Invasive Spartina alterniflora-induced factors affecting epibenthos distribution in coastal salt marsh, China

Artificially introduced cordgrass, Spartina alterniflora, rapidly colonized the intertidal flats of the Jiangsu coast, eastern China. The epibenthos on an intertidal flat invaded by S. alterniflorawere studied, to identify how local epibenthos species react to an altered environment. Epibenthic samples and surficial sediment samples were collected along a shore-normal profile in 50 quadrats at ten stations across the Spartina salt marsh; and five control quadrats for a station located on the barren sandy-mud flat. The grain size param- eters of the surficial sediments show that S. alterniflora altered the grain size gradient along the profile of the intertidal zone by trapping fine-grained sediments. Spartina alterniflora could inhabit lower elevation- s than indigenous salt marsh vegetation, thus creating larger areas of finer surficial sediments, which was suitable for not only native epibenthic species but also species which do not exist on the barren sandy-mud flat. Correlation analyses show that the epibenthos were sensitive to sediment grain size and type, on the invaded S. alterniflora salt marsh. Further, there was an interspecific relationship affecting the distribution of epibenthos. The results show that epibenthos preferred ecological niches, within the Spartina salt marsh, even in the same sampling station.

Seasonal and Spatial Variations of Macro Benthos in the Intertidal Mudflat of Southern Yellow River Delta,China in 2007/2008

In order to examine the seasonal and spatial distributions of benthic animals in the intertidal mudflat of the southern Yellow River Delta,field investigations were carried out in 2007 and 2008 and multiple methods were applied.Results showed that,the biomass of macro benthos ranged at 0.75-1151.00 g wet m^(-2) and averaged at 156.31 g wet m^(-2),in which Mactra veneriformis accounted for 75.6%-93.4% of the total macro benthic biomass.More than 90% of macro benthos inhabited in the middle and low tide lines,and higher biomass occurred in early summer and lower in winter.Statistical analysis showed that:1)M.veneriformis growth was primarily favored at higher temperature and lower salinity;2)after long time interaction,benthic bivalve grazers led to patching distributions of Chlorophyll a(Chl a);3)macro benthic biomass positively related with Chl a when the concentration of Chl a was low,but they were negatively related when Chl a concentration was high;and 4)furthermore,the biomass of benthic bivalves peaked in the sediment with median grain size about 0.55 mm,but decreased gradually in coarse or fine sediments.The secondary productivity ranged at 0.37-283.68 g m^(-2)yr^(-1) and averaged at 47.88 g m^(-2) yr^(-1),in which 69.7% was contributed by M.veneriformis It was estimated that primary production was transformed to secondary production at a rate of 6.87%approximately,which implies that there is a local sustainability of high bivalve production.

Potential ecological risks of Cd for different benthos in artificial reefs

Inductively coupled plasma mass spectrometry is used to detect Cdforbenthos in the artificial reef .The results show that： Cd of benthos is varied from0.011μg/L to 0.541 μg/L, and averages 0.188 ± 0.220 μg/L. The distribution of Cddecreased in the order： gonads〉 gills〉 muscle in different tissues. The enrichmentregalurity in muscle Cd of different benthos was Oratosquilla, crab, fish, shrimp,ocellatus. Its health risk factor is far less than 1, indicating that Cd hasn’t obvious healthrishks on exposure population.

A preliminary study on benthos food web structure oftidal zone in the Laoshan Bay by using stable carbon isotopes

By anayses of carbon isotopic composition (δ13C values) of the benthos collected in the Laoshan Bay in August 1993 and February and May 1994, it is found that the main food sources of the benthos can be divided into four groups in terms of carbon isotope composition: Particulate Organic Matter (POM), benthic diatoms, benthic macroalgae and the organic matter in sediments. The results show that the carbon isotopic composition of the benthic animals has a close relation with that of the food they take in. The Carbon isotopic compositions of benthos may be useful in elucidating their food sources. The carbon isotopic data have confirmed that POM is the main food source of the benthic filter feeders such as bivalves; crustaceans have a wide range of δ13C values, showing their food source has diversity; benthic diatoms are an important fraction of the food for most of gastropods. A preliminary investigation of the benthic-pelagic coupling in that region using the stable carban isotopic tracers has confirmed the importance of POM as a food source for benthos in this region, but the organic matter in sediments and benthic diatoms are also relatively important for a lot of benthic animals. The benthic-pelagic coupling in the Laoshan Bay temperate ecosystem is not so tight as that in ecosystems at higher latitudes such as northeastern water polynya.

A STUDY ON THE QUANTITY OF SHALLOW SEA BENTHOS IN GREAT WALL BAY, ANTARCTICA

Based on the investigation material acquired during the three cruises of the 4 Chinese Antarctic Research Expedition at 19 quantitative dredging stations and 4 trawling stations from the period December 1987 to March 1988, this paper studies the quantity of the benthos in Great Wall Bay,the distributive characteristics and variations, and points out that the stock number of the benthos in the bay is extremely large and that there are two large ranged high mass area and 2 - 3 low small-ranged mass area. The instability of the sediments is the cause for the low.mass areas. The warm season is the vigorous reproductive period of the various kinds of the benthos and the monthly variation of the quantity is remarkable.

Biological Evaluation of Water Quality for Benthos in Typical Rivers of Eastern Jilin Province

Benthos are aquatic organisms living at the bottom of water bodies for all or most of their life history.Apart from the settled and moving living,their forms of habitat are mostly attached to the hard substrate like rocks or soft bases such as mud and sand.In addition,there are benthic species that attach to the plant surfaces or other benthic animals,and inhabit the intertidal zone.In terms of feeding methods,most benthic animals feed on suspended matter and sediment.Most of them are invertebrates and are a complex ecological group.According to the size,they can be divided into macrobenthos and meio-benthos[1].Benthos are an important part of the water ecosystem.Using a typical river(Gaya River)in eastern Jilin Province,this paper analyzed the water quality,the components of benthic organisms and their biological density through sampling surveys of three typical locations in the upper,middle and lower reaches of the Gaya River.In addition,it made a biological evaluation of the water quality of the Gaya River.

Striking Century-Long Changes in Marine Benthos

One of the oldest published records of benthic fauna was made in 1893 by dredging along transects from soft bottoms, sand and shell debris to rocky bottoms in an archipelago at the Swedish Skagerrak coast. Three of the transects were revisited in 2010 and then fewer taxa were recorded and the shared species between sampling dates at the transects were only between 8% and 12%. The main causes for the drastic changes are suggested to be large-scale eutrophication changing the vegetation composition and variation of climatic factors.

The Spatio-temporal Patterns of Macro Benthos Functional Groups and the Associated Factors Affecting Them after Wetland Restoration

This study examines how the spatiotemporal patterns of functional groups of macro benthos responded to coastal wetland restoration projects. Compared with the traditional single-species approach, methods for identifying functional groups of macro benthos more comprehensively reflect the states of the wetland, i.e., spatiotemporal patterns and the related influencing factors. In this study, the macro benthos samples, soil samples, and plant samples were collected at each same sample site in April, July, and October of 2017 and January of 2018. After classification of the macro benthos functional groups according to some traits, the factors influencing the functional groups were examined by a linear stepwise regression. The results showed that all macro benthos were classified into 11 different functional groups based on their traits of forms of locomotion, feeding habits, and food gathering methods. The semi-mobile suspensivores(FDX), semi-mobile surface detritivores(SDX), and Jawed mobile carnivores(CMJ) were the main groups observed in a year. Regression analysis showed that particle size,moisture content, and plant height were important common factors influencing most groups. The main influencing factor of FDX was particle size(P=0.020). Moisture content(P=0.004), plant cover degree(P=0.008), and particle size(P=0.032) comprised the main restrictions of SDX in summer. Soil salinity(P=0.040) and plant height(P=0.011)were the factors influencing CMJ in autumn and winter. This study shows the changing characteristics of macro benthos functional groups to promote coastal wetland restoration and future biogeomorphological studies.

Polycyclic aromatic hydrocarbons in benthos of the northern Bering Sea Shelf and Chukchi Sea Shelf

Eighteen polycyclic aromatic hydrocarbons(PAHs)were detected in benthos collected onboard the‘Snow Dragon’in the Northern Bering Sea Shelf and Chukchi Sea Shelf during the 6 th Chinese National Arctic Research Expedition(CHINARE 2014).18 PAHs for all biota samples ranged from 34.2 to 128.1 ng/g dry weight(dw),with the highest concentration observed in fish muscle(Boreogadus saida)samples close to St.Lawrence Island.The PAH composition pattern was dominated by the presence of lighter 3 ring(57%)and 2 ring(28%)PAHs,indicating oil-related or petrogenic sources as important origins of PAH contamination.Concentrations of alkyl-PAHs(1-methylnaphthalene and 2-methylnaphthalene)were lower than their parent PAH(naphthalene)in all biological tissue,and their percentage also decreased significantly(p<0.05)compared with those in the corresponding sediment.There were no significant relationships between PAH concentrations and trophic levels,which is possibly due to the combined results of the complex benthic foodweb in the subarctic/Arctic shelf region,as well as a low assimilation/effective metabolism for PAHs.According to toxic potency evaluation results from TCDD toxic equivalents(TEQs)and Ba P-equivalent(Ba PE)values,whelk(Neptunea heros)and starfish(Ctenodiscus crispatus)are two macroinvertebrate species showing relatively higher dioxin-like toxicity and carcinogenic risk.

Advances in Chinese Arctic and subarctic research in marine biology and ecology with emphasis on the Pacific Arctic sector

The Arctic is one of the most sensitive regions that respond through feedback to global climate changes. Climatic, hydrological and ecological changes in the Arctic are clear evidence of global warming. In 2012 and 2014, the 5th and 6th Chinese National Arctic Research Expeditions undertook studies in the Bering Sea, the Arctic Ocean （including the Chukchi Sea）, and the Norwegian Sea. These studies provided us with a better understanding of the marine biology and ecology in the Arctic and subarctic regions, particularly in the Pacific Arctic sector. Rapid changes observed in the Arctic environment include the shrinking of cold-water masses in the Bering Sea in the summer, and elevated water temperatures promoting phytoplankton blooms, leading to an increase in phytoplankton transferred to higher trophic levels. As a result, the transfer efficiency of organic matter toward the bottom weakened, leading to a reduction in benthic biomass. This is consistent with expectations that the overall carbon and energy flux will ultimately switch from the dominant mode of sea ice-algae-benthos to one of phytoplankton-zooplankton. Influenced by Pacific water inflow, fluvial runoff and melting sea ice, the Chukchi Sea exhibited different responses to various environmental changes. Interactions between water masses led to other interannual ecological shifts. With the increase in sea ice melt and sunlight in the central region of the Arctic Ocean, the relative abundance of heterotrophic bacteria is expected to increase, and play a vital role in the Arctic microbial loop.

The relationship between soft-bottom macrobenthic communities and environmental variables off Ningjin,eastern Shandong Peninsula

Macrobenthic infauna and associated environmental factors influencing the benthic community in the eastern coastal region of Shandong Peninsula were analyzed in four seasonal surveys from January 2007 to October 2007 （30 stations in winter,20 stations in other three seasons）,in order to understand the community structure and the factors unfluencing the benthic distribution.PRIMER 6.0 and SPSS 15.0 software packages were adopted to analyze the environmental and macrobenthic data.The results show that there were 260 macrobenthic species in total collected from the research region.The composition of species is： Polychaeta （94 species）,Crustacea （75）,Mollusca （56） and Echinoderm （12）,among which,only 23 species were common species in the cruises of every season.The dominant species varied from season to season;however,the polychaete species Paralacydonia paradoxa Fauvel and Echinoderm species Amphioplus japonicus （Matsumoto） were always present year-round.The abundance and biomass of the macrobenthos in the research region were variable from season to season.The results of CLUSTER and MDS analysis show that the similarities of macrobenthic structures between the stations were low;most of the similarities were at about 30% of similarity value,only two stations were up to 70%.In accordance with the similarity values of the macrobenthic structures,we divided the 20 stations into five groups by arbitrary similarity level of 30%.The ABC curve indicates that the marcofauna communities in the research region had not been disturbed massively,except two stations,SB1 and SB3.Ecologically,benthos were controlled by a combination of factors such as salinity,phytoplankton,zooplankton,SiO 3Si and temperature,and no single factor could be considered as an ecological master factor.

Enhancement of the benthic communities around an isolated island in the Antarctic Ocean

Insular marine biotas are often richer in faunal diversity than those from the open sea in the same geo- graphical region. The existence of particular island effects were tested under polar conditions by compar- ing infaunal benthic assemblages on Peter I Island with those of similar latitudes in the open ocean at the Bellingshausen Sea and also from the coast of the Antarctic Peninsula. Sampling was carried out aboard the R/V Hesperides during the expedition named BENTART-2003 from 24 January to 3 March 2003. Benthic samples were collected at 18 stations ranging from 90 to 2 044 m depth, using an USNEL-type box corer （BC） dredge. Representatives of 32 higher taxa of invertebrates were found. Univariate and multivariate analyses revealed various patterns in the data. First, significant differences in polychaete abundance were detected between the stations located in the open sea and the remaining sites （island plus mainland sites）. Bivalve abundances were also distinct between island and mainland sampling sites. Sediment columns taken from the island seafloor exhibited the highest rate of bioturbation by the infauna. These findings confirm the model that islands develop distinct assemblages characterized by the enhancement of the benthic commu- nities even in cold waters. Several abiotic factors were measured simultaneously at the seafloor and along the water column to investigate faunal distribution patterns. Significant correlations were found between the benthic assemblages and a combination of two environmental variables： ＂island effect＂ （measured as a categorical variable） and the redox state of sediments. Richer and more complex benthic assemblages were found in Peter I Island＇s sea bottom, whereas the more depauperate bottoms remained in the open sea.

A study on benthic community structure in west of the Taiwan Strait and near the Taiwan Shoals

Community structures on benthic organisms in the Taiwan Strait based on 4 surveys during 1984～1985 are studied. Seven communities can be divided according to cluster analysis and community structure indexes. The distribution, structural feature of different communities, relation between environmental factors and community are also discussed. The benthic organism community takes the Asymmetron cultellum as the resourcetive at the vast and deep east area in the south of the Taiwan Strait. The results provide new data for resource exploitation and biology study.

A Multilevel Core Sampler Device to Directly Estimate Food Supply Accessible to Waders

To understand food webs functioning in intertidal soft-sediments, it is critical to assess the macrobenthic prey fraction accessible to waders. Here we describe a simple core sampler device allowing to directly relating the vertical distribution of macrozoobenthos to waders bill length. Bill length measurements were used as a proxy of probing depth to estimate the amount of food supply accessible. Several metal plates can be inserted in the core sampler at different heights according to the bill length data of the studied species. These data are provided in a literature survey. For each species, the bill length variability is then explicitly taken into account in the estimation of food accessibility. The core is transparent to check for the quality of the sample. It could also be used to estimate a Benthic Habitat Quality index (BHQ) based on characteristics of the vertical structure of the sediment. This multilevel core is easy to build and to adapt to any studied wader species of the intertidal zone, floodplains or other wetlands. The samples are obtained with the same effort as with usual circular cores leading to the possibility to survey large area. With one core sample, the ecological information that can be achieved at once is threefold: 1) benthic community structure (partitioned in several depths), 2) estimate of the accessible food fraction to waders (range of values) and 3) habitat quality index assessment.

Vertical redistribution of drifting benthic invertebrates in the Kedrovaya River, Primorsky Region of Russia

The vertical distribution of morphologically different drifting invertebrates (mayfly and dipteran larvae) in a small salmon river was studied. Drifting invertebrates were caught with the Astakhov’s sampler equipped with three driftnets placed one above another. The average annual drift rate in different levels of a water column was practically the same, while the drift density decreased from the bottom to the surface. Over the course of 24 hours, the drifting organisms did not show clear preference for a particular water layer. Invertebrates were constantly redistributed between the upper and lower levels at approximately 30 - 90 min intervals. This redistribution appears to be linked to the fact that invertebrates of the same taxa, which entered into water column from different bottom sites become active at different times.

The Limnology of Ohana Lake, a Potential Manmade Aquaculture System in Nigeria

The concentrations of heavy metals (Fe > Zn > Cu > Pb > Ag) in bottom sediments and fish gills in Ohana Lake, were found to be significantly high and far exceeded FEPA and WHO environmental standards for water quality by 1.5 to 18 times, respectively. Six classes of each of phytoplankton and zooplankton with a total of 35 phytoplankton taxa comprising 46 species i.e. 35(46) and 22(28) faunal were observed. The class Chlorophyceae dominated the phytoplankton community with 18(22) followed by Cyanobacteria 6(10). The aquatic fauna was dominated by the Rotifera 8(11), followed by the Copepoda 6(9). The benthic flora community consisted of five classes of phytoplankton made up of 28(36). The class Bacillariophyceae 11(15) dominated the group followed by Chlorophyceae 10(11). Benthic fauna were made up of seven classes of 13(13). The dominant class Nemata 4(4) was followed closely by Protozoa 2(3). Ohana Lake is fast turning to a eutrophic ecosystem with accompanied algal bloom due to very high nutrient contents. The equitability or evenness indices (J) for both phytoplankton and zooplankton were lowly indicating generally low species diversities as well as predominantly unstable ecosystem. The aquacultural implications of these parameters are discussed.

Ecological impacts of the expansion of offshore wind farms on trophic level species of marine food chain

The global demand for renewable energy has resulted in a rapid expansion of offshore wind farms(OWFs)and increased attention to the ecological impacts of OWFs on the marine ecosystem.Previous reviews mainly focused on the OWFs’impacts on individual species like birds,bats,or mammals.This review collected numerous field-measured data and simulated results to summarize the ecological impacts on phytoplankton,zooplankton,zoobenthos,fishes,and mammals from each trophic level and also analyze their interactions in the marine food chain.Phytoplankton and zooplankton are positively or adversely affected by the‘wave effect’,‘shading effect’,oxygen depletion and predation pressure,leading to a ±10% fluctuation of primary production.Although zoobenthos are threatened transiently by habitat destruction with a reduction of around 60% in biomass in the construction stage,their abundance exhibited an over 90% increase,dominated by sessile species,due to the‘reef effect’in the operation stage.Marine fishes and mammals are to endure the interferences of noise and electromagnetic,but they are also aggregated around OWFs by the‘reef effect’and‘reserve effect’.Furthermore,the complexity of marine ecosystem would increase with a promotion of the total system biomass by 40% through trophic cascade effects strengthen and resource partitioning alternation triggered by the proliferation of filter-feeders.The suitable site selection,long-term monitoring,and life-cycle-assessment of ecological impacts of OWFs that are lacking in current literature have been described in this review,as well as the carbon emission and deposition.

Environmental variables affecting the gillnet catches and condition of Labiobarbus festivus and Osteochilus hasseltii in northern Malaysia

The influences of technical factors on the catching efficiencies of gillnets are well understood,but less is known about the importance of environmental factors and how these might concurrently affect target-species condition.Here we address this deficit for two economically important southeast Asian cyprinids(Labiobarbus festivus and Osteochilus hasseltii)during a one-year study at a key fishing location in Lake Kenyir,Malaysia.Three gillnets(each 200 m long,2 m deep and comprising either 38-,51-,or 76-mm mesh)were deployed each month concurrent with sampling of benthic macroinvertebrates and various environmental parameters.Various multivariate analyses(detrended correspondence analysis,redundancy analysis and permutational multivariate analysis of variance)were used to explore potential relationships between the extrinsic variables(mesh size,sampling season,water quality and,based on known prey items,benthic macroinvertebrates)and gillnet catches and the biological condition(growth co-efficient and hepatosomatic index)of the target species.Catches of L.festivus(the most abundant species)were positively influenced by water turbidity without seasonal effects,while their biological condition was positively influenced by benthic macroinvertebrates(mostly Trichoptera)and the concentrations of DO and phosphate,and negatively influenced by water temperature.By comparison,seasonal influences on the catches and biology of O.hasseltii were somewhat size specific with positive and negative effects of the monsoon on small and large fish,respectively.The abundance of phytoplankton also positively affected the catches of O.hasseltii,while their biological condition was positively influenced by water temperature,but negatively influenced by water turbidity.Such species-specific differences were attributed to life histories,and although the more abundant L.festivus might be best sought during any period of turbidity,effort should be focused during the monsoon when individuals have optimal condition(and therefore better flesh quality).In contrast,larger O.hasseltii might be best sought during non-monsoon months concurrent with greater catches and optimal condition.Collecting similar data for other freshwater species both nationally and internationally might facilitate future efforts at fine-tuning gillnet fishing effort.

Impacts of OWF installations on fisheries:A Literature Review

There is an increasing demand for energy in the world.It is well known that non-renewable energy reserves will be irreversibly used at some point.The effects of climate change and limited fossil energy resources have led to an increasing interest in generating energy such as electricity from renewable energy resources.Wind energy is currently the most important renewable energy source for electricity generation which is rapidly becoming a key objective of most European and other countries due to a high demand,both economically and politically.Wind energy provides a safe,clean,sustainable and competitive alternative for conventional sources of energy.European countries like Germany,the Netherlands,United Kingdom,Denmark and Sweden are currently operating offshore wind farms(OWFs)and have plans to increase the production of electricity by wind power.The growth of OWFs has raised concerns about their impact on the marine environment.Focus of this review is to show possible impacts of OWFs on the physical and biological environment reviewing existing knowledge from the literature.