Academic literature on the topic 'Marine benthic species'

Abstract One of the ecological roles of seagrass ecosystems is as a habitat for marine organisms. Benthos is a group of marine biota that lives on the bottom of the waters and can be found in seagrass ecosystems. This study aims to inventory the diversity of benthic organisms in seagrass ecosystems in Liki, Befondi and Meossu island. This research is part of the second leg of the Nusa Manggala Expedition which was held in 2018 on Liki Island, Meossu and Befondi, the northern waters of Papua.. Benthos data was collected using cores at 0 m, 50 m and 100 m on the line transect. The results of this study indicate that the highest density of seagrass is on Liki Island. In addition, 33 species of benthic organisms were found on Liki Island, 42 species on Meossu Island and 20 species on Befondi Island. The highest abundance and diversity of benthic organisms was found on Meossu Island. The dominant benthic organisms come from the gastropod class with the species having the highest abundance, Euplica scripta. Based on this research, it is suspected that there is a relationship between the condition of the seagrass ecosystem and the abundance and diversity of benthos.

Many Antarctic marine benthic macroinvertebrates are chemically protected against predation by marine natural products of different types. Antarctic potential predators mostly include sea stars (macropredators) and amphipod crustaceans (micropredators) living in the same areas (sympatric). Recently, alien species (allopatric) have been reported to reach the Antarctic coasts, while deep-water crabs are suggested to be more often present in shallower waters. We decided to investigate the effect of the chemical defenses of 29 representative Antarctic marine benthic macroinvertebrates from seven different phyla against predation by using non-native allopatric generalist predators as a proxy for potential alien species. The Antarctic species tested included 14 Porifera, two Cnidaria, two Annelida, one Nemertea, two Bryozooa, three Echinodermata, and five Chordata (Tunicata). Most of these Antarctic marine benthic macroinvertebrates were chemically protected against an allopatric generalist amphipod but not against an allopatric generalist crab from temperate waters. Therefore, both a possible recolonization of large crabs from deep waters or an invasion of non-native generalist crab species could potentially alter the fundamental nature of these communities forever since chemical defenses would not be effective against them. This, together with the increasing temperatures that elevate the probability of alien species surviving, is a huge threat to Antarctic marine benthos.

Resting stages are the strategy for species to avoid the variability of environmental conditions. In coastal confined marine habitats, variability of conditions is higher than in the open sea, and bottoms accumulate plankton resting stages in the so-called “marine cyst banks”. The benthic-pelagic coupling generated by this bi-location of plankton, however, is not clearly evident for all the involved species. This result is due to the still scant knowledge of the life cycles and life histories of single species. The study of plankton dynamics from the benthos point of view is useful and informative and it increases the potential complexity of a planktonic community in a confined area. Keywords: plankton, life cycles, resting stages, cysts, benthic-pelagic coupling, resurrection ecology.

Modern marine plankton communities include a broad diversity of metazoans that are suspension-feeding or micropredatory as adults. Many benthic marine species have larval stages that reside, and often feed, in the plankton for brief to very long periods of time, and most marine benthic communities include large numbers of suspension-feeders. This has not always been the case. Cambrian benthic communities included relatively few suspension-feeders. Similarly, there were few metazoan clades represented in the plankton, either as adult suspension-feeders or as larvae. Review of the fossil record suggests that the diversification of the plankton and suspension-feeding marine animals began in the Late Cambrian and continued into the Ordovician. These changes were accompanied by, and probably influenced, concurrent major changes in the marine realm, including an increase in tiering within benthic communities, the replacement of the Cambrian fauna by the Paleozoic fauna, and a general taxonomic diversification. The ultimate cause of these changes is uncertain, but it appears likely that the plankton was and is a refuge from predation and bioturbation for adults and larvae alike. The expansion in plankton biomass thus provided increased ecological opportunities for suspension-feeders in the plankton and benthos.

Pollution associated with marine debris is of global ecological concern, as it threatens wildlife and local economies. Submerged marine debris alters local benthic species composition and community characteristics. The study site of Jaguri, Jeju Island, where a variety of submerged marine debris was found, was used to investigate the impact of submerged marine debris on the macrobenthic fauna of sandy and rocky substrates. The dominant macrobenthos taxon differed by sediment type; the polychaete Armandia lanceolata was dominant in sandy bottom environments and the mollusk Leiosolenus lischkei was dominant in rocky bottom environments. The presence of marine debris was associated with differences in biomass in both the soft and rocky areas. The site without debris had higher biomass in the soft area, and the site with nets had a higher density of benthic animals within the site with debris. In the rocky area. the site with debris had a higher biomass. Macrobenthos were affected by the type of deposited marine debris and the type of sediment substrate. This study provides a basis for future studies on the impact of debris on marine ecosystems and identified the benthos species affected by marine debris.

Benthic communities were studied in nine Polish coastal lakes of the Baltic Sea; representing three levels of hydrological connection with the sea (isolated, periodically connected, and permanently connected), with resultant differences in salinity (freshwater, transitional, and brackish). The lakes classified in this way allowed us to investigate biodiversity in relation to the degree of environmental pressure. Stress intensity in coastal water bodies, resulting from contrasting marine and terrestrial influences, varied from mild to severe. Spatial variation in environmental predictors affected species richness more strongly than seasonal fluctuations. The broader the spatial salinity gradient, the smaller the species number recorded. Differences in the intensity of natural instability only slightly affected species number and α-diversity. In Baltic coastal lakes, characterized by low salinity (max. 7.5 PSU), benthic faunal communities were dominated by large populations of opportunistic species. This applied primarily to closed systems and those periodically influenced by seawater intrusion. The marine component of fauna played a more important role in increasing the diversity of benthos in permanently open water bodies (brackish). The highest density of benthic fauna was recorded in them, whereas low values were associated with the strongest instability, observed in lakes periodically linked with the sea (transitional).

Marine heatwaves (MHWs) have been documented around the world, causing widespread mortality of numerous benthic species on shallow reefs (less than 15 m depth). Deeper habitats are hypothesized to be a potential refuge from environmental extremes, though we have little understanding of the response of deeper benthic communities to MHWs. Here, we show how increasing depth moderates the response of seaweed- and coral-dominated benthic communities to an extreme MHW across a subtropical–temperate biogeographical transition zone. Benthic community composition and key habitat-building species were characterized across three depths (15, 25 and 40 m) before and several times after the 2011 Western Australian MHW to assess resistance during and recovery after the heatwave. We found high natural variability in benthic community composition along the biogeographic transition zone and across depths with a clear shift in the composition after the MHW in shallow (15 m) sites but a lot less in deeper communities (40 m). Most importantly, key habitat-building seaweeds such as Ecklonia radiata and Syctothalia dorycarpa which had catastrophic losses on shallow reefs, remained and were less affected in deeper communities. Evidently, deep reefs have the potential to act as a refuge during MHWs for the foundation species of shallow reefs in this region.

Microbes in marine sediments constitute up to five-sixths of the planet’s total biomass, but their diversity is little explored, especially for those forming associations with unicellular protists. Heterotrophic ciliates are among the most dominant and diversified marine benthic protists and comprise hotspot niches of bacterial colonization. To date, studies using culture-independent single-cell approaches to explore microbiomes of marine benthic ciliates in nature are almost absent, even for the most ubiquitous species. Here, we characterize the major bacterial groups associated with a representative marine benthic ciliate, Geleia sp. YT, collected directly from the coastal zone of Yantai, China. PacBio sequencing of the nearly full-length 16Sr RNA genes was performed on single cells of Geleia. Fluorescence in situ hybridization (FISH) analysis with genus-specific probes was further applied to locate the dominant bacterial groups. We identified a Variovorax-like bacterium as the major epibiotic symbiont residing in the kineties of the ciliate host. We provide evidence of a nucleus-associated bacterium related to the human pathogen Mycoplasma, which appeared prevalently in the local populations of Geleia sp. YT for 4 months. The most abundant bacterial taxa associated with Geleia sp. YT likely represent its core microbiome, hinting at the important roles of the ciliate-bacteria consortium in the marine benthos. Overall, this work has contributed to the knowledge of the diversity of life in the enigmatic marine benthic ciliate and its symbioses.

Sampling data on abiotic parameters and benthic communities in the northern lagoon of Tunis were obtained seasonally from November 1999 to November 2000. Abiotic parameters studied revealed evident improvement of water quality compared with previous. Indeed, management has re-established a tidal marine influence (Gulf of Tunis), induced a remarkable change in physico-chemical parameters and as a consequence, a regulation of the lagoon environmental quality. A total of 90 species of benthic macroinvertebrates, belonging to seven different taxa were collected in the northern lagoon of Tunis. A comparison of ecological indices indicate significant variations in the spatial and seasonal distribution and structure of the benthic community and reflect changes that might be related to open marine water and climatic influences as well as effects of discharge of the neighbouring city. Generally, the lagoon macrobenthic community appeared to be better structured, richer and more diverse than the one described before sanitation works began. However, significant disturbance of the benthic communities is detected in the south-eastern lagoon zone (C) and is dominated by disturbance indicator species. In contrast, the Station A2 which is sufficiently influenced by marine currents, is dominated by species of marine affinity and indicates an undisturbed zone. Multivariate analysis indicates heterogeneity in the benthic community structure between stations and suggests that the most significant variations of abundance occur in the groups: Anthozoa, Placophora, Cephalopoda, Ascidia and Echinodermata. The results of correspondence analysis also testify to a gradational distribution of benthic species in relation to hydrological and edaphic (organic matter) factors.

A total of 261species of marine benthic algae under 121genera,comprising 72 taxa belonging to 26 genera of Chlorophyta, 45 taxa belonging to 18 genera of Phaeophyta and 144 taxa belonging to 77 genera of Rhodophyta growing along the Tanintharyi Coastal Zone, Deltaic Coastal Zone and Rakhine Coastal Zone, were recorded. In general, diversity ratios of seaweeds occur in 3 Coastal Zones is 3:1:4 between the Tanintharyi Coastal Zone (146 taxa), Deltaic Coastal Zone (53 taxa) and Rakhine Coastal Zone (224 taxa).Among these, 89 species of marine benthic algae, including 25 taxa of green, 9 taxa of brown and 55 taxa of red algae, were newly recorded from Myanmar waters. The latitudinal distribution of marine benthic algae along the Myanmar Coastal Zones reveals 25 species of marine benthic algae which uniquely occur in low lattitute in the Tanintharyi Coastal Zone and 111 species which exclusively predominate in high lattitutein the Rakhine Coastal Zone. Monostroma, Ulva, Caulerpa and Codium of Chlorophyta, Dictyota, Spatoglossum, Hormophysa, Turbinaria and Sargassum of Phaeophyta and Phycocalidia, Dermonema, Gelidiella, Halymenia, Solieria, Hypnea, Gracilaria,Gracilariopsis, Hydopuntia, Catenella and Acanthophora of Rhodophyta could be considered as of dependable natural resources of Myanmar to produce the sea-vegetables and phycocolloids. Mariculture of some economically important marine red algae such as Gracilaria spp., Hydopuntia spp., Catenella spp. And Kappaphycus alvarezii was described. Current status and prospects of phycocolloid industries producing alginate, agar-agar and carrageenansfrom raw materials of seaweeds of Myanmar were discussed. Checklist, distribution and conservation of marine benthic algae were briefly presented.

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In the present work we performed a study and characterization of benthic macrofauna of the intertidal fringe of PecÃm beach between the years 2006 and 2011 in order to obtain information about the taxonomic diversity of species and deepen knowledge about the ecology of these organisms in the face of new environmental conditions imposed by the deployment of Marine Terminal of Port of PecÃm. Seventy-one taxa belonging to seven taxonomic groups: Porifera, Cnidaria, Mollusca, Annelida (Polychaeta), Arthropoda (Crustacea), Echinodermata and Chordata were listed. Six species of marine benthic invertebrates introduced: the bivalve mollusc Isognomon bicolor, Donax gemmula and Heterodonax bimaculatus, the crustacean Decapoda Charybdis hellerii and the polychaete Phragmatopoma caudata were listed. The species Phragmatopoma caudata, Donax gemmula and Heterodonax bimaculatus were classified as cryptogenic and Isognomon bicolor and Charybdis hellerii as exotic detected in the natural environment. Heterodonax bimaculatus is first recorded in the state of CearÃ, extending its distribution along the Brazilian coast. Specific preferences of benthic macrofauna in relation to the variability of substrates were found. This fact influences the composition and distribution of taxa, has been identified a greater number of taxonomic groups (seven) in consolidated substrate when compared to taxonomic groups (three) identified in the unconsolidated substrate. There were no significant changes in the composition of local benthic macrofauna when compared to other coastal regions of the state. The quantitative fluctuations observed in populations seem to be related to a response of organisms to coastal dynamics, indicating an adaptive process of species to new environmental conditions of the area. It was observed a decrease in the average percentage of coverage of organisms in consolidated substrate, and there were no significant differences in the average number of organisms in unconsolidated substrate between the years 2008 and 2011. With reference to the collect frequency (monthly, bimonthly and quarterly) was observed that the average percentage of coverage of organisms in consolidated substrate and the average amount of organisms in unconsolidated substrate showed no significant differences among the three study periods during the years 2008 and 2011. The quantitative and qualitative data obtained in this study suggest that the introduced species in the intertidal fringe PecÃm beach have not, so far, caused significant impacts on local benthic macrofauna, although they may be considered as a potential threat to the structure of these communities. Shipping accomplished through the Marine Terminal of Port of PecÃm seems to be the vector responsible for the introduction of new species in local macrozoobenthos.
No presente trabalho foi realizado o levantamento e carac-terizaÃÃo da macrofauna bentÃnica da faixa entremarÃs da praia do PecÃm, no perÃodo de 2006 a 2011, com a finalidade de obter informaÃÃes sobre a diversidade taxonÃmica das espÃcies e aprofundar o conhecimento sobre a ecologia desses organismos frente Ãs novas condiÃÃes ambientais impostas pela implantaÃÃo do Terminal PortuÃrio do PecÃm. Foram identificados 71 tÃxons pertencentes a 7 grupos taxonÃmicos: Porifera, Cnidaria, Mollusca, Annelida (Polychaeta), Arthropoda (Crustacea), Echinodermata e Chordata. Como espÃcies introduzidas foram identificados os moluscos bivalves Isognomon bicolor, Donax gemmula e Heterodonax bimaculatus, o crustÃceo decÃpoda Charibdys hellerii e o poliqueta Phragmatopoma caudata. As espÃcies Phragmatopoma caudata, Donax gemmula e Heterodonax bimaculatus foram classificadas como criptogÃnicas e Isognomon bicolor e Charibdys hellerii como exÃticas detectadas em ambiente natural. Heterodonax bimaculatus à registrado pela primeira vez para o estado do CearÃ, ampliando sua distribuiÃÃo na costa brasileira. Foram constatadas preferÃncias especÃficas da macrofauna bentÃnica com relaÃÃo à variabilidade dos substratos o que influencia na composiÃÃo e distribuiÃÃo dos tÃxons, tendo sido identificada uma maior quantidade de grupos taxonÃmicos (7) no substrato consolidado quando comparada aos grupos taxonÃmicos (3) identificados no substrato inconsolidado. NÃo foram observadas alteraÃÃes significativas na composiÃÃo da macrofauna bentÃnica local quando comparada com a de outras localidades costeiras do estado. As flutuaÃÃes quantitativas observadas nas populaÃÃes parecem estar relacionadas a uma resposta dos organismos à dinÃmica costeira, indicando um processo adaptativo das espÃcies Ãs novas condiÃÃes ambientais da Ãrea. Foi verificado um decrÃscimo no percentual mÃdio de cobertura dos organismos no substrato consolidado, nÃo tendo sido observado diferenÃas significativas na quantidade mÃdia de organismos no substrato inconsolidado entre os anos de 2008 e 2011. Com relaÃÃo à periodicidade de coleta (mensal, bimestral e trimestral) observou-se que o percentual mÃdio de cobertura de organismos no substrato consolidado e a quantidade mÃdia de organismos no substrato inconsolidado nÃo apresentaram diferenÃas significativas entre os trÃs perÃodos analisados durante os anos de 2008 e 2011. Os dados quantitativos e qualitativos obtidos nesse estudo sugerem que as espÃcies introduzidas na faixa entremarÃs da praia do PecÃm nÃo tÃm, atà o momento, causado impactos significativos na macrofauna local, embora possam ser consideradas como uma potencial ameaÃa à estrutura dessas comunidades. O transporte marÃtimo realizado atravÃs do Terminal PortuÃrio do PecÃm parece ser o vetor responsÃvel pela introduÃÃo de novas espÃcies no macrozoobentos local.

Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau...
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau...
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau. Deuxième étude : des durées d’échantillonnage intermédiaires d’une à deux semaines (l’échelle des traitements allant d’un jour à un mois) étaient la durée optimale de déploiement de la plaque de fixation pour la détection des espèces « rares » (c’est-à-dire, des le début du recrutement). Une analyse au niveau de l’assemblage montre toutefois que l’augmentation de la durée et de la fréquence de l’échantillonnage augmentait logarithmiquement le nombre total d’espèces rares observées. Ces résultats espèce par espèce et au niveau de l’assemblage démontrent que la modification des éléments temporels de l’échantillonnage, tels que la durée et la fréquence, peut affecter considérablement la détection d’espèces. Troisième étude : après avoir évalué plusieurs sources spatiales et temporelles (le site, la région, la saison, et l’année), le moment choisi pour le déploiement des plaques est apparu comme étant la plus grande source de variabilité du recrutement benthique d’espèces rares. En particulier, le moment optimal pour la détection précoce serait en automne (a) lorsque le recrutement saisonnier d’espèces envahissantes établies tend à atteindre un pic et (b) lorsque la détection au niveau du site d’espèces envahissantes rares tend à se produire. Quatrième étude : l’échelle spatiale dominante dans le recrutement d’espèces rares est la plus petite (centaine de mètres). Cette échelle dominante peut être interprétée comme étant la bonne échelle spatiale pour la détection d’espèces rares. Une analyse plus poussée a montré que si l’échantillonnage a été structuré de manière aléatoire, l’échantillonnage à des échelles intermédiaires (millier de mètres) devient l’échelle optimale pour la détection d’espèces rares. Ces résultats élucident les différences de variabilité naturelle de la population benthique entre multiples échelles d’espace et de temps pour des espèces rares et communes. Ces études écologiques font partie d’une boîte à outils de détection précoce nécessaire à la gestion des espèces envahissantes marines en renseignant sur la manière dont l’échantillonnage des espèces rares doit être faite à multiples échelles spatio-temporelles. Des expériences de terrain similaires optimisant la détection d’espèces rares (au-delà de l’utilisation de plaques de fixation pour détecter les organismes benthiques dans les provinces Maritimes canadiennes) devraient être réalisées pour d’autres taxons, régions, t outils d’échantillonnage—en particulier, les envahisseurs à haut risque prévus, les invasions futures, et les outils récemment développés.
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau. Deuxième étude : des durées d’échantillonnage intermédiaires d’une à deux semaines (l’échelle des traitements allant d’un jour à un mois) étaient la durée optimale de déploiement de la plaque de fixation pour la détection des espèces « rares » (c’est-à-dire, des le début du recrutement). Une analyse au niveau de l’assemblage montre toutefois que l’augmentation de la durée et de la fréquence de l’échantillonnage augmentait logarithmiquement le nombre total d’espèces rares observées. Ces résultats espèce par espèce et au niveau de l’assemblage démontrent que la modification des éléments temporels de l’échantillonnage, tels que la durée et la fréquence, peut affecter considérablement la détection d’espèces. Troisième étude : après avoir évalué plusieurs sources spatiales et temporelles (le site, la région, la saison, et l’année), le moment choisi pour le déploiement des plaques est apparu comme étant la plus grande source de variabilité du recrutement benthique d’espèces rares. En particulier, le moment optimal pour la détection précoce serait en automne (a) lorsque le recrutement saisonnier d’espèces envahissantes établies tend à atteindre un pic et (b) lorsque la détection au niveau du site d’espèces envahissantes rares tend à se produire. Quatrième étude : l’échelle spatiale dominante dans le recrutement d’espèces rares est la plus petite (centaine de mètres). Cette échelle dominante peut être interprétée comme étant la bonne échelle spatiale pour la détection d’espèces rares. Une analyse plus poussée a montré que si l’échantillonnage a été structuré de manière aléatoire, l’échantillonnage à des échelles intermédiaires (millier de mètres) devient l’échelle optimale pour la détection d’espèces rares. Ces résultats élucident les différences de variabilité naturelle de la population benthique entre multiples échelles d’espace et de temps pour des espèces rares et communes. Ces études écologiques font partie d’une boîte à outils de détection précoce nécessaire à la gestion des espèces envahissantes marines en renseignant sur la manière dont l’échantillonnage des espèces rares doit être faite à multiples échelles spatio-temporelles. Des expériences de terrain similaires optimisant la détection d’espèces rares (au-delà de l’utilisation de plaques de fixation pour détecter les organismes benthiques dans les provinces Maritimes canadiennes) devraient être réalisées pour d’autres taxons, régions, t outils d’échantillonnage—en particulier, les envahisseurs à haut risque prévus, les invasions futures, et les outils récemment développés.
As a consequence of anthropogenic activities, biological invasions have become a global problem that can cause ecological (e.g., biodiversity and habitat), economic (industries), and social (human wellbeing) harm. Prevention and early detection of new invasions are vital components of managing risks and impacts to ecosystems and economies. Prevention is, of course, preferred but early detection is a critical step that can ultimately stop future spread of invasive species because it provides an opportunity for eradication before population growth and spread. Despite being a cost- and time-effective management option, early detection requires considerably high sampling effort to detect incipient invasive populations at the early stages of their invasion. Using the marine benthic system as a model, four inter-related studies were carried out to identify sampling strategies that could enhance our ability to detect rare invasive populations and to understand ecological patterns and processes of benthic recruitment across multiple scales of space and time. Specifically, these experimental field studies aimed to (1) evaluate the relationship between propagule supply and settlement in a closed invasive population, (2) determine the optimal sampling duration and frequency using settlement plates to detect rare species, (3) ascertain the relative importance of spatial and temporal sources of variation in benthic recruitment, and (4) examine how the spatial scale of sampling affects species detection by analyzing recruitment patterns at multiple scales across four orders of magnitudes ranging from tens of metres to tens of kilometres. First study: Contrary to the expectation of a strong relationship between supply and initial settlement, larval supply was instead a limited determinant of settlement at mesoscales. This finding suggests that the strength of this relationship weakens as the spatial scale increased from previously reported small-scale field observations to mesoscales of the present study. Nonetheless, a quarter of the variation in settlement can still be explained by supply over short timescales (one week). Therefore, this relationship supports the utility of settlement plates as an effective tool for early detection at mesoscales within a marina because low densities of recruitment on plates correspond to low abundances of invasive propagules in the water column...
As a consequence of anthropogenic activities, biological invasions have become a global problem that can cause ecological (e.g., biodiversity and habitat), economic (industries), and social (human wellbeing) harm. Prevention and early detection of new invasions are vital components of managing risks and impacts to ecosystems and economies. Prevention is, of course, preferred but early detection is a critical step that can ultimately stop future spread of invasive species because it provides an opportunity for eradication before population growth and spread. Despite being a cost- and time-effective management option, early detection requires considerably high sampling effort to detect incipient invasive populations at the early stages of their invasion. Using the marine benthic system as a model, four inter-related studies were carried out to identify sampling strategies that could enhance our ability to detect rare invasive populations and to understand ecological patterns and processes of benthic recruitment across multiple scales of space and time. Specifically, these experimental field studies aimed to (1) evaluate the relationship between propagule supply and settlement in a closed invasive population, (2) determine the optimal sampling duration and frequency using settlement plates to detect rare species, (3) ascertain the relative importance of spatial and temporal sources of variation in benthic recruitment, and (4) examine how the spatial scale of sampling affects species detection by analyzing recruitment patterns at multiple scales across four orders of magnitudes ranging from tens of metres to tens of kilometres. First study: Contrary to the expectation of a strong relationship between supply and initial settlement, larval supply was instead a limited determinant of settlement at mesoscales. This finding suggests that the strength of this relationship weakens as the spatial scale increased from previously reported small-scale field observations to mesoscales of the present study. Nonetheless, a quarter of the variation in settlement can still be explained by supply over short timescales (one week). Therefore, this relationship supports the utility of settlement plates as an effective tool for early detection at mesoscales within a marina because low densities of recruitment on plates correspond to low abundances of invasive propagules in the water column...

Contemporary efforts to conserve and restore the marine environment are centred on regulating anthropogenic activities in defined ocean areas through marine protected areas (MPAs). This spatially explicit approach is contingent upon a good understanding of the biology and distribution of species. However, our understanding of many rare and threatened benthic species, for which conservation MPAs are currently being designated, is poor. The fan mussel, Atrina fragilis (Pennant 1777), a rare and vulnerable sessile benthic species that shows a reduced distribution compared to historical accounts, was used as a case species. Identifying the larvae of sessile benthic species is an essential first step in informing their conservation. Here, the first description of larva belonging to A. fragilis is presented along with key life-history traits. A point process modelling framework appropriate for the analysis of presence-only data, along with techniques to address both observer bias and uncertainties with historical occurrence records, were employed to successfully predict the distribution of A. fragilis, revealing potentially important drivers in its current distribution. The transport of A. fragilis larva, taking into account key aspects of life-history, habitat suitability and fine scale hydrodynamics, was modelled to investigate potential levels of connectivity within the Scottish sea area, allowing the potential supply of larvae to areas of suitable habitat and the Scottish MPA network to be evaluated. To date there has been no consideration of the likely effectiveness of measures in most inshore MPAs. Here we assessed the siting of MPAs in relation to fishing intensity and seabed ruggedness on the west coast of Scotland. The results suggest little reduction in fishing pressure is effected by current restrictions on activity in the subset of MPAs investigated, with protection principally being applied to rugged areas that may already act as natural refugia for vulnerable benthic species such as A. fragilis.

Low light intensity habitats harbor unique sciophilous benthic communities and are a source of novel and unique sponge fauna. However, the community structure of these habitats is poorly studied to date. Thus, this study attempts to understand the composition and structure of sciophilous sponge populations in southeast Florida. Fifty limestone plates were placed on a shallow reef in Fort Lauderdale for two years (2010-2012). To identify the sponge community and their patterns over time, all plates were photographed at the end of each year. Then, samples were taken from each of the live sponge specimens observed on the plates and processed in the laboratory for taxonomical identification. A total of 45 different sponge species were found, the majority corresponding to the Poecilosclerida Order. Eighteen were identified to species level, twenty-two to genus, and five were undetermined. Eight sponges constitute new records to Florida, and four are potentially new species. The most dominant species include Oscarella sp.1, Dysidea etheria, Mycale sp.1, Halisarca caerula and Tedania ignis. Species richness significant varied among years, and species cover among sectors (inner and outer reef). However, sponge assemblages were similar between years with slightly variation between sectors. This study found a diverse and complex composition and structure of sponges that is quite distinct from the sponge assemblages on the open reefs. A guide of the biodiversity of cryptic sponge species was created to facilitate further studies in low light intensity habitats.

The development of offshore wind farms and marine renewable energy devices in the Mediterranean is central to both national, and international, energy strategies for countries bordering the Mediterranean Sea. The ecological impacts of marine renewable energy development in the Mediterranean region, although essential for policy makers, are as yet unknown. The Northern Adriatic is identified as a plausible site for offshore wind farm development. Using the wider region (Adriatic and Northern Ionian) as a case study, this thesis examines the likely impact to the marine environment if an offshore wind farm is established. Site suitability, based on wind speed, bathymetry, and larvae connectivity levels are investigated along with the plausibility of the turbines operating as artificial reefs in the area. As offshore wind farms may alter the larval connectivity and supply dynamics of benthic populations, a connectivity map was constructed to identify areas of high and low connectivity in the Adriatic Sea. The Puglia coast of Italy is a likely larval sink, and displays some of the highest connectivity within the region, suggesting potential inputs of genetic materials from surrounding populations. Considering offshore wind farms could operate as artificial reefs, an in-situ pilot project was established to simulate the presence of wind turbines. Macroinvertebrates colonized the new substrata within the first few months but were lower in abundance when compared to a natural hard substrata environment. Time, turbine location, and the material used for turbine construction all affected the macro-invertebrate communities. In addition, fish abundances, and diversity were lower around the simulated OWF foundations in comparison to a natural hard substrata environment, and no increases in fish abundance occurred around the simulated turbines when compared to reference sites of soft substrata. This observation was validated with the use of an ecosystem modelling software (Ecopath with Ecosim), which simulated the overall ecosystem level impacts that would occur if 50 offshore monopile wind turbines were introduced to the Northern Ionian and colonized by macroinvertebrate communities. When compared to the baseline scenario (no simulated introduction of an OWF), the introduction of new habitat had no discernible impacts to the structure or functioning of the marine ecosystem. Noticeable changes to the ecosystem were only apparent if fishing restrictions were enforced in parallel with the simulated offshore wind farm; the ecosystem appears to become more structured by top down predation. In addition seabirds are also impacted by the reduction of fishing discards as a food source. These results are the first attempt to quantify the suspected benefits of offshore wind farms operating as de-facto marine protected areas.

Parmi les outils qui permettent de mieux comprendre les systèmes naturels, la modélisation écologique a connu un essor particulièrement important depuis une vingtaine d’années. Les modèles écologiques, représentation simplifiée d’une réalité complexe, permettent de mettre en avant les facteurs environnementaux qui déterminent la niche écologique des espèces et de mieux comprendre leur réponse aux changements de l’environnement. Dans le cas des faunes marines antarctiques, la modélisation écologique fait face à plusieurs défis méthodologiques. Les jeux de données de présence des espèces sont très souvent agrégés dans le temps et dans l’espace, à proximité des stations de recherche. Ces données sont souvent trop peu nombreuses pour caractériser l’espace environnemental occupé par les espèces ainsi que leur physiologie. Enfin, les jeux de données environnementales manquent encore de précision pour finement représenter la complexité des habitats marins. Dans ces conditions, est-il possible de générer des modèles performants et justes à l’échelle de l’océan Austral ? Quelles sont les approches possibles et leurs limites ? Comment améliorer les méthodes afin de générer de meilleurs modèles ? Au cours de ce travail de thèse, trois types de modèles ont été étudiés et leurs performances évaluées. (1) Les modèles physiologiques de type DEB (Dynamic Energy Budget) simulent la manière dont l’environnement abiotique influe sur le métabolisme des individus et proposent une représentation de la niche fondamentale des espèces. (2) Les modèles de distribution d’espèces (SDMs pour Species Distribution Models) prédisent la probabilité de distribution des espèces en étudiant la relation spatiale entre données de présence et environnement. Ils proposent une représentation de la niche réalisée des espèces. Enfin (3), les modèles de dispersion de type lagrangien prédisent le mouvement de propagules dans les masses d’eau. Les résultats montrent que les modèles physiologiques réussissent à simuler les variations métaboliques des espèces antarctiques en fonction de l’environnement et à prédire les dynamiques de populations. Cependant, davantage de données sont nécessaires pour pouvoir caractériser finement les différences physiologiques entre populations et évaluer correctement les modèles. Les résultats obtenus pour les SDMs montrent que les modèles générés à l’échelle de l’océan Austral et leurs prédictions futures ne sont pas fiables du fait du manque de données disponibles pour caractériser l’espace occupé par les espèces, du manque de précision des scénarios climatiques futurs et de l’impossibilité d’évaluer les modèles. De plus, les modèles extrapolent sur une très grande proportion de l’espace projeté. L’apport d’information complémentaire sur les limites physiologiques des espèces (observations, résultats d’expériences, sorties de modèles physiologiques) permet de réduire l’extrapolation et d’augmenter la capacité des modèles à décrire la niche réalisée des espèces. L’agrégation spatiale des données, qui influençait les prédictions et l’évaluation des modèles a également pu être corrigée. Enfin, les modèles de dispersion ont montré un potentiel intéressant pour révéler le rôle des barrières géographiques ou à l’inverse, la connectivité spatiale, mais également le lien existant entre distribution, physiologie et histoire phylogénétique des espèces. Ce travail de thèse propose de nombreux conseils et fournit des codes annotés parfois sous forme de tutoriels, afin de constituer une aide utile aux futurs travaux de modélisation sur les espèces marines antarctiques
Among tools that are used to fill knowledge gaps on natural systems, ecological modelling has been widely applied during the last two decades. Ecological models are simple representations of a complex reality. They allow to highlight environmental drivers of species ecological niche and better understand species responses to environmental changes. However, applying models to Southern Ocean benthic organisms raises several methodological challenges. Species presence datasets are often aggregated in time and space nearby research stations or along main sailing routes. Data are often limited in number to correctly describe species occupied space and physiology. Finally, environmental datasets are not precise enough to accurately represent the complexity of marine habitats. Can we thus generate performant and accurate models at the scale of the Southern Ocean ? What are the limits of such approaches ? How could we improve methods to build more relevant models ? In this PhD thesis, three different model categories have been studied and their performance evaluated. (1) Mechanistic physiological models (Dynamic Energy Budget models, DEB) simulate how the abiotic environment influences individual metabolism and represent the species fundamental niche. (2) Species distribution models (SDMs) predict species distribution probability by studying the relationship between species presences and the environment. They represent the species realised niche. (3) Dispersal lagrangian models predict the drift of propagules in water masses. Results show that physiological models can be developed for marine Southern Ocean species to simulate the metabolic variations in link with the environment and predict population dynamics. However, more data are necessary to highlight detailed physiological contrasts between populations and to accurately evaluate models. Results obtained for SDMs suggest that models generated at the scale of the Southern Ocean and future simulations are not relevant, given the lack of data available to characterise species occupied space, the lack of precision and accuracy of future climate scenarios and the impossibility to evaluate models. Moreover, model extrapolate on a large proportion of the projected area. Adding information on species physiological limits (observations, results from experiments, physiological model outputs) was shown to reduce extrapolation and to improve the capacity of models to estimate the species realised niche. Spatial aggregation of occurrence data, which influenced model predictions and evaluation was also succefully corrected. Finally, dispersal models showed an interesting potential to highlight the role of geographic barriers or conversely of spatial connectivity and also the link between species distribution, physiology and phylogeny history. This PhD thesis provides methodological advices, annoted codes and tutorials to help implement future modelling works applied to Southern Ocean marine species

Aquatic sediments are, by surface, the largest habitat on Earth. A wide diversity of organisms inhabit these sediments and by their actions they have a large influence on and also mediate many ecosystem processes. Several of these processes, such as decomposition and remineralisation of organic matter are important on a global scale and are essential to sustain life on Earth. The main aim of this thesis was to use an experimental ecosystem ecology approach in order to study some of these ecosystem processes in marine sediments and how they are linked to biodiversity. Paper I and II found that an increased species richness of sediment deposit feeders increases the processing of organic matter from phytoplankton settled on the sea-floor, and that species-rich communities have a more efficient resource utilization of deposited organic matter. The results in paper IV and V also suggest that there is a link between microbial diversity in sediments and the degradation of organic contaminants. Paper V also shows that antibiotic pollution is a potential threat to natural microbial diversity and microbially mediated ecosystem services. The introduction of invasive species to ecosystems is another major threat to biodiversity and was studied in Paper II and III, by investigating the ecology of Marenzelleria arctia, a polychaete worm recently introduced in the Baltic Sea. Paper II suggests that M. arctia mainly utilize food resources not used by native deposit feeders, thus potentially increasing the benthic production in the Baltic Sea by increasing resource use efficiency. Paper III, however, show that M. arctia is protected from predation by the native benthic invertebrate predators, due to its ability to burrow deep in the sediment, suggesting that predation on M. arctia by higher trophic levels is restricted, thereby limiting trophic transfer. In conclusion, this thesis gives some examples of the importance of marine biodiversity for the generation of a few key ecosystem processes, such as organic matter processing and the degradation of harmful contaminants.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: In press.

Chapter 13 “Marine environments” focuses on different applications of eDNA to study marine biodiversity. After a brief description of the current knowledge on DNA cycle in pelagic and benthic environments, this chapter revisits how DNA metabarcoding, and more generally environmental genomics have revolutionized the field of marine microbiology through the discovery of novel taxa and by unveiling large-scale patterns of diversity for marine bacteria, protists, and viruses. This chapter then presents recent applications of DNA metabarcoding for both basic research or biomonitoring purposes to study marine invertebrates and fish populations and diversity, as well as the detection of invasive species. Current gaps and methodological challenges are also discussed.

This publication contains papers submitted by young scientists at MMBI KSC RAS and their colleagues at the Murmansk Arctic State University and Murmansk State Technical University. The papers are devoted to hydrological and hydrochemical processes, sedimentation processes, spread of man-caused radionuclides, species composition and distribution of benthic organisms, physiology of brown seaweed, and behavior of marine mammals.

Bryozoans are aquatic animals that form colonies of connected individuals. They take a variety of forms: some are bushy and moss-like, some are flat and encrusting and others resemble lace. Bryozoans are mostly marine, with species found in all oceans from sublittoral to abyssal depths, but freshwater species also exist. Some bryozoans are of concern as marine-fouling organisms and invasive species, while others show promise as sources of anticancer, antiviral and antifouling substances. Written by experts in the field, Australian Bryozoa Volume 1: Biology, Ecology and Natural History is the first of two volumes describing Australia’s 1200 known species of bryozoans, the richest diversity of bryozoans of any country in the world. It contains chapters on the discovery of bryozoans, their morphology, classification and fossil history, their roles in biosecurity and marine benthic environments, and potential uses in biotechnology and ocean acidification. It provides an authoritative reference for biology students, academics and others interested in marine biology.

This chapter describes the taxonomy of Amphipoda, which contains over 9500 species worldwide. Most marine amphipods are benthic, but a few have lost their ancestral links with the seabed and are planktonic. The chapter covers their life cycle, ecology, general morphology, and identification. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, recent changes which might have occurred, and lists relevant taxonomic sources.

This chapter describes the taxonomy of ctenophores. The ctenophores, or comb jellies, are gelatinous metazoans belonging to a small and entirely marine phylum of about 150 species. They are mostly planktonic, with the exception of the benthic order Platyctenida, where only the larvae are planktonic. The chapter covers their life cycle, ecology, and generalizmorphology. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, recent changes which might have occurred, and lists relevant taxonomic sources.

This chapter describes the taxonomy of Ostracoda, small bivalved crustaceans ranging in size from 0.2 to > 30 mm. The majority are benthic and belong to the subclass Podocopa. The chapter focuses on the holoplanktonic oceanic species. It covers their life cycle, ecology, and general morphology. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, recent changes which might have occurred, and lists relevant taxonomic sources.

AbstractThe Arabian Gulf’s coastal and marine ecosystems are being negatively impacted by various factors such as population growth, coastal development, industrial and desalination plant discharge, and offshore oil and gas activities. However, seagrass meadows continue to show resilience and provide ecosystem values and services. This paper provides an overview of the seagrass meadows in the United Arab Emirates (UAE) in terms of their extent, species composition, threats, and conservation initiatives. The UAE’s coastline supports three seagrass species that are home to numerous marine species such as dugongs, green sea turtles, fish, and benthic invertebrates. With an area of around 2950 km2, subtidal seagrasses grow to a depth of 16 m and are one of the largest marine ecosystems in the Emirates. Seagrass beds also contribute significantly to blue carbon, with Abu Dhabi seagrasses estimated to have over 52 tonnes per hectare. The primary threats to seagrass meadows include dredging, landfill, and associated sedimentation, as well as environmental extremes such as high summer sea temperatures. However, conservation initiatives such as marine protected areas (MPAs) and federal laws have been implemented to protect these crucial coastal ecosystems.

AbstractHemichordates are benthic marine invertebrates closely related to chordates. Several species, including Ptychodera flava in the phylum Hemichordates, can undergo whole body regeneration from a small fragment. P. flava is widely distributed in the warm Indo-Pacific region and is easily collected in the lower tidal zone of a shallow beach with a coral reef. Here, we describe the methods for animal collection and preparation of regenerating tissues. The prepared tissues can be used for various molecular and/or histological experiments. We also demonstrate how to examine gene expression patterns in the tissues using whole mount in situ hybridization.

Most (but by no means all) benthic species have larval stages which use the water column for dispersal. As indicated in the previous chapter, a key process affecting recruitment to sediment systems is the need to disperse larvae in order to colonize new areas, even to the extent of releasing larvae at spring tides when the tidal excursion will be greatest, thus effecting an even greater dispersal. Seasonal release of larvae is the norm: most species develop gametes in spring and spawn in late spring or early summer (see Rasmussen 1973 for an excellent data set of the times of planktonic larval occurrence and settlement by many important north-west European boreal benthic species). Some species, however, avoid the high competition for food at this time and release gametes in autumn and winter. Thus larvae of benthic organisms are a key and often dominating component of the spring–summer plankton and play important roles as food for planktonic species such as fish larvae. Conversely, a number of planktonic species have resting stages in sediments. The most important of these are undoubtedly the diatoms and many flagellates, and also certain calanoid copepods such as Acartia, which are of course key components of the phytoplankton and zooplankton respectively. Diatom cysts are often found, and there is increased interest in the survival and hatching processes of dinoflagellate cysts that lead to harmful algal blooms. Similarly, the seasonal occurrence of many zooplankton species results from hatching of resting stages in the sediment (see Smetacek (1995), Boero et al. (1996), Pati et al. (1999) and Boero and Bonsdorff (2008) for reviews). The implication of many important planktonic species having benthic resting phases is that by predating cysts, benthic species may be able to control abundances of planktonic species. In this context the meiofauna are important predators (Pati et al. 1999). It is now important to consider the scales of temporal variation in benthic assemblages. First, seasonal changes occur in benthic assemblages of soft sediments even in the depths of the deep sea (e.g. Hsü and Thiede 1992). In spring, as light levels and temperature increase, a plankton bloom occurs.

The benthos does not, of course, live in isolation from other parts of the ecosystem. Here we consider the roles that the benthos plays in the system and how the complex interactions that are found can be modelled using ecosystem models. First, we examine methods that allow us to establish food webs based not only on examining each species in the field and in laboratory feeding studies, but also using stable isotopes of carbon and nitrogen to ascertain the likely feeding mode of a species. It is relatively easy to determine the mode of feeding of some benthic organisms (see for example the excellent review of Fauchald and Jumars 1979, although this is now slightly dated and requires revision). Polychaetes have characteristic feeding structures, so one can determine from their morphology whether they are filter feeders, deposit feeders, or predators. Bivalves show similar morphological characteristics and it is easy to determine whether they are deposit or filter feeders. Some polychaetes have large jaws, e.g. the nereids, and one might assume that they are predators. Yet when Nereis vexillosa was studied in detail (Woodin 1977), it was found that it attached pieces of algae to its tube, which grew and were used for food, so-called ´gardening´. Nereids also are able to filter feed by creating a mucous bag and pumping water through their burrows, which filters the water; the mucous bag is then consumed. More recently, studies have shown varied and possibly opportunistic feeding by different benthic species; for example Christensen et al. (2000) showed how the suspension- and deposit-feeding abilities of nereids influenced sediment nutrient fluxes. These studies show that it is perhaps not so straightforward as once thought to interpret feeding mode simply from morphological features. The definition of functional groups and feeding guilds is increasingly used to help explain and interpret ecological functioning (e.g. Elliott et al. 2007 discuss the rationale behind functional groups). The eminent and immensely experienced benthic biologist Tom Pearson (2001) shows in detail that while the concept of functional groups gives us a greater understanding of the benthos, the idea is criticized by some as we do not have sufficient information about feeding types and modes of life of many benthic species.

This chapter focuses on a series of shallow, coastal subtidal environments. It shows how grass beds, rocky reefs, kelp forest systems, and coral reefs are the most productive and diverse subtidal benthic environments. The habitats are dominated by highly productive benthic primary producers, which also contribute to the structural habitat and qualify as ecosystem engineers. The chapter notes how coral reefs and nearby environments showcase remarkable mutualisms and species which develop strong defences despite the intensity of predation. It looks into coral reef restoration and describes how this involves the establishment of marine protected areas, the restoration of predators and grazers, and the direct transplant of coral species decimated by disturbance and disease.

Abstract The green turtle (Chelonia mydas) is a marine species with a broad pantropical distribution (Bowen et al. 1992) and is the most abundant large herbivore in marine ecosystems (Bjorndal et al. 2000). The southern Great Barrier Reef (sGBR) green turtle stock is one of the most important breeding populations of green turtles in the western South Pacific region (FitzSimmons et al. 1997) with benthic foraging grounds in Australian, Indonesian, Papua New Guinean, Coral Sea, and New Caledonian waters (Limpus et al. 1992). The Great Barrier Reef and coastal Queensland benthic habitat component of this stock includes a spatially disjunct metapopulation with foraging grounds that span 12° latitude and 1800 km with foraging grounds that range from tropical waters in the northern Great Barrier Reef (nGBR) to warm temperate waters in southern coastal Queensland (Figure 30.1) (Chaloupka 2002a). Pelagic juveniles recruit to these benthic habitat foraging grounds after pelagic development in the western South Pacific Ocean (Limpus and Chaloupka 1997).

Extending into the Arabian Gulf, Qatar is surrounded by a number of islands mostly scattered by the eastern coastline. With the unique physical characteristics of the Gulf, which is a highly saline sea with high seawater temperatures, there is an urge need to investigate the macroalgae living in such harsh environment. Macroalgae plays an important role in the food web as they are primary producers and providers of food for other organisms. They also provide shelter and habitat in the marine ecosystem for herbivorous fish and other invertebrate animals. Additionally, macroalgae plays an outstanding role in reducing CO2 from the atmosphere and increasing the level of dissolved oxygen in their immediate environment. However, there are few studies on marine macroalgae in Qatar and no previous studies found related to macroalgae from the islands around Qatar. The present work contributes to the macroalgae research by providing the first survey of distribution and diversity of benthic marine macroalgae in islands around Qatar. The marine benthic green, red and brown macroalgae of intertidal and subtidal in marine zone areas around Qatar were collected during Qatar’s Islands project, which started 2018. The collected macroalgae are documented and a total of 67 species of macroalgae are recorded for all islands around Qatar, 24 Chlorophyta (Green algae), 25 Rhodophyta (Red algae) and 18 species Phaeophyta (Brown algae). The Red algae are dominant taxon in term of species richness, accounting for an average of 37% of the species at all study sites. The islands which had more species are Al-Beshaireya 58 Species, Al-Aaliya 53 Species, Sheraouh 48 Species, Janan 43 Species and Bu Felaita 37 Species. Our results show that islands located at eastern and southeastern coast of Qatar have more diversity of algae species than those located at the western and northwestern coast.

Ocean currents contain a remarkable amount of kinetic energy and have potential worldwide capability. Initial tests to harness current power focus on the Straits of Florida where the Florida Current has a total flow capacity of about 30 × 106 m3 s−1. Generation of clean electricity from ocean currents off southeast Florida is based on a power extractor comprised by open-center turbine technology. This innovative turbine provides safe passage for fish and other aquatic species. The water-column array of energy production units (EPUs) will have a 350 km2 footprint, based on a 600 m (10 rotor diameters) downstream separation distance between EPUs with a lateral separation of 400 m. Water depths for the EPU field are in the range of 100 to 500 m. With such a large area of water column and benthic habitat utilized, environmental concerns must be overcome, including routing of transmission lines to shore. Risks and vulnerabilities of the proposed ocean current generated electricity include failure of individual EPUs and damage to sensitive coastal marine environments during installation.

The impacts of human-induced changes in coastal environments on shellfish farming need to be mitigated. Suspended farming species, such as oysters, greatly impact planktonic communities and benthic environments via filter feeding and bio-deposition. To more effec-tively manage coastal environments and achieve ecologically sustainable shellfish farming, interactions between coastal marine environments and aquaculture activities need to be properly assessed. We examined interactions between coastal biogeochemical environments and suspended oyster farming in Shizugawa Bay of northeastern Japan. We found that particulate organic matter (POM) produced at the oyster farm (e.g., exfoliated periphyton and/or oyster feces) locally increased the concentrations of chlorophyll a and daytime dis-solved oxygen in the bottom layer. Based on the estimated budget of POM at the bay scale, the oyster feeding rate was a couple of orders of magnitude lower than the net primary production and POM inputs at the bay boundaries (e.g., offshore and in rivers). The rela-tively high exposure of the bay and high seawater mixing rate may explain the lack of mac-roscale environmental impacts of oyster cultures at the bay scale. We also found that despite the oligotrophic environment, the oyster growth rate was higher in the bay, compared with previous estimates in other coastal areas. To understand the mechanisms sustaining the production of phytoplankton and oysters, further examinations from the perspective of nu-trient cycling in the bay are required.

The impacts of human-induced changes in coastal environments on shellfish farming need to be mitigated. Suspended farming species, such as oysters, greatly impact planktonic communities and benthic environments via filter feeding and bio-deposition. To more effec-tively manage coastal environments and achieve ecologically sustainable shellfish farming, interactions between coastal marine environments and aquaculture activities need to be properly assessed. We examined interactions between coastal biogeochemical environments and suspended oyster farming in Shizugawa Bay of northeastern Japan. We found that particulate organic matter (POM) produced at the oyster farm (e.g., exfoliated periphyton and/or oyster feces) locally increased the concentrations of chlorophyll a and daytime dis-solved oxygen in the bottom layer. Based on the estimated budget of POM at the bay scale, the oyster feeding rate was a couple of orders of magnitude lower than the net primary production and POM inputs at the bay boundaries (e.g., offshore and in rivers). The rela-tively high exposure of the bay and high seawater mixing rate may explain the lack of mac-roscale environmental impacts of oyster cultures at the bay scale. We also found that despite the oligotrophic environment, the oyster growth rate was higher in the bay, compared with previous estimates in other coastal areas. To understand the mechanisms sustaining the production of phytoplankton and oysters, further examinations from the perspective of nu-trient cycling in the bay are required.

Owing to its worldwide use as an anti-fouling agent, tributyltin (TBT) is a common contaminant of marine ecosystems. Its wide distribution, high hydrophobicity and persistence have raised concern about bioaccumulation, potential biomagnifications in food webs, and adverse effects on the environment and human health. The most frequent and acute effect of TBT is found in gastropods, usually living in shallow waters, rarely at depths more than 100 m. This study reports about the first case of imposex in a deep water buccinid whelk Neptunea convexa collected at 1437 m in the Sea of Okhotsk. Among five collected specimens, the two were imposex females at the 1st stage of imposex development, while the rest three were males with normally developed penises. Most probably, TBT entered the whelk’s body by eaten benthic organisms, which feed on detritus with traces of TBT, but other reasons, such as heavy metal pollution, are also discussed.

Owing to its worldwide use as an anti-fouling agent, tributyltin (TBT) is a common contaminant of marine ecosystems. Its wide distribution, high hydrophobicity and persistence have raised concern about bioaccumulation, potential biomagnifications in food webs, and adverse effects on the environment and human health. The most frequent and acute effect of TBT is found in gastropods, usually living in shallow waters, rarely at depths more than 100 m. This study reports about the first case of imposex in a deep water buccinid whelk Neptunea convexa collected at 1437 m in the Sea of Okhotsk. Among five collected specimens, the two were imposex females at the 1st stage of imposex development, while the rest three were males with normally developed penises. Most probably, TBT entered the whelk’s body by eaten benthic organisms, which feed on detritus with traces of TBT, but other reasons, such as heavy metal pollution, are also discussed.

The War in the Pacific National Historical Park (WAPA), a protected area managed by the National Park Service (NPS), was established "to commemorate the bravery and sacrifice of those participating in the campaigns of the Pacific Theater of World War II and to conserve and interpret outstanding natural, scenic, and historic values on the island of Guam." Coral reef systems present in the park represent a vital element of Guam?s cultural, traditional, and economical heritage, and as such, are precious and in need of conservation. To facilitate the management of these resources, NPS determined that a scleractinian (stony coral) species survey was necessary to establish a baseline for existing coral communities and other important factors for conservation. EnviroScience, Inc. performed a survey of stony coral species, coral habitat, and current evidence of stressors at WAPA?s H?gat and Asan Units in 2022. This report summarizes these findings from a management perspective and compares its findings to previous survey data from 1977 and 1999 (Eldridge et al. 1977; Amesbury et al. 1999). WAPA is located on the tropical island of Guam, located on the west-central coast of the island, and encompasses 2,037 acres. Underwater resources are a significant component of the park, as 1,002 acres consists of water acres. The park is comprised of seven units, of which two of these, the H?gat and Asan Beach Units, include all the oceanic water acres for the park. The H?gat Beach Unit (local spelling, formerly known as ?Agat?) is located at the south-west portion of the park and consists of 38 land acres and 557 water acres (NPS 2003). The Asan Beach Unit consists of 109 acres of land and 445 water acres (NPS 2003). A current baseline for existing coral communities and other important factors for conservation necessitates the need for up-to-date data on the location, presence, relative abundance, and present health of corals. Park managers need this updated data to determine where and how to best focus conservation priorities and identify restoration opportunities. Management actions in park reef areas informed by this inventory included identifying locations where there were: high rates of sedimentation; high coral biomass; rare or threatened species, with a priority given to species endemic to Guam and listed as ?threatened? under the U.S. Endangered Species Act (ESA; Acropora globiceps, A. retusa, A. speciosa, and Seriatopora aculeata); coral persistence and decline, disease and/or nuisance species, including the crown-of-thorns starfish (Acanthaster cf. solaris, ?COTS?) and the sponge Terpios hoshinota; and bleached areas. All work carried out was in accordance with the NPS statement of work (SOW) requirements, which involved a quantitative inventory using both new and pre-existing transects. The resulting transects totaled 61 (including the four from the 1999 study), each measuring 50 meters in length and distributed across depths of up to 50 feet. Divers took photo-quadrat samples covering an area of approximately 9 m?, encompassing 50 photo-quadrats of dimensions 0.50 m x 0.36 m (n=50). The collective area surveyed across all 61 transects amounted to ~549 m?. Additionally, a qualitative search was conducted to enhance documentation of coral species that have limited distribution and might not be captured by transects, along with identifying harmful species and stressors. Timed roving diver coral diversity surveys were carried out at a total of 20 sites occurring within the waters of WAPA, including eight sites at the H?gat unit and 12 sites at the Asan unit. The findings from this report reveal significant disparities in benthic cover compositions between H?gat and Asan units. The H?gat unit exhibits high abundances of turf algae and unconsolidated sediment while the Asan beach unit presents a different scenario, with hard coral as the dominant benthic cover, followed closely by crustose coralline algae (CCA). The Asan unit is also more difficult to access from shore or boat relative to H?gat which provides that unit some protection from human influences. The Asan beach unit's prevalence of hard coral, CCA, and colonizable substrate suggests a more favorable environment for reef growth and the potential benefits of maintaining robust coral cover in the area. These distinct differences in benthic communities highlight the contrasting ecological dynamics and habitats of the two study areas. Across both H?gat and Asan beach unit transects, a total of 56 hard coral species were recorded from 27 genera, with 44 species recorded from the H?gat unit and 48 species recorded from the Asan unit. Of the four historical transects surveyed in the Asan unit from 1999, three experienced declines in percent coral cover (17.38-78.72%), while the fourth had an increase (10.98%). During the timed roving diver coral diversity surveys, a total of 245 hard coral species, including 241 scleractinian coral species representing 49 genera and 4 non-scleractinian coral species representing 4 genera were recorded. Uncertainties related to coral identification, unresolved boundaries between morphospecies, differences in taxonomists' perspectives, and the rapidly evolving state of coral taxonomy have significant implications for species determinations during coral diversity surveys. While the recent surveys have provided valuable insights into coral diversity in WAPA waters, ongoing taxonomic research and collaboration among experts will be essential to obtain a more comprehensive and accurate understanding of coral biodiversity in the region. Of the several ESA coral species that were searched for among the H?gat and Asan beach units, Acropora retusa was the only coral species found among quantitative transects (n=2) and A. globiceps was observed during coral diversity surveys. Acropora speciosa, which was dominant in the upper seaward slopes in 1977, is now conspicuously absent from all the surveys conducted in 2022 (Eldredge et al., 1977). The disappearance and reduction of these once-dominant species underscores the urgency of implementing conservation measures to safeguard the delicate balance of Guam's coral reefs and preserve the diversity and ecological integrity of these invaluable marine ecosystems. Other formerly common or locally abundant species were infrequently encountered during the diversity surveys, including Acropora monticulosa, A. sp. ?obtusicaulis?, A. palmerae, Stylophora sp. ?mordax?, Montipora sp. ?pagoensis?, and Millepora dichotoma. Significant bleaching-associated mortality was recorded for these species, most of which are restricted to reef front/margin zones exposed to moderate-to-high levels of wave energy. Sedimentation was present in both H?gat and the Asan units, though it was more commonly encountered in H?gat transects. While significant portions of the reef area within the WAPA H?gat unit are in poor condition due to a variety of stressors, some areas still hosted notable coral communities, which should be a potential focus for park management to prevent further degradation. There is a need for more effective management of point source pollution concerns, particularly when subpar wastewater treatment or runoff from areas with potential pollution or sediment-laden water is flowing from nearby terrestrial environments. Future monitoring efforts should aim to establish a framework that facilitates a deeper understanding of potential point source pollution incidents. This would empower park managers to collaborate with adjacent communities, both within and outside of park boundaries, to mitigate the localized impacts of pollution (McCutcheon and McKenna, 2021). COTS were encountered during transect surveys as well as in coral diversity surveys. including along the upper reef front/reef margin at site Agat-CS-2. The frequency of these observations, particularly in the WAPA H?gat unit and where stress-susceptible corals are already uncommonly encountered, raise concern about the ability of the populations of these coral species to recover following acute disturbance events, and calls in to question the ability of some of these species to persist in WAPA waters, and in Guam?s waters more broadly. More frequent crown-of-thorns control efforts, even if only a handful of sea stars are removed during a single effort, may be required to prevent further loss to vulnerable species. There were several documented incidents of Terpios hoshinota covering large sections of branching coral in the reef flat along transects, but it is still unclear how detrimental this sponge is to the overall reef system. There is a concern that elevated levels of organic matter and nutrients in the water, such as those resulting from sewage discharge or stormwater runoff, could lead to increased Terpios populations (De Voogd et al. 2013). Consequently, it is important to track populations in known areas of sedimentation and poor water quality. The presence of unique species at single survey sites within the study areas underscores the ecological importance of certain locations. Some species are known to occur in other locations in Guam, while a few may be limited to specific sites within WAPA waters. These differences are likely influenced by environmental and biological factors such as poor water quality, severe heat stress events, chronic predation by crown-of-thorns sea stars, disease, and reduced herbivore populations. These factors collectively shape the condition of the benthic community, leading to variations in species distribution and abundance across the study sites. Documenting coral stress and identifying potentially harmful species allows for proactive management strategies to prevent the establishment of nuisance or detrimental species while populations are still manageable. Updated data on the location, presence, relative abundance, and health of corals is essential for park managers to prioritize conservation efforts and identify restoration opportunities effectively. Observations from this report raise concerns about the health and resilience of coral ecosystems in the H?gat unit and emphasize the need for knowledge of local factors that shape benthic community structure. Understanding the drivers responsible for these variations is crucial for effective conservation and management strategies to preserve the ecological balance and overall health of coral reefs in both units. Continued monitoring efforts will be critical in assessing long-term trends and changes in benthic cover and enabling adaptive management approaches to safeguard these valuable marine ecosystems in the face of ongoing environmental challenges.