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The present subchapter focuses on benthic shrimps, worms, gastropods, bivalves and other invertebrates living on or in the sea floor that are important food sources for fishes, marine mammals, seabirds and humans, as well as invertebrate species that are targeted by some commercial fisheries. Those taxa form the basis for some of the most productive ecosystems on the planet (e.g., estuaries and coral reefs), rivalling tropical forests (Valiela, 1995) and creating habitats covering more of the Earth’s surface than all other habitats combined (Snelgrove and others, 1997). Changes in ocean use, the harvesting of organisms, climate change, pollution and invasive species contribute to global alterations in nature at rates unprecedented in human history. Historically, coastal biota have experienced greater pressures and impacts than the deep sea, but the depletion of coastal marine resources and new technologies create both the capacity and incentive to fish, mine and drill in some of the deepest parts of the ocean (McCauley and others, 2015). Alterations of biodiversity often erode economies, livelihoods, food security, health and quality of life worldwide (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), 2019)., peer-reviewed

This study reports some responses to hydrologic alteration of benthic animals in the downstream reaches of reservoir dams for figuring out what kind of hydrologic alteration by dam operation makes influence to benthic animals. Some correlations between reduced ratio of index of hydrologic alteration (IHA) and quotient of similarity (QS) of the number of taxa of Ephemeroptera, Plecoptera and Trichoptera (EPT) shows that reduction of annual maxima flow degrades number of EPT taxa and on the other side increase of annual minima flow degrades number of EPT taxa.

There is a global increase in urbanization, which contributes to the loss and fragmentation of urban wetland and pond habitats. Urban ponds have an important role in the ecology of urban areas, as they provide essential habitats for aquatic species. The objective of this study is to demonstrate ecological engineering approaches to restoring aquatic biological communities in an urban pond ecosystem, which can be used to achieve water purification of such ecosystems globally. The general approach of first cleaning out the ponds and then systematically applying different treatments of plants and fish was designed and implemented in the field. We used three replicated ponds per engineering treatment to determine which of the treatments was the best option based on an assessment of water quality and biological indicators. The main findings of this study were as follows: a combination of aquatic animals and aquatic plants can provide the best water purification performance; furthermore, macrobenthos, such as Bellamya purificata, can be used as biological indicator species for monitoring dominant species and water quality in a local urban pond ecosystem. In conclusion, maintaining biological species diversity over different trophic levels can provide the best water purification performance in urban pond ecosystems.

To evaluate food habits of the Japanese clawed salamander larvae (Onychodactylus japonicus), we examined stomach contents of 22 individuals collected from a natural mountain brook in a tributary of the Kurokawa River in Kiso Fukushima, Nagano Prefecture, central Japan. Their diet composition did not differ between fast and slow current conditions. The diet reflected the natural benthos communities of the brook, in which mayfly nymphs and caddisfly larvae accounted for 70–88%. The salamander larvae selectively foraged on caddisfly and fly larvae in the two current conditions. In the slow current condition, their prey preference was detected in the prey group including terrestrial invertebrates. Our results suggest that theprey items of O. japonicus larvae hinge primarily on the natural benthos communities.

Aquatic animals play an important role in the energy flow and matter cycling in the wetland ecosystem. However, little is known about their effects on pollutant removal performance and microbial community in constructed wetlands. This work presents an initial attempt to investigate the effects of Misgurnus anguillicaudatus (loach) and Cipangopaludina cathayensis (snail) on nutrient removal performance and microbial community of constructed wetlands (CWs). Compared with a control group, CW microcosms with aquatic animals exhibited better pollutant removal performance. The removal efficiencies of total phosphorus (TP) in the loach group were 13.1% higher than in the control group, and snails increased the ammonium removal most effectively. Moreover, the concentration of total organic carbon (TOC) and TP in sediment significantly reduced with the addition of loaches and snails (p &lt, 0.05), whereas the concentration of total nitrogen (TN) showed an obvious increase with the addition of loaches. High-throughput sequencing showed a microbial community structure change. Loaches and snails in wetlands changed the microbial diversity, especially in the Proteobacteria and denitrifying community. Results suggested that benthic aquatic animals might play an important role in CW ecosystems.

Distribution of soft sediment benthic fauna and the environmental factors affecting them were studied, to investigate changes across spatial and temporal scales. Investigations took place at Lough Hyne Marine Reserve using a range of methods. Data on the sedimentation rates of organic and inorganic matter were collected at monthly intervals for one year at a number of sites around the Lough, by use of vertical midwater-column sediment traps. Sedimentation of these two fractions were not coupled; inorganic matter sedimentation depended on hydrodynamic and weather factors, while the organic matter sedimentation was more complex, being dependent on biological and chemical processes in the water column. The effects of regular hypoxic episodes on benthic fauna due to a natural seasonal thermocline were studied in the deep Western Trough, using camera-equipped remotely-operated vehicle to follow transects, on a three-monthly basis over one year. In late summer, the area below the thermocline of the Western Trough was devoid of visible fauna. Decapod crustaceans were the first taxon to make use of ameliorating oxygen conditions in autumn, by darting below the thermocline depth, most likely to scavenge. This was indicated by tracks that they left on the surface of the Trough floor. Some species, most noticeably Fries’ goby Lesueurigobius friesii, migrated below the thermocline depth when conditions were normoxic and established semi-permanent burrows. Their population encompassed all size classes, indicating that this habitat was not limited to juveniles of this territorial species. Recolonisation by macrofauna and burrowing megafauna was studied during normoxic conditions, from November 2009 to May 2010. Macrofauna displayed a typical post-disturbance pattern of recolonisation with one species, the polychaete Scalibregma inflatum, occurring at high abundance levels in March 2010. In May, this population had become significantly reduced and a more diverse community was established. The abundance of burrowing infauna comprising decapods crabs and Fries’ gobies, was estimated by identifying and counting their distinctive burrow structures. While above the summer thermocline depth, burrow abundance increased in a linear fashion, below the thermocline depth a slight reduction of burrow abundance occurred in May, when oxygen conditions deteriorated again. The majority of the burrows occurring in May were made by Fries’ gobies, which are thought to encounter low oxygen concentrations in their burrows. Reduction in burrow abundance of burrowing shrimps Calocaris macandreae and Callianassa subterranea (based on descriptions of burrow structures from the literature), from March to May, might be related to their reduced activity in hypoxia, leading to loss of structural burrow maintenance. Spatial and temporal changes to macrofaunal assemblage structures were studied seasonally for one year across 5 sites in the Lough and subject to multivariate statistical analysis. Assemblage structures were significantly correlated with organic matter levels in the sediment, the amounts of organic matter settling out of the water column one month before macrofaunal sampling took place as well as current speed and temperature. This study was the first to investigate patterns and processes in the Lough soft sediment ecology across all 3 basins on a temporal and spatial scale. An investigation into the oceanographic aspects of the development, behaviour and break-down of the summer thermocline of Lough Hyne was performed in collaboration with researchers from other Irish institutions.

The ecological role of foraminifers has been largely unknown partly owing to difficulties in determining their individual biomass, although foraminifers are abundant in surface marine sediments. The present study provides a reliable and inexpensive method for the quantification of the protein content of hard-shelled foraminifers as a measure of biomass while preserving the tests for later analyses (e.g. morphometry, stable isotopes), using nanospectrophotometry. The protein biomass, is significantly correlated with size, and shell weight of Ammonia tepida (n = 102, p < 0.00001, R2 = 0.462, and n = 181, p < 0.00001, R2 = 0.855). Variability in the relation between test size and weight, and cell biomass may result from natural variability in horizontal and vertical microenvironments encompassing metabolic state, as well as variability in test morphometry and calcite mass (i.e. test weight). In turn, knowing the sizeand species-specific biomass of foraminifers adds valuable information on the trophic and ecologic conditions of modern and ancient marine environments, in particular on the reconstruction of the regional palaeoproductivity and flux of organic matter., peer-reviewed

Without industrial and urban development and their effects on marine ecosystem, due to high biotic potential, Khure-Mussa would be one of the productive coastal areas. Because of sensitivity and vulnerability to environmental changes this area are classified in sensitive ecologic area. This study was conducted to evaluation ecological health status in Khure-Mussa in the Northwest of Persian Gulf by using benthic indices. Twenty creeks in Khure-Mussa area were set up for study and sampling in four seasons from winter 2008 to autumn 2009. Monthly water sampling for physico-chemical parameters was done by bottle sampler and seasonal samples of surface sediment were collected by Peterson grab sampler (0.125m^2) .At each station three samples for macrobenthic study and one sample for grain size analysis and organic matter determination were obtain. Totally, 187589 macrobenthic individual were collected and separated. Among identified groups, Polychaetes with total number108906, Crustacean with total number 46561, Bivalve with total number 14156 and seapen with total number 9841 were the dominant groups and were included 58, 25, 8 and 5 percentage of total number respectively. The highest abundance in the spring and the lowest abundance in the summer were observed. According to mean abundance, Somaily creek and Khure-mussa (3) station showed the highest and the lowest abundance respectively. Seapen is included more than 90 % of total biomass. The range of Shannon diversity index was (1.95-3.58) which the minimum and the maximum values were found in Shipping and Patil station respectively. Significance benthic biological parameters (abundance and richness) in different creeks explained the variation of benthic community structure in studied creeks. In addition, seasonal significant differences were found in these parameters due to seasonal changes in benthic animal s succession. The results of grain size analysis showed that the range of siltclay was (63.6-95.59). According to AMBI index values, all of the studied creeks are classified in slightly pollution level and disturbed condition except for Petrochemical station that placed in moderate pollution level. The BOPA index values in all stations showed more than threshold level (0.19) that means bad and weak ecological condition. The highest and the lowest ITI index values were observed in Oil exporting port station (64.92) and Ghazaleh creek (29.53) respectively. The others were grouped in 30-60 range that means moderate pollution level and disturbed ecological status. The values of ABC (Abundance Biomass Curve) that explained the relation between macrobenthic biomass and abundance, were calculated near zero from 0.1 to -0.1 in all studied creeks that show moderate condition for living animals. In general the studied creeks showed pollution potential and benthic biological parameters indicated downward trend in ecological quality and health status.

Without industrial and urban development and their effects on marine ecosystem, due to high biotic potential, Khure-Mussa would be one of the productive coastal areas. Because of sensitivity and vulnerability to environmental changes this area are classified in sensitive ecologic area. This study was conducted to evaluation ecological health status in Khure-Mussa in the Northwest of Persian Gulf by using benthic indices. Twenty creeks in Khure-Mussa area were set up for study and sampling in four seasons from winter 2008 to autumn 2009. Monthly water sampling for physico-chemical parameters was done by bottle sampler and seasonal samples of surface sediment were collected by Peterson grab sampler (0.125m2) .At each station three samples for macrobenthic study and one sample for grain size analysis and organic matter determination were obtain. Totally, 187589 macrobenthic individual were collected and separated. Among identified groups, Polychaetes with total number108906, Crustacean with total number 46561, Bivalve with total number 14156 and seapen with total number 9841 were the dominant groups and were included 58, 25, 8 and 5 percentage of total number respectively. The highest abundance in the spring and the lowest abundance in the summer were observed. According to mean abundance, Somaily creek and Khure-mussa (3) station showed the highest and the lowest abundance respectively. Seapen is included more than 90 % of total biomass. The range of Shannon diversity index was (1.95-3.58) which the minimum and the maximum values were found in Shipping and Patil station respectively. Significance benthic biological parameters (abundance and richness) in different creeks explained the variation of benthic community structure in studied creeks. In addition, seasonal significant differences were found in these parameters due to seasonal changes in benthic animal s succession. The results of grain size analysis showed that the range of siltclay was (63.6-95.59). According to AMBI index values, all of the studied creeks are classified in slightly pollution level and disturbed condition except for Petrochemical station that placed in moderate pollution level. The BOPA index values in all stations showed more than threshold level (0.19) that means bad and weak ecological condition. The highest and the lowest ITI index values were observed in Oil exporting port station (64.92) and Ghazaleh creek (29.53) respectively. The others were grouped in 30-60 range that means moderate pollution level and disturbed ecological status. The values of ABC (Abundance Biomass Curve) that explained the relation between macrobenthic biomass and abundance, were calculated near zero from 0.1 to -0.1 in all studied creeks that show moderate condition for living animals. In general the studied creeks showed pollution potential and benthic biological parameters indicated downward trend in ecological quality and health status. Iranian Fisheries Science Research Institute Published

While studying regularities of the distribution of bioceonoses of the sea ground fauna, the abundance of animals and the amount of biomass, a direct connection can be noticed with the granulometric composition of bottom sediments and the depth. Coarser sediments of the bottom make optimum conditions for the development of zoobenthos. With the sediments getting finer and the depth decreasing, the biomass of some zoobenthic organisms also decreases (e. g., Macoma baltica), but the abundance of polychaetes (Pygospio elegans) notably increases. In the Nida–Juodkrantė water area where the bottom is vcovered with fine and intermediate sand, the dominant are the Pygospio elegans–Macoma baltica– Mesidotea entomon biocoenoses which are very important as a food resource for benthophagous fish, especially cod. This work offers an analysis of background data on macrozoobenthic communities at different depths of the Nida–Juodkrantė water area (the economic zone of the Republic of Lithuania). Zoobentoso bendrijos užima svarbią vietą Baltijos jūros priekrantės ekosistemos funkcionavime. Nidos–Juodkrantės dugno biocenozių struktūra ir produktyvumas priklauso nuo grunto granulometrinės sudėties, jūros gylio ir organizmų tarpusavio ryšio. Gargždu, rieduliais ir morena padengtas jūros dugnas – tai substratas Mytilus edulis moliuskų kolonijoms. Ši biocenozė paplitusi tik giluminėje tirtos akvatorijos zonoje ir yra svarbi biofiltracijai. Didelį neigiamą poveikį ekosistemai daro patekę į vandenį naftos produktai. Jei įvyktų avarija D-6 naftos gręžinyje ir išsilietų daugiau naftos, Mytilus edulis biocenozė būtų pažeista. Tai neišvengiamai turėtų didelę neigiamą įtaką visai ekosistemai. Didesnėje Nidos–Juodkrantės jūros akvatorijos dalyje, kur dugno nuosėdas sudaro smulkus ir vidutinis smėlis, vyrauja polichetų Pygospio elegans, moliuskų Macoma baltica ir vėžiagyvių Mesidotea (Saduria) entomon biocenozė, kuri svarbi bentofaginių žuvų mityboje. Čia patekę į vandenį naftos produktai labai pablogintų žuvų pašarų bazę.

All marine species studied thus far show rhythmic temporal patterns in their behavioural, physiological, and molecular functions, which are collectively known as biological rhythms. Biological rhythms are generated by biological clocks that time biological functions and are synchronized by geophysical cycles, such as the solar light-dark cycle and tidal cycle. On continental margins, behavioural rhythms can be detected by diel (i.e., 24-hour based) or seasonal periodical trawling as a consequence of massive inward and outward displacements of populations to and from the sample areas. As a result, significant errors in population/stock and biodiversity assessments performed by trawling may occur if timing of sampling is not taken into account. The increasing number of cabled and permanent multiparametric seafloor observatories now allows direct, continuous, and long-lasting monitoring of benthic ecosystems and analysis in relation to several habitat cycles. This review describes the adaptation of this technology to investigations of rhythmic behaviour by focusing on automated video imaging. Diel fluctuations in the number of video-observed individuals can be used as a measure of average population rhythmic behaviour. The potential implementation of automated video image analysis in relation to animal tracking and classification procedures based on the combined use of morphometric tools and multivariate statistics is detailed in relation to populational and community studies. Based on video cameras mounted at multiparametric cabled observatories, an integrated time-series analysis protocol using chronobiomedical procedures is proposed to place video-recorded bioinformation in an oceanographic context.