (earlier referred to as Scaumenac Bay), the Escuminac Formation, lowermost Upper Devonian, yields an abundant and diverse fish fauna and flora. Both vertebrates and plant fossils from the locality are reknowned throughout the world. The excellent preservation, including that of endocranial anatomy, enabled Jarvik to describe and illustrate fine anatomical details of the osteolepiform Eusthenopteron. That gives the wrong impression that Miguasha is throughout the Escuminac Formation an outstanding Conservat Fossil-Lagerstätte.The cliffs at Miguasha bear fishes throughout the approximately 120 m thick Escuminac Formation. The lithology of the sediments changes throughout the sequence. Close to the base of the formation, acanthodians and anaspid-like agnathans occur in laminites, sometimes hundreds on one horizon. In these laminites, soft tissue preservation may occur (anapsid-like agnathans), and diagenetic transformations of acanthodians into organic substance led to misinterprations and recognition of the “larval chordate Scaumenella.” Most common within the sequence are limy concretions with different fish fossils, most commonly Bothriolepis. Three-dimensionally preserved fishes occur within the sandstone-siltstones and sometimes within the concretions. In all these cases, dermal bone is preserved, and in few cases chondral bone too, as in Eusthenopteron. One can characterize these fossiliferous sections of the Escuminac Formation as Concentration Fossil-Lagerstätte, whereas the laminites are Conservat Fossil-Lagerstätten.The depositional environment was previously interpreted as an intermontaneous basin, based on tectonic and paleogeographic position. More recent paleogeographic reconstructions show a connection with Scottish deposits and to marine deposits in the present day North Sea. The lack of invertebrates and of marine plant remains, and the occurrence of vertebrates in other localities were used as additional indicators for freshwater deposition.The sedimentological features are ambiguous, the turbidites, such as those found at Miguasha, can occur in marine or large freshwater bodies. Conchostracans occur, sometimes in the thousands on a single plane, in the basal part of the Escuminac Formation. They occur today in freshwater or brackish environments; the same species as the one in the Escuminac Formation is reported from lower Upper Devonian marine deposits in the Baltic (Koknese, Latvia). A detailed comparison of the fish fauna with other lower Upper Devonian fish faunas indicates a coastal marine environment. That is supported by rare trace fossils and by different chemical analyses of the sediments and 87S/86S analysis of Bothriolepis bones.In conclusion, earlier interpretations of the paleogeographic position of the Escuminac Formation at Miguasha and chemical and faunal indicators contradict each other in the interpretation of the paleoenvironment of the formation.
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Steneck, Robert S., Michael H. Graham, Bruce J. Bourque, Debbie Corbett, Jon M. Erlandson, James A. Estes et Mia J. Tegner. « Kelp forest ecosystems : biodiversity, stability, resilience and future ». Environmental Conservation 29, no 4 (décembre 2002) : 436–59. http://dx.doi.org/10.1017/s0376892902000322.
Texte intégralRésumé :
Kelp forests are phyletically diverse, structurally complex and highly productive components of coldwater rocky marine coastlines. This paper reviews the conditions in which kelp forests develop globally and where, why and at what rate they become deforested. The ecology and long archaeological history of kelp forests are examined through case studies from southern California, the Aleutian Islands and the western North Atlantic, well-studied locations that represent the widest possible range in kelp forest biodiversity. Global distribution of kelp forests is physiologically constrained by light at high latitudes and by nutrients, warm temperatures and other macrophytes at low latitudes. Within mid-latitude belts (roughly 40–60° latitude in both hemispheres) well-developed kelp forests are most threatened by herbivory, usually from sea urchins. Overfishing and extirpation of highly valued vertebrate apex predators often triggered herbivore population increases, leading to widespread kelp deforestation. Such deforestations have the most profound and lasting impacts on species-depauperate systems, such as those in Alaska and the western North Atlantic. Globally urchin-induced deforestation has been increasing over the past 2–3 decades. Continued fishing down of coastal food webs has resulted in shifting harvesting targets from apex predators to their invertebrate prey, including kelp-grazing herbivores. The recent global expansion of sea urchin harvesting has led to the widespread extirpation of this herbivore, and kelp forests have returned in some locations but, for the first time, these forests are devoid of vertebrate apex predators. In the western North Atlantic, large predatory crabs have recently filled this void and they have become the new apex predator in this system. Similar shifts from fish- to crab-dominance may have occurred in coastal zones of the United Kingdom and Japan, where large predatory finfish were extirpated long ago. Three North American case studies of kelp forests were examined to determine their long history with humans and project the status of future kelp forests to the year 2025. Fishing impacts on kelp forest systems have been both profound and much longer in duration than previously thought. Archaeological data suggest that coastal peoples exploited kelp forest organisms for thousands of years, occasionally resulting in localized losses of apex predators, outbreaks of sea urchin populations and probably small-scale deforestation. Over the past two centuries, commercial exploitation for export led to the extirpation of sea urchin predators, such as the sea otter in the North Pacific and predatory fishes like the cod in the North Atlantic. The large-scale removal of predators for export markets increased sea urchin abundances and promoted the decline of kelp forests over vast areas. Despite southern California having one of the longest known associations with coastal kelp forests, widespread deforestation is rare. It is possible that functional redundancies among predators and herbivores make this most diverse system most stable. Such biodiverse kelp forests may also resist invasion from non-native species. In the species-depauperate western North Atlantic, introduced algal competitors carpet the benthos and threaten future kelp dominance. There, other non-native herbivores and predators have become established and dominant components of this system. Climate changes have had measurable impacts on kelp forest ecosystems and efforts to control the emission of greenhouse gasses should be a global priority. However, overfishing appears to be the greatest manageable threat to kelp forest ecosystems over the 2025 time horizon. Management should focus on minimizing fishing impacts and restoring populations of functionally important species in these systems.
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Elliott, M., et Paul F. Kingston. « The sublittoral benthic fauna of the estuary and Firth of Forth, Scotland ». Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 93, no 3-4 (1987) : 449–65. http://dx.doi.org/10.1017/s0269727000006874.
Texte intégralRésumé :
SynopsisThe structure of the sublittoral benthic macro-invertebrate populations of the Forth estuary and firth, Scotland, is described, giving the species richness, abundance and biomass for the area from the freshwater tidal limit to the North Sea boundary. Eight faunal associations have been defined, which include classical Petersen communities in the marine area and transition associations within the estuary. The spatial distributions of the associations are predominantly the result of the physical environment, but superimposed on the effects of salinity, sediment type and bathymetry are the effects of urbanisation, industrialisation, dredging and spoil disposal and thermal discharges. The benthos of the major part of the firth has been little affected, although that of the peripheral and estuarine areas does show anthropogenic effects.The water column-benthos and fisheries-benthos interactions are also discussed. Elevated levels of nutrients in the water column may be the cause of enriched benthic populations in the firth and an assessment of the fish-benthos coupling indicates an estuarine functioning similar to other northwestern European areas.
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Rindsberg, Andrew K., et Jack C. Pashin. « Ichnology of a reworked strandplain complex : Mississippian Hartselle Sandstone of Alabama ». Paleontological Society Special Publications 6 (1992) : 247. http://dx.doi.org/10.1017/s2475262200008078.
Texte intégralRésumé :
The Hartselle Sandstone of northern Alabama represents a mesotidal strandplain complex of Hombergian (middle Chesterian) age that was reworked by a transgressing sea. Transgressive reworking resulted in complex facies patterns that can best be deciphered by ichnology. Thickly bedded, unbioturbated beach to shoreface sandstone is widespread at the base of the formation. Wavy-bedded back-barrier to shelf sandstone and shale predominate in the middle and upper parts of the formation and contain distinctive assemblages of trace fossils, invertebrates, and plants.Barriers with a broad, gently sloping beach face and muddy coastal swamps typified the Hartselle strandplain which extended across northern Alabama. Barrier and coastal-swamp deposits lack trace fossils but locally contain an indigenous lycopod flora including stumps and Stigmaria root systems.Back-barrier tidal flats and lagoon deposits have trace-fossil assemblages dominated by bivalve traces that probably represent brackish environments. Marginal-marine sandstone contains chiefly monospecific assemblages and is reworked by bivalves and unknown organisms; Lockeia, Uchirites, and Rosselia are dominant at different sites. The Lockeia assemblage includes bedding surfaces with crowded bivalve resting traces. The abundance, density, and small size of monospecific burrows suggests estuarine conditions with high food supply and rapid larval colonization. The Uchirites assemblage is characterized by bivalve trails, representing probably brackish substrates with a high sedimentation rate.Shelf sandstone and shale include bivalve resting traces and trails (Lockeia ispp., Uchirites isp. aff. U. triangularis, Walcottia rugosa, and W. imbricata), asteroid and ophiuroid resting traces (Asteriacites stelliforme and Pentichnus pratti), trilobite resting traces and trackways (Rusophycus ispp. and Petalichnus isp.), and dwelling burrows, feeding burrows, trails, and trackways of unknown organisms (Chondrites-like burrows, Phycodes isp., Haplotichnus isp., Rosselia isp., Planolites montanus, Nereites missouriensis, Tasmanadia twelvetreesi, imbricate burrows, and wavelike burrows). Some shelf areas even supported diverse calcified faunas containing crinoids, fenestrate bryozoans, and articulate brachiopods.The Hartselle Sandstone is a facies mosaic that records indundation of an extensive strandplain complex and a distinctive stratigraphic succession of lithofacies and biofacies. Hartselle ichnofacies have unique aspects, but are similar to those of other marginal-marine Carboniferous strata in eastern North America. The paleoecologic complexity of the Hartselle Sandstone helps to establish the dynamic range of Carboniferous ecosystems, which have yet to be fully explored.
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Coston-Guarini, Jennifer, François Charles et Jean-Marc Guarini. « Modelling the Dynamics of Outbreak Species : The Case of Ditrupa arietina (O.F. Müller), Gulf of Lions, NW Mediterranean Sea ». Journal of Marine Science and Engineering 12, no 2 (18 février 2024) : 350. http://dx.doi.org/10.3390/jmse12020350.
Texte intégralRésumé :
An outbreak species exhibits extreme, rapid population fluctuations that can be qualified as discrete events within a continuous dynamic. When outbreaks occur they may appear novel and disconcerting because the limiting factors of their dynamics are not readily identifiable. We present the first population hybrid dynamic model that combines continuous and discrete processes, designed to simulate marine species outbreaks. The deterministic framework was tested using the case of an unexploited benthic invertebrate species: the small, serpulid polychaete Ditrupa arietina. This species is distributed throughout the northeast Atlantic Ocean and Mediterranean Sea; it has a life cycle characterised by a pelagic dispersive larval stage, while juveniles and adults are sedentary. Sporadic reports of extremely high, variable densities (from <10 to >10,000 ind.m−2) have attracted attention from marine ecologists for a century. However, except for one decade-long field study from the Bay of Banyuls (France, Gulf of Lions, Mediterranean Sea), observations are sparse. Minimal formulations quantified the processes governing the population dynamics. Local population continuous dynamics were simulated from a size-structured model with a null immigration–emigration flux balance. The mathematical properties, based on the derived hybrid model, demonstrated the possibilities of reaching an equilibrium for the population using a single number of recruits per reproducer. Two extrapolations were made: (1) local population dynamics were simulated over 180 years using North Atlantic Oscillation indices to force recruitment variability and (2) steady-state population densities over the Gulf of Lions were calculated from a connectivity matrix in a metapopulation. The dynamics reach a macroscopic stability in both extrapolations, despite the absence of density regulating mechanisms. This ensures the persistence of D. arietina, even when strong, irregular oscillations characteristic of an outbreak species are observed. The hybrid model suggests that a macroscopic equilibrium for a population with variable recruitment conditions can only be characterised for time periods which contain several outbreak occurrences distributed over a regional scale.
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Paat, Englin Meiva, Defny S. Wewengkang et Henki Rotinsulu. « AKTIVITAS ANTIMIKROBA EKSTRAK ETIL ASETAT JAMUR LAUT YANG DIISOLASI DARI KARANG LUNAK Sarcophyton sp. DARI PERAIRAN DESA TUMBAK KECAMATAN PUSOMAEN ». PHARMACON 9, no 1 (28 février 2020) : 142. http://dx.doi.org/10.35799/pha.9.2020.27421.
Texte intégralRésumé :
ABSTRACT Soft coral is one type of Coelenterata that lives at sea, namely coral reef waters. Soft Coral acts as one of the constituent animals of coral reef ecosystems and is the largest supplier of growth compounds, such as carbonate compounds in which 50% of the bioactive compounds found in these invertebrates are toxic. This study aims to determine the antimicrobial activity of marine fungi associated with soft coral Sarcophyton sp., which was obtained from Tumbak Village, Posumaen Sub-district, Southeast Minahasa Regency, North Sulawesi. The antimicrobial testing uses diffusion methods to determine the inhibitory activity against Staphylococcus aureus (Gram positive bacteria), Escherichia coli (Gram negative bacteria) and Candida albicans (fungi). The results showed that the antimicrobial activity of fungal extracts isolated from soft coral Sarcophyton sp., against bacteria, Escherechia coli, and Candida albicans by measuring the inhibitory activity is the formation of clear zones which categorize as medium, whereas for Staphylococcus aureus bacteria do not have antimicrobial activity. Keywords: Antimicrobial, Soft Coral (Sarcophyton sp.), Staphylococcus aureus, Eschrichia coli, Candida albicans ABSTRAK Karang Lunak merupakan salah satu jenis Coelenterata yang hidupnya dilaut yaitu perairan terumbu karang. Karang Lunak berperan sebagai salah satu hewan penyusun ekosistem terumbu karang dan pemasok senyawa pertumbuhan terbesar yaitu senyawa karbonat yang dimana sebanyak 50 % senyawa bioaktif yang terdapat pada invetebrata ini bersifat toksik. Penelitian ini bertujuan untuk mengetahui adanya aktivitas antimikroba dari jamur laut yang berasosisasi dengan karang lunak Sarcophyton sp., yang diperoleh dari desa Tumbak Kecamatan Posumaen Minahasa Tenggara Sulawesi Utara. Pengujian daya antimikroba menggunakan metode difusi untuk mengetahui aktivitas penghambatan yang diuji terhadap Staphylococcus aureus (bakteri Gram positif), Eschrichia coli (bakteri Gram negatif) dan Candida albicans (jamur). Hasil penelitian menunjukkan bahwa adanya aktivitas antimikroba ekstrak jamur yang diisolasi dari karang lunak Sarcophyton sp., terhadap bakteri, Escherechia coli, dan jamur Candida albicans dengan pengukuran daya hambat yaitu terbentuknya zona bening yang ada dalam kategori sedang, sedangkan untuk bakteri Staphylococcus aureus tidak memiliki aktivitas antimikroba. Kata Kunci: Antimikroba, Karang Lunak (Sarcophyton sp.), Staphylococcus aureus, Eschrichia coli, Candida albicans
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Lekan, Thomas M. « “A Delicate Equilibrium of the Most Complex Sort” ». Historical Studies in the Natural Sciences 53, no 2 (1 avril 2023) : 147–88. http://dx.doi.org/10.1525/hsns.2023.53.2.147.
Texte intégralRésumé :
This article examines the intertidal ecological research of the commercial lab owner and popular science writer Edward F. Ricketts, best known as the prototype for John Steinbeck’s character “Doc” in the novel Cannery Row (1945). Ricketts’s friendship with Steinbeck and unconventional philosophical style have regrettably overshadowed his scientific work, particularly his novel faunal zonation surveys of the North American Pacific littoral in the 1930s and 1940s. These surveys resulted in a landmark handbook, Between Pacific Tides (1939), designed for novices and specialists alike. Ricketts’s work demonstrates how the place of ecological investigation (Billick and Price)—here Monterey Bay’s pounding surf, storm-tossed debris, eclectic bohemianism, and the collaborative energies at Hopkins Marine Station—“imprinted” West Coast animal ecology. At first, Ricketts adopted the physiological methods and conceptions of ecological holism he had learned at the University of Chicago under mentor Warder C. Allee in the early 1920s. Allee had conducted his investigations of intertidal organisms in the relatively placid bays and estuaries at the Woods Hole research center on Cape Cod, Massachusetts. Allee envisioned animal aggregations as higher-order societies guided by “unconscious cooperation” and evolving toward a climax state. Yet Ricketts found that physiochemical factors, such as temperature and salinity, could not explain the distribution of organisms amid the Pacific’s far more precarious rough-and-tumble surf, nor could they account for fierce competition among organisms. Rejecting Allee’s cooperative metaphors, Ricketts came to see community structure as an unintended result of tidepool invertebrates’ Darwinian struggle to occupy resource niches—a “set of sieves” that transferred nourishment from one part of the aggregation to the next, binding it together in interlocking food webs. Through dialogue with Steinbeck about the implications of modern physics during their Sea of Cortez voyage (1940), Ricketts developed a “unified field hypothesis” to conceptualize the dynamic interwovenness created by transfers of metabolic energy. Yet Steinbeck ultimately held fast to a super-organismic understanding of ecological holism—a hierarchical relationship between constituents and the whole that underlays the novelist’s idea of the human “phalanx” in Grapes of Wrath and other works. The article offers new insights about the ecological origins of Steinbeck and Ricketts’s disputes over “non-teleological” reasoning and the pair’s divergent understandings of nature, society, and progressive politics.
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Gómez, Luis Alfonso, et Camilo Bernando García. « Variaciones adaptativas en la talla de la megafauna bentónica de fondos blandos tropicales en función de parámetros bióticos y abióticos ». Revista de Biología Tropical 65, no 3 (27 mars 2017) : 1002. http://dx.doi.org/10.15517/rbt.v65i3.25579.
Texte intégralRésumé :
Understanding and predicting adaptations in body size of megabenthic invertebrates remains a major challenge in marine macroecology. This study was conducted in order to investigate size variations of benthic megafauna in the tropics and to identify the effect of biotic and abiotic factors that may produce changes to these organisms, testing unresolved hypothesis and paradigms of deep sea ecology from subtropical and temperate areas. The study area covered the continental shelf of the Colombian Caribbean. The samples were collected during 1998, 2001 and 2005, using semi-globe demersal net for a water depth of 10 to 500 m. The most common species were selected for further study: Eudolium crosseanum, Cosmioconcha nitens, Nuculana acuta (mollusks), Astropecten alligator, Brissopsis atlantica, B. elongata (equinoderms), Anasimus latus, Chasmocarcinus cylindricus and Achelous spinicarpus (crustaceans). Generalized Additive Models were used to detect significant changes in size and to infer the effects of biotic and environmental factors on organisms’ size. The dependent variable was size and the predicting model variables were depth, temperature, intraspecific density, interspecific density, richness, latitude, and longitude. A total of 7 000 individuals were measured. Six species showed an increase in body size towards deeper and colder sites. These species inhabit shallow and deep environments that exceed a variation in temperature of 10 °C. There was a remarkable size reduction in areas affected by the Magdalena River, possibly due to major physicochemical changes caused by the river. This region has the lowest planktonic primary productivity within the study area. An increase in sizes was observed north of the Magdalena River (long 74°W - 71°W & lat of 11°N - 13°N), which may be attributable to the coastal upwelling occurring in this part of Colombia. The relationship between the density of benthic organisms and size was not clear. However, five species showed an inverse relation with intraspecific density and three with interspecific density. Temperature and depth were the variables that best explained the variations in size. Most of the studied species showed an increase in body size when temperature dropped along the bathymetric range. The trend of increasing size in deeper zones is contrary to the prediction of the optimal size theoretical model (but consistent with recent studies), which indicates a reduction in organisms’ size in the deep sea, due to food limitation with increasing depth. It is possible that this increase in size is an adaptation to maximize energy, which is frequently observed in the coldest habitats of several species. Future studies in Caribbean should examine variations in size of benthic megafauna towards deeper zones (more than 500 m), were temperature is less variable and then other factors can play a more important role determining the size of these organisms.
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Imbs, Andrey B., Ekaterina V. Ermolenko, Valeria P. Grigorchuk, Tatiana V. Sikorskaya et Peter V. Velansky. « Current Progress in Lipidomics of Marine Invertebrates ». Marine Drugs 19, no 12 (25 novembre 2021) : 660. http://dx.doi.org/10.3390/md19120660.
Texte intégralRésumé :
Marine invertebrates are a paraphyletic group that comprises more than 90% of all marine animal species. Lipids form the structural basis of cell membranes, are utilized as an energy reserve by all marine invertebrates, and are, therefore, considered important indicators of their ecology and biochemistry. The nutritional value of commercial invertebrates directly depends on their lipid composition. The lipid classes and fatty acids of marine invertebrates have been studied in detail, but data on their lipidomes (the profiles of all lipid molecules) remain very limited. To date, lipidomes or their parts are known only for a few species of mollusks, coral polyps, ascidians, jellyfish, sea anemones, sponges, sea stars, sea urchins, sea cucumbers, crabs, copepods, shrimp, and squid. This paper reviews various features of the lipid molecular species of these animals. The results of the application of the lipidomic approach in ecology, embryology, physiology, lipid biosynthesis, and in studies on the nutritional value of marine invertebrates are also discussed. The possible applications of lipidomics in the study of marine invertebrates are considered.