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Magda Vincx - One of the best experts on this subject based on the ideXlab platform.
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effects of chronic and heavy pollution on macro and Meiobenthos of havana bay cuba
Revista de Investigaciones Marinas, 2009Co-Authors: Maickel Armenteros, Magda Vincx, Alejandro Perezangulo, Reinaldo Regadera, Jesus Beltran, Wilfrida DecraemerAbstract:Infaunal communities (macro- and Meiobenthos) and abiotic environmental factors were sampled at four stations in Havana Bay, Cuba in June, 2006. A comparison of concentration of pollutants with reference values indicated that the bay is heavily polluted. Several kinds of pollutants: hydrocarbons from petroleum, heavy metals, organic matter, and organochlorine pesticides were recorded from sediment and eutrophication was present in water. There were differences in the nature of contamination between the inlets: the most polluted were Marimelena, fundamentally by metals of industrial origin (Cr, Co, Mn, Ni, V), and Atares mainly by metals of urban origin (Pb and Zn) and organic enrichment. The infaunal communities (macro- and Meiobenthos) were strongly depleted in number of taxa and density; and defaunation occurred in the most polluted inlet of the bay. Only pollutiontolerant species of free-living marine nematodes (Sabatieria pulchra, Terschellingia longicaudata, and Parodontophora xenotricha) were present in very low densities in the sediments. The most plausible explanation of these features was the deleterious effects of pollution on infauna. Hydrodynamic regime apparently modules the effects of pollution on nematode assemblages in entrance channel of the Bay by increasing the available microhabitat and/or enhancing process of colonization.
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Meiobenthos of the central arctic ocean with special emphasis on the nematode community structure
Deep Sea Research Part I: Oceanographic Research Papers, 2000Co-Authors: Ann Vanreusel, Lisa M Clough, Kim Jacobsen, William G Ambrose, Jutamas Jivaluk, Valerie Ryheul, R Herman, Magda VincxAbstract:We investigated the abundance of the Meiobenthos and the biomass and community structure of the nematodes in the central Arctic Ocean along two separate transects during 1991 and 1994. Meiobenthos abundances ranged from (100 to 600 individuals per 10 cm2, in the same order of magnitude as in other oligotrophic areas of the world’s deep ocean. Nematodes were the numerically dominant meiofaunal group at every station. Nematode biomass ranged from ( 1t o 48lg dry weight per 10 cm2. A combination of water depth and latitude explained 55% of the variability among stations in nematode biomass and 67% of the variability of total abundance, implying that both vertical and advective #uxes are important sources of food to the meiofaunal communities.The dominant nematode genus was Monhystera, a detrivorous/bacterivorous deposit feeder, suggesting that bacteria may play an important role in the food web of the Meiobenthos in the Central Arctic. Multivariate analysis of genera abundances revealed di!erences among stations in the Eurasian and Amerasian Basins. During 1994, however, the deep stations in the Eurasian Basin were more similar to the other Amerasian stations, while the single deep station in the Makarov Basin was most similar to the other Eurasian Basin stations. The structure of meiofaunal communities in the central Arctic may provide insight into spatial variability in the Arctic Ocean. ( 2000 Elsevier Science Ltd. All rights reserved.
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The Meiobenthos of Subtidal Sandbanks on the Belgian Continental Shelf (Southern Bight of the North Sea)
Estuarine Coastal and Shelf Science, 2000Co-Authors: Jan Vanaverbeke, T. Gheskiere, Magda VincxAbstract:Abstract The Belgian Continental Shelf (BCS) is characterized by a set of isolated subtidal sandbank systems, which greatly increase the habitat heterogeneity of the area. The Meiobenthos of these sandbanks was investigated during 1997 and 1998. In total, 10 sandbanks have been sampled, belonging to three different geographically isolated systems: the Flemish Banks, the Hinder Banks and the Zeeland Banks. No obvious differences in sedimentological characteristics between the sandbanks were found, but biologically some differences could be detected. The more offshore Hinder Banks had the most diverse Meiobenthos, while the Flemish Banks harboured the lowest number of meiobenthic taxa. Seasonal and regional differences in terms of densities are a result of a coupling with the primary production in the water column, with October showing highest densities and the offshore Hinder Banks harbouring lowest densities. The Meiobenthos on the sandbanks was less dense (450–500 ind. 10 cm −2 ) than that in the deeper channels between the sandbanks (1250–1600 ind. 10 cm −2 ). These differences were attributed to high hydrodynamic stress around the sandbanks, preventing phytoplankton from reaching the sandbanks. Moreover, higher current speed above the sediment increases the risk for the Meiobenthos of being eroded or suspended during storms. Four different communities could be identified. These did not reflect the geographical position on the BCS but seem to be influenced by local differences in sedimentological characteristics within sandbanks and sandbank systems. These sedimentological differences influenced the taxon diversity as well. Sediment preferences for less abundant taxa were investigated in several ways, and results indicated that sediments with a median grain-size were poor in terms of densities and number of taxa, while coarser sediments were richer in taxon diversity. Sediments with a median grain-size between 300–450 μm were rich both in terms of diversity and density, while sediments with a median grain-size of >450 μm still showed high diversity, but lower densities.
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interactions between epibenthos and Meiobenthos in a high intertidal avicennia marina mangrove forest
Mangroves and Salt Marshes, 1997Co-Authors: J Schrijvers, R Schallier, J Silence, J Okondo, Magda VincxAbstract:Many studies in the muddy intertidal zone of temperate regions haveindicated meiofaunal communities to be mainly affected by epibenthicpredation and disturbance rather than competition. Few studies, however,have dealt with mangrove sediments of tropical areas. In addition to aparallel study in a Ceriops tagal (Perr.) Rob. zone, a manipulativeexclusion technique was used to trace the dominant biological interactionsstructuring the Meiobenthos of an East African Avicennia marina (Forsk.)Vierh. mangrove forest.
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spatial patterns of westerschelde Meiobenthos
Estuarine Coastal and Shelf Science, 1994Co-Authors: Karline Soetaert, Magda Vincx, J Wittoeck, M Tulkens, D Van GansbekeAbstract:Abstract The meiobenthic fauna of the Westerschelde, a highly polluted and physically disturbed estuary in the south-west Netherlands, was investigated. Samples were taken in spring from six transects, including the intertidal, subtidal and channel area, and located along the salinity gradient. The samples were subdivided into slices to examine the vertical distribution of Meiobenthos. Meiobenthos densities were higher in the intertidal than in most permanently submersed areas; the subtidal sites below 7 salinity were nearly devoid of meiobenthic life. Nematodes were by far the most abundant meiobenthic organisms in the intertidal, but were less dominant in the other areas. Gastrotrichs, turbellarians, copepods and large ciliates were usually more numerous in the subtidal and channels compared to the intertidal, both in relative and absolute terms. Vertical distribution of the Meiobenthos was rather heterogeneous. Most intertidal stations exhibited a subsurface density peak, whereas in the subtidal and channel area, both subsurface and surface maxima were found. The nematode fauna was examined in more detail and the distributional characteristics of the most important species, with respect to salinity, grain size, water depth and sediment depth were reported. The majority of species had their centre of distribution in the intertidal, although some extended substantially into the subtidal zone. Only a few species had a predominantly subtidal distribution. Most nematode species penetrated relatively deep into the sediment and only some species were real surface dwellers. The nematode diversity per unit of surface reflected more or less the density differences and was higher in the intertidal than in the subtidal sites within a comparable salinity regime. When expressed per common number of individuals, however, there were no differences in diversity in the different areas. Canonical correspondence analysis showed sediment depth to be as important as water depth, salinity or sedimentary characteristics in the determination of community structure. Intertidal communities exhibited a well-developed community gradient with depth into the sediment, whereas the vertical structure of subtidal and channel stations was different from the intertidal zonation and in some cases showed a distorted pattern. This was probably caused by sediment disturbance due to higher current velocities and dredging activities in these regions. It is argued that, although at some subtidal sites a characteristic subtidal nematode population may persist, in many cases the sublittoral of the Westerschelde is either too dynamic an environment or food availability is too low to meet requirements for growth and reproduction of the nematodes. The populations are probably not self-sustaining but persist due to continuous replenishment from less harsh areas by means of the estuarine circulation.
V. O. Mokievsky - One of the best experts on this subject based on the ideXlab platform.
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quantitative distribution of the Meiobenthos in baidaratskaya bay kara sea
Oceanology, 2017Co-Authors: A. A. Udalov, D V Kondar, M A Miljutina, D M Miljutin, F V Sapojnikov, V. O. MokievskyAbstract:The quantitative characteristics and spatial distribution of the Meiobenthos in Baidaratskaya Bay (Kara sea) were analyzed based on data collected in 1994–2007. The extremely high density of the Meiobenthos (up to 8121 ind/10 cm2, average 2318 ind/10 cm2) makes it possible to consider Baidaratskaya Bay among the most productive Arctic regions. The spatial distribution of the Meiobenthos was mostly determined by the depth and sediment properties in the subtidal zone of the bay. The density of meiobenthic organisms decreased with depth, and with the increase of the small sediment fraction. The difference in the meiobenthic densities between the two coastal areas of the bay (Yamal and Jugora CAs) is also revealed. Such difference caused by the combined effects of small-scale and mesoscale factors, mainly by the grain size. Opposite changes in the meio- and macrobenthic biomass with depth is shown.
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Metazoan Meiobenthos and nematode assemblages in the Nyegga Region of methane seepage (Norwegian Sea)
Russian Journal of Marine Biology, 2014Co-Authors: D. A. Portnova, V. O. Mokievsky, H. Haflidason, K. TodtAbstract:Based on visual observations in the Nyegga (Norwegian Sea) methane seep area we defined arbitrary boundaries and defined the following types of microbiotopes: the siboglinid field, bacterial mat, and background sediment. The metazoan Meiobenthos consisted of 14 major taxa; the Nematoda dominated at seven of the eight stations. The taxonomic diversity of metazoan Meiobenthos in the siboglinid fields was higher than that in the background bottom area. The average population density in siboglinid microbiotope exceeded the abundance of organisms in the background sediments by 1.3 times. The nematode population and total Meiobenthos varied in bacterial maths. The modal size fraction of Meiobenthos and nematodes regardless of microbiotopes fell on samples that were obtained on sieves with 63–125 μm mesh sizes. In total, 88 nematod species belonging to 26 families and 63 genera were recorded. The species diversity decreased in the direction from the background biotope to siboglinid fields and further to bacterial mats.
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Quantitative distribution of Meiobenthos and the structure of the free-living nematode community of the mangrove intertidal zone in Nha Trang bay (Vietnam) in the South China Sea
Russian Journal of Marine Biology, 2011Co-Authors: V. O. Mokievsky, A. V. Tchesunov, A. A. Udalov, Nguen Duy ToanAbstract:Meiobenthic studies were performed in an intertidal area in the Be River estuary (Nha Trang Bay, Vietnam). The study area is an area of riverine-type mangroves that have been heavily damaged by human impacts, including timber cutting and waste. Three biotopes are situated in the middle intertidal zone: a fringe of Rhizophora stylosa , a bush area composed of Avicennia aff. alba behind it, and muddy sand with fiddler crabs ( Uca spp.), which is free of mangrove plants. Three replicate samples of Meiobenthos were collected in each biotope and each sample was subdivided into two layers: 0–1 and 1–4 cm. The abundance of metazoan Meiobenthos varied from 735 specimens/10 cm^2 in the Uca spp. biotope to 244 specimens/10 cm^2 beneath the Rhizophora trees. Six taxonomic groups of high rank were found among the meiofauna: Nematoda, Copepoda (Harpacticoida), Oligochaeta, Turbellaria, Kinorhyncha, and Foraminifera (Allogromiida). The spatial variability of Meiobenthos and its key taxa was estimated and the spatial distribution patterns of free-living nematode species were described. About 90% of the total Meiobenthos inhabited the upper 0–1 cm of the sediments. Nematodes constituted 90–95% of all meiobenthic organisms in the samples. A total of 48 species of free-living nematodes were found in the investigated mangrove intertidal area. In terms of species composition and set of dominants, the nematode community is comprised of three local assemblages: one of them inhabits the uppermost centimeter in the Uca and Avicennia biocenoses; the second assemblage occupies the upper sediment layer in the Rhizophora stand; a less abundant but specific assemblage of several nematode species occurs in the subsurface sediments at all three sites.
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quantitative distribution of the Meiobenthos in the large aral sea in 2003 and 2004
Journal of Marine Systems, 2009Co-Authors: V. O. MokievskyAbstract:Abstract Living Meiobenthos samples were collected in the Large Aral Sea in 2003 and 2004 from water depths ranging from 0 to 39 m. The near-bottom water salinity at the sampling sites varied from 88 to 109‰. Meiobenthos, which occurred at all stations, consisted of nematodes, harpacticoides, ostracods and turbellarians. Unicellular organisms (foraminifera) were also present. The density of Meiobenthos showed a significant spatial variation. Nematodes predominated in most samples. The maximal abundance of free-living nematodes (1440 specimens/10 cm 2 ) was recorded in 2003 at a depth of 10 m, at a site with 88.9‰ salinity and a water temperature of 13.6 °C. The maximal abundance of nematodes in 2004 was 750 specimens/10 cm 2 at about the same depth and salinity, but with a considerably higher water temperature (24.5 °C). The highest value for the harpacticoid copepods density was 116 specimens/10 cm 2 at 1 m depth. The high spatial Meiobenthos variation is to a considerable extent related to the sediment characteristics at the sampling stations.
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the Meiobenthos of the molloy deep 5 600 m fram strait arctic ocean
EPIC3Vie et milieu-life and environment 53(1) pp. 1-13, 2003Co-Authors: Thomas Soltwedel, V. O. Mokievsky, Maria Miljutina, David Thistle, Kay VopelAbstract:The Meiobenthos (including foraminiferans) of the Molloy Deep (Fram Strait, Arctic Ocean) was studied along a 15 km transect crossing the deep in NW-SE direction. Four stations between 5416 and 5569 m water depth were sampled during summer months between 1997 and 2001. In comparison with other abyssal and hadal regions of the World Ocean, meiofauna abundances were extremely high, ranging from 2153 to 2968 ind. / 10 cm² (values for the uppermost 5 cm of the sediments). The analysis of biogenic sediment compounds (e.g. chloroplastic pigments, particulate proteins) confirmed comparably high amounts of organic matter in the sediments, presumably favouring increased faunal densities and biomasses. Subsurface peaks in meiobenthic abundances at 1 - 2 cm sediment depth are most probably due to substantial disturbance and/or predation by dense herds of small holothurians (Elpidia glacialis), obviously inhabiting the entire Molloy Deep in very high numbers. Faunal composition of the meiobenthic community of the Molloy Deep was similar to other deep-sea regions. Foraminiferans were the dominant taxa of the total Meiobenthos (48.5 - 59.9 %), whereas nematodes dominated the metazoan meiofauna (91.7 - 95.8 %). The total meiofauna of the Molloy Deep consisted of relatively small organisms compared to other/shallower oceanic regions, which could not be explained by reduced food availability to the benthos.
Ann Vanreusel - One of the best experts on this subject based on the ideXlab platform.
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Meiobenthos assemblages in the mekong estuarine system with special focus on free-living marine nematodes
Ocean Science Journal, 2010Co-Authors: Ngo Xuan Quang, Nic Smol, Ann Vanreusel, Nguyen Ngoc ChauAbstract:Meiobenthos assemblages in eight estuaries of the Mekong river system were investigated in August 2008 (from the Cua Tieu estuary to the Tran De estuary). In each estuary, one sampling station was established for Meiobenthos sampling. Twelve major taxa of Meiobenthos were recorded in this estuarine system, including Nematoda, Copepoda, Turbellaria, Polychaeta, Oligochaeta, Tardigrada, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Gastropoda, and Crustacean Nauplii larvae. The densities of the Meiobenthos range from 581 to 3168 inds/10 cm^2. Nematodes always occupy the highest numbers with a percentage ranging from 64–99%. There are 135 nematode genera recorded in this study with the following as dominant genera Desmodora, Leptolaimus, Halalaimus, Thalassomonhystera, Theristus, Daptonema, Rhynchonema, Parodontophora , and Oncholaimus . Although the biodiversity of the Meiobenthos at higher taxa level is not high compared to other marine environments, the estimates of nematode biodiversity at the genus level indicates high values. The increase in number of genera with increasing sampling intensity illustrate that the diversity is underestimated and would have been higher if the authors had considered a larger number of individuals, more replicates per station, and more sampling stations.
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Meiobenthos of the central arctic ocean with special emphasis on the nematode community structure
Deep Sea Research Part I: Oceanographic Research Papers, 2000Co-Authors: Ann Vanreusel, Lisa M Clough, Kim Jacobsen, William G Ambrose, Jutamas Jivaluk, Valerie Ryheul, R Herman, Magda VincxAbstract:We investigated the abundance of the Meiobenthos and the biomass and community structure of the nematodes in the central Arctic Ocean along two separate transects during 1991 and 1994. Meiobenthos abundances ranged from (100 to 600 individuals per 10 cm2, in the same order of magnitude as in other oligotrophic areas of the world’s deep ocean. Nematodes were the numerically dominant meiofaunal group at every station. Nematode biomass ranged from ( 1t o 48lg dry weight per 10 cm2. A combination of water depth and latitude explained 55% of the variability among stations in nematode biomass and 67% of the variability of total abundance, implying that both vertical and advective #uxes are important sources of food to the meiofaunal communities.The dominant nematode genus was Monhystera, a detrivorous/bacterivorous deposit feeder, suggesting that bacteria may play an important role in the food web of the Meiobenthos in the Central Arctic. Multivariate analysis of genera abundances revealed di!erences among stations in the Eurasian and Amerasian Basins. During 1994, however, the deep stations in the Eurasian Basin were more similar to the other Amerasian stations, while the single deep station in the Makarov Basin was most similar to the other Eurasian Basin stations. The structure of meiofaunal communities in the central Arctic may provide insight into spatial variability in the Arctic Ocean. ( 2000 Elsevier Science Ltd. All rights reserved.
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the metazoan Meiobenthos along the continental slope of the goban spur ne atlantic
Journal of Sea Research, 1997Co-Authors: J Vanaverbeke, C H R Heip, Karline Soetaert, Ann VanreuselAbstract:Abstract The metazoan Meiobenthos along the continental slope of the Goban Spur (NE Atlantic) was studied in the framework of the OMEX-programme (EC-MAST II). Meiobenthic densities, the vertical distribution of the Meiobenthos in the sediment, and the biomass and generic composition of the dominant group, the nematodes, were investigated at different water depths. The meiobenthic communities along the depth gradient of the continental slope followed the usual trends: the communities were dominated by nematodes, and meiobenthic densities, total nematode biomass, and mean individual nematode weight decreased with increasing water depth. The shelf station had significantly higher densities, nematode biomass and mean individual weight than the deeper stations. The nematode communities along the OMEX slope were divided into a ‘shelf break’ community (206 m) and a ‘down slope’ community (1034–2760 m), with the station at 670 m depth as a transition station. It is suggested that the changes in the nematode community composition along the slope of the Goban Spur are related to the amount of oxygen (and the presence/absence of an oxic mineralisation pathway) in the sediment. The Meiobenthos tended to be more concentrated towards the sediment surface with increasing water depth.
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Meiobenthos of the deep northeast atlantic
Advances in Marine Biology, 1994Co-Authors: Magda Vincx, Thomas Soltwedel, Brian J Bett, A Dinet, Tim Ferrero, A J Gooday, Pjd Lambshead, Olaf Pfannkuche, Ann VanreuselAbstract:This chapter throws the attention on the Meiobenthos of the deep northeast Atlantic. The main purpose of this chapter is to summarize new results from an area lying between 15°N and 53°N and extending from the continental margin of western Europe and northwest Africa to the Mid-Atlantic Ridge. It considers first the nature and scope of meiofaunal research in the northeast Atlantic and then discuss the environmental parameters, which are believed to influence meiofaunal organisms. This chapter then discusses the various types and scales of pattern observed among meiofaunal populations within the study area, progressing from the large-scale bathymetric and latitudinal trends and then to small-scale horizontal patterns within particular areas. Faunal densities and faunal composition are considered separately and compared with data from other regions. This chapter also deals with the distribution of meiofauna within sediment profiles and the temporal variability of populations. This chapter concludes by discussing the recent review of deep-sea meiofauna, which focused mainly on the abundance and biomass data from different oceans and on the relationship between the biomass of the meiofauna and that of other faunal components
Thomas Soltwedel - One of the best experts on this subject based on the ideXlab platform.
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Recolonisation of new habitats by meiobenthic organisms in the deep Arctic Ocean: an experimental approach
Polar Biology, 2012Co-Authors: Daniela Freese, Ingo Schewe, Thomas Soltwedel, Corinna Kanzog, Michael KlagesAbstract:Commercial exploitation and abrupt changes of the natural conditions may have severe impacts on the Arctic deep-sea ecosystem. The present recolonisation experiment mimicked a situation after a catastrophic disturbance (e.g. by turbidites caused by destabilised continental slopes after methane hydrate decomposition) and investigated whether the recolonisation of a deep-sea habitat by meiobenthic organisms is fostered by variations in nutrition and/or sediment structure. Two “Sediment Tray Free Vehicles” were deployed for 1 year in summer 2003 at 2,500 m water depth in the Arctic deep-sea in the eastern Fram Strait. The recolonisation trays were filled with different artificial and natural sediment types (glass beads, sand, sediment mixture, pure deep-sea sediment) and were enriched with various types of food (algae, yeast, fish). After 1 year, Meiobenthos abundances and various sediment-related environmental parameters were investigated. Foraminifera were generally the most successful group: they dominated all treatments and accounted for about 87 % of the total Meiobenthos. Colonising Meiobenthos specimens were generally smaller compared to those in the surrounding deep-sea sediment, suggesting an active recolonisation by juveniles. Although experimental treatments with fine-grained, algae-enriched sediment showed abundances closest to natural conditions, the results suggest that food availability was the main determining factor for a successful recolonisation by Meiobenthos, and the structure of recolonised sediments was shown to have a subordinate influence.
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spatial and temporal variations in deep sea meiofauna assemblages in the marginal ice zone of the arctic ocean
Deep-Sea Research Part I. Oceanographic Research Papers, 2007Co-Authors: E Hoste, S Vanhove, Ingo Schewe, Thomas Soltwedel, Ann VanreuselAbstract:Abstract In order to understand the response of the deep-sea Meiobenthos to a highly varying, ice-edge-related input of phytodetritus, we investigated the abundance and composition of the Meiobenthos at the arctic long-term deep-sea station HAUSGARTEN (79°N, 4°E) along a bathymetric transect (1200–5500 m water depth) over 5 consecutive years (from 2000 to 2004) in relation to changes in environmental conditions. Results showed high sediment-bound pigment concentrations (chlorophyll a and degradation products) ranging from 4.5 to 41.6 μg/cm3, and coinciding high meiobenthic densities ranging from 149±3 to 3409±525 ind/10 cm2. Nematodes dominated the metazoan meiofaunal communities at every depth and time (85–99% of total meiofauna abundance), followed by harpacticoid copepods (0–4.6% of total meiofauna abundance). The expected pattern of gradually decreasing meiobenthic densities with increasing water depth was not confirmed. Instead, the bathymetric transect could be subdivided into a shallow area with equally high nematode and copepod densities from 1000 to 2000 m water depth (means: 2259±157 Nematoda/10 cm2, and 50±4 Copepoda/10 cm2), and a deeper area from 3000 to 5500 m water depth with similar low nematode and copepod densities (means: 595±52 Nematoda/10 cm2, and 11±2 Copepoda/10 cm2). Depth-related investigations on the Meiobenthos at the HAUSGARTEN site showed a significant correlation between Meiobenthos densities, microbial exo-enzymatic activity (esterase turnover) and phytodetrital food availability (chlorophyll a and phaeophytines). In time-series investigations, our data showed inter-annual variations in meiofauna abundance. However, no consistent relationship between nematode and copepod densities, and measures for organic matter input were found.
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the Meiobenthos of the molloy deep 5 600 m fram strait arctic ocean
EPIC3Vie et milieu-life and environment 53(1) pp. 1-13, 2003Co-Authors: Thomas Soltwedel, V. O. Mokievsky, Maria Miljutina, David Thistle, Kay VopelAbstract:The Meiobenthos (including foraminiferans) of the Molloy Deep (Fram Strait, Arctic Ocean) was studied along a 15 km transect crossing the deep in NW-SE direction. Four stations between 5416 and 5569 m water depth were sampled during summer months between 1997 and 2001. In comparison with other abyssal and hadal regions of the World Ocean, meiofauna abundances were extremely high, ranging from 2153 to 2968 ind. / 10 cm² (values for the uppermost 5 cm of the sediments). The analysis of biogenic sediment compounds (e.g. chloroplastic pigments, particulate proteins) confirmed comparably high amounts of organic matter in the sediments, presumably favouring increased faunal densities and biomasses. Subsurface peaks in meiobenthic abundances at 1 - 2 cm sediment depth are most probably due to substantial disturbance and/or predation by dense herds of small holothurians (Elpidia glacialis), obviously inhabiting the entire Molloy Deep in very high numbers. Faunal composition of the meiobenthic community of the Molloy Deep was similar to other deep-sea regions. Foraminiferans were the dominant taxa of the total Meiobenthos (48.5 - 59.9 %), whereas nematodes dominated the metazoan meiofauna (91.7 - 95.8 %). The total meiofauna of the Molloy Deep consisted of relatively small organisms compared to other/shallower oceanic regions, which could not be explained by reduced food availability to the benthos.
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metazoan Meiobenthos along continental margins a review
Progress in Oceanography, 2000Co-Authors: Thomas SoltwedelAbstract:The sediment-inhabiting meiofauna is a major component of benthic ecosystems, particularly in the deep sea. Knowledge on the deep-sea Meiobenthos has increased considerably during recent decades, and attempts have been made to relate standing stocks with various environmental factors. The flux of organic matter from surface productivity to the seafloor has been proven to exert considerable control on benthic standing stocks. The energy content of sedimentating organic matter generally decreases with water depth because of degradation processes within the water column. Consequently, benthic standing stocks decrease with increasing water depth. Generally enhanced densities of benthic animals are to be expected in areas of increased surface production and subsequently enhanced flux of organic matter to the seafloor. Thus, meiobenthic densities and biomasses should show perceptible differences not only with water depth, but also between areas with different primary productivity in surface layers. The objective of this paper is to condense current information focusing on the abundance of metazoan meiofauna along continental margins, and to compare meiofauna stocks from various climatic regions of the world, representing areas of diverse productivity in the water column. Results clearly demonstrate regional differences on global scale: richer communities were generally found in areas with increased productivity and enhanced input of organic matter to the seafloor.
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Meiobenthos of the deep northeast atlantic
Advances in Marine Biology, 1994Co-Authors: Magda Vincx, Thomas Soltwedel, Brian J Bett, A Dinet, Tim Ferrero, A J Gooday, Pjd Lambshead, Olaf Pfannkuche, Ann VanreuselAbstract:This chapter throws the attention on the Meiobenthos of the deep northeast Atlantic. The main purpose of this chapter is to summarize new results from an area lying between 15°N and 53°N and extending from the continental margin of western Europe and northwest Africa to the Mid-Atlantic Ridge. It considers first the nature and scope of meiofaunal research in the northeast Atlantic and then discuss the environmental parameters, which are believed to influence meiofaunal organisms. This chapter then discusses the various types and scales of pattern observed among meiofaunal populations within the study area, progressing from the large-scale bathymetric and latitudinal trends and then to small-scale horizontal patterns within particular areas. Faunal densities and faunal composition are considered separately and compared with data from other regions. This chapter also deals with the distribution of meiofauna within sediment profiles and the temporal variability of populations. This chapter concludes by discussing the recent review of deep-sea meiofauna, which focused mainly on the abundance and biomass data from different oceans and on the relationship between the biomass of the meiofauna and that of other faunal components
Elena V Anufriieva - One of the best experts on this subject based on the ideXlab platform.
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macrostructure of benthos along a salinity gradient the case of sivash bay the sea of azov the largest hypersaline lagoon worldwide
Journal of Sea Research, 2019Co-Authors: Nickolai V Shadrin, Elena V Kolesnikova, Tatiana Revkova, Alexander Latushkin, Anna Chepyzhenko, Nikolay Dyakov, Elena V AnufriievaAbstract:Abstract In 2018, total suspended solids (TSS) and dissolved organic matter (DOM) were studied as well as macrostructure of the macro- and Meiobenthos (by sampling soft-sediments and algal mats) along a spatial salinity gradient from 30 to 88 g l−1 in Sivash Bay. The main goals of the study were to evaluate current ecosystem state, analyze long-term trends and verify the suggestions made previously. There was a significant increase in TSS and DOM with increasing salinity. No correlation between the number of taxa in the sample and salinity was found for Meiobenthos and total benthos, but a negative reliable relationship was obtained for macrobenthos of the soft bottom. Salinity had significant relationships with the total number of taxa in a sample and with the number of macrobenthic taxa associated with floating filamentous green alga mats. There was a positive relationship between the total abundance of soft-bottom benthos and the total number of macrotaxa. In 2013, before the closure of the channel, the number of soft-bottom macrobenthos taxa was 11, in 2015–8, and in 2018 – only 5. These changes negatively correlated with changes of salinity and TSS in 2013–2018. There was an exponential increase in abundance and the percentage of chironomid larvae in the total number of benthos from 2013 to 2018, which was significantly positively correlated with changes in salinity and TSS. Macro- and Meiobenthos showed different responses to the salinity increase. Currently, hypoxic and anoxic events often occur in Sivash Bay under floating algal mats, and this also may suppress taxon diversity in macrobenthos more than in Meiobenthos.
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do separated taxa react differently to a long term salinity increase the Meiobenthos changes in bay sivash largest hypersaline lagoon worldwide
Knowledge and Management of Aquatic Ecosystems, 2019Co-Authors: Nickolai Shadrin, Elena V Kolesnikova, Tatiana Revkova, Alexander Latushkin, Anna Chepyzhenko, Nikolay Dyakov, Inna Drapun, Elena V AnufriievaAbstract:In the world's largest hypersaline lagoon Bay Sivash, its ecosystem twice transformed from a previous state to a new one due to human intervention. Before the North Crimean Canal construction, it was hypersaline (average salinity of 140 g l−1 ). The canal was built between 1963 and 1975, which resulted in intensive development of irrigated agriculture discharging drainage water into the bay. Between 1988 and 2013, salinity gradually dropped to average of 18–23 g l−1 ; a new ecosystem with a different biotic composition formed. In April 2014, the supply of Dnieper water into the North Crimean Canal ceased. This resulted in a gradual salinity increase in the bay to an average of 52 g l−1 in 2015. The start of second ecosystem shift was observed in 2015. In 2018, TSS, DOM and Meiobenthos were studied in a salinity gradient from 30 to 88 g l−1 . There was an increase in TSS and DOM with increasing salinity. The Meiobenthos structure was significantly different in the bottom community and floating mats of filamentous green algae. No correlation was recorded between the number of meiobenthic macrotaxa in the sample and salinity. From 2013 to 2018, changes were seen in the taxocene structure of Nematoda and Harpacticoida. Changes in Nematoda were more dramatic and prolonged than in Harpacticoida. The structure of the Harpacticoida and Ostracoda taxocenes are less variable and more stable than that of the Nematoda taxocene. One of the reasons may be more mobility of Harpacticoida/Ostracoda than Nematoda and/or better osmoadaptation mechanisms.