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1
Pućko, Monika, Gary A. Stern, Robie W. Macdonald, Liisa M. Jantunen, Terry F. Bidleman, Fiona Wong, David G. Barber, and Søren Rysgaard. "The delivery of organic contaminants to the Arctic food web: Why sea ice matters." Science of The Total Environment 506-507 (February 2015): 444–52. http://dx.doi.org/10.1016/j.scitotenv.2014.11.040.
Повний текст джерела
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Chang, N. N., J. C. Shiao, G. C. Gong, S. J. Kao, and C. H. Hsieh. "Contributions of riverborne inorganic and organic matters to the benthic food web in the East China Sea as inferred from stable isotope ratios." Biogeosciences Discussions 10, no. 1 (January 24, 2013): 1051–81. http://dx.doi.org/10.5194/bgd-10-1051-2013.
Повний текст джерелаАнотація:
Abstract. Coastal areas adjoining rivers are nourished by both the riverborne nutrients and organic matters. Annually, the East China Sea (ECS) receives large quantities of particulate organic carbon transported from the Changjiang (Yangtze River), as well as nutrients, which have brought about high primary production in the ECS. This study evaluated the respective contributions of terrigenous organic matters (allochthonous food source) and nutrient-induced marine production (autochthonous food source) to the ECS benthic ecosystem by analyzing the stable isotope compositions for zooplankton, benthic crustacea and demersal fish. Zooplankton exhibited consistently higher δ13C values (−21.31‰ ~ −19.22‰) in the inner shelf than in the outer shelf. The δ13C signals of fish (−19.64‰ ~ −13.46‰) and crustacea (−18.87‰ ~ −15.00‰) showed strong reliance on the marine production across the ECS continental shelf, regardless of distance from the shore. Moreover, the benthic crustacea and fish exhibited significantly higher δ13C values in the highly productive inshore sites and the δ13C values decreased seawards, implying a higher intrusion of atmospheric CO2 and lower photosynthetic fractionation due to algal blooming in the inner shelf. The δ13C values of fish also showed significant positive correlations with the concentration of surface chlorophyll a and nitrogen. Riverborne nutrients closely linked marine benthic consumers to the terrestrial watershed and tightly coupled the pelagic and benthic ecosystems in the ECS. The stable isotope compositions of benthic consumers can act as an indicator for pelagic trophic status. The future research combining analyses of stable isotope and community structure may improve assessment on the balance between contribution and risk of phytoplankton blooms.
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Printsmann, Anu, and Tarmo Pikner. "The Role of Culture in the Self-Organisation of Coastal Fishers Sustaining Coastal Landscapes: A Case Study in Estonia." Sustainability 11, no. 14 (July 20, 2019): 3951. http://dx.doi.org/10.3390/su11143951.
Повний текст джерелаАнотація:
The cultural sustainability of coastal landscapes relies heavily on the community’s self-organisation in fish foodways. The theoretical framework concentrates on cultural sustainability, foodways, land–sea interactions, and community of practice. The data presented in this article were part of the SustainBaltic Integrated Coastal Zone Management plan, consisting mainly of semi-structured and focus group interviews with stakeholders, supported by background information from various available sources. The results are outlined by descriptions of self-organisation, community matters, and food forming cultural sustainability of coastal landscapes. The self-organisation in community of practice among coastal fishers is slowly progressing by negotiating common resources and voicing concerns about ecological, economic, and social sustainability. Foodways, which comprise the indispensable ingredient for sustaining a way of life that has produced traditional coastal landscapes, are always evolving.
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YOUNG, MARGARET A. "Fragmentation or interaction: the WTO, fisheries subsidies, and international law." World Trade Review 8, no. 4 (September 17, 2009): 477–515. http://dx.doi.org/10.1017/s1474745609990140.
Повний текст джерелаАнотація:
AbstractSubsidies to the fishing sector have trade and ecological consequences, especially for fisheries that are over-exploited. In response, WTO members are negotiating to clarify and improve the Agreement on Subsidies and Countervailing Measures. Yet significant legal challenges constrain this ongoing effort because fisheries conservation and management matters are often addressed by the United Nations Convention on the Law of the Sea, instruments of the Food and Agriculture Organization, and other legal regimes to which some WTO members have not consented. This article analyses modes of learning and information exchange within the WTO regime, and compares the proposed use of standards, benchmarks, and peer review in the draft fisheries subsidies rules with existing arrangements between the WTO and organizations such as the OECD and product standard-setting bodies. It argues that novel deliberative strategies of regime interaction are more important in resolving the challenges posed by international law's fragmentation than adherence to strict mandates or legal hierarchies.
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Dudarev, Alexey, Valery Chupakhin, Sergey Vlasov, and Sveta Yamin-Pasternak. "Traditional Diet and Environmental Contaminants in Coastal Chukotka II: Legacy POPs." International Journal of Environmental Research and Public Health 16, no. 5 (February 27, 2019): 695. http://dx.doi.org/10.3390/ijerph16050695.
Повний текст джерелаАнотація:
The article is the second in the series of four that present the results of a study on environmental contaminants in coastal Chukotka, conducted in the context of a multi-disciplinary investigation of indigenous foodways in the region. The article presents the results of the analysis of legacy Persistent Organic Pollutants (POPs) found in the samples of locally harvested food and indoor matters, collected in 2016 in coastal Chukotka. Temporal trends and circumpolar comparisons of POPs in food have been carried out. Estimated daily intakes (EDIs) of POPs by local food consumption were calculated based on the food intake frequencies (questionnaire data). Concentrations of the studied legacy POPs in marine mammal blubber were relatively high (up to 100–200 µg/kg ww) but not exceeding the allowable limits. Gray whale blubber and whale mantak were the most contaminated foods, followed by the ringed, spotted and bearded seal blubber, then by walrus blubber and fermented walrus (deboned walrus parts aged in subterranean pits, typically over a period of 6 months). At the backdrop of general decrease or invariability (compared to the previous coastal Chukotka study 15 years ago) of the majority of POPs, an increasing tendency of HCB, mainly in marine mammals, were noted. Legacy POPs in marine mammals sampled in Chukotka were generally much lower than in those sampled in Alaska and northern Canada. We suggest that the Alaska Coastal Current from the Bering Sea plays a major role in this phenomenon. Analyses of the additional sources of in-home food contamination (home-brewed alcohol, domestic insecticides) have revealed relatively high levels of HCHs, DDTs and PCBs, which still represent a share of dietary exposure of local people to POPs.
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Bhandari, Bipul, Ram Devi Tachamo Shah, and Subodh Sharma. "STATUS, DISTRIBUTION AND HABITAT SPECIFICITY OF BENTHIC MACRO-INVERTEBRATES: A CASE STUDY IN FIVE TRIBUTARIES OF BUDDHIGANGA RIVER IN WESTERN NEPAL." Journal of Institute of Science and Technology 23, no. 1 (January 1, 2019): 69–75. http://dx.doi.org/10.3126/jist.v23i1.22198.
Повний текст джерелаАнотація:
Benthic macro-invertebrates are organisms that inhabit the bottom of substrates such as sediments, debris, logs, macrophytes and filamentous algae of streams, rivers and lakes for some span of their lifecycle. They are important part of food chain since they are source of food for different species of fishes and process organic matters. These organisms are considered vital tools to assess any environmental change caused by anthropogenic interference in the river ecosystems. In this study, we sampled macro-invertebrates from 5 different rivers across altitudinal ranges of 600- 800 m and 1500-1700 m above sea level. We observed that the macro-invertebrate diversity varied substantially across altitudinal ranges. The diversity of macro-invertebrates was higher in lower altitudinal range, where 11 families were found, more than the higher altitudinal range. Some rare and dominant families were also identified in our study. We also examined the substrate specificity of macro-invertebrates. Results revealed that Ephemeroptera,Tricoptera, Coleoptera, Diptera and Odonata were found in all seven substrates namely bedrock, boulder, cobble, stone, pebble, gravel and sand. The richness and abundance of macro-invertebrates were documented in cobble, stone and pebble substrates. Similarly we also investigated the ecological river quality class of rivers using Ganga River System Biotic Score-Average Score per Taxon (GRS-BioS/ASPT) system which indicated good status. The outcomes of this study serve as a baseline data since no prior research has been done in these rivers.
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PAVLOVA, I. Y. "THEORETICAL AND ANALYTICAL REVIEW OF THE DEFINITION OF "FOOD SECURITY" AND THE ROLE OF THE PORTS OF GREATER ODESSA IN OVERCOMING THE GLOBAL CRISIS." Economic innovations 24, no. 4(85) (December 20, 2022): 142–49. http://dx.doi.org/10.31520/ei.2022.24.4(85).142-149.
Повний текст джерелаАнотація:
Topicality. With the beginning of the full-scale invasion of the russian federation on the territory of Ukraine, economic activity suffered serious damage, including damage to agriculture. Which in turn leads to a problem in the sphere of ensuring state and international food security.Aim and tasks. The purpose of the article is the theoretical substantiation of the definition of "food security" and the analysis of the activities of the ports of Great Odesa in relation to the regulation of the crisis situation in matters of international food security.Materials and methods. Empirical, theoretical, analytical and synthesis models of scientific research were used in this article. The graphic method of scientific research and the grouping method were also used in the work.Research results. The article analyzes the scientific literature and legal acts of the theoretical apparatus of the term "food security". This term was generalized to a single concept based on current events taking place in Ukraine. An analysis of the operation of the ports of Greater Odessa (Odesa, Chornomorsk, Pivdenny) was also carried out, based on data for 2021 and current indicators obtained from the modern database "Black Sea Grain Initiative Vessel Movements". During the analysis, it was determined that agricultural products such as corn (1.821 million tons and 1.757 million tons, respectively) are mostly exported from the ports of Chornomorsk and Pivdenny. Wheat, in turn, is in second place in the ranking of the most popular exported agricultural crops, but it is the first in the port of "Odesa" - 1.261 million tons. A rating of exporting countries was also compiled: Turkey took first place, followed by Italy, Spain, the Netherlands, Egypt, and others.Conclusion. The conducted analysis of the current state of food security, especially the influence of the seaports of Greater Odessa on solving the crisis situation, indicates that, of course, there is a decrease in the export of grain crops to the countries of Asia, Europe and Africa, but the experience gained during the implementation of the "Grain Agreement" can be used in order to improve the transport management of food security of Ukraine.
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Auger, P. A., F. Diaz, C. Ulses, C. Estournel, J. Neveux, F. Joux, M. Pujo-Pay, and J. J. Naudin. "Functioning of the planktonic ecosystem of the Rhone River plume (NW Mediterranean) during spring and its impact on the carbon export: a field data and 3-D modelling combined approach." Biogeosciences Discussions 7, no. 6 (December 14, 2010): 9039–116. http://dx.doi.org/10.5194/bgd-7-9039-2010.
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Abstract. Low-salinity water (LSW, Salinity < 37.5) lenses detached from the Rhone River plume under specific wind conditions tend to favour the biological productivity and potentially a transfer of energy to higher trophic levels on the Gulf of Lions (GoL). A field cruise conducted in May 2006 (BIOPRHOFI) followed some LSW lenses by using a lagrangian strategy. A thorough analysis of the available data set enabled to further improve our understanding of the LSW lenses' functioning and their potential influence on marine ecosystems. Through an innovative 3-D coupled hydrodynamic-biogeochemical modelling approach, a specific calibration dedicated to river plume ecosystems was then proposed and validated on field data. Exploring the role of ecosystems on the particulate organic carbon (POC) export and deposition on the shelf, a sensitivity analysis to the particulate organic matter inputs from the Rhone River was carried out from 1 April to 15 July 2006. Over such a typical end-of-spring period marked by moderate floods, the main deposition area of POC was identified alongshore between 0 and 50 m depth on the GoL, extending the Rhone prodelta to the west towards the exit of the shelf. Moreover, the main deposition area of terrestrial POC was found on the prodelta region, which confirms recent results from sediment data. The averaged daily deposition of particulate organic carbon over the whole GoL is estimated by the model between 40 and 80 mgC/m2, which is in the range of previous secular estimations. The role of ecosystems on the POC export toward sediments or offshore areas was actually highlighted and feedbacks between ecosystems and particulate organic matters are proposed to explain paradoxical model results to the sensitivity test. In fact, the conversion of organic matter in living organisms would increase the retention of organic matter in the food web and this matter transfer along the food web could explain the minor quantity of POC of marine origin observed in the shelf sediments. Thus, the effective carbon deposition on the shelf might be strongly dependent on the zooplankton presence in the GoL. Owing to their fertilizing ability in phosphorus, the LSW lenses could then have indirectly a negative impact on the carbon deposition on the shelf by favouring the development of large phytoplankton fuelling in turn zooplankton communities. The effective carbon deposition would then be delayed out of the GoL, unless a novel transfer of matter occurs toward higher trophic levels further in the open sea through small pelagic fishes.
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Stiller-Reeve, Mathew, Erling Rosnes, Mari Eiliertsen, Sofia Ramalho, Victor Poddevin, and Giuliana Panieri. "Life from bad smells." Septentrio Educational, no. 1 (April 28, 2023): 27–33. http://dx.doi.org/10.7557/8.7049.
Повний текст джерелаАнотація:
Focus:
To understand that hydrogen sulphide indicates that there is life at the bottom of the deep-sea.
Learning objectives:
With this activity, we create a nasty smell similar to hydrogen sulphide from rotting organic matter. We use that smell as a foundation for a discussion/lesson on interesting life, animals and food webs from the deep sea floor.
Key words:
Deep-sea, hydrogen sulphide, chemosynthesis, nematodes, tube worms, food webs.
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Soltwedel, T., O. Pfannkuche, and H. Thiel. "The Size Structure of Deep-Sea Meiobenthos in the North-Eastern Atlantic: Nematode Size Spectra in Relation to Environmental Variables." Journal of the Marine Biological Association of the United Kingdom 76, no. 2 (May 1996): 327–44. http://dx.doi.org/10.1017/s0025315400030587.
Повний текст джерелаАнотація:
The size distribution of benthic nematodes was investigated along different gradients of food availability in various regions of the north-eastern Atlantic: I, across the continental margin and II, with increasing distance from the continental rise. An overall trend for miniaturization with increasing distance from the food source was found. Moreover, our results indicate that seasonally varying food supply or a periodically pulsed input of organic matter to the sea floor affects nematode size spectra. The hypothesis is proposed that the life cycle of deep-sea nematode species and hence the size structure of their populations are related to seasonal energy availability. This dependence might result in one year life spans of deep-sea nematodes and probably other meiofauna.
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Xu, Qinzeng, Qiang Xu, Xuelei Zhang, Quancai Peng, and Hongsheng Yang. "Fatty acid component in sea cucumber Apostichopus japonicus from different tissues and habitats." Journal of the Marine Biological Association of the United Kingdom 96, no. 1 (October 23, 2015): 197–204. http://dx.doi.org/10.1017/s002531541500168x.
Повний текст джерелаАнотація:
Fatty acids (FA) are a non-protein energy source and can act as trophic biomarkers in benthic food webs. We analysed the FA profiles of sea cucumber Apostichopus japonicus, comparing tissues of body wall, gut sediment and ovaries in two habitats. Rongcheng Bay: kelp raft cultivation area with high organic matter in sediment; Laoshan Bay: strong current with low sediment organic matter. The results showed that body wall and ovary tissues were rich in long chain polyunsaturated FA (LC-PUFA), which contributed ~31% to the FA dissimilarity between the two tissues. SIMPER (similarity percentages routine) results showed that C20:5ω3 (EPA), C18:1ω7, C20:4ω6 (AA), C16:0, C14:1 and C20:1ω11 contributed to dissimilarity between the body wall and ovary tissues, while 16:1ω7, 20:5ω3, C16:0, C18:1ω7, C18:0 and C14:1 contributed more to the dissimilarity of body wall tissues between the two habitats. FA biomarkers showed that sea cucumbers from the two habitats had different food sources, with brown kelp and vascular plants being the main food for sea cucumbers in Rongcheng and diatoms for those in Laoshan. To better understand differences in FA composition in sea cucumbers, more research is needed examining a wider diversity of tissue types and habitats.
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Kim, Bo, Jinyoung Jung, Youngju Lee, Kyoung-Ho Cho, Jong-Ku Gal, Sung-Ho Kang, and Sun-Yong Ha. "Characteristics of the Biochemical Composition and Bioavailability of Phytoplankton-Derived Particulate Organic Matter in the Chukchi Sea, Arctic." Water 12, no. 9 (August 21, 2020): 2355. http://dx.doi.org/10.3390/w12092355.
Повний текст джерелаАнотація:
Analysis of the biochemical composition (carbohydrates, CHO; proteins, PRT; lipids, LIP) of particulate organic matter (POM, mainly phytoplankton) is used to assess trophic states, and the quantity of food material is generally assessed to determine bioavailability; however, bioavailability is reduced or changed by enzymatic hydrolysis. Here, we investigated the current trophic state and bioavailability of phytoplankton in the Chukchi Sea (including the Chukchi Borderland) during the summer of 2017. Based on a cluster analysis, our 12 stations were divided into three groups: the southern, middle, and northern parts of the Chukchi Sea. A principal component analysis (PCA) revealed that relatively nutrient-rich and high-temperature waters in the southern part of the Chukchi Sea enhanced the microphytoplankton biomass, while picophytoplankton were linked to a high contribution of meltwater derived from sea ice melting in the northern part of the sea. The total PRT accounted for 41.8% (±7.5%) of the POM in the southern part of the sea, and this contribution was higher than those in the middle (26.5 ± 7.5%) and northern (26.5 ± 10.6%) parts, whereas the CHO accounted for more than half of the total POM in the northern parts. As determined by enzymatic hydrolysis, LIP were more rapidly mineralized in the southern part of the Chukchi Sea, whereas CHO were largely used as source of energy for higher trophic levels in the northern part of the Chukchi Sea. Specifically, the bioavailable fraction of POM in the northern part of the Chukchi Sea was higher than it was in the other parts. The findings indicate that increasing meltwater and a low nutrient supply lead to smaller cell sizes of phytoplankton and their taxa (flagellate and green algae) with more CHO and a negative effect on the total concentration of POM. However, in terms of bioavailability (food utilization), which determines the rate at which digested food is used by consumers, potentially available food could have positive effects on ecosystem functioning.
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Cəlal qızı Muxtarova, Şəkər, and Aytən Rasim qızı Xanbutayeva. "Macrophytes and their ecology in the Caspian ecosystem." NATURE AND SCIENCE 13, no. 08 (October 23, 2021): 14–17. http://dx.doi.org/10.36719/2707-1146/13/14-17.
Повний текст джерелаАнотація:
Algae is a phototrophic organism and is the primary and main food source of organic matter. They can originate organic matter from inorganic substances such as, dry plants. In the process of photosynthesis, they release O2 and absorb CO2 and make it possible for the entire marine animal population. Macrophytobenthos plays a crutial role in the coastal ecosystem of the Caspian Sea. Macrophytes and seaweed provide a sustainable flow of organic matter to heterotrophic organisms and create a plant biotope for invertebrates and phytophilic fish. The dynamics of aquatic vegetation mainly determines changes in benthic communities, their distribution and resources. The level of the Caspian Sea and its salinity determine the distribution of aquatic plants, phytobenthos and of course fluctuations and changes in the level of the Caspian Sea play an important role in the dynamics of aquatic vegetation. Key words: Caspian Sea, macrophytes, flora, ecosystem, macrophytobentos
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PETIHAKIS, G., K. TSIARAS, G. TRIANTAFYLLOU, S. KALARONI, and A. POLLANI. "Sensitivity of the N. AEGEAN SEA ecosystem to Black Sea Water inputs." Mediterranean Marine Science 15, no. 4 (December 23, 2014): 790. http://dx.doi.org/10.12681/mms.955.
Повний текст джерелаАнотація:
The effect of Black Sea Water (BSW) inputs on the North Aegean Sea productivity and food web dynamics was investigated, by means of sensitivity simulations, investigating the effect of the inflowing BSW, in terms of inorganic nutrients and dissolved organic matter. The model used has been successfully applied in the area in the past and extensively presented. Considering the importance of the microbial loop in the ecosystem functioning, the role of the dissolved organics and in order to achieve a more realistic representation of the Dissolved Organic Matter pool, the bacteria sub-model was appropriately revised. The importance of the microbial loop is highlighted by the carbon fluxes where almost 50% of carbon is channelled within it. The impact of dissolved organic matter (DOM) (in the inflowing to the Aegean Sea, BSW) appears to be stronger than the impact of dissolved inorganic nutrients, showing a more extended effect over the N Aegean. Bacterial production and biomass is more strongly affected in the simulations by modified DOM, unlike phytoplankton biomass and production, which are more dependent on the inflowing nutrients and particularly phosphorus (inorganic and dissolved organic). In the phytoplankton composition, the dinoflagellates appear to be mostly affected, being favoured by higher nutrient availability at the expense of all other groups, particularly picoplankton, indicating a shift to a more classical food chain.
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Lovestrand, Erik. "Oysters for the Future: Proper Oyster Culling Techniques Matter." EDIS 2017, no. 2 (May 9, 2017): 2. http://dx.doi.org/10.32473/edis-sg143-2017.
Повний текст джерелаАнотація:
The eastern oyster (Crassostrea virginica) provides many important functions in coastal environments, from serving a crucial role in the estuary’s food web to improving water quality for beachgoers and wildlife. Oysters are also a popular food choice for people. At times the commercial industry landings value has topped $8 million annually in Florida. This 2-page facts sheet is one in a series that highlights some of the key ecological and human factors important to the long-term sustainability of this valuable fishery. Written by Erik Lovestrand and published by the Florida Sea Grant College Program, April 2017.
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DENIS, JEREMY, RYM BOUAZIZ, BRAHIM DRAREDJA, JEAN MARIE MUNARON, ABDELLAH BORHANE DJEBAR, RACHID AMARA, FRANÇOIS LE LOC’H, and 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 (May 12, 2023): 211–28. http://dx.doi.org/10.12681/mms.30180.
Повний текст джерелаАнотація:
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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Svetashev, Vasily I. "Investigation of Deep-Sea Ecosystems Using Marker Fatty Acids: Sources of Essential Polyunsaturated Fatty Acids in Abyssal Megafauna." Marine Drugs 20, no. 1 (December 23, 2021): 17. http://dx.doi.org/10.3390/md20010017.
Повний текст джерелаАнотація:
Abyssal seafloor ecosystems cover more than 50% of the Earth’s surface. Being formed by mainly heterotrophic organisms, they depend on the flux of particulate organic matter (POM) photosynthetically produced in the surface layer of the ocean. As dead phytoplankton sinks from the euphotic to the abyssal zone, the trophic value of POM and the concentration of essential polyunsaturated fatty acids (PUFA) decrease. This results in pronounced food periodicity and limitations for bottom dwellers. Deep-sea invertebrate seston eaters and surface deposit feeders consume the sinking POM. Other invertebrates utilize different food items that have undergone a trophic upgrade, with PUFA synthesized from saturated and monounsaturated FA. Foraminifera and nematodes can synthesize arachidonic acid (AA), eicosapentaenoic acid (EPA), while some barophylic bacteria produce EPA and/or docosahexaenoic acid. FA analysis of deep-sea invertebrates has shown high levels of PUFA including, in particular, arachidonic acid, bacterial FA, and a vast number of new and uncommon fatty acids such as 21:4(n-7), 22:4(n-8), 23:4(n-9), and 22:5(n-5) characteristic of foraminifera. We suppose that bacteria growing on detritus having a low trophic value provide the first trophic upgrading of organic matter for foraminifera and nematodes. In turn, these metazoans perform the second-stage upgrading for megafauna invertebrates. Deep-sea megafauna, including major members of Echinodermata, Mollusca, and Polychaeta display FA markers characteristic of bacteria, foraminifera, and nematodes and reveal new markers in the food chain.
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Dawson, H. M., K. R. Heal, A. Torstensson, L. T. Carlson, A. E. Ingalls, and J. N. Young. "Large Diversity in Nitrogen- and Sulfur-Containing Compatible Solute Profiles in Polar and Temperate Diatoms." Integrative and Comparative Biology 60, no. 6 (September 22, 2020): 1401–13. http://dx.doi.org/10.1093/icb/icaa133.
Повний текст джерелаАнотація:
Synopsis Intense bottom-ice algal blooms, often dominated by diatoms, are an important source of food for grazers, organic matter for export during sea ice melt, and dissolved organic carbon. Sea-ice diatoms have a number of adaptations, including accumulation of compatible solutes, that allows them to inhabit this highly variable environment characterized by extremes in temperature, salinity, and light. In addition to protecting them from extreme conditions, these compounds present a labile, nutrient-rich source of organic matter, and include precursors to climate active compounds (e.g., dimethyl sulfide [DMS]), which are likely regulated with environmental change. Here, intracellular concentrations of 45 metabolites were quantified in three sea-ice diatom species and were compared to two temperate diatom species, with a focus on compatible solutes and free amino acid pools. There was a large diversity of metabolite concentrations between diatoms with no clear pattern identifiable for sea-ice species. Concentrations of some compatible solutes (isethionic acid, homarine) approached 1 M in the sea-ice diatoms, Fragilariopsis cylindrus and Navicula cf. perminuta, but not in the larger sea-ice diatom, Nitzschia lecointei or in the temperate diatom species. The differential use of compatible solutes in sea-ice diatoms suggests different adaptive strategies and highlights which small organic compounds may be important in polar biogeochemical cycles.
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Rolff, C., and R. Elmgren. "Use of riverine organic matter in plankton food webs of the Baltic Sea." Marine Ecology Progress Series 197 (2000): 81–101. http://dx.doi.org/10.3354/meps197081.
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POPA, Elisabeta Elena, Alexandra Andreea ANGHEL, Ioana STANCIU, Amalia Carmen MITELUT, Paul Alexandru POPESCU, Mihaela Cristina DRAGHICI, Mihaela GEICU-CRISTEA, and Mona Elena POPA. "PRELIMINARY RESEARCH ON USING ORGANIC SEA BUCKTHORN POWDER IN BREAD MAKING." AgroLife Scientific Journal 11, no. 2 (December 31, 2022): 136–41. http://dx.doi.org/10.17930/agl2022218.
Повний текст джерелаАнотація:
Bread is a food product that represents an important element in human nutrition, considered a convenient type of food, being consumed daily in large quantities in many parts of the world. Adding functional ingredients in bakery products was highly researched lately, because of their ability in the reduction of some chronic diseases besides improving of basic nutritional functions. The aim of the present paper was to obtain bread with different quantities of organic dried sea buckthorn powder (Sorana variety), as functional ingredient. For sample characterization, some phisico-chemical (dry matter %, aw) and nutritional parameters (antioxidant activity, total phenolic content) were determined, as well as sensorial analysis. The study obtained promising results regarding the use of sea buckthorn powder as ingredient in bread making.
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Lopez-Fernandez, P., S. Bianchelli, A. Pusceddu, A. Calafat, A. Sanchez-Vidal, and R. Danovaro. "Bioavailability of sinking organic matter in the Blanes canyon and the adjacent open slope (NW Mediterranean Sea)." Biogeosciences 10, no. 5 (May 23, 2013): 3405–20. http://dx.doi.org/10.5194/bg-10-3405-2013.
Повний текст джерелаАнотація:
Abstract. Submarine canyons are sites of intense energy and material exchange between the shelf and the deep adjacent basins. To test the hypothesis that active submarine canyons represent preferential conduits of available food for the deep-sea benthos, two mooring lines were deployed at 1200 m depth from November 2008 to November 2009 inside the Blanes canyon and on the adjacent open slope (Catalan Margin, NW Mediterranean Sea). We investigated the fluxes, biochemical composition and food quality of sinking organic carbon (OC). OC fluxes in the canyon and the open slope varied among sampling periods, though not consistently in the two sites. In particular, while in the open slope the highest OC fluxes were observed in August 2009, in the canyon the highest OC fluxes occurred in April–May 2009. For almost the entire study period, the OC fluxes in the canyon were significantly higher than those in the open slope, whereas OC contents of sinking particles collected in the open slope were consistently higher than those in the canyon. This result confirms that submarine canyons are effective conveyors of OC to the deep sea. Particles transferred to the deep sea floor through the canyons are predominantly of inorganic origin, significantly higher than that reaching the open slope at a similar water depth. Using multivariate statistical tests, two major clusters of sampling periods were identified: one in the canyon that grouped trap samples collected in December 2008, concurrently with the occurrence of a major storm at the sea surface, and associated with increased fluxes of nutritionally available particles from the upper shelf. Another cluster grouped samples from both the canyon and the open slope collected in March 2009, concurrently with the occurrence of the seasonal phytoplankton bloom at the sea surface, and associated with increased fluxes of total phytopigments. Our results confirm the key ecological role of submarine canyons for the functioning of deep-sea ecosystems, and highlight the importance of canyons in linking episodic storms and primary production occurring at the sea surface to the deep sea floor.
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Lopez-Fernandez, P., S. Bianchelli, A. Pusceddu, A. Calafat, A. Sanchez-Vidal, and R. Danovaro. "Bioavailability of sinking organic matter in the Blanes canyon and the adjacent open slope (NW Mediterranean Sea)." Biogeosciences Discussions 9, no. 12 (December 17, 2012): 18295–330. http://dx.doi.org/10.5194/bgd-9-18295-2012.
Повний текст джерелаАнотація:
Abstract. Submarine canyons are sites of intense energy and material exchange between the shelf and the deep adjacent basins. To test the hypothesis that active submarine canyons represent preferential conduits of available food for the deep-sea benthos, two mooring lines were deployed at 1200 m depth from November 2008 to November 2009 inside the Blanes canyon and on the adjacent open slope (Catalan Margin, NW Mediterranean Sea). We investigated the fluxes, biochemical composition and food quality of sinking organic carbon (OC). OC fluxes in the canyon and the open slope varied among sampling periods, though not consistently in the two sites. In particular, while in the open slope the highest OC fluxes were observed in August 2009, in the canyon the highest OC fluxes occurred in April–May 2009. For almost the entire study period, the OC fluxes in the canyon were significantly higher than those in the open slope, whereas OC contents of sinking particles collected in the open slope were consistently higher than those in the canyon. This result confirms that submarine canyons are effective conveyors of OC to the deep sea, particles transferred are predominantly of inorganic origin, significantly higher than that reaching the open slope at a similar water depth. Using multivariate statistical tests, two major clusters of sampling periods were identified: one in the canyon that grouped trap samples collected in December 2008, concurrently with the occurrence of a major storm at the sea surface, and associated with increased fluxes of nutritionally available particles from the upper shelf. Another cluster grouped samples from both the canyon and the open slope collected in March 2009, concurrently with the occurrence of the seasonal phytoplankton bloom at the sea surface, and associated with increased fluxes of total phytopigments. Our results confirm the key ecological role of submarine canyons for the functioning of deep-sea ecosystems, and highlight the importance of canyons in linking episodic storms and primary production occurring at the sea surface to the deep sea floor.
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Kortsch, Susanne, Raul Primicerio, Maria Fossheim, Andrey V. Dolgov, and Michaela Aschan. "Climate change alters the structure of arctic marine food webs due to poleward shifts of boreal generalists." Proceedings of the Royal Society B: Biological Sciences 282, no. 1814 (September 7, 2015): 20151546. http://dx.doi.org/10.1098/rspb.2015.1546.
Повний текст джерелаАнотація:
Climate-driven poleward shifts, leading to changes in species composition and relative abundances, have been recently documented in the Arctic. Among the fastest moving species are boreal generalist fish which are expected to affect arctic marine food web structure and ecosystem functioning substantially. Here, we address structural changes at the food web level induced by poleward shifts via topological network analysis of highly resolved boreal and arctic food webs of the Barents Sea. We detected considerable differences in structural properties and link configuration between the boreal and the arctic food webs, the latter being more modular and less connected. We found that a main characteristic of the boreal fish moving poleward into the arctic region of the Barents Sea is high generalism, a property that increases connectance and reduces modularity in the arctic marine food web. Our results reveal that habitats form natural boundaries for food web modules, and that generalists play an important functional role in coupling pelagic and benthic modules. We posit that these habitat couplers have the potential to promote the transfer of energy and matter between habitats, but also the spread of pertubations, thereby changing arctic marine food web structure considerably with implications for ecosystem dynamics and functioning.
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Shin, Donghoon, Tae Hee Park, Chung-Il Lee, Kangseok Hwang, Doo Nam Kim, Seung-Jong Lee, Sukyung Kang, and Hyun Je Park. "Characterization of Trophic Structure of Fish Assemblages in the East and South Seas of Korea Based on C and N Stable Isotope Ratios." Water 14, no. 1 (December 28, 2021): 58. http://dx.doi.org/10.3390/w14010058.
Повний текст джерелаАнотація:
The aim of this study was to assess seasonal variation in the food-web structure of fish assemblages in the East (two sites) and the South (one site) Seas of Korea, and to compare the isotopic niche areas between the regions. To do this, we analyzed the community structures and the δ13C and δ15N values for fish assemblages, and their potential food sources collected during May and October 2020. There were spatial differences in the diversity and dominant species of fish assemblages between the two seas. The fish assemblages in the South Sea had relatively wide ranges of δ13C and δ15N (−22.4‰ to −15.3‰ and 7.4‰ to 13.8‰, respectively) compared to those (−22.1‰ to −18.0‰ and 9.8‰ to 13.6‰, respectively) in the East Sea. The δ13C and δ15N values of suspended particulate organic matter, zooplankton, and fish assemblages differed significantly among sites and between seasons (PERMANOVA, p < 0.05, in all cases). Moreover, isotopic niche indices were relatively higher in the South Sea compared to those in the East Sea. Such differences in food-web characteristics among sites are likely due to the specific environmental effects (especially, major currents) on the differences in the species compositions and, therefore, their trophic relationships. Overall, these results allow for a deeper understanding of the changing trophic diversity and community structure of fish assemblages resulting from climate variability.
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Palomar, N. E., M. A. Juinio-Meñez, and I. Karplus. "Feeding habits of the burrowing shrimp Alpheus macellarius." Journal of the Marine Biological Association of the United Kingdom 84, no. 6 (November 23, 2004): 1199–202. http://dx.doi.org/10.1017/s0025315404010641h.
Повний текст джерелаАнотація:
The diet and feeding behaviour of the burrowing shrimp Alpheusmacellarius (Decapoda: Alpheidae) in sea grass beds in the Philippines were evaluated in the present study through field and laboratory activities. Sediment organic matter and sea grass appear to be important food sources for the shrimp based on the combined results of field surveys, gut content, stable isotope (δ13C) and sediment C content analyses. There was a significant positive correlation between organic matter content in the sediment and shrimp densities. In terms of behaviour, observations under controlled set-ups detected marked trends in duration and frequency of feeding. Feeding bouts became longer and more recurrent as the days progressed. Periodicity was exhibited with burrowing generally performed in the morning and feeding in the afternoon. A deposit-feeding mode was predominant in tank conditions as demonstrated by the shrimp's behaviour and burrow features.
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Mathieu-Resuge, Margaux, Fabienne Le Grand, Gauthier Schaal, Edouard Kraffe, Anne Lorrain, Yves Letourneur, Hugues Lemonnier, Julie Benoît, and Sébastien Hochard. "Assimilation of shrimp farm sediment by Holothuria scabra: a coupled fatty acid and stable isotope approach." Aquatic Living Resources 33 (2020): 3. http://dx.doi.org/10.1051/alr/2020004.
Повний текст джерелаАнотація:
Deposit-feeding sea cucumbers are efficient nutrient recyclers and have the potential to contribute to the limitation of organic matter load in polyculture or integrated aquaculture systems. Assessing how they assimilate organic matter originating from other farmed species is therefore important for the development of such multi-species farming systems. Here, a coupled stable isotope − fatty acid approach was used to characterize the assimilation of organic matter from shrimp (Penaeus stylirostris) farming by Holothuria scabra in an experimental culture system. H. scabra were reared in mesocosms on shrimp farming-originating sediment with and without additional food sources (maize and fish meals). Although fatty acid results did indicate that shrimp-farming sediment was assimilated by holothurids, we found no evidence of maize waste and fish meal contribution to H. scabra organic carbon (no effect on δ13C, no accumulation of meal-specific fatty acids). However, a strong effect of fish meal on H. scabra δ15N was observed, suggesting that this additional food source could represent an alternative source of nitrogen for holothurids. Finally, this study supports the culture of H. scabra as a perspective to reduce sedimentary organic matter excess associated with shrimp farms, and suggest that the addition of selected food sources might contribute to increasing the content in some nitrogen organic compounds in holothurid tissues.
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Leu, Eva, Thomas A. Brown, Martin Graeve, Jozef Wiktor, Clara J. M. Hoppe, Melissa Chierici, Agneta Fransson, Sander Verbiest, Ane C. Kvernvik, and Michael J. Greenacre. "Spatial and Temporal Variability of Ice Algal Trophic Markers—With Recommendations about Their Application." Journal of Marine Science and Engineering 8, no. 9 (September 2, 2020): 676. http://dx.doi.org/10.3390/jmse8090676.
Повний текст джерелаАнотація:
Assessing the relative importance of sea ice algal-based production is often vital for studies about climate change impacts on Arctic marine ecosystems. Several types of lipid biomarkers and stable isotope ratios are widely used for tracing sea ic-associated (sympagic) vs. pelagic particulate organic matter (POM) in marine food webs. However, there has been limited understanding about the plasticity of these compounds in space and time, which constrains the robustness of some of those approaches. Furthermore, some of the markers are compromised by not being unambiguously specific for sea ice algae, whereas others might only be produced by a small sub-group of species. We analyzed fatty acids, highly branched isoprenoids (HBIs), stable isotope ratios of particulate organic carbon (POC) (δ13C), as well as δ13C of selected fatty acid markers during an Arctic sea ice algal bloom, focusing on spatial and temporal variability. We found remarkable differences between these approaches and show that inferences about bloom characteristics might even be contradictory between markers. The impact of environmental factors as causes of this considerable variability is highlighted and explained. We emphasize that awareness and, in some cases, caution is required when using lipid and stable isotope markers as tracers in food web studies and offer recommendations for the proper application of these valuable approaches.
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Giannelli, Virginia, David N. Thomas, Christian Haas, Gerhard Kattner, Hilary Kennedy, and Gerhard S. Dieckmann. "Behaviour of dissolved organic matter and inorganic nutrients during experimental sea-ice formation." Annals of Glaciology 33 (2001): 317–21. http://dx.doi.org/10.3189/172756401781818572.
Повний текст джерелаАнотація:
AbstractIt is well established that during sea-ice formation, crystals aggregate into a solid matrix, and dissolved sea-water constituents, including inorganic nutrients, are rejected from the ice matrix. However, the behaviour of dissolved organic matter (DOM) during ice formation and growth has not been studied to date. DOM is the primary energetic substrate for microbial heterotrophic activity in sea water and sea ice, and therefore it is at the base of the trophic fluxes within the microbial food web. The aim of our study was to compare the behaviour of DOM and inorganic nutrients during formation and growth of sea ice. Experiments were conducted in a large indoor ice-tank facility (Hamburg Ship Model Basin, Germany) at −15°C. Three 1 m3 tanks, to which synthetic sea water, nutrients and dissolved organic compounds (diatom-extracted DOM) had been added, were sampled over a period of 5 days during sea-ice formation. Samples were collected throughout the experiment from water underlying the ice, and at the end from the ice as well. Brine was obtained from the ice by centrifuging ice cores. Inorganic nutrients (nitrate and phosphate) were substantially enriched in brine in comparison to water and ice phases, consistent with the processes of ice formation and brine rejection. Dissolved organic carbon (DOC) was also enriched in brine but was more variable and enriched in comparison to a dilution line. No difference in bacteria numbers was observed between water, ice and brine. No bacteria growth was measured, and this therefore had no influence on the measurable DOC levels. We conclude that the incorporation of dissolved organic compounds in newly forming ice is conservative. However, since the proportions of DOC in the brine were partially higher than those of the inorganic nutrients, concentrating effects of DOC in brine might be different compared to salts.
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Duffy, G. A., T. Horton, and D. S. M. Billett. "Deep-sea scavenging amphipod assemblages from the submarine canyons of the Iberian Peninsula." Biogeosciences Discussions 9, no. 6 (June 27, 2012): 7831–51. http://dx.doi.org/10.5194/bgd-9-7831-2012.
Повний текст джерелаАнотація:
Abstract. Submarine canyons have often been identified as hotspots of secondary production with the potential to house distinct faunal assemblages and idiosyncratic ecosystems. Within these deep-sea habitats, assemblages of scavenging fauna play a vital role in reintroducing organic matter from large food falls into the wider deep-sea food chain. Free-fall baited traps were set at different depths within three submarine canyons on the Iberian Margin. Amphipods from the traps were identified to species level and counted. Scavenging amphipod assemblages were compared at different depths within each canyon, between individual canyon systems, and between the abyssal plain and submarine canyon sites. Samples from canyons were found to contain common abyssal plain species but in greater than expected abundances. Community composition differed significantly between the submarine canyons and abyssal plains. It is proposed that this is a result of the high organic carbon input into canyon systems owing to their interception of sediment from the continental shelf and input from associated estuarine systems.
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Udoumoh, Unwana I., Akindele F. Assian Alonge, Ubong E. Ehiomogue, Precious O., Joseph U. Okoko, and Israel I. Ahuchaogu. "A Review of the Impacts of Climate Change on Soil Conditions and Global Food Security." IIARD INTERNATIONAL JOURNAL OF GEOGRAPHY AND ENVIRONMENTAL MANAGEMENT 9, no. 3 (September 2, 2023): 43–58. http://dx.doi.org/10.56201/ijgem.v9.no3.2023.pg43.58.
Повний текст джерелаАнотація:
As people around the world increasingly feel the impacts of climate change, the collective call for action grows louder and louder. The effects of climate change on soil conditions and global food security food - often neglected in favor of tropical storms, and sea level rise - are receiving more and more mainstream attention. Soils are intricately linked to the atmospheric/climate system through the carbon, nitrogen, and hydrologic cycles. Because of this, altered climate will have an effect on soil processes and properties. Recent studies indicate at least some soils may become net sources of atmospheric c, lowering soil organic matter levels. Soil erosion by wind and water is also likely to increase. This brief seeks to summarize the relationship between climate change, soil conditions and food insecurity, highlighting suitable agricultural innovations for climate change adaptation for global food security..
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Zoccarato, L., and S. Fonda Umani. "Major constrains of the pelagic food web efficiency in the Mediterranean Sea." Biogeosciences Discussions 12, no. 6 (March 16, 2015): 4365–403. http://dx.doi.org/10.5194/bgd-12-4365-2015.
Повний текст джерелаАнотація:
Abstract. Grazing pressure plays a key role on plankton communities affecting their biodiversity and shaping their structures. Predation exerted by 2–200 μm protists (i.e. microzooplankton and heterotrophic nanoplankton) influences the carbon fate in marine environments channeling new organic matter from the microbial loop toward the "classic" grazing food web. In this study, we analyzed more than 80 dilution experiments carried out in many Mediterranean sites at the surface and in the meso-bathypelagic layers. Our aims were to investigate prey-predator interactions and determine selectivity among energy sources (in terms of available biomass), efficiency in the exploitation and highlight likely constrains that can modulate carbon transfer processes within the pelagic food webs. Generally, microzooplankton shown higher impacts on prey stocks than heterotrophic nanoflagellates, expressing larger ingestion rates and efficiency. Through different trophic conditions characterized on the base of chlorophyll a concentration, microzooplankton diet has shown to change in prey compositions: nano- and picoplankton almost completely covered consumer needs in oligotrophy and mesotrophy, while microphytoplankton (mostly diatoms) represented more than 80% of the consumers' diet in eutrophy, where, nevertheless, picoplankton mortality remained relatively high. Ingestion rates of both consumers (nano- and microzooplankters) increased with the availability of prey biomasses and consequently with the trophic condition of the environment. Nevertheless, overall the heterotrophic fraction of picoplankton resulted the most exploited biomass by both classes of consumers. Ingestion efficiency (as the ratio between available biomass and ingestion rate) increased at low biomasses and therefore the highest efficiencies were recorded in oligotrophic conditions and in the bathypelagic layers.
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Hoving, H. J. T., S. L. Bush, S. H. D. Haddock, and B. H. Robison. "Bathyal feasting: post-spawning squid as a source of carbon for deep-sea benthic communities." Proceedings of the Royal Society B: Biological Sciences 284, no. 1869 (December 20, 2017): 20172096. http://dx.doi.org/10.1098/rspb.2017.2096.
Повний текст джерелаАнотація:
In many oceanic carbon budgets there is a discrepancy between the energetic requirements of deep-sea benthic communities and the supply of organic matter. This suggests that there are unidentified and unmeasured food sources reaching the seafloor. During 11 deep-sea remotely operated vehicle (ROV) surveys in the Gulf of California, the remains (squid carcasses and hatched-out egg sheets) of 64 post-brooding squid were encountered. As many as 36 remains were encountered during a single dive. To our knowledge this is one of the largest numbers of natural food falls of medium-size deep-sea nekton described to date. Various deep-sea scavengers (Ophiuroidea, Holothuroidea, Decapoda, Asteroidea, Enteropneusta) were associated with the remains. Although many of the 80 examined ROV dives did not encounter dead squids or egg sheets ( n = 69), and the phenomenon may be geographically and temporally restricted, our results show that dead, sinking squid transport carbon from the water column to the seafloor in the Gulf of California. Based on food fall observations from individual dives, we estimate that annual squid carcass depositions may regionally contribute from 0.05 to 12.07 mg C m −2 d −1 to the seafloor in the areas where we observed the remains. The sinking of squid carcasses may constitute a significant but underestimated carbon vector between the water column and the seafloor worldwide, because squid populations are enormous and are regionally expanding as a result of climate change and pressure on fish stocks. In the future, standardized methods and surveys in geographical regions that have large squid populations will be important for investigating the overall contribution of squid falls to regional carbon budgets.
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Kokarev, Valentin, Anna K. Zalota, Andrey Zuev, Alexei Tiunov, Petr Kuznetsov, Olga Konovalova, and Nadezhda Rimskaya-Korsakova. "Opportunistic consumption of marine pelagic, terrestrial, and chemosynthetic organic matter by macrofauna on the Arctic shelf: a stable isotope approach." PeerJ 11 (June 29, 2023): e15595. http://dx.doi.org/10.7717/peerj.15595.
Повний текст джерелаАнотація:
Macrofauna can contribute substantially to the organic matter cycling on the seafloor, yet the role of terrestrial and chemosynthetic organic matter in the diets of microphagous (deposit and suspension) feeders is poorly understood. In the present study, we used stable isotopes of carbon and nitrogen to test the hypothesis that the terrestrial organic matter supplied with river runoff and local chemosynthetic production at methane seeps might be important organic matter sources for macrofaunal consumers on the Laptev Sea shelf. We sampled locations from three habitats with the presumed differences in organic matter supply: “Delta” with terrestrial inputs from the Lena River, “Background” on the northern part of the shelf with pelagic production as the main organic matter source, and “Seep” in the areas with detected methane seepage, where chemosynthetic production might be available. Macrobenthic communities inhabiting each of the habitats were characterized by a distinct isotopic niche, mostly in terms of δ13C values, directly reflecting differences in the origin of organic matter supply, while δ15N values mostly reflected the feeding group (surface deposit/suspension feeders, subsurface deposit feeders, and carnivores). We conclude that both terrestrial and chemosynthetic organic matter sources might be substitutes for pelagic primary production in the benthic food webs on the largely oligotrophic Laptev Sea shelf. Furthermore, species-specific differences in the isotopic niches of species belonging to the same feeding group are discussed, as well as the isotopic niches of the symbiotrophic tubeworm Oligobrachia sp. and the rissoid gastropod Frigidoalvania sp., which are exclusively associated with methane seeps.
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STEWART, F. J., and C. H. FRITSEN. "Bacteria-algae relationships in Antarctic sea ice." Antarctic Science 16, no. 2 (June 2004): 143–56. http://dx.doi.org/10.1017/s0954102004001889.
Повний текст джерелаАнотація:
Energy transfer in microbial food webs is partly quantified by the relationship between bacterial and algal biomass. Tight spatial relationships suggest active bacterial assimilation of dissolved photosynthate in temperate marine and fresh waters. However, studies in the Antarctic suggest that bacterial biomass generation from algal-derived dissolved organic matter is highly variable across seasons and habitats. Regression analysis was used to measure how bacteria covaried with algae in sea ice and water column habitats at three sites around Antarctica. Bacteria and algae were positively related in sea ice of the Weddell Sea during early winter 1992 (r2 = 0.16, slope = 0.24) and across sea ice and upper water column habitats of the Ross Sea during summer 1999 (r2 = 0.52, slope = 0.50). Conversely, bacteria and algae exhibited no discernible relationship in the water column and first year ice habitats of the Western Antarctic Peninsula region in winter 2001 (r2 = 0.003, slope = −0.04). Low algal production and residual biomass probably limited bacterial production and facilitated bacteria-algae uncoupling in winter sea ice of the Western Antarctic Peninsula. Winter sea ice algal biomass was probably limited by a relatively late date of initial ice formation, reduced multi-year ice coverage, and a lack of radiant energy in the winter ice pack.
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Lentzou, G., Ch Templalexis, and G. Xanthopoulos. "Effect of air drying on quality characteristics and mass transfer kinetics of osmotically dehydrated sea buckthorn by stevia." Food Research 4, no. 4 (March 27, 2020): 1140–50. http://dx.doi.org/10.26656/fr.2017.4(4).031.
Повний текст джерелаАнотація:
Sea buckthorn is ranked among the most significant super foods worldwide. Its fruits and leaves are used as fresh or dried in food, pharmaceutical and cosmetic industry. As super food any pre-treatment should sustain this property and hence this research was focused on osmotic dehydration of sea buckthorn by stevia also a super food. Therefore, water loss, sugar gain, acidity, ascorbic acid and water diffusivity were evaluated during osmotic dehydration of sea buckthorn by two stevia solutions, 15ο and 30οBrix and following were air-dried at 50οC by comparing the effect of steam blanching per case. Steam blanched samples exhibited increased water loss at the end of the process, 55% at 30οBrix and 48% at 15οBrix, compared to untreated samples where losses were 43% (30οBrix) and 28% (15οBrix) respectively. Ascorbic acid was significantly reduced, exceeding 50% in steam blanched samples and 23% in untreated samples. Steam blanched samples dehydrated at 15oBrix exhibited 82% dry matter increase and only 39% the untreated samples. Similarly, samples dehydrated at 30oBrix exhibited 84% dry matter increase and 53% when no steam blanching was applied. Solid gain was seven times less compared to water loss which is attributed to high molecular weight of steviol glycoside. The osmotic dehydration and airdrying curves were described effectively by Peleg and Fick models, and Logarithmic and Fick models respectively, having in all cases R2 adj>99% and SEE<0.2. The water diffusivity of steam blanched samples was 3.2-5.57×10-11 m 2 /s for water loss and 1.27- 2.03×10-11 m 2 /s for solid gain at 30oBrix and 2.12-4.27×10-11 m 2 /s and 0.91-1.98×10-11 m 2 /s at 15oBrix. Finally, the water diffusivity of steam blanched samples during air-drying was 2.11-2.29×10-11 m 2 /s and 1.56-1.66×10-11 m 2 /s in the case of untreated samples.
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Rosen, D. AS, and A. W. Trites. "Digestive efficiency and dry-matter digestibility in Steller sea lions fed herring, pollock, squid, and salmon." Canadian Journal of Zoology 78, no. 2 (March 5, 2000): 234–39. http://dx.doi.org/10.1139/z99-201.
Повний текст джерелаАнотація:
Dry-matter digestibility and energy digestive efficiency were measured in six juvenile Steller sea lions (Eumetopias jubatus) fed three diets each consisting of a single species: herring, pollock, and squid. Two of the animals were also fed pink salmon. Dry-matter digestibility (DMD) and digestive efficiency (DE) were measured using the energy and manganese concentration in fecal and food samples. DE values were high for all prey species (herring: 95.4 ± 0.7% (mean ± SD), pollock: 93.9 ± 1.4%, salmon: 93.4 ± 0.5%, squid: 90.4 ± 1.3%). Steller sea lions appear to digest prey of high energy density more efficiently than prey of low energy density. DMD values were also high for all prey species (herring: 90.1 ± 1.8%, pollock: 86.5 ± 3.4%, salmon: 87.3% ± 2.6, squid: 90.5 ± 1.2%). The low DMD value for pollock compared with herring and squid was due to the high proportion of bony material in pollock. There was a strong linear relationship between DE and DMD for each prey type, but the terms cannot be used interchangeably. DE measures are more meaningful than DMD in conveying the energetic benefits derived by sea lions from different types of prey. Species-specific measures of the digestible energy obtained from an array of prey items are a necessary component in understanding the bioenergetic consequences of consuming different prey species.
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Jeffreys, R. M., E. H. Fisher, A. J. Gooday, K. E. Larkin, D. S. M. Billett, and G. A. Wolff. "The trophic and metabolic pathways of foraminifera in the Arabian Sea: evidence from cellular stable isotopes." Biogeosciences 12, no. 6 (March 18, 2015): 1781–97. http://dx.doi.org/10.5194/bg-12-1781-2015.
Повний текст джерелаАнотація:
Abstract. The Arabian Sea is a region of elevated productivity with the highest globally recorded fluxes of particulate organic matter (POM) to the deep ocean, providing an abundant food source for fauna at the seafloor. However, benthic communities are also strongly influenced by an intense oxygen minimum zone (OMZ), which impinges on the continental slope from 100 to 1000 m water depth. We compared the trophic ecology of foraminifera on the Oman and Pakistan margins of the Arabian Sea (140–3185 m water depth). These two margins are contrasting both in terms of the abundance of sedimentary organic matter and the intensity of the OMZ. Organic carbon concentrations of surficial sediments were higher on the Oman margin (3.32 ± 1.4%) compared to the Pakistan margin (2.45 ± 1.1%) and sedimentary organic matter (SOM) quality estimated from the Hydrogen Index was also higher on the Oman margin (300–400 mg HC mg TOC−1) compared to the Pakistan margin (< 250 mg HC mg TOC−1). The δ13C and δ15N values of sediments were similar on both margins (−20 and 8‰, respectively). Stable isotope analysis (SIA) showed that foraminiferal cells had a wide range of δ13C values (−25.5 to −11.5‰), implying that they utilise multiple food sources; indeed δ13C values varied between depths, foraminiferal types and between the two margins. Foraminifera had broad ranges in δ15N values (−7.8 to 27.3‰). The enriched values suggest that some species may store nitrate to utilise in respiration; this was most notable on the Pakistan margin. Depleted foraminiferal δ15N values, particularly at the Oman margin, may reflect feeding on chemosynthetic bacteria. We suggest that differences in productivity regimes may be responsible for the differences observed in foraminiferal isotopic composition. In addition, at the time of sampling, whole jellyfish carcasses (Crambionella orsini) and a carpet of jelly detritus were observed across the Oman margin transect. Associated chemosynthetic bacteria may have provided an organic-rich food source for foraminifera at these sites. Our data suggest that foraminifera in OMZ settings can utilise a variety of food sources and metabolic pathways to meet their energetic demands.
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Bell, LE, BA Bluhm, and K. Iken. "Influence of terrestrial organic matter in marine food webs of the Beaufort Sea shelf and slope." Marine Ecology Progress Series 550 (May 25, 2016): 1–24. http://dx.doi.org/10.3354/meps11725.
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Dell'Anno, A., A. Pusceddu, C. Corinaldesi, M. Canals, S. Heussner, L. Thomsen, and R. Danovaro. "Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia." Biogeosciences 10, no. 5 (May 2, 2013): 2945–57. http://dx.doi.org/10.5194/bg-10-2945-2013.
Повний текст джерелаАнотація:
Abstract. The bioavailability of organic matter in benthic deep-sea ecosystems, commonly used to define their trophic state, can greatly influence key ecological processes such as biomass production and nutrient cycling. Here, we assess the trophic state of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively, by using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Two out of the three sampling periods occurred a few months after dense shelf water cascading events. The benthic deep-sea ecosystems investigated in this study were characterized by high amounts of bioavailable organic matter when compared to other deep-sea sediments. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in primary productivity of surface waters reported for the two regions. Similarly, sediments of the Catalan margin were characterized by significantly higher food quantity and quality in spring, when the phytoplankton bloom occurs in surface waters, than in summer and autumn. Differences in the benthic trophic state of canyons against open slopes were more evident in the Portuguese than in the Catalan margin. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Overall, our findings suggest that the intensity of primary production processes along with the lateral transfer of organic particles, even amplified by episodic events, can have a role in controlling the quantity and distribution of bioavailable organic detritus and its nutritional value along these continental margin ecosystems.
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Pozzato, L., D. Van Oevelen, L. Moodley, K. Soetaert, and J. J. Middelburg. "Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone." Biogeosciences Discussions 10, no. 6 (June 26, 2013): 10399–428. http://dx.doi.org/10.5194/bgd-10-10399-2013.
Повний текст джерелаАнотація:
Abstract. The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ) to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient in these sediments. Moreover, metazoans directly consume labile particulate organic matter resources and thus compete with bacteria for phytodetritus.
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Schmidt, Katrin, Thomas A. Brown, Simon T. Belt, Louise C. Ireland, Kyle W. R. Taylor, Sally E. Thorpe, Peter Ward, and Angus Atkinson. "Do pelagic grazers benefit from sea ice? Insights from the Antarctic sea ice proxy IPSO<sub>25</sub>." Biogeosciences 15, no. 7 (April 4, 2018): 1987–2006. http://dx.doi.org/10.5194/bg-15-1987-2018.
Повний текст джерелаАнотація:
Abstract. Sea ice affects primary production in polar regions in multiple ways. It can dampen water column productivity by reducing light or nutrient supply, provide a habitat for ice algae and condition the marginal ice zone (MIZ) for phytoplankton blooms on its seasonal retreat. The relative importance of three different carbon sources (sea ice derived, sea ice conditioned, non-sea-ice associated) for the polar food web is not well understood, partly due to the lack of methods that enable their unambiguous distinction. Here we analysed two highly branched isoprenoid (HBI) biomarkers to trace sea-ice-derived and sea-ice-conditioned carbon in Antarctic krill (Euphausia superba) and relate their concentrations to the grazers' body reserves, growth and recruitment. During our sampling in January–February 2003, the proxy for sea ice diatoms (a di-unsaturated HBI termed IPSO25, δ13C = −12.5 ± 3.3 ‰) occurred in open waters of the western Scotia Sea, where seasonal ice retreat was slow. In suspended matter from surface waters, IPSO25 was present at a few stations close to the ice edge, but in krill the marker was widespread. Even at stations that had been ice-free for several weeks, IPSO25 was found in krill stomachs, suggesting that they gathered the ice-derived algae from below the upper mixed layer. Peak abundances of the proxy for MIZ diatoms (a tri-unsaturated HBI termed HBI III, δ13C = −42.2 ± 2.4 ‰) occurred in regions of fast sea ice retreat and persistent salinity-driven stratification in the eastern Scotia Sea. Krill sampled in the area defined by the ice edge bloom likewise contained high amounts of HBI III. As indicators for the grazer's performance we used the mass–length ratio, size of digestive gland and growth rate for krill, and recruitment for the biomass-dominant calanoid copepods Calanoides acutus and Calanus propinquus. These indices consistently point to blooms in the MIZ as an important feeding ground for pelagic grazers. Even though ice-conditioned blooms are of much shorter duration than blooms downstream of the permanently sea-ice-free South Georgia, they enabled fast growth and offspring development. Our study shows two rarely considered ways that pelagic grazers may benefit from sea ice: firstly, after their release from sea ice, suspended or sinking ice algae can supplement the grazers' diet if phytoplankton concentrations are low. Secondly, conditioning effects of seasonal sea ice can promote pelagic primary production and therefore food availability in spring and summer.
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Jeffreys, R. M., E. H. Fisher, A. J. Gooday, K. E. Larkin, G. A. Wolff, and D. S. M. Billett. "The trophic and metabolic pathways of foraminifera in the Arabian Sea: evidence from cellular stable isotopes." Biogeosciences Discussions 11, no. 12 (December 20, 2014): 18145–88. http://dx.doi.org/10.5194/bgd-11-18145-2014.
Повний текст джерелаАнотація:
Abstract. The Arabian Sea is a region of elevated productivity with the highest globally recorded fluxes of particulate organic matter (POM) to the deep ocean, providing an abundant food source for fauna at the seafloor. However, benthic communities are also strongly influenced by an intense oxygen minimum zone (OMZ), which impinges on the continental slope at bathyal depths. We compared the trophic ecology of foraminifera on the Oman and Pakistan margins of the Arabian Sea (140–3185 m water depth). Organic carbon concentrations of surficial sediments were higher on the Oman margin (3.32 ± 1.4%) compared to the Pakistan margin (2.45 ± 1.1%) and sedimentary organic matter (SOM) quality estimated from the Hydrogen Index was also higher on the Oman margin (300–400 mg HC (mg TOC)−1) compared to the Pakistan margin (<250 mg HC (mg TOC)−1). δ13C and δ15N values of sediments were similar on both margins (−20 and 8‰, respectively). Stable isotope analysis (SIA) showed that foraminiferal cells had a wide range of δ13C values (−25.5 to −11.5‰), implying that they utilise multiple food sources; indeed δ13C values varied between depths, foraminiferal types and between the two margins. Foraminifera had broad ranges in δ15N values (−7.8 to 27.3‰). The enriched values suggest that some species may store nitrate to utilise in respiration; this was most notable on the Pakistan margin. Depleted foraminiferal δ15N values were identified on both margins, particularly the Oman margin, and may reflect feeding on chemosynthetic bacteria. We suggest that differences in productivity regimes between the two margins may be responsible for the differences observed in foraminiferal isotopic composition. In addition, at the time of sampling, whole jellyfish carcasses (Crambionella orsini) and a carpet of jelly detritus were observed across the Oman margin transect. Associated chemosynthetic bacteria may have provided an organic-rich food source for foraminifera at these sites. Our data suggest that foraminifera in OMZ settings can utilise a variety of food sources and metabolic pathways to meet their energetic demands.
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Gorbatenko, K. M., I. V. Melnikov, and S. I. Kiyashko. "Seasonal dynamics in fish and squid trophic status in the pelagic Sea of Okhotsk, based on d13C and d15N stable isotope data analysis." Trudy VNIRO 181 (2020): 52–68. http://dx.doi.org/10.36038/2307-3497-2020-181-52-68.
Повний текст джерелаАнотація:
Seasonal trophic dynamics was analyzed based on d13C and d15N stable isotope mass content in the Sea of Okhotsk 35 nekton species (fish and squid (Teuthida)). It was shown that considerable differences between species in stable isotope mass contents were associated with diet type. The d15N average values of the Sea of Okhotsk species were 4.5 ‰ in spring, 7.5 ‰ in summer, and 5.4 ‰ in autumn. The summer increase was caused by the appearance of juvenile fish and squid with low trophic status and minimal d15N values, and the autumn decline was due increased trophic status of growing up young individuals. Variability range in d15N values was 11.5 ‰ for all nekton species in summer including migrants into the Sea of Okhotsk from the Pacific Ocean. Relatively narrow variability range in d13C for nekton species, of 2.2–3.3 ‰, reflects seasonal homogeneity in the trophic web basement in the pelagic Sea of Okhotsk. The structure of the food web of the pelagic nekton, presented according to the d15N and d13C data, provides useful information on the pathways of organic matter transfer to the pelagic zone at the upper trophic levels and can be further used to construct trophodynamic models of the Sea of Okhotsk.
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Duffy, G. A., T. Horton, and D. S. M. Billett. "Deep-sea scavenging amphipod assemblages from the submarine canyons of the Western Iberian Peninsula." Biogeosciences 9, no. 11 (November 26, 2012): 4861–69. http://dx.doi.org/10.5194/bg-9-4861-2012.
Повний текст джерелаАнотація:
Abstract. Submarine canyons have often been identified as hotspots of secondary production with the potential to house distinct faunal assemblages and idiosyncratic ecosystems. Within these deep-sea habitats, assemblages of scavenging fauna play a vital role in reintroducing organic matter from large food falls into the wider deep-sea food chain. Free-fall baited traps were set at different depths within three submarine canyons on the Iberian Margin. Amphipods from the traps were identified to species level and counted. Scavenging amphipod assemblages were compared at different depths within each canyon and between individual canyon systems. Using data from literature, abyssal plain assemblages were compared to submarine canyon assemblages. Samples from canyons were found to contain common abyssal plain species but in greater than expected abundances. It is proposed that this is a result of the high organic carbon input into canyon systems owing to their interception of sediment from the continental shelf and input from associated estuarine systems. Community composition differed significantly between the submarine canyons and abyssal plains. The cause of this difference cannot be attributed to one environmental variable due to the numerous inherent differences between canyons and abyssal plains.
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Viitasalo, Markku, and Erik Bonsdorff. "Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning." Earth System Dynamics 13, no. 2 (April 11, 2022): 711–47. http://dx.doi.org/10.5194/esd-13-711-2022.
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Abstract. Climate change has multiple effects on Baltic Sea species, communities and ecosystem functioning through changes in physical and biogeochemical environmental characteristics of the sea. Associated indirect and secondary effects on species interactions, trophic dynamics and ecosystem function are expected to be significant. We review studies investigating species-, population- and ecosystem-level effects of abiotic factors that may change due to global climate change, such as temperature, salinity, oxygen, pH, nutrient levels, and the more indirect biogeochemical and food web processes, primarily based on peer-reviewed literature published since 2010. For phytoplankton, clear symptoms of climate change, such as prolongation of the growing season, are evident and can be explained by the warming, but otherwise climate effects vary from species to species and area to area. Several modelling studies project a decrease of phytoplankton bloom in spring and an increase in cyanobacteria blooms in summer. The associated increase in N:P ratio may contribute to maintaining the “vicious circle of eutrophication”. However, uncertainties remain because some field studies claim that cyanobacteria have not increased and some experimental studies show that responses of cyanobacteria to temperature, salinity and pH vary from species to species. An increase of riverine dissolved organic matter (DOM) may also decrease primary production, but the relative importance of this process in different sea areas is not well known. Bacteria growth is favoured by increasing temperature and DOM, but complex effects in the microbial food web are probable. Warming of seawater in spring also speeds up zooplankton growth and shortens the time lag between phytoplankton and zooplankton peaks, which may lead to decreasing of phytoplankton in spring. In summer, a shift towards smaller-sized zooplankton and a decline of marine copepod species has been projected. In deep benthic communities, continued eutrophication promotes high sedimentation and maintains good food conditions for zoobenthos. If nutrient abatement proceeds, improving oxygen conditions will first increase zoobenthos biomass, but the subsequent decrease of sedimenting matter will disrupt the pelagic–benthic coupling and lead to a decreased zoobenthos biomass. In the shallower photic systems, heatwaves may produce eutrophication-like effects, e.g. overgrowth of bladderwrack by epiphytes, due to a trophic cascade. If salinity also declines, marine species such as bladderwrack, eelgrass and blue mussel may decline. Freshwater vascular plants will be favoured but they cannot replace macroalgae on rocky substrates. Consequently invertebrates and fish benefiting from macroalgal belts may also suffer. Climate-induced changes in the environment also favour establishment of non-indigenous species, potentially affecting food web dynamics in the Baltic Sea. As for fish, salinity decline and continuing of hypoxia is projected to keep cod stocks low, whereas the increasing temperature has been projected to favour sprat and certain coastal fish. Regime shifts and cascading effects have been observed in both pelagic and benthic systems as a result of several climatic and environmental effects acting synergistically. Knowledge gaps include uncertainties in projecting the future salinity level, as well as stratification and potential rate of internal loading, under different climate forcings. This weakens our ability to project how pelagic productivity, fish populations and macroalgal communities may change in the future. The 3D ecosystem models, food web models and 2D species distribution models would benefit from integration, but progress is slowed down by scale problems and inability of models to consider the complex interactions between species. Experimental work should be better integrated into empirical and modelling studies of food web dynamics to get a more comprehensive view of the responses of the pelagic and benthic systems to climate change, from bacteria to fish. In addition, to better understand the effects of climate change on the biodiversity of the Baltic Sea, more emphasis should be placed on studies of shallow photic environments. The fate of the Baltic Sea ecosystem will depend on various intertwined environmental factors and on development of the society. Climate change will probably delay the effects of nutrient abatement and tend to keep the ecosystem in its “novel” state. However, several modelling studies conclude that nutrient reductions will be a stronger driver for ecosystem functioning of the Baltic Sea than climate change. Such studies highlight the importance of studying the Baltic Sea as an interlinked socio-ecological system.
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Yin, J., S. A. Cumberland, R. M. Harrison, J. Allan, D. E. Young, P. I. Williams, and H. Coe. "Receptor modelling of fine particles in Southern England using CMB including comparison with AMS-PMF factors." Atmospheric Chemistry and Physics Discussions 14, no. 17 (September 24, 2014): 24523–72. http://dx.doi.org/10.5194/acpd-14-24523-2014.
Повний текст джерелаАнотація:
Abstract. PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January–February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulphate and sea salt. Good mass closure was achieved with 8% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15% and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4% and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is rather similar for the two methods. However, appreciably different concentrations were calculated for the individual primary organic matter contributions, although for most source categories the CMB and AMS-PMF results were highly correlated (r2 = 0.69–0.91). In comparison with the CMB model, the AMS appears to over-estimate the biomass burning/coal and food cooking sources by a factor of around 1.5 to 2 while estimates of the traffic source are rather similar for each model. The largest divergence is in the primary/secondary organic matter split, with the AMS estimating an appreciably smaller secondary component. Possible reasons for these discrepancies are discussed, but despite these substantial divergences, the strong correlation of the two methods gives some confidence in their application.
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Yin, J., S. A. Cumberland, R. M. Harrison, J. Allan, D. E. Young, P. I. Williams, and H. Coe. "Receptor modelling of fine particles in southern England using CMB including comparison with AMS-PMF factors." Atmospheric Chemistry and Physics 15, no. 4 (February 26, 2015): 2139–58. http://dx.doi.org/10.5194/acp-15-2139-2015.
Повний текст джерелаАнотація:
Abstract. PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January–February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulfate and sea salt. Good mass closure was achieved with 81% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15 and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4 and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is rather similar for the two methods. However, appreciably different concentrations were calculated for the individual primary organic matter contributions, although for most source categories the CMB and AMS-PMF results were highly correlated (r2 = 0.69–0.91). In comparison with the CMB model, the AMS appears to overestimate the biomass burning/coal and food cooking sources by a factor of around 1.5 to 2 while estimates of the traffic source are rather similar for each model. The largest divergence is in the primary/secondary organic matter split, with the AMS estimating an appreciably smaller secondary component. Possible reasons for these discrepancies are discussed, but despite these substantial divergences, the strong correlation of the two methods gives some confidence in their application.
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Pruski, A. M., C. Decker, E. Stetten, G. Vétion, P. Martinez, K. Charlier, C. Senyarich, and K. Olu. "Energy transfer in the Congo deep-sea fan: From terrestrially-derived organic matter to chemosynthetic food webs." Deep Sea Research Part II: Topical Studies in Oceanography 142 (August 2017): 197–218. http://dx.doi.org/10.1016/j.dsr2.2017.05.011.
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Christaki, U., F. Van Wambeke, D. Lefevre, A. Lagaria, L. Prieur, M. Pujo-Pay, J. D. Grattepanche, et al. "Microbial food webs and metabolic state across oligotrophic waters of the Mediterranean Sea during summer." Biogeosciences 8, no. 7 (July 12, 2011): 1839–52. http://dx.doi.org/10.5194/bg-8-1839-2011.
Повний текст джерелаАнотація:
Abstract. The abundance and activity of the major members of the heterotrophic microbial community – from viruses to ciliates – were studied along a longitudinal transect across the Mediterranean Sea in the summer of 2008. The Mediterranean Sea is characterized by a west to-east gradient of deepening of DCM (deep chlorophyll maximum) and increasing oligotrophy reflected in gradients of biomass and production. However, within this well documented longitudinal trend, hydrological mesoscale features exist and likely influence microbial dynamics. Here we present data from a W-E transect of 17 stations during the period of summer stratification. Along the transect the production and fate of organic matter was investigated at three selected sites each one located in the centre of an anticyclonic eddy: in the Algero-Provencal Basin (St. A), the Ionian Basin (St. B), and the Levantine Basin (St. C). The 3 geographically distant eddies showed low values of the different heterotrophic compartments of the microbial food web, and except for viruses in site C, all integrated (0–150 m) stocks were higher in reference stations located in the same basin outside the eddies. During our study the 3 eddies showed equilibrium between GPP (Gross Primary Production) and DCR (Dark Community Respiration). Integrated PPp (Particulate Primary Production) values at A, B and C varied from ~140 to ~190 mg C m−2.
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Ricevuto, Elena, Salvatrice Vizzini, Claudio Lardicci, and Abilio Soares Gomes. "Spatial variability of macrozoobenthic community and trophic structure of a subtropical lagoon on southeastern Brazil's Atlantic coast." Brazilian Journal of Oceanography 61, no. 2 (June 2013): 113–28. http://dx.doi.org/10.1590/s1679-87592013000200004.
Повний текст джерелаАнотація:
The objective of this study was to investigate the macrobenthic community of two compartments of the Maricá-Guarapina lagoon system, along the coast of Rio de Janeiro, Brazil, in relation to its abiotic sediment factors. An additional discrimination between sites was made, wherever the macrophyte Typha domingensis was found. This vegetation supposedly represents a potentially important food source for consumers. Furthermore, the trophic pathways were analyzed functionally by means of stable isotope analysis to assess the role of organic matter sources for consumers in the study area. In conclusion, the results showed differences between abiotic features in the compartments of the lagoon system, which, although they have affected the different species' distribution, have led to a homogeneous low-diversity system. Macrozoobenthic species tend to change with increasing distance from the sea, with a slightly different distribution in the two compartments. The macrophyte T. domingensis did not exercise any great influence on the biotic distribution and was not the main food source for consumers in the lagoon system, where, instead, sedimentary organic matter and macrophyte detritus also seem to play an important role in the trophic web.