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In Sevastopol Bay, a decrease in the number of species and the disappearance of some zoobenthos communities was recorded back in the 1920–1930s and persisted until the 1960–1990s. Only five species of macrozoobenthos were the most resistant to high anthropogenic load and eutrophication in those years. The relative recovery of the species composition and the improvement of benthic biological parameters have been observed in the bay since the beginning of the 21st century. The zoobenthos was replenished by 39 new species which here were not marked earlier. The largest number of species was recorded for Mollusca, Crustacea, and Polychaete. These changes occurred even in those areas of the bay where previously benthic animals were absent in zoobenthos samples or found in very small numbers, conditionally a dead zone. The reduction in the eutrophic level, the improvement in the oxygen regime, and the expansion of the area with oxidizing conditions in the bottom sediment were the major factors in the improving benthic habitats in Sevastopol Bay. These ecological changes coincided with increase in the water temperature in the summer period. Positive zoobenthos tendencies are typical for Romanian and Bulgarian coasts in the last decade. [ABSTRACT FROM AUTHOR]

The current state of zoobenthic communities has been studied for lakes Sukkozero and Gimolskoe in the western part of the Republic of Karelia (Muezersky district). Under conditions of highly colored and low mineralized waters, chironomid larvae, caddisflies, mayflies, and oligochaetes predominate in the communities. Biomass and abundance ranged within 0.41–0.75 g/m2 and 315–685 ind./m2 in Lake Sukkozero and 0.41–0.93 g/m2 and 220–346 ind./m2 in Lake Gimolskoe in 2017–2018. The highest abundance and biomass were noted in the biotopes of silty sediments (overgrown littoral and profundal); the lowest were at the sandy littoral. According to the quantitative parameters of zoobenthos, Lake Sukkozero was an oligotrophic water body; Lake Gimolskoe was mesotrophic. Using common biotic indices to assess the ecological quality of waters (indices Mayer's, oligochaete, chironomid, and saprobity), it was revealed that low mineralization and high humus content might affect their performance and distort the assessment of real organic pollution. [ABSTRACT FROM AUTHOR]

The results of long-term studies are used to present, for the first time, the structural organization of zoobenthos communities and the dynamics of their density and biomass in rivers and brooks of the the Khektsir Ridge, including the boundaries of the Bol'shekhekhtsirskii Reserve, Khektsirskii Wildlife Reserve (the southern part of the Russian Far East). The benthic organisms were found to contain 23 groups (22 groups in the spring and summer, 19 groups in the autumn, and 8 groups in the winter). Leading in the occurrence frequency (>90%) were chironomids, mayflies, and oligochaetes. The chironomids and amphipods accounted for 37.0 and 19.1% of the total benthos density, and mollusks and amphipods, for 32.1 and 29.7% of the total biomass, respectively. Dominants in terms of density and biomass were amphipods; chironomids dominated in terms of density, and mollusks, in terms of biomass. The mean density of benthic organisms was 637 ± 21 spec./m2, and the mean biomass was 1.8 ± 0.2 g/m2. The benthic communities of rift segments in the rithral zone were found to be most productive. It is shown that the seasonal and long-term dynamics of zoobenthos communities is pronounced and can be traced in the group composition, structure, and quantitative characteristics. [ABSTRACT FROM AUTHOR]

Lake vegetation is divided into 3 ecological groups: hygrophytes, hydrophytes and hydratophytes. Hygrophytes make up 27.2%, hydrophytes-9.0% and hydrophytes-63.6%. Hygrophytes are plants that grow in moist places, on the shores, and hydrophytes are half aquatic. This plant species is found in small numbers in the lake. Hydrotophytes are dominant in abundance and biomass. The area of the lake is 7,200 hectares, of which the water part is 3,800 hectares, the area of wetlands covered by various parts is 3,400 hectares. The lake is rich in organic nutrients. A wide variety of higher algae grows in the lake (Phragmites communis, typha angustifolia, Potamogeton crispus, Myriophyllum spicatum, Ceratophyllum demersum, Chara infarmedia, Spirogyra, as well as many species of algae), which prevents sunlight from penetrating into the water to a depth of 3 meters, which negatively affects the development of zooplankton.

The biomass of chironomids in the Vaya Lake during the period 2003-2007 was studied. In the spring and summer of 2004, the biomass was estimated by the highest values, and in the spring and summer of 2006 -- the lowest. The species with the greatest participation in the biomass were: Chironomus riparius, Cryptochironomus defectus, Chironomus gr. plumosus, Cricotopus sylvestris, Tanytarsus gregarious and Cricotopus algarum. The stations along the central axis of the lake had the highest similarity. Dendrogram of chironomid biomass similarity showed high similarity (greater than 80%) for sites 3, 4 and 12. [ABSTRACT FROM AUTHOR]

The spatial structure of the zoobenthos in Lake Yuzhny Volos is studied in the different seasons of the year. The types of seasonal distribution of total abundance and biomass of macrozoobenthos, its main taxonomic groups, and individual species and the influence of key environmental factors on them (dissolved oxygen and temperature) are determined. There are two peaks of quantitative metrics of zoobenthos. The first peak was due to macrophytes, where Dreissena polymorpha, Asellus aquaticus, and different types of chironomids dominated on all seasons. The second peak was due to the development of the relict crustacean Monoporeia affinis. [ABSTRACT FROM AUTHOR]

Biomass is a fundamental ecological measure used to quantify ecosystem structure and function. It is costly to measure but can be estimated using conversion factors based on established relationships between different biomass measures, however such conversion factors may not be applicable across broad geographic regions. For temperate benthic fauna, currently available mass-to-mass conversion factors were largely established in Northern Hemisphere ecosystems. Here, we present conversion factors for temperate Australian benthic fauna typically found in microtidal coastal bays and estuaries (14 taxa encompassing five classes: Polychaeta; Bivalvia; Gastropoda; Crustacea; Insecta). We derived 126 conversion factors using two statistical techniques between several mass measures (e.g. wet mass, dry mass, ash-free dry mass, shell-free masses) with specimens from three preservation methods (ethanol, formalin, frozen). Our conversion factors were generally not congruent with those obtained from the literature. We also found that the choice of prediction method used to derive conversion factors can be a substantial source of error in biomass estimation that has largely been overlooked in mass-to-mass conversion. Log-linear ordinary least squares regression models provided substantially more accurate predictions than simple mean ratios. We outline an analytical approach for future use to derive more globally comparable conversion factors for estuarine benthic fauna. • First biomass conversion factors for benthic fauna in southern temperate estuaries. • Choice of prediction method is a substantial source of error in biomass estimation. • Log-linear ordinary least squares regression models gave most accurate predictions. • Propose analytical approach for developing conversion factors. [ABSTRACT FROM AUTHOR]

The article is devoted to the study of seasonal dynamics and quantity of the zoobenthos distribution in the north-west part of the South Caspian Sea. During the research covering the period from 2009 until 2010, 59 macrobenthos organisms belonging to the ten systemic groups were identified. Maximum quantity of species was identified in spring and summer (31 - 59 species), while minimum in autumn (24 - 42 species). Maximum development of organisms was identified in summer (146.27 g m-2), while minimum in autumn (77.12 g m-2). The key role in the benthos biomass formation belonged to shellfish, comprising 67.7 to 69.1% of total benthos biomass

Background. The study of the fish feed base of the Khatanga River is necessary due to the fact that the river is used for commercial fishing of valuable fish species. The last description of the communities of zooplankton and zoobenthos of the Khatanga River was carried out according to the data of 1946, respectively, there is no more up-to-date information about the state of hydrobiological communities. The aim of this work is to establish the taxonomic composition and quantitative characteristics of zooplankton and zoobenthos communities, as well as to assess the trophic status of the Khatanga River. Materials and methods. Studies of the river were conducted at 5 stations: in 2014-in the areas of the settlements of Novorybnoye and Kresty, in 2015-at 25 km, 45 km and 67 km from the mouth of the river, in 2018-2020-in the area of the settlement of Khatanga. Samples of zooplankton and zoobenthos were collected and processed according to the methods generally accepted in Russian hydrobiology. All samples were taken in three repetitions. Results, conclusions. During the 2014–2015 and 2018– 2020 studies, 33 taxa were identified in zooplankton, and 37 in zoobenthos. The average values of zooplankton abundance and biomass ranged from 57±57 to 477±441 ind./m3 and from 0.52±0.52 to 3.12±0.64 mg/m3, respectively, and zoobenthos – from 260 to 2642 ind./m2 and from 0.65 to 4.04 g/m2, respectively. Rotifers were dominant in the zooplankton community in terms of quantitative parameters, while chironomids, oligochaetes, and mollusks were dominant in the zoobenthos. According to the development of zooplankton and zoobenthos, the river belongs to the "low-feed" fishing facilities. The trophic category of the Khatanga River is defined as "ultra – oligotrophic" by zooplankton, and "α-mesotrophic" by zoobenthos.

The species composition and quantitative characteristics of the zoobenthos in Lake Pyasino and rivers flowing into it after a diesel spill have been analyzed. The production of zoobenthos and potential production of benthivorous fish in Lake Pyasino have been calculated. A small number of zoobenthos species and low values of abundance and biomass are revealed. In the Bezymyanny Stream, the mouth of the Daldykan River, and the Ambarnaya River, oligochaetes Limnodrilus hoffmeisteri Claparede and Tubifex tubifex (O. F. Muller) dominate in the zoobenthos abundance and biomass. In Lake Pyasino and the Pyasina River outflow, larvae of caddis flies, chironomids, stoneflies, and amphipods prevail. In the area of the deepwater silted station of Lake Pyasino, oligochaetes L.hoffmeisteri develop, the proportion of which in the benthic fauna at this station (40 and 79% of the total biomass and abundance, respectively) is maximal. The amphipod Monoporeia affinis (Lindström) dominates in terms of biomass at this station. A decrease in the chironomid diversity, an increase in the proportion of polysaprobic oligochaetes, and lower values of the Shannon index in Lake Pyasino in 2020 when compared to 1992 are found. The low abundance (2181 ± 2048 ind./m2) and biomass (2.01 ± 1.85 g/m2) of zoobenthos in the lake results in low values of zoobenthos production and the potential production of benthivorous fish (3 kg/ha per season). Based on the state of zoobenthos, an improvement in water quality has been observed from river sections exposed to the oil spill to the lake and the source of the River Pyasina. [ABSTRACT FROM AUTHOR]

Background. Zoobenthos is an essential component of the fish food base. Therefore, an assessment of fish productivity for this indicator is necessary for any comprehensive fisheries research in water bodies. The purpose of the study was to study the seasonal dynamics of zooplankton development to determine fish productivity by this indicator of one of the sections of the river Sura. Materials and methods. Zoobenthos samples were taken in the studied reservoir at three points of the selected station in the middle of the month of the ice-free period from April to November, 2014–2015. (and in May, 2016). Fishery products were calculated taking into account coefficients adapted to the Volga region. A comparative analysis with neighboring reservoirs (the natural channel of the Sura River and the Penza River, a sand pit) was carried out according to the results of our own research. Results. During the study period, 52 taxa of macrozoobenthos were identified (in 2014 – 27, in 2015 – 35). Changes in the species composition of zoobenthos over the years amounted to 65 %. The monthly changes in the species composition in different years turned out to be close on average (38 and 41 %, respectively). In numbers, bivalve mollusks, small-worm worms, and diptera insect larvae dominated in different months. By biomass – bivalves and gastropods, small-worms. In 2014, the monthly zoobenthos abundance varied by 1,2–2,5 times, and the biomass by 0,9–3,0 times. In 2015, the monthly abundance of zoobenthos differed 1,1–5,9 times, and biomass 1,4–3,9 times. The differences between the monthly indices by years in terms of numbers were 1,2–3,7 times, and in biomass 1,1–2,7 times. On average, between years the abundance of zoobenthos in 2014 was 1,2 times higher than in 2015, and in biomass 1,2 times lower without Anodontastagnalis. In seasonal and interannual dynamics, the state of zoobenthos in the Gorodskoye reservoir is estimated as quite stable. Conclusions. In the City Reservoir there is a free food base for zoobenthos and it can be stocked with valuable species of benthophagous fish (carp) to increase fish stocks and meet the needs of amateur fishermen of the city of Penza. The highest indices of zoobenthos biomass were observed in 2015 in the spring period (April, May). Indicators close to the seasonal average were recorded in all other months of the ice-free period.

Purpose. To study food resources, feeding conditions and trophic relationships of the brown trout (Salmo trutta morpha fario), rainbow trout (Oncorhynchus mykiss), and European grayling (Thymallus thymallus) in a Transcarpatioan river. Methodology. The material on the food resources and feeding of the brown trout, rainbow trout, and European grayling was collected in summer period of 2012 on the Shypit river. The study was performed on two different sites of the river: the first one was located on the middle pre-mountain reach of the river (upstream of the Hydroelectric power plant), the second one – on the mountain reach of the river (near tourist base) on typical biotopes: I – with boulders and riffles with fast current; II – with medium size stones and low riffles with moderate current; III – with small stones, sand and slow current. The material was collected and processed according to standard and unified hydrological, ichthyological, and trophological methods. Findings. We studied the level of macrozoobenthos development and obtained data on feeding and trophic relationships among brown trout, rainbow trout, and European grayling on different biotopes on pre-mountain and mountain reaches of the Shypit river. The number of “soft” macrozoobenthos on different biotopes varied from 972 to 2576 ind./m2 with biomasses from 6.3 to 121.8 g/m2. Total diet overlap index (DOI) between brown trout and rainbow trout on the biotope with boulders and fast current in the pre-mountain reach was 32.4% by number and 20.3% by biomass, while that on the mountain reach was 49.6% and 52.9%, respectively. On the biotope with medium size stones and moderate current, the diet overlap index between rainbow trout and European grayling in the pre-mountain reach was 19.0% by number and 27.9% by biomass. Originality. First study of the diet and tropic relationships of the brown trout, rainbow trout, and еuropean grayling on different reached of the Shypit river. Practical value. The results of this work can be used when calculating the amounts of brown trout, rainbow trout, and European grayling to be stocked into rivers of the Transcarpathian region.

The qualitative and quantitative characteristics of zoobenthos and zooperiphyton of two model oxbow lakes in the Middle Ob basin are presented. Three sites in each oxbow lake are examined: the apex (or "pond") site least connected with the river, the middle part, and the site near the channel flowing into the river. The specific longitudinal structure of the taxonomic composition and the abundance of zoobenthos and zooperiphyton has been revealed. The most favorable conditions for zoobenthos are in the pond site and, for zooperiphyton, they are in the middle of an oxbow lake and near the channel. In order to identify and understand the general patterns of aquatic ecosystem functioning, the results are discussed in light of well-known theoretical concepts: the ecotone, the edge effect, and the lake continuum. [ABSTRACT FROM AUTHOR]

Size spectra are important descriptors of community structure and can indicate changes in community functioning in response to shifts in environmental conditions. There are relatively few assessments of benthic size spectra, and most are based on summer samples alone. Processes influencing size spectra, such as recruitment and predation pressure, vary seasonally, and understanding this variation is necessary to interpret patterns in time or space. Here we compare summer and winter biomass size spectra in the central basin of Kongsfjorden (west Spitsbergen). We recorded seasonal changes in the quality of organic matter available to the benthos, indicated by higher chloroplastic pigments concentrations in surface sediments in summer, as well as in differences in total abundance and biomass of both macrofauna and meiofauna. No significant seasonal differences were documented by multiple regression models for the normalized biomass and size classes. The slope of a linear relationship between normalized biomass and size classes was − 0.54 ± 0.02 indicating a productive system, compared to ecosystems like estuaries. Summer–winter invariability of size spectra suggests that benthic community functioning in this Arctic fjordic system is relatively independent from the seasonality in the supply of organic matter produced in water column. [ABSTRACT FROM AUTHOR]

The biomass and the qualitative parameters of zoobenthos¹ of Lake Sevan (Armenia) were observed during the different strategies of water level management (1928-2016) where after 20 m water level drop (1933-2001) the water level increased on about 4 m (2002-2017). During this period the annual wet biomass varied between 3 and 37 G M-2. Changes in feeding structure of the benthic community: ratio between first level consumers: detritivores, herbivores and filter feeders, and between first and second (predators) levels consumers are less visible but sign about important qualitative changes followed by quantitative ones. This facilitates prediction of the abundance of the zoobenthos and its structure in future years. Further, changes in relative proportions of the zoobenthos comprised by feeding groups provide clear indices of progress toward rehabilitation of the lake. [ABSTRACT FROM AUTHOR]

The production characteristics of zooplankton and zoobenthos communities have been studied in several lakes and reservoirs. Their relationship with the primary production of plankton and the biomass of the communities is shown. The P/B ratio in the zooplankton community is five times higher than the ratio in the benthic communities. The greatest number of stenobiont species in the zooplankton communities is recorded at a water transparency close to 4 m. [ABSTRACT FROM AUTHOR]

Aim. The assessment of the ecological status of watercourses of Delta of the Volga River on the structure of benthic communities. The main objective of our researches was the assess the ecological status of watercourses of Delta of the Volga River on the basis of the analyzes of the structural-functional characteristics of benthic communities.Location. Delta of the Volga River was the area of researches.Methods. Processing samples of zoobenthos of the studied watercourses of Delta of the Volga River was produced according to standard techniques. (Zhadan V.I.,1960, Vinberg G.G., 1984, Abakumov V.A., 1992). Altogether were selected and processed 516 samples of zoobenthos. Species identification was done using the "Atlas of invertebrates of the Caspian Sea" (Birshtein A.Ya., 1968)and “The determinant to freshwater invertebrates…” (Kutikova L.A., 1977). Next, based on the obtained data, we determined the abundance and biomass of species per m2 surface area of the bottom. To the assessment of the ecological status of watercourses of Delta of the Volga River by the structure of microzoobenthos we used the following indicators: number of species, abundance (N, specimens/m2), biomass (B, g/m2), percentage of principal taxonomic groups, oligogenic index of Parele (D1) (Parele E. A., 1974), biotic index of Wudiwiss in the modification of Nasibulina (B) (Nasibulina B. M., 1995), the index of species diversity of Shannon-Uiver (H, bit/copy) (Shitikov V. K., 2003).Results. The obtained results of the assessment of the ecological status of watercourses in the Delta of the Volga River by the structure of benthic communities show that the same species having in different water bodies their different representation and structural-functional characteristics were the kernel of bottom fauna. According to the values of the modified biotic index of Wudiwiss and oligochaetae index of Parele calculated for the whole period of studies, the water quality in the Volga River (from Barbasi to water-post, Astrakhan), and the sleeves Buzan and Akhtuba was characterized as "slightly contaminated"with the dominance of β-mesosaprobic organisms. n the sleeveless Bushma, Kizan', Bakhtemir characterised as "polluted" with a predominance of β-α-mesosaprobic. The picture of the distribution of quantitative indicators of zoobenthos in the Delta of the Volga River in average perennial aspect had uneven character, with the manifestation of a clear trend to decreasing their values from the Eastern part of the Delta (the Volga River) to the West (the sleeve Bakhtemir).Main conclusions. Thereby, on the basis of qualitative and quantitative characteristics of zoobenthos and calculated biological indices it was noted that the water quality of watercourses in the Delta of the Volga River can be characterized as "Slightly contaminated and "Polluted". In the average perennial aspect in the watercourses of Delta of the Volga River was observed uneven distribution of quantitative indicators of zoobenthos with the manifestation of a clear trend to decreasing their values from the Eastern part of the Delta to the West.

The Neva Estuary situated in the eastern part of the Gulf of Finland is one of the largest estuaries of the Baltic Sea. At present, heavy nutrient and organic matter loading, mainly from the Neva River and point sources in the upper estuary are the most serious environmental problem for the Neva Estuary and adjacent parts of the eastern Gulf of Finland. Long-term studies of mid-summer primary production and mineralization of organic matter were conducted in upper and middle parts of the Neva Estuary. A considerable increase of production and biomass of phytoplankton was observed in the middle part of the estuary during the last decades mainly due to an increase in biomass of cyanobacteria. However, they are mostly concentrated in the upper water layers and only a small part of them reached the near bottom water layers and may be used as a food by zoobenthos. The mineralization of organic matter in the water column was twice higher than primary production that indicates the importance of allochthonous organic matter in the carbon budget of the both parts of the estuary. The carbon isotope signature of seston and most of the zoobenthic species in the upper part of the estuary was close to the signature of allochthonous carbon leaking from watershed (− 27‰). Higher values of δ 13 C of seston in the upper mix layer of the Middle estuary indicate intensive primary production in mid-summer. The carbon isotopic signature of zoobenthos in this part of the estuary was also in general lower than in the Neva Bay reflected higher importance of autochthonous organic matter in food webs of the estuary. [ABSTRACT FROM AUTHOR]

In order to reveal the differentiated responses of plankton and zoobenthos to water quality on both annual and seasonal time scales, an ecological study on plankton and zoobenthos community was conducted during 2011 to 2015 in Nansi Lake in northern China. Different dynamics were found among phytoplankton, zooplankton, and zoobenthos in terms of density, biomass, and biodiversity. On an annual time scale and with deterioration of water quality, density and biomass of plankton and zoobenthos showed different variations, while phytoplankton (density, biomass, and biodiversity) changed significantly when water quality improved. On a seasonal time scale, density and biomass of phytoplankton showed significant differences between spring and summer. Results of Pearson's correlation analysis revealed that phytoplankton, zooplankton, and zoobenthos were significantly affected by different environmental factors. Our study demonstrated that phytoplankton was more sensitive to water quality changes than zooplankton and zoobenthos. These results suggest that density and biomass of phytoplankton could rapidly reflect water quality, whereas biodiversity of phytoplankton could indicate long-term status of water quality combined with the physico-chemical parameters of water. The results could contribute to predicting the dynamics of plankton and zoobenthos in freshwater lakes and to selecting effective bio-indicators for ecosystem health assessment of freshwater lakes. [ABSTRACT FROM AUTHOR]

Three alpine lakes (Oiskoe, Karovoe, Raduzhnoe) of mountain range Ergaki were sampled in 11- 15 September 2008. Species (taxonomic) composition, number of species, abundance and biomass of phytoplankton and zooplankton, phytobenthos and zoobenthos of each lake were studied for the first time. Coefficients of species similarity of plankton and benthos assemblages between lakes were calculated. Results of fishing in the lake Oiskoe were presented. As found, species diversity of plankton and benthos assemblages of the lakes were low and the lowest one was in the fishless lake Karovoe. Similarity of species composition between lakes were low (0,09-0,40). Biota of the lakes in general consisted of species with widespread distribution, with the exception of some species, namely Alona werestschagini Sinev known (in Russia) from Altai and north of Europe only, and Arctodiaptomus dahuricus Borutzky known from Transbaikalia. Thus areals of these species were expanded, but Arctodiaptomus may be a new species (subspecies) Despite of the low abundance and biomass of phyto- and zooplankton (characteristic of oligotrophic lakes) and low or moderate zoobenthos biomass (characteristic of oligotrophic-mesotrophic lakes), catched individuals of fish Thymallus arcticus Pallas were fat (mark 3-4) and their guts were filled. Apparently food supply is sufficient for good fitness of the existed grayling population.

The qualitative and quantitative parameters and distribution of zoobenthos in Lake Sevan (Armenia) we re determined in May and November 2015 at 21 semi-transects of the lake. The comparison of data over the past 5years with the results obtained in 2015 shows, that thewater level raising and the enlargement of macrophyte zone formed zoobenthos community, characterized by high values of abundance and biomass, as well as by higher species dive rsity. During the period of raising the water level of Lake S evan (2005-2015) fifty-three species of benthic invertebrates were recorded, from which 2 species of dragonflies and 1 species of gastropod in 2015. In Minor Sevan both by quantityand by biomass dominated oligochaetes. For the first time from 1980, in 2015 the proportion of Chironomidae in average quantity and biomass of zoobenthos of Major Sevan was exceeded the proportion of oligochaetes. [ABSTRACT FROM AUTHOR]

Artificial substrates are omnipresent today in most estuaries mostly in form of massive rip-rap used for groynes and jetties. In the Weser estuary, Germany, 60% of the shoreline is covered with such artificial substrates while, natural rocky substrate is lacking, as in all Wadden Sea estuaries. This large quantity of artificial substrates may be colonized by a benthic hard-substrate community which differs from the local natural soft-substrate assemblage. In this study we examined species compositions, abundances, biomass, and numbers of species of subtidal benthic communities on groynes and in the natural habitat, the sediment, along the salinity gradient of the Weser estuary. Species composition changed on both substrates significantly with salinity and was also significantly different between the substrates. In a comparison with the sediment, the groynes did not provide any benefit for non-indigenous nor for endangered species in terms of abundance, biomass, and number of species, but represent habitats with higher total abundances and biomass; though some non-indigenous species even occurred exclusively on groynes. In particular, groynes supported filter-feeding organisms which play an important role by linking benthic and pelagic food webs. The dominance of the suspension feeders affects crucial estuarine ecosystem services and may have important implications for the estuarine management by altering the estuarine ecological quality status. Hence, artificial substrates should be considered in future conservation planning and in ecological quality monitoring of the benthic fauna according to the European Water Framework Directive. [ABSTRACT FROM AUTHOR]

ABSTRACT Two new ecological niche clustering approaches are presented in this paper: first, an importance/dominance evaluation model, based on both density and biomass, is devised to evaluate the importance (contribution) of a specific species in its community; second, an integrated index encoding approach is constructed to spatially cluster all dominant species at a sampling site. Two approaches are employed to study ecological niche clustering of the Huai River Basin zoobenthos in order to identify key regions for ecosystem restoration. Results show that habitat changes will significantly impact Corbicula fluminea (Müller), whereas influences on Corbicula nitens (Philippi) will be the least significant. Total phosphorus has the greatest impact on zoobenthos, and high-concentrated ammonia nitrogen is also detrimental. Decreasing the discharge of both phosphorus and ammonia nitrogen in the Huai River Basin is therefore required to facilitate restoration. Changing habitat parameters has only a limited effect on alteration of zoobenthos structure. The application of these niche clustering approaches has identified priority locations for ecological restoration in the Huai River Basin. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The results of a study of zoobenthos and zooperiphyton of two rivers of the Ob’ River middle reaches are shown. A comparative analysis of the composition and abundance values of two ecological groups of zoobenthos and zooperiphyton hydrobionts has revealed the difference in their taxonomic compositions and dominant complexes. The similarity in total number and biomass of zoobenthos and zooperiphyton in the large river and the higher values of zooperiphyton quantitative development in a medium river have been identified. [ABSTRACT FROM AUTHOR]

Distribution of crustaceans in 3 transects (including depths of 10, 25, 50, 75, 100, and 200 m) of oligotrophic soft bottoms of the Levantine Sea shelf located near Kumkuyu, Limonlu, and Erdemli was studied in 2000 to show its association with depth-dependent environmental parameters in representative months of each season (winter, spring, summer, and autumn). A total of 90 crustacean species was found; species richness was highest in winter and autumn and between 50 and 100 m in depth. There was a peak value in abundances in the warm season and at a depth interval of 10 to 50 m, whereas highest values of biomass were recorded in May and August and at a depth of 25 m. A seasonal variation at depths shallower than 75 m was observed for evenness values, which were more stable in deeper waters in all seasons. Two main crustacean assemblages were determined, the first corresponding to shallow bottoms (10, 25-100 m) and the other to deeper bottoms (150-200 m). Besides the grain size and total organic carbon content of the sediment, depth is the most important factor in determining the crustacean assemblage. Hydrographic characteristics of the water column made up 2 seasonal crustacean assemblages: the first in February and May, and the other in August and November. Therefore, all factors governing the crustacean distribution were found to be related to the bottom depth. [ABSTRACT FROM AUTHOR]

Spatio-temporal variations of soft-bottom zoobenthic communites in Mersin Bay were examined at seven stations between February and October 2009. A total of 337 species were encountered, of which Polychaeta had the highest number of species (136 species), and Mollusca possessed the highest number of individuals (65% of total specimens) and biomass (59% of total biomass). The highest benthos density (max. 9760 ind. m−2) and biomass (max. 133 g m−2) were found at shallow-water stations, whereas the highest diversity index values were calculated at the deepest station. The molluscs Cerithidium diplax, Corbula gibba and Bittium reticulatum dominated the area. Changes of zoobenthic communities were spatial rather than temporal and were strongly correlated with depth and the sediment structures. A total of 40 alien species were found in the area, of which 15 species were possibly transported to the area by ships and the others were Lessepsian migrants. The most domiant alien species in the area were C. diplax, Finella pupoides, Notomastus mossambicus and Amphiodia obtecta. Alien species formed dense populations at shallow water stations, and accounted for 12% of total number of species and 31% of total number of individuals in the area. The community parameters estimated for alien species significantly differed among stations but not among sampling periods. The main factors negatively affecting the number of alien species and individuals were depth, the clay percentage and total organic carbon concentration in sediment. The number of native species and individuals in the area show moderate positive correlations with those of aliens. [ABSTRACT FROM AUTHOR]

Water levels of Lake Sevan (Armenia) were artificially lowered by nearly 20 m between 1949 and 1997. Lowered water levels, combined with increased eutrophication, were associated with seasonally anoxic conditions (lasting 1-4 months) near the bottom of the profundal zone each year during 1976-2004. In addition, the extents of the macrophyte zone and of certain substrate types were severely reduced following drawdown. Maximal depth of occurrence decreased by 2-44 m for at least for 50 species of benthic macroinvertebrates between 1982 and 2004 compared to 1937-1961. Species richness of benthic macroinvertebrates declined from 25 to three species at depths where seasonal anoxia occurred. Total biomass increased by a factor of 10 from the period 1928-1948 to 1976-1979 then declined by a factor of 3 to 4 between 1987 and 2004. Energy flow through detritivores was more than tripled during 1976-2004 compared to 1928-1971, a result of increased plankton primary production. In contrast, energy flow through herbivorous benthic macroinvertebrates decreased by a factor of nearly 5, due to reduced areal coverage of macrophytes. Energy flow through filter feeders did not change over the time period examined, but energy flow through the entire zoobenthos community was nearly tripled. The biomasses of Oligochaeta, Chironomidae, and total zoobenthos showed a delayed response to changes in primary production of 7-9, 2, and 2-4 years, respectively. These patterns may provide a basis to predict results of restoration efforts based on the abundance of the zoobenthos in future years as the level of the lake is restored and water quality improves. [ABSTRACT FROM AUTHOR]

As a result of integrated studies carried out at the end of August-September 2008-2010, the icthyofauna and food reserve for fish in Oiskoe lake (Ergaky range) were investigated. The trophic status of the lake was estimated based on the biomass of phyto- and zooplankton and zoobenthos. The potential icthyomass, fish production and possible fishing amount were estimated based on calculations of the average biomass and production per season for zooplankton and zoobenthos. [ABSTRACT FROM AUTHOR]

Abstract: In coastal areas, reef-builder worms often are bio-engineers by structuring their physical and biological environment. Many studies showed that this engineering role is determined by the densities of the engineer species itself, the highest densities approximately corresponding to the most stable areas from a sedimentological point of view, and hosting the richest and the most diverse benthic fauna. Here, we tested the potential influence of the spatio-temporal dynamics and the spatial fragmentation of one of the largest European intertidal reefs generated by the marine worm Lanice conchilega (Pallas, 1766) (Annelida, Polychaeta) on the associated benthic macrofauna. We demonstrated that the worm densities do have a significant positive role on the abundance, biomass, species richness and species diversity of the benthic macrofauna and that the reef stability also significantly influences the biomass and species diversity. Moreover, the reef fragmentation has significant negative effects on the abundance, biomass and species richness. In addition to L. conchilega densities, the stability and the spatial fragmentation of the reef also significantly structure the associated benthic assemblages. This study demonstrates the interest of “benthoscape ecology” in understanding the role played by marine engineer species from a spatial point of view. [Copyright &y& Elsevier]

The faunal composition, structure of the zoobenthos communities, and seasonal changes in two springs in the south of Irkutsk area are investigated. Both springs have the water temperature 4-5°C all year round. The fauna consists of widely distributed hydrobionts, crenobionts, stygobionts, and near-water organisms. Arctic relicts and elements of the Lake Baikal fauna are found. In macroinvertebrate communities, chironomid larvae dominate (by abundance and biomass), as do oligochaetes (by abundance). The lowest quantitative parameters are recorded in autumn-winter, and the highest parameters, in spring (March-April). Then they abruptly decline owing to emergence of amphibiotic insects. The structure of spring communities has regional specificity. By biomass of macrozoobenthos, the springs are comparable with mesotrophic and even eutrophic lakes. [ABSTRACT FROM AUTHOR]

On the basis of data for the period 1998-2008, a faunistic review of invasive species of zoobenthos in the upper reaches of the Kuybyshev Reservoir is given. In total, 30 species are revealed: polychaetes-3; oligochaetes-2; leeches-1; mollusks-5; crustaceans-19 (gammarids-9; corophiums-2; cumaceans and mysids-3 each; narrow-clawed crayfish Astacus leptodactilus and shrimp Macrobrachium nipponense). Invasive species account for 10.8% of the total zoobenthos taxonomic composition. For the first time in the Kuybyshev Reservoir, the following species were noted: polychaete Hypaniola kowalewskii; oligochaete Potamothrix heuscheri; gastropod mollusk Physella acuta; crustaceans Pterocuma pectinata, Stenocuma cercaroides, Dikerogammarus villosus, and Pontogammarus robustoides. Quantitative indices of the main systematic groups and selected mass invader species are presented. The decrease in number and biomass of the majority of species is noted. The exception is the mollusk D. bugensis, whose abundance during the study period increased by approximately a factor of ten. [ABSTRACT FROM AUTHOR]

Abstract: The 500km2 of tidal flats at the Banc d''Arguin, Mauritania, are a wintering site for over 2 million shorebirds, making this one of the areas with the highest density of shorebirds in the world. In earlier studies, it was found that these huge numbers of birds are dependent on a rather low biomass of benthic animals. To explain this paradoxical situation, we hypothesized that the earlier assessments of biomass in late winter and early spring do not reflect a year-round situation. Benthic biomass may be high when the birds arrive in autumn to be subsequently grazed down in the course of winter. To test this hypothesis, we have determined benthic biomass in September 1988. The result has been compared with a biomass value obtained in February–April 1986 with the same methods and at the same stations. These two biomass values do not differ significantly; so our hypothesis has to be rejected. It has to be admitted, however, that our experimental design cannot discern between differences due to the year of sampling and those due to the season. [Copyright &y& Elsevier]

Abstract: Mollusc and annelid polychaete macrofaunal assemblages were studied in a sublittoral sandy bottom of 1.8km2 extension, along the western Calabrian coast (low Tyrrhenian Sea). The strict coupling of the local sedimentary dynamics with the benthic assemblages was investigated on a small spatial scale (patchiness), at the mesoscale depth-related gradients and at the level of functional/trophic habits. Non-metrical correlations (ρ), index of dispersion (Di) and dispersion weighted abundances, averaged per depth level highlighted the response of some characteristic species to the patchiness of sediments as well as to the predominant environmental gradients. Species habits and trophic guilds, that were assessed in terms of biomass (wet weight) and secondary “pseudo-production” (abundance×biomass), clarified the differential functional response of the assemblages at different depth levels. Polychaetes reached 84.86% abundance and showed a highly clumped distribution of sessile species (Ditrupa arietina, Aponuphis brementi, Chone acustica, Spiophanes kroyeri); to a lower extent the motile species (Hyalinoecia tubicola, Marphisa bellii, Phylo foetida) were present. Molluscs reached 15.14% abundance and only some bivalve taxa showed significant aggregated distributions (Corbula gibba, Tellina donacina, Tellina distorta), whereas gastropod species were more evenly distributed. Total biomasses were almost equal between the two taxonomic groups (46.41gWW on average). Biotic–environmental rank matching highlighted depth, very fine sands (60–200μm), sorting grade, skewness index and pH as being the most influential factors in the distributions of some species, followed secondarily by coarse silts (40–60μm) and coarser sands (200–2000μm). Within the local context of water/sediment oligotrophy, the adaptive strategies of macrofauna to a highly seasonal supply of autochthonous phytoplanktonic seston associated with imported macro debris and terrigenous components were emphasized. Evidence of such a differential nutrient supply was the clear functional differentiation of the shallower levels from the deeper ones, and the presence of an intermediate zone which was selectively dominated, in terms of abundance and biomass, by microphagous filter/suspension feeders. Moreover, the shortage of burrowing deposit feeders as well as the prevalence of motile macrophagous omnivores beyond 20m depth may be considered as ecologically correlated aspects. [Copyright &y& Elsevier]

Abstract: The objectives of the present study were to describe the species composition, diversity and distribution of the zoobenthic assemblages, to estimate the abundance and biomass of the dominant species, and to identify the main environmental factors determining the distribution patterns of the invertebrates from a freshwater to an estuarine zone in a temperate estuary of South America. The Río de la Plata estuary is a microtidal system characterized by a high concentration of suspended solids. Fifty-three taxa of meso- and macro-invertebrates were identified in the samples collected during November and December 2001. Molluscs, annelids, crustaceans and nematodes were found at 90% of the sampling sites. Molluscs comprised up to about 90% of the total zoobenthos biomass: the remaining percentage corresponded mainly to annelids and less to nematodes and crustaceans. An ecocline along the salinity gradient could be observed for the benthic assemblages from the freshwater to the estuarine zone in Rio de la Plata. A Canonical Correspondence Analysis shows that results from sampling sites in the outer zone were strongly related to salinity, depth and pH and less to oxygen and percentage of clay. The results from stations in the inner zone, and part of the middle zone, were mainly related to the occurrence of sand and contents of NH4 +–N, NO3 −–N, and PO4 3−–P. [Copyright &y& Elsevier]

Corer samples of zoobenthos were collected in 20 coastal water bodies of western Estonia including 2 inner parts of bays of the Baltic Sea, 5 lagoons weakly connected with the sea, and 13 freshwater lakes in August 2004. Reigi laht, an open bay, was the only site where brackishwater taxa dominated; in the same bay, eumeiobenthic small Nematoda were very abundant. At all other sites, the bulk of meiobenthos was formed of small, pseudomeiobenthic individuals of Chironomidae and Oligochaeta, while eumeiobenthos, consisting here mainly of Nematoda and Ostracoda, was outnumbered by the former. The near-bottom planktic Cladocera and Copepoda were also common. Freshwater taxa dominated in all lagoons and lakes, with scarce brackish-water species accompanying them in the lagoons as well as in some lakes. The abundance and biomass of pseudoand eumeiobenthos, as well as of planktic crustaceans, were higher in the lagoons than in the freshwater lakes. [ABSTRACT FROM AUTHOR]

Structural and functional characteristics of zoobenthos of the Cheshskaya Bay (SE Barents Sea) were studied at 21 stations in June/July 1995. Strong prevailing cyclonic and tidal currents result in relatively uniform temperature and salinity in the area. Sediments consist mainly of sand and pebbles, while the flux of suspended matter from rivers locally increases the share of finer fractions. Analysis of species composition (419 taxa), abundance (up to 4,200 ind m−2 and up to 29,000 ind m−2 with juveniles) and biomass (up to >6,000 g wet wt m−2) indicates high species richness in most parts of the bay, especially in the northeast. Analysis of community structure using production characteristics of species revealed a general predominance of suspension feeders partitioned into seven communities. The dominant species of these communities were Mytilus edulis and Balanus crenatus (Type 1), B. crenatus (Type 2), Modiolus modiolus and Verruca stroemia (Type 3), Flustra foliacea and V. stroemia (Type 4), Hydrallmania falcata (Type 5), V. stroemia and Chirona hameri (Type 6), and Ophelia limacina (Type 7). The structure of the communities is mainly regulated by sediment type, water depth and, to some extent, by riverine input. [ABSTRACT FROM AUTHOR]

Xiangxi Bay, a typical bay of the Three Gorges Reservoir (TGR) in China, was formed in June 2003 after the impoundment of the TGR. We investigated the community structure of zoobenthos in Xiangxi Bay from August 2003 to August 2004. Benthic abundance and biomass were calculated per unit area of sediment. A total of 26 taxa were identified. They included two families of Lamellibranchia (7.7% of the total taxa number), two families of Oligochaeta (50%), Chironomidae (38.5%), and one other animal (3.8%). The average density and biomass were 276 ind./m2 and 0.301 g/m2, respectively. Oligochaetes and chironomids constituted the major groups, and Limnodrilus hoffmeisteri, Procladius sp., Branchiura sowerbyi, Tubificidae sp1. and Polypedilum scalaenum group sp. were the common taxa in this reservoir system. Among them, L. hoffmeisteri and Procladius sp. were the dominant species, and contributed 37.0% and 28.3% of the total density, respectively. The standing crop of zoobenthos in Xiangxi Bay was relative low, compared with other similar reservoirs. Our studies demonstrate that the standing crop increased gradually with time. The total density and biomass in August 2004 were 8.8 and 14.3 times those of the initial impoundment, separately. Oligochaetes did not become the sole dominant group, indicating that the sediment loading in Xiangxi Bay may be not serious. [ABSTRACT FROM AUTHOR]

Abstract: Mass occurrence of macroalgae is a phenomenon attributed to eutrophication, and can lead to drastic changes in the benthic communities on soft bottoms. While the negative effects of macroalgal blooms on the macrozoobenthos have been studied extensively, the effects of the infauna on the macroalgal material have not previously been studied in the northern Baltic Sea. The impact of the infaunal species Nereis diversicolor and Saduria entomon on the burial and biomass of Enteromorpha spp., Cladophora glomerata and Fucus vesiculosus, was assessed through a series of microcosm experiments. Results show that S. entomon did not significantly affect the biomass of the algae, nor actively relocate them. N. diversicolor redistributed the filamentous green algae into the sediment, down to 4 cm at most, and decreased the biomass of the filamentous algae by 140–360%. Furthermore, the loss of biomass promoted in presence of polychaetes proved to be a density dependent process. The effect on the perennial macroalgal species, F. vesiculosus, was less clear, as no redistribution or significant change in macroalgal biomass was observed. Our findings show that infauna can contribute to a loss in macroalgal biomass through feeding and burrowing activities leading to the redistribution and incorporation of the detritus into bioturbated sediment. [Copyright &y& Elsevier]

We characterised benthic invertebrate community composition in 11 oligotrophic, alpine lakes. Nematodes were the most abundant benthic taxa in most lakes but community composition differed markedly. Several relationships between the invertebrate taxa were found but there was no strong evidence that competition or predation shaped the benthic community structure. Most lakes were dominated by a few nematode species with cosmopolitan distribution. Obligate and/or facultative parthenogenetic species were most abundant. With increasing species richness, the overall sex-ratio increased and the relative abundance of parthenogenetic species decreased. [ABSTRACT FROM AUTHOR]

Abstract: High-latitude seas are mostly covered by multi-year ice, which impacts processes of primary production and sedimentation of organic matter. Because of the warming effect of West Spitsbergen Current (WSC), the waters off West Spitsbergen have only winter ice cover. That is uncommon for such a high latitude and enables to separate effects of multiyear-ice cover from the latitudinal patterns. Macrofauna was sampled off Kongsfjord (79°N) along the depth gradient from 300 to 3000m. The density, biomass and diversity at shallow sites situated in a canyon were very variable. Biomass was negatively correlated with depth (, p<0.001), and ranged from 61gwwm-2 (212m) to 1gwwm-2 (2025m). The biomasses were much higher than in the multiyear-ice covered High Arctic at similar depths, while resembling those from temperate and tropical localities. Species richness (expressed by number of species per sample and species–area accumulation curves) decreased with depth. There was no clear depth-related pattern in diversity measures: Hurbert rarefaction, Shannon–Wiener or Pielou. The classic increase of species richness and diversity with depth was not observed. Species richness and diversity of deep-sea macrofauna were much lower in our study than in comparable studies of temperate North Atlantic localities. That is related to geographic isolation of Greenland–Icelandic–Norwegian (GIN) seas from the Atlantic pool of species. [Copyright &y& Elsevier]

Abstract: Size structure, taxonomic composition and bioturbation potential of benthic metazoan communities were examined at three contrasting sites on the northwest European continental margin as part of a wider study of biogeochemical cycling in the deep-sea benthic boundary layer. Sampling was conducted in the Hatton–Rockall Basin (1100 m depth), on the North Feni Ridge (1920 m) and in the South Rockall Trough (3580 m) on two cruises bracketing the expected 1998 spring phytodetrital flux. Density and biomass of epibenthic megafauna declined with depth and were consistent with previous data from the deep northeast Atlantic. Aggregations of the hexactinellid sponge Pheronema carpenteri occurred at 1100 m. The percentage contribution of suspension-feeders to megafaunal biomass at the lower slope sites was much higher than expected for these depths. Macrofauna (sensu stricto) were consistently undersampled by a box corer relative to an hydraulically damped multiple corer. Estimated macrofaunal densities declined with depth. Polychaete trophic group structure was very different at the three sites, with more small carnivores at 1100 m, surface deposit and interface-feeders at 1920 m, and a higher representation of subsurface deposit-feeders at 3580 m. Meiofaunal densities were low in comparison with published data from comparable depths in the northeast Atlantic. Meiofaunal numbers increased at all three sites from May to July 1998. The increase at 1920 m was statistically significant and was associated with the greatest phytodetrital accumulation observed during the study period. The relative contribution of the mega-, macro- and meiofauna to benthic metazoan biomass did not vary consistently with depth, and no trend was apparent in a review of data from other studies in the North Atlantic. Depth-related patterns in community size structure recorded from previous North Atlantic studies were not all replicated, suggesting the importance of local hydrodynamics and other environmental factors. There was no obvious link between faunal parameters and biodiffusion coefficients or mixing modes estimated from radiotracer profiles. Diffusion-analogue 210Pbexcess profiles recorded at 3580 and 1100 m resulted from a combination of macrofaunal and megafaunal sediment mixing, some of it advective. At 1920 m, a combination of deep megafaunal subduction and near-surface concentration of macrofaunal feeding activity produced subsurface radiotracer peaks. The poorly known burrowing megafauna probably play a significant role in bioturbation at all three sites. [Copyright &y& Elsevier]

This work presents new empirical and dynamical models for benthic algae in lakes. The models were developed within the framework of a more comprehensive lake ecosystem model, LakeWeb, which also accounts for phytoplankton, bacterioplankton, two types of zooplankton (herbivorous and predatory), macrophytes, prey fish and predatory fish. The new dynamic model provides seasonal variations (the calculation time is 1 week). It is meant to account for all factors regulating the production and biomass of benthic algae for lakes in general. This work also presents and uses a new data-base established by us from published sources. Many of the lakes included in this study are situated in the former Soviet Union. They were investigated during the Soviet period and the data and results have up until now been largely unknown in the West. We present empirical models for benthic algae, and show that the biomass of benthic algae in whole lakes can be estimated from the ratio between the lake area above the Secchi depth to the total lake area and the primary production of phytoplankton. We also present several critical tests of the dynamical model. The dynamical and empirical models give corresponding results over a wide limnological domain. We provide algorithms for (1) the production rate of benthic algae (2) the elimination rate (related to the turnover time of benthic algae), (3) the rate of benthic algae consumption by zoobenthos, and (4) the rate of physical erosion of benthic algae. Our results indicate that the production of benthic algae is highly dependent on lake morphometry and sediment character, as well as water clarity, and less dependent on nutrient (phosphorus) concentrations in water and sediments. This work provides new quantitative support to such conclusions and also a useful model for predictions of production and biomass of benthic algae. [ABSTRACT FROM AUTHOR]

Zoobenthic communities of Neva Bay and the eastern Gulf of Finland were determined using a complex of structure indices, such as species composition, number of species, abundance, biomass, and indices calculated on their basis, in particular the Shannon diversity index. The state of the ecosystems and the quality of the water of Neva Bay and the eastern Gulf of Finland were assessed using the Integrated Index (IP) specially devised for these ecosystems. It was shown that in 1994 through 2001 the role of oligochaetes in Neva Bay increased gradually, whereas the role of other taxa of benthic invertebrates declined. The water quality in the major part of Neva Bay was assessed by IP for 2001 as "polluted--dirty" and the state of the ecosystem as "crisis". In the northern shallow area of the eastern Gulf of Finland eurybiont species of the freshwater complex, i.e. oligochaetes, chironomid larvae, and molluscs of the Pisidiidae family, dominated in terms of biomass over other groups of aquatic organisms during the study period. The assessment of the state of the eastern Gulf of Finland in 2001 showed that with an increase of depth and salinity in the western direction the degree of pollution declined. [ABSTRACT FROM AUTHOR]

The mining company Karelian Pellet in NW Russia extracts iron ore and processes it locally into iron pellets. The production operations have effects on the environment in the form of air pollution (SO2 and dust) and waste water emissions. The waste waters from the process and the mining pits are let out into a dammed basin, formerly the natural Lake Kostomuksha. This basin flows north-east through several small lakes (e.g., Poppalijärvi, Kento) to the larger lake Middle Kuito and the White Sea. For these small lakes an exceptionally high mineral content, high pH value, and high concentrations of potassium, lithium and nitrogen in the water have been characteristic. However, the total phosphorus content (6–9 μg l-1) is slightly lower than in the Lake Upper Kuito (11–13 μg l-1) which acts as a reference lake. Biota from bacteria to fish were quantitatively sampled in August 2000 and 2001. Our results suggest a twice higher biomass of both phytoplankton (mainly picoalgae) and fish (biomass per unit effort) in the lakes downstream from the mine in comparison to the reference lake. Zooplankton and zoobenthos biomass both peak in L. Kento, the lake in the middle of the outflow series. The fish fauna (seven to eight species caught) is the same in all lakes and is dominated by perch and roach. Both grow well and roach show best growth in L. Poppalijärvi, next to the waste basin. Perch gills show some histopathological changes which do not, however, appear to affect either growth or reproduction. [ABSTRACT FROM AUTHOR]

In different parts of the Dutch Wadden Sea, relationships between intertidal level and abundance of marine macrozoobenthos were similar. Numerical densities, biomass and species richness increased from values close to 0 at the high-water level to maximum values around mean-tide level (numbers) or halfway between this level and low-tide level (biomass). Species richness hardly declined below mean-tide level, whereas mean weight per individual continued to increase from high- to low-water level.Biomass was about 45 g ash-free dry weight per m2 at its maximum and declined in an approximately linear way to values close to 0 at the high-water level and to about 7 g per m2 at the low-water level. These two linear relationships were used to predict biomass changes on intertidal flats of the Wadden Sea at various scenarios of sea-level rise and bottom subsidence. Net sea-level rise is expected to result in increased amounts of intertidal zoobenthos in areas with predominantly high tidal flats, but in declines in lower areas. However, such changes will occur only if sea-level rise proceeds too fast to be compensated by extra sedimentation. Bottom subsidence as a consequence of gas extraction is expected to be too small to cause any measurable change in the benthic fauna. [Copyright &y& Elsevier]