Macrobenthic Community Research Articles

Community structure and ecological quality assessment of macrobenthos in the coastal sea areas of Northern Yantai, China

Four cruises in the Bohai Sea and northern Yellow Sea off Yantai, China, in April and August of 2020, collected data on the species composition and community structure characteristics of macrobenthos in these sea areas. Temporal and spatial changes in the dominant macrobenthic species between April and August were also analyzed. The M-AMBI and environmental data were used to assess the benthic ecological quality of the coastal waters off Yantai. The results revealed differences in macrobenthic community structure and ecological quality status between the two sea areas. The main findings are as follows: A total of 7 phyla and 153 macrobenthic species were collected; 113 and 101 species were recorded in the Bohai Sea and northern Yellow Sea areas, respectively, and estimated abundance was 301 ind. m-2 and 598 ind. m-2 (p < 0.01), and biomass was 10.20 g m-2 and 14.65 g m-2, respectively. The dominant species comprised small-sized polychaetes and bivalves. The main dominant species were Glycinde bonhourei, Micronephthys oligobranchia, Sternaspis chinensis, and Moerella hilaris. The number of species differed significantly between seasons (p < 0.05). A comparison of the dominant species and community structure of the macrobenthos between seasons showed that more obvious replacement occurred in the Bohai Sea. There were major differences in community structure of the macrobenthos between the two areas. Macrobenthos abundance was positively correlated with depth, dissolved oxygen, and sand substrate, and negatively correlated with bottom-water temperature, pH, and fine silt or clay substrate. In April, sites with low ecological value were at the ports of Laizhou and Longkou and Yangma Island, with the water quality likely affected by intensive bivalve aquaculture, port activities, and river discharge; in August, low-ecological-value sites were the middle of Laizhou Bay, Longkou Port, west of Daheishan Island, and coastal water between the cities of Yantai and Weihai. Overall, the sea areas off Yantai were generally deemed to be in a “good” state of ecological quality.

Microhabitat thermal environment controls community structure of macrobenthos on coastal infrastructures

The proliferation of coastal infrastructure in the context of coastal development, urbanization, and global change is inevitably related to the transformation of coastal community structure. For restoration of biodiversity in these human-disturbed coastal ecosystems, it is vital to untangle the community structure and thermal environments, with the consideration of the microhabitat-scale thermal environment variations. In the present study, we measured the species richness, α-diversity (i.e. the species composition of each surface of breakwaters), and β-diversity (i.e. the dissimilarities among macrobenthic communities of different surfaces of breakwater) of macrobenthos on the breakwaters on a tropical shore for understanding the variation of the community structure of macrobenthos; we also monitored the operative temperatures in different surfaces of the breakwaters during the experimental period for investigating the roles of microhabitat thermal environment on the community structure of macrobenthos on the artificial infrastructure. Our results showed that there were higher species richness and abundance in the thermally benign microhabitats. The variations of β-diversity indicated that the community structure underwent dramatic changes in different microhabitats and seasons. The population dynamics of thermal-sensitive species (e.g. Patelloida pygmaea, Cellana toreuma, and Siphonaria japonica) largely contributed to the changes in community structure. Redundancy analysis (RDA) results showed that maximum temperature, temperature predictability (i.e. the degree to which a temperature data point in a time series is influenced by its historical values), and heating rate were important thermal characteristics driving community structure on the artificial infrastructure. These results indicate the heterogeneity of thermal environments among different microhabitats is crucial for maintaining the community structure of macrobenthos on the artificial infrastructure and suggest that structural complexity should be considered for biodiversity conservation in the design and construction of coastal infrastructure.

RESPONSE OF TAXONOMIC AND FUNCTIONAL BENTHIC MACROFAUNA RICHNESS TO LAND USE AND LAND COVER AT BRAZILIAN RESERVOIRS DURING EXTREME DROUGHT

Introduction: Reservoirs are artificial aquatic ecosystems created by damming rivers, and are influenced by different sorts of impacts. Anthropic land use and occupation are one of the main causes of the loss of environmental quality and biological diversity in aquatic ecosystems. The objective of this work was to evaluate the effects of land use and occupation on the taxonomic and functional richness of benthic macroinvertebrates in reservoirs in the Brazilian semiarid region during a period of extreme drought. Material and methods: The study was conducted in six reservoirs located in the semiarid region from Brazilian Northeast (Paraíba and Rio Grande do Norte states): Sabugí, Passagem das Traíras, Cruzeta, Cordeiro, Sumé and Poções. The collections of benthic macrofauna, physical and chemical variables of water and the mapping of land use and occupation were performed for the years 2014 and 2019, in June and September. The sampling period was characterized as the most severe drought in the last 50 years in this study area. The land use and occupation were verified through the semi-supervised classification method of images captured by the Landsat 8 satellite, within 100 meters of the reservoir margin. The diversity of benthic macrofauna was analyzed through the taxonomic richness and functional richness, according to five functional characteristics: feeding trophic groups, breathing mode, voltinism, body size and body protection. To check for significant differences in physical and chemical water variables and taxonomic and functional richness among land use and land cover categories we performed PERMANOVA test. Results and Discussion: Seven land use and land cover categories were found in the reservoirs studied in the years 2014 and 2019, these are: water, agriculture, pasture, exposed soil, human occupation, open vegetation (native and exotic species of small/medium size with continuous spacing) and tree/shrub vegetation (native and exotic species of medium/large size with associated herbaceous stratum and predominance of semi-continuous dorsel). In all reservoirs the prevalent-use was pasture. Physical and chemical variables of water varied significantly among land use and land cover types, they were soluble reactive phosphate (p=0.02), total phosphorus (p=0.002) and water volume (p=0.01). The highest concentrations of total phosphorus were associated with predominant human occupation and soluble reactive phosphate with agriculture. The highest percentage of water volume was associated with a predominant use of tree/shrub vegetation. In reservoirs of semiarid regions with low connectivity due to intermittent rivers and extreme drought periods, adjacent anthropic activities such as agriculture, pasture and human occupation are the main external sources of nutrients. The taxonomic and functional richness of benthic macrofauna was higher in areas of open vegetation, however, it did not vary significantly between land use and land cover categories. Conclusions: Our results show that the effects of anthropic use and occupation in reservoirs associated with water scarcity lead to the homogenization of the macrobenthic community, which can generate negative consequences in processes sustained by the community.

Variability at multiple spatial scales in intertidal and subtidal macrobenthic communities in a fjord with glaciers, Magellanic Subantarctic ecoregion, Chile

It has been observed in high-latitude marine environments of the Southern Hemisphere that the variability in the ecological patterns of macrobenthic communities show variations at different spatial scales (i.e. cm to km), mainly influenced by environmental stress gradients. We examined macrobenthic communities of intertidal and subtidal habitats in a glacial fjord using taxonomic, ecological and oceanographic approaches, estimating vertical and horizontal variation using a nested design with different spatial scales ranging from centimeters to kilometers (quadrats, patches, shore and sites respectively). We found that vertical patterns in taxon richness and community structure were significant in both habitats. These patterns also showed horizontal variability at different spatial scales, becoming more pronounced at smaller scales (quadrats). The dominant taxa in the intertidal (macroalga) and subtidal (macroinvertebrate) communities also exhibited a scale-dependent distribution pattern, indicating that the greatest horizontal variation occurs at small spatial scales. Annual and opportunistic green algae such as Ulva intestinalis and Cladophora flexuosa were dominant in the intertidal, while the dominant taxa in the subtidal were the filter-feeding bivalve Aulacomya atra and the suspensivorous hydrozoan Symplectoscyphus marionensis. The results were related to biological interactions and local abiotic factors characteristic of an estuarine system influenced by glaciers, with lower salinity and temperature and higher turbidity in sites close to glaciers. The information generated on diversity patterns is very relevant and can serve as a baseline in the evaluation of ecological patterns of shallow macrobenthic communities in environmental gradients influenced by glaciers in the Magellanic Subantarctic ecoregion.

Benthic quality assessment of a hypersaline lake along the southeast coast of India

The study describes macrobenthic community structure for assessing the benthic quality of a hypersaline lake along the southeast coast of India. Sediment and water samples were collected during November 2018 (Northeast Monsoon — NEM), April (Pre-Monsoon — PRM), and July 2019 (Southwest Monsoon — SWM). Based on salinity distribution the lake can be characterized into four regions viz., Northern inlet, Middle inlet, Southern inlet, and Central region. Seasonal analysis showed that the middle inlet and the central region of the lake experience hypersaline conditions throughout the year. Macrobenthic abundance and diversity index were high during SWM compared to other seasons. Some macrobenthic species (Cirratulus filiformis, Pagurapseudopsis gymnophobia, Apseudes chilkensis, Tanais sp.) showed a high preference for non-hypersaline regions while their presence in hypersaline regions was comparatively low/sparse. The present study identified that polychaete species such as Dendonereis aestuarina, Sigambra parva, Capitella capitata, Heteromastus similis can survive in hypersaline (> 60) conditions. The seasonal benthic quality status of the lake assessed by the AZTI Marine Biotic Index (AMBI) indicated heavily disturbed conditions during NEM and slightly disturbed during SWM.

Macrobenthic diversity and its bioindicator potential in urban reservoirs: A Sri Lanka case study

AbstractStudies addressing the macrobenthic diversity and their potential as bioindicators in water quality assessment programs are sparse for Sri Lanka. The present study investigated the macrobenthic diversity in relation to water quality parameters in some urban reservoirs in the Western Province of Sri Lanka, assessing their potential as bio‐indicators in water quality assessment programs. The six study reservoirs included the Ihalagama Tank, Peralanda Tank, Kesbewa Tank, Boralesgamuwa Tank, Bolgoda Lake and Beira Lake. The microbenthic fauna abundance at randomly selected locations (n = 9) in each reservoir and selected water quality parameters (temperature; pH; electrical conductivity; total dissolved solids; BOD5; dissolved nitrates; total dissolved phosphate and alkalinity of the overlying water at each location were measured between July 2020 and January 2021, using standard data collection methods). The species richness (SR), species heterogeneity (H′) and species evenness (J) of the macrobenthic fauna in each reservoir were calculated, and the abundance and water quality data analysed using ANOVA and PCA as appropriate. A total of 13 macrobenthic taxa (Glyphidrilus sp., Limnodrilus socialis, Dero sp., Stratiomyd larva, Chironomid larva, Bellamya sp., Melanoides tuberculata, Gyraulus sp., Lymnaea sp., Paludomus sp., Thiara sp., Ancylus sp. and Mesostoma sp.) were observed from the six study reservoirs. The oligochaete tubificid worm L. socialis dominated the sediment samples, accounting for more than 94.7% of the total macrobenthic abundance, with the highest relative abundance of this species observed in Beira Lake (99.3%). The species richness of the macrobenthic community was highest in the Ihalagama and Kesbewa tanks (SR = 5), while it was the lowest in the Peralanda Tank (SR = 2). Since the benthic community was mainly dominated by L. socialis, the lowest species heterogeneity and species evenness values were observed in Beira Lake (H′ = 0.05; J = 0.03). The values of the water quality parameters among the study reservoirs varied, with Beira Lake exhibiting significantly high BOD5, dissolved nitrate, and total dissolved phosphate values (p < .05) than the other reservoirs, indicating a higher degree of eutrophication. Furthermore, the SR, J and H′ values for the study reservoirs decreased with increasing BOD5, dissolved nitrate and total dissolved phosphate levels. Thus, it was concluded that the abundance and diversity of macrobenthic fauna are primarily governed by water quality parameters. Furthermore, L. socialis can be used as a potential bioindicator organism in water quality assessment programs in urban reservoirs.

Comparing grab and dredge sampling for shoreface benthos using ten years of monitoring data from the Sand Motor mega nourishment

Epifauna and infauna are often sampled by different types of sampling devices including grabs, and dredges, depending on various factors such as local environmental conditions, research questions and available budget. Because grabs and dredges have a different species-specific selectivity, both methods could be complementary but for some research questions they could give comparable results. In this study, a comparison is made between macrobenthos (epifauna and infauna) sampled simultaneously by a Van Veen grab and a quantitative benthic dredge, based on a large dataset that was collected from 2010 to 2019 as part of an extensive monitoring program to study the impact of the Sand Motor, a mega beach nourishment that was implemented in 2011 on the sandy North Sea coast in the Netherlands. Because of the larger mesh size of the sieve in the benthic dredge (5 mm) compared to the Van Veen (1 mm), only larger mollusks, echinoderms and crustaceans are identified in the dredge samples. This resulted in a lower number of taxa and average densities in the 676 benthic dredge samples (42 taxa and 98.7 ind. m−2, respectively) compared to the 636 Van Veen samples (228 taxa and 1380.9 ind. m−2, respectively). Due to the larger sampling area of the benthic dredge (10–15 m2) compared to the Van Veen (0.1 m2) the chance to encounter a species is higher in a benthic dredge than in a Van Veen grab sample. Although the benthic dredge only samples a subset of the benthic community that is sampled by the Van Veen grab, multivariate (nMDS) analysis of the data showed remarkable similarities between Van Veen and benthic dredge samples with major gradients correlated to water depth and temporal changes in environmental conditions due to the presence of the Sand Motor. This suggests that both techniques are indicative for the spatial variation and development of the macrobenthic community.

Effect of cyclonic storm Vardah on the community structure and ecosystem functioning of macrobenthic fauna in the intertidal region of South Andaman Islands

An investigation was carried out to understand the effect of a cyclone Vardah on the functioning of macrobenthos. The assessment was accomplished by comparing before cyclone (BC) and after cyclone (AC) data of macrobenthos. Additionally, temporal changes in the faunal assemblages were evident through multivariate techniques. Five distinguished assemblages could be noticed through the Bray–Curtis similarity representing different phases of the cyclone. The cyclonic effect also resulted in the recruitment of some macrobenthic species and the loss of a few during the study period. Biological trait analysis identified subsurface deposit feeders, upward and downward conveyers, Ecological Group IV, mid-mobile macrobenthos and size class of 2–4 cm as the important groups that dominated the functioning of the macrobenthic community immediately after the cyclone. The resilience and recruitment of macrobenthos were explained using functional redundancy.

Recovery of Macrobenthic Food Web on Rocky Shores Following the Hebei Spirit Oil Spill as Revealed by C and N Stable Isotopes

The impact of large-scale oil spills on organisms can lead to modifications of the food web structure. To assess the effects of the Hebei Spirit oil-spill accident on the trophic structure of the macrobenthic community on intertidal rocky shores along Taean Peninsula on the western coast of Republic of Korea 4 years after the Hebei Spirit oil spill, we analyzed carbon and nitrogen stable isotope ratios of macrobenthic consumers and their potential food sources in two heavily oil-impacted and one non-impacted sites. The results show no significant differences in isotopic ratios of feeding groups and their potential food sources between the polluted and reference sites, suggesting similar trophic structures given similar resource use by consumers. Similar isotopic niches and substantial overlap areas of feeding groups between the affected and reference sites suggest that the oil-impacted sites have re-achieved the trophic functions of the natural ecosystem. This study provides valuable information on the ecological processes of trophic recovery in coastal ecosystems impacted by oil spills.

Community Structures of Benthic Macrofauna in Reclaimed and Natural Intertidal Areas in Bahrain, Arabian Gulf

Costal reclamation has been carried out extensively along the coastlines of the Arabian Gulf during the last decades. As a small archipelago country, coastal reclamation continues to be a major option for securing land to meet the needs of the expanding population and economic development in Bahrain. Macrobenthic communities often reflect the integrity of ecosystems as they respond to natural and anthropogenic stressors. This study characterized the community structures of macrobenthic invertebrates in three reclaimed intertidal areas and a protected natural mudflat in Bahrain (August 2019 and December 2020). Macrobenthic community structures and sediment characteristics differed significantly between natural and reclaimed areas. A total of 43 species were recorded in the four study areas, of which 38 were collected from the natural mudflat. Polychaetes dominated macrobenthic communities, followed by molluscs and crustaceans. Polychaetes accounted for more than 90% of the communities in the reclaimed coastal areas. Macrobenthic monitoring is considered essential for detecting changes in coastal and marine ecosystems due to dredging and reclamation activities along the coastlines of the Arabian Gulf. The findings of this study can provide insights into the ecological dynamics of macrobenthic communities in reclaimed coastal areas for environmental monitoring and coastal planning and management in the Arabian Gulf.

Species and functional diversity of marine macrobenthic community and benthic habitat quality assessment in semi-enclosed waters upon recovering from eutrophication, Bohai Bay, China

This study investigated the structure and function of macrobenthic community in Bohai Bay upon improvement of water quality due to pollution abatement. A total of 166 species were collected in the summer and autumn sampling, with an increase in sensitive species recorded as compared to data from previous studies. While historical variations in species richness indicated signs of improvement in community structure, results of functional diversity indices revealed that the macrobenthic community in Bohai Bay was still in an early stage of recovery. From BIO-ENV analysis, habitat instability may hinder how community responded to water quality improvement. Results of the benthic habitat quality assessment also indicated that the ecological status in most areas of Bohai Bay was classified as good, while a few estuarine regions were categorized in a poor status.

Macrobenthic community towards sustainable aquatic ecosystem: a systematic review along the coastal waters of Malaysia

ABSTRACT Macrobenthos animals are an architect of a variety of roles including as a part of the food web of aquatic ecosystem and improve the structure of the sediment and can determine the quality of the water. Macrobenthos communities have shown their potential role in biomonitoring to analyze contaminant loads due to high sensitivity to organic pollutants along the coastal water area. Besides, it is also used to determine heavy metals and petroleum hydrocarbons in coastal water due to their long sustainability with chemicals are primarily related with industrial calamities and occupational activities. Based on above perspectives, this systematic review has shown interesting findings about the macrobenthic diversity including community composition in the coastal areas of Malaysia. The study has focused on the diversity and abundance of macrobenthos communities along some potential coastal areas of Malaysia which emphasis on the states of Johor, Pulau Pinang, Selangor, Pahang, Terengganu, and Sarawak. Several studies have evidently revealed that pollutants and human activities have contributed to loss of macrobenthos towards abundance (individuals/m2) and species richness. The highest abundance of macrobenthos was Coleoptera sp. (1650 ind./m2 followed by Hemiptera sp. (860 ind./m2) were observed in Sarawak and Crustacea sp. (597 ind/m2) was found in Selangor, respectively. While Crustacea (10 ind/m2) was found as the lowest in the coastal water Pahang only. A major shortcoming among the studies was sampling time along with sampling method which was observed in this systematic review of different studies of macrobenthic assemblages in the coastal waters of Malaysia. However, the existing study reveals the baseline information on macrobenthic community which are still inadequate in Malaysia. Hence, a long-term monitoring for eco-biology and species diversity of macrobenthic assemblages are necessary for their sustainable development in this fascinating tropical coastal water of Malaysia.

Variations in the macrobenthic invertebrates in relation to physico-chemical characteristics and WQI in Lake Qarun, Egypt

The seasonal relationship between the physico-chemical characteristics and the macrobenthic fauna community was studied in Lake Qarun, Egypt. Lake Qarun receives a huge amount of agricultural drainage water from the neighboring cultivated land via El-Batts and El-Wadi drains. Generally, the obtained results have shown a decrease in dissolved oxygen, transparency and increase in COD, NO3– and NH3 at the stations in front of El-Batts and El-Wadi drains due to the continuous pollutants discharged into the Lake's water. The WQI revealed that the water quality of Lake Qarun is poor for aquatic life. The macrobenthic community consisted of sixteen species belonging to three phyla, Mollusca (7 species) that was dominated by Cerastoderma glaucum, Annelida (4 species) that was dominated by Limnodrillus spp. and Arthropoda (5 species) that was dominated by Balanus pallidus. The structure and abundance of macrobenthic species were affected by many factors especially pollution from the drainage water contaminated with sewages, which affected all living organisms in the Lake. The WQI values of Lake Qarun ranged from 32.30 to 38.40 (poor class) and the average value in the whole area was 35.89 ± 1.64 that is ranked as poor for the aquatic life utilization. To avoid this undesirable effect, the pollutants that flow into the Lake must be treated before being discharged.

Diversity and distribution of benthic invertebrates dwelling rivers of the Kruger National Park, South Africa

Meiobenthos (or meiofauna) are microscopic invertebrates that inhabit biofilms and interstitial spaces in rivers. They are diverse and extremely abundant, and they perform essential ecological functions by linking microbial production to higher trophic levels (e.g. macrobenthic invertebrates and fishes). However, meiobenthic communities remain poorly studied in Africa. Here, we sampled meio- and macrobenthic invertebrate communities associated with biofilms and sediments across an upstream–downstream gradient along the Olifants, Sabie and Crocodile rivers flowing through the Kruger National Park (KNP). We expected to link differences in community structure to environmental gradients as those rivers show different degrees of anthropogenic stress as they enter the park. Both meio- and macrobenthic communities differed across rivers and also structured along an upstream–downstream gradient. The upstream sites, which were the closest to the park borders, consistently showed a lower diversity in all three rivers. There, the invasive snail Tarebia granifera strongly dominated (making up 73% – 87% of the macrobenthos), crowding hard substrates, while concomitantly the abundances of biofilm-dwelling meiobenthos like nematodes and rotifers were substantially reduced. Nevertheless, the diversity and evenness of communities then tended to increase as water flowed downstream through the park, suggesting a beneficial effect of protected river reaches on benthic invertebrate diversity. However, for the Crocodile River, which makes up the southern border of the park, this trend was less conspicuous, suggesting that this river may experience the greatest threats. More generally, benthic invertebrate communities were driven by the concentrations of phosphates, sulphates, ammonium and organic matter and by substrate characteristics.Conservation implications: Meiobenthic organisms are very abundant in KNP rivers and react to environmental gradients; thus, they should be more considered for bio-monitoring or conservation of comprehensive assemblages of animals. Interestingly, protected reaches tended to show a reduced dominance of the invasive T. granifera and a higher diversity of benthic invertebrates.

Macrobenthic community status at coastal cage aquaculture area in Xuan Dai bay, Phu Yen province, Vietnam

Lobster cage culture started around 1990 in Xuan Dai bay and grew fast in recent years, contributing significantly to the socio-economic development of the region. But the impact on the ecological environment of cage culture operation also needs to consider. This paper points out the status of the macrobenthic community, studied at two stations inside the cage culture area (X1, X2) and one reference station (Xr) in the non-cage culture area. A total of 90 samples with 5 replicate samples per station were collected in six surveys during the dry and rainy seasons from June 2019 to May 2020. These samples were classified and recorded into 80 taxa belonging to 49 families and 5 classes. The class Polychaetes had the most diverse species composition with 53 taxa (66% of the total number of taxa). The crustacean group had 14 taxa (18%) belonging to 13 families; Molluscs had 9 taxa (11%) belonging to 6 families of class Bivalvia. The echinoderms had 4 taxa (5%). Capitella capitata, a species known as an indicator of organic pollution, was recorded in both stations of the culture area but was not present at the reference station. Furthermore, some dominant species presented in the culture stations such as Cossura longocirrata (contributed 43.52% in station X1) and Ceratonereis sp. (contributed 27.57% in station X2). These species are considered opportunistic species that can adapt to disturbed environmental conditions. Significantly, the species of echinoderms group were only recorded in the reference station. The species composition was only about 24% similar to those at the cage culture stations. The species richness index (D) values ranged from 1.50 (X2.6) to 6.82 (Xr.3). The diversity index (H′) varied from 0.88 (X2.4) to 2.98 (Xr.3). The evenness index (J) had the lowest average value at station X2 (J = 0.59 ± 0.20) and the highest value at the reference station Xr (J = 0.78 ± 0.03). The indices D, H′ and J of the macrobenthic community at the reference stations have higher average values compared to those estimated at cage culture stations. These results proved cage culture activities have gradually impacted the benthic fauna, reduced biodiversity, and encouraged the appearance of opportunistic species. Thus, further studies on the macrobenthic community dynamic with ecological criteria are necessary to establish a set of biological indicators to monitor the environmental quality of the coastal aquaculture area.

Microplastics shift macrobenthic community structures near a coastal nuclear power plant under construction in North East China

Coastal sediments are considered to be a potential sink for microplastics, which mainly derived from the land-based sources. This study investigated microplastic pollution in the sediments of 20 stations near a nuclear power plant under construction in North East China and analyzed its impacts on macrobenthic communities. The average abundance of microplastics in three stations close to the nuclear power plant was 0.33 items/g, which was approximately 10 times higher than those in the distant stations. The clustering of microplastic characteristics (sizes, shapes, and colors) showed that the three stations near the plant were in one group, and the distant stations were in another group. A total of 105 macroinvertebrate species belonging to 7 phyla were identified in all stations, and the dominant phyla were Annelida and Arthropoda. Spearman rank correlation showed that rare taxa (83 species with a contribution <1 %) were positively correlated with microplastics and As, and redundancy analysis demonstrated that the distribution patterns of macrobenthic communities were similar to those of microplastics. Moreover, co-occurrence networks showed that the rare taxa were positively correlated with microplastics. Therefore, microplastics released from the nuclear power plant under construction might shift the structure of macrobenthic communities, especially the rare taxa.

Assessing pressure drivers on the benthic ecosystem in the coastal zone of Western Messinia, Greece

The Messinia region, located in the South – West of the Peloponnese, Greece, is an ecologically valuable area comprising of several important coastal habitats (including coastal lagoons, seagrass meadows, and Mediterranean rhodolith beds) eliciting its inclusion in the Natura 2000 network. Land-based anthropogenic pressures are likely to influence the ecological status of this coastal zone. Here we identify those regional pressures and use physico-chemical elements of the ecosystem, and the status of the macrofauna communities to assess the level of environmental degradation in the coastal and lagoon water bodies. High organic load from the catchment area, geomorphological and hydrological features of the water bodies are the major drivers affecting the ecological quality of the region. The lagoon is severely degraded due to both a high nutrient input from the surrounding river basin (likely due to agricultural run-off), and a relatively low level of connectivity with the marine environment (due to alterations in the regional hydrology). In contrast, the coastal zone is classified as being at a high or good ecological status and seems scarcely impacted by anthropogenic pressures. The macrobenthic communities reflect how vulnerable the lagoon is to multiple stressors (and in particular agricultural practices), and highlight the necessity of defining and implementing holistic, river-basin based management plans for the Gialova lagoon, and the surrounding coastal area of Messinia.

Variation of food web structure in macrobenthic communities in low diversity system as determined by stable isotope-based community-wide metrics

Recognition of spatial and temporal variations of food webs is of fundamental importance for understanding ecological processes and biodiversity management. Changes in trophic organization alter routing patterns and dynamics of energy fluxes among ecosystem compartments and ultimately affect the ecosystem functioning. In this study, stable isotopes of carbon and nitrogen (δ13C and δ15N) were employed to define trophic niche and diversity as well as redundancy of four macrofaunal benthic communities in a low diversity, brackish system of the Puck Lagoon (southern Baltic Sea). The Bayesian mixing models were used to delineate community-wide metrics at different trophic levels. Benthic macrovegetation appeared to facilitate directly and indirectly development of different trophic niches for consumers by diversification of basic carbon resources and providing habitat structure. In habitat with dense vegetation, diverse food sources supported benthic fauna of different feeding modes. Communities from sandy bottom with low biomass of macrophytes showed compact food webs of lower trophic diversity. Reliance on one dominant resource (suspended particulate organic matter-SPOM, and phytoplankton) resulted here in simplification of food web structure with a large proportion of species with one feeding mode (suspension feeders). Widening of δ13C range (CR) and δ15N range (NR) in the cold season was related to the extended carbon isotope ratios of organic matter sources and the presence of omnivorous and carnivorous fish that migrated towards the shoreline. A decreased trophic diversity during a vegetative season (spring-summer) was attributed to a narrowed isotopic range of primary producers that incorporated isotopically similar biogenic substances. Geographical and seasonal differences of trophic structure highlighted important natural variation of benthic communities which can benefit ecological restoration programmes and biodiversity management of coastal and marine areas.

Effects of vehicle traffic and trampling on the macrobenthic community of Amazonian macrotidal sandy beaches

AbstractWe report for the first time the effects of vehicle traffic and beachgoer trampling on macrobenthic communities of Amazonian sandy beaches. Sampling was performed during four consecutive months with different beach use intensity in 2017 (before, during vacation, and two months after the vacation period) on three contrasting beaches with regard to disturbance (Urban: Atalaia; Intermediate: Farol-Velho; and Protected: Corvinas) in the intertidal zone along two equidistant transects at seven equidistant sampling stations from the high-tide water mark to the swash zone. At each sampling station, four biological and sediment samples were randomly collected. Also, in each station, the sediment compaction was determined using a manual penetrometer. Physical sediment variables remained constant over time in all beaches, whereas differences were found in sediment compaction over the months. Macrobenthic community differences in density and richness among months were observed at Atalaia and Farol-Velho beaches. In contrast, Corvinas beach remained constant throughout the study period. Furthermore, the vulnerability of the polychaetesThoracophellia papillata,Scolelepis squamataandParaonissp. indicates that they might be potential indicators of recreational activity impact.

Spatio-Temporal Variations in Macrobenthic Community Distribution on the Central Red Sea Coast: Role of Heavy Metal Content of the Sediment

Spatio-Temporal Variations in Macrobenthic Community Distribution on the Central Red Sea Coast: Role of Heavy Metal Content of the Sediment