Van Veen Grab Research Articles

Near-field changes in the seabed and associated macrobenthic communities due to marine aggregate extraction on tidal sandbanks: A spatially explicit bio-physical approach considering geological context and extraction regimes

Based on data from Multibeam Echosounders (MBES) and Van Veen grab samples, near-field effects of marine aggregate extraction by trailing suction hopper dredgers in the Belgian part of the North Sea were assessed on a decadal scale. The combined approach allowed to investigate and compare seabed and macrobenthic community characteristics for three extraction areas with similar ecological settings, but with a different geological context and each subjected to a different extraction regime. MBES measurements detected slight alterations of the seabed for areas exposed to a continuous, low extraction regime (monthly average volume = 17 to 83 × 103 m3). However, no significant changes in sediment composition nor the macrobenthic community could be attributed to this low extraction regime. High and continuous extraction in the most intensely extracted area (monthly average volume = 164 × 10³ m³) increased surface heterogeneity and created a local depression, hereby exposing clay and gravel from the underlying geological layer. In this area, the highest environmental impact was observed, as the physical changes in the seabed triggered a shift towards a more heterogeneous, transitional macrobenthic community including opportunistic species and species typically associated with muddy sands. Together with the species already present, this resulted in a local increase in macrobenthos density, species richness and biomass. A high but periodic extraction without screening activity on the most offshore located extraction area (monthly average volume = 230 × 10³ m³, averaged for those months where extraction took place) led to a redistribution of the medium to fine sand fraction and a winnowing of coarse sediment and shell fragments. The decreased median grain size induced a shift in the macrobenthic community from a typical medium to coarse sand Hesionura elongata community towards medium to fine sand representatives of the Nephtys cirrosa community, although the overall macrobenthic density and biomass in this extraction area remained stable. Based on these results, we conclude that extraction regime and local geological context are important factors driving the near-field environmental impact of marine aggregate extraction on tidal sandbanks.

Macrobenthic infaunal assemblage structure in nearshore and offshore seabeds of Ghana

Abstract. Commey NA, Armah AK, Lamptey E. 2021. Macrobenthic infaunal assemblage structure in nearshore and offshore seabeds of Ghana. Indo Pac J Ocean Life 5: 50-60. This research aimed to compare and contrast the sediment properties and benthic macrofaunal assemblage composition of nearshore and offshore habitats. Also, the existing state of benthic macrofaunal assemblages in the Jubilee Fields, Ghana in 2015 is determined. A baseline is established for these communities before constructing a coal-powered plant in the nearshore area of Ekumfi Aboano, Ghana (deep-sea). The research was conducted in the shallower nearshore Ekumfi Aboano (average depth: 15 m) and deeper offshore portions of the Jubilee Fields (average depth: 1,250 m). A Van Veen grab was used to collect sediment samples from the nearshore area, while a box corer was used to collect samples from the deep water. PRIMER was used to look into the distribution of benthic macrofauna. Using GRADISTAT, it was determined that the nearshore sediment (mean grain size of 99.80 m) is fairly sorted with very fine sand. In contrast, offshore sediment (mean grain size of 109.79 m) was poorly sorted and comprised of extremely coarse silty fine sand. It was determined from studies of macrobenthic infauna that there were 11,131 individuals in the nearshore environment, with a density of 38 individuals/m2, and 22,105 individuals in the deep-sea environment, with a density of 47 individuals/m2. Data for the nearshore and offshore environments showed a total of 194 and 983 polychaetes, 827 and 696 crustaceans, 35 and 229 mollusks, 14 and 37 echinoderms, and 43 and 260 "others" (foraminiferans, nematodes, nemerteans, and sipunculids). Crustaceans > polychaetes > molluscs > others > echinoderms dominated the shallow Ekumfi seabed, whereas polychaetes > crustaceans > molluscs > others > echinoderms dominated the offshore Jubilee seabed. There were 116 species discovered close to shore, while 188 were discovered in the deep water. Both locations displayed a high level of diversity (H' > 4; 1-D > 0.9) and were evenly distributed (J' > 0.8). The nearshore was dominated by arthropods (74.30%), while the offshore was dominated by polychaetes (44.58%). A greater variety of macrobenthic infauna was found in the deep sea compared to the nearshore, with a difference of 75% between the two environments.

High Species Richness and Extremely Low Abundance of Cumacean Communities Along the Shelf and Slope of the Gulf of Guinea (West Africa)

The Gulf of Guinea belongs to the most scarcely sampled marine basins in the oceans of the world. We have analyzed diversity and distribution patterns of cumacean communities on the shelf and slope, along the coast of Ghana. The material was collected in October and November of 2012 using a van Veen grab (0.1 m2) on nine transects. Six stations were located at each transect (25, 50, 100, 250, 500, and 1,000 m). Sixty-three species of Cumacea were recorded withLeuconandEocumaas the most speciose genera, with 12 and eight species, respectively. Comparisons of species richness with literature data pointed that the Ghanaian coast hosts very diverse communities. About 95% of species were new to science, and the number of cumacean species known from the West Africa increased by over 100%. Nevertheless, most of the species had extremely low abundance, 13 singletons and 15 doubletons were found. Mean density of cumaceans was estimated at only 1.5 ind./0.1 m2. Species accumulation curve did not reach the asymptotic level, suggesting undersampling, despite the fact that sampling effort was high (250 samples). The highest species richness was recorded in the inner shelf (25–50 m) and on the slope (1,000 m). Cluster analysis separated shallow water communities from deeper regions on the shelf and upper slope. The most unique species composition was found at 1,000 m. Principal component analysis showed the importance of oxygen, sediments, and human-related disturbance for distribution of cumacean communities. In the shallows, oxygen content and presence of gravel were the most important factors structuring communities. In the deeper bottom areas (250–1,000 m), cumacean fauna was affected by local pollution, mainly by higher concentration of barium, other heavy metals, and THC.

Ecological status based on the diversity of macrozoobenthic in Cengkok coastal waters, Banten Bay, Indonesia

Cengkok Coastal waters is one of the estuaries in Banten Bay. This coastal area has been subjected to various anthropogenic stresses in recent years, which can affect the structure of the macrozoobenthic communities. This study aims to estimate the ecological status of the waters using macrozoobenthic diversity in the bay. The study was conducted from May to September 2019 at five stations. Macrozoobenthic were sampled using a Van Veen grab sampler. Analysis was carried out to reveal genera composition, density, diversity, evenness, dominance indices in the bay. The results showed that macrozoobenthic obtained consisted of Bivalvia, Gastropod, Polychaeta and Malacostraca. Based on time, the density of macrozoobenthic was higher in August 2019 and lower in September. The diversity index range from 0.872 to 1.443. The evenness index range from 0.368 to 0.698, and the dominance index from 0.487 to 0.711. Based on location, the highest density of macrozoobenthic was at St. 5 and the lowest at St. 2. The diversity index range from 0.547 to 1.875. The evenness index from 0.254 to 0.737 and dominance index from 0.374 to 0.813. Macrozoobenthic in this area was strongly influenced by the salinity fluctuation of the coastal waters. Based on the values of the diversity, evenness and dominance indices, this coastal waters has diversity ranged from low to moderate, with dominant macrozoobenthic at certain times and locations.

Microplastic sampling techniques in freshwaters and sediments: a review.

Pollution by microplastics is of increasing concern due to their ubiquitous presence in most biological and environmental media, their potential toxicity and their ability to carry other contaminants. Knowledge on microplastics in freshwaters is still in its infancy. Here we reviewed 150 investigations to identify the common methods and tools for sampling microplastics, waters and sediments in freshwater ecosystems. Manta trawls are the main sampling tool for microplastic separation from surface water, whereas shovel, trowel, spade, scoop and spatula are the most frequently used devices in microplastic studies of sediments. Van Veen grab is common for deep sediment sampling. There is a need to develop optimal methods for reducing identification time and effort and to detect smaller-sized plastic particles.

Distribution of Total Mercury in the Sedimentary Environment in Lake Ahémé, Southern Benin (West Africa)

This study focuses on the spatio-temporal assessment of mercury pollution of the sedimentary environment of Lake Ahémé in southwestern Benin Republic. Sediment samples were taken from 32 sites in July 2018 and then in December 2019, covering the two major climatic seasons of the southern area of the country. Sampling was done according to a grid design of the entire area of the ecosystem. The surface sediment samples were collected at a depth between 0 and 5 cm in three takes at each site with a Van Veen grab. Samples were frozen, lyophilized at -40°C, crushed, sieved and homogenized. The fraction less than 63 µm in size was collected for the mercury determination by a Direct Mercury Analyser (DMA) operating by atomic absorption according to the US EPA 7473 method. The results obtained reveal that, in 2018, mercury is more concentrated in the northern and central part of the lake varying from 109 μg/Kg (center) to 132 μg/Kg (north) while in 2019, the central and southern zones of the lake were more concentrated in mercury, with 162 and 87 μg/Kg respectively. However, the values of the geo-cumulation index Igéo varies from 0 to 1, showing that Lake Ahémé is slightly polluted at these sites.

Direct Mercury Analyzer (DMA) determination of mercury distribution in the sediments of lake Nokoué in Benin Republic-West Africa

Mercury pollution of water bodies constitutes a hazard to both the aquatic life and the populations consuming fishery products. To anticipate the probable eco-toxicological risks that may arise from the largest lake in southern Benin, the present work aims at assessing the mercury status of the sediments of Lake Nokoué, while identifying the areas exposed to anthropogenic mercury contamination. 45 sites were sampled according to a grid plan covering the entire ecosystem of the lake. Employing a Van Veen grab, surface sediments are collected at a depth from 0 to 5 cm in three catches at each site. The composite samples formed at equal mass on the three portions were frozen, lyophilized at - 40 °C, crushed, sieved and homogenized. Fraction less than 63 µm was collected for the mercury content determination by Direct Mercury Analyzer (DMA) operating by atomic absorption according to the US EPA 7473 method. The mercury concentration varies from 1.56 µg/kg to 164.88 µg/kg with an average value of 35.18 µg per kg of sediment. The south-eastern zone of the lake is more concentrated in mercury with a summation of the mercury content of 530.3 µg/kg of sediment. However, the lake has moderate contamination overall (1 ≤ FC ≤ 3).
 Keywords: Pollution, contamination, mercury, sediment, Lake Nokoué.

Determination of total petroleum hydrocarbons and selected heavy metal (Pb, CO, V, Ni) concentration levels in surficial sediments of the Arvand River Estuary and their impact on benthic macroinvertebrates assemblages

ABSTRACT In the current study, the determination of total petroleum hydrocarbons (TPHs) and selected heavy metal (Pb, Co, V, Ni) concentration levels in surficial sediments of the Arvand River and their impacts on benthic invertebrate assemblages are investigated. For this purpose, a total of 100 surface sediment samples from 10 stations were collected for TPHs, heavy metals, macroinvertebrates, TOM, and grain size measurements using a Van-Veen grab sampler during winter 2018. A Horiba U10 multiparameter probe was used at each station for the in-situ measurement of environmental variables of water samples close to river bottom using a Nansen bottle sampler. Sediment quality guidelines along with Pearson’s correlation analysis and calculated diversity indices revealed that Arvand River Estuary (ARE) is threatened by contamination, especially with respect to Ni, Pb, and TPHs. The relatively high concentrations of Ni in most stations and Pb in some stations comparing to guidelines and other regions can be related to industrial activities as well as passing several ships and boats in the region. Shannon–Wiener diversity values recorded in the present study ranged between 0 and 2.01 indicating heavy to moderate pollution status in ARE. Altogether, the present study findings could be useful as the baseline for future research and better management for reducing contaminant levels.

Macrobenthos as bioindicator of ecological status in the Yekshabe creek-estuary, Persian Gulf

The present study was conducted with the aim of identification of macrobenthos in the Yekshabe estuary in Persian Gulf. Sampling of macrobenthos was performed from spring 2015 for one year. It was carried out seasonally by the Van Veen Grab (0.04 m2) at four stations, with three replications. The identified macrobenthos belonged to 51 families, 70 genera, 80 species, 4 classes (including Polychaeta, Malacostraca, Bivalvia, Gastropoda) and 5 Phyla. The average total density of macrobenthos was 760±614 per square meter. The most frequently observed classes of macrobenthos belonged to Polychaeta (67.8%), Malacostraca (18.5%), Bivalvia (11.6%) and Gastropoda (1.2%), respectively. According to the results of the Kruskal–Wallis test, there was no significant difference between the macrobenthos classes among the different sampling stations. The highest values of the Shannon-Wiener index of diversity (3.07) and the Margalef's richness index (4.66) were observed in spring, whereas the highest value of the Pielou's evenness index (0.95) was observed in autumn. The values of all indices at station 4 were the highest as compared to those of the others. The results of ANOVA test showed that the mean values of the indices were significantly different (p <0.05) in different seasons, whereas the mean values were not significantly different at stations

Research Article: New report for Pristinella jenkinae Stephenson, 1931 (Annelida: Oligochaeta: Naididae) geographical distribution from Southern Caspian Sea basin, Mazandaran province -Iran

Pristinella jenkinae(Stephenson, 1931) is a freshwater cosmopolitan oligochaete. This species was found during limnological investigation in two rivers alongside Iranian coasts and has not been previously reported from Iran’s freshwater fauna and Southern Caspian Sea basin. The specimens of P. jenkinaewere collected bimonthly from Cheshmehkileh and Sardabrood rivers and estuaries (river mouth) using a Van Veen grab (0.03 m2) and Surber (0.1 m2, 0.2 mm-mesh size) samplers at three stations in each estuary (S1: riverine, S2: estuary and S3: marine ecosystem) with three replicates from November 2014 through September 2015. Results of temporal distribution showed that the highest and lowest density and biomass of this species were in January (102.3±68.3 ind m-2 and 0.075±0.034g m-2) and in September (24.4±12.3 ind m-2 and 0.020±0.005g m-2), respectively which were significantly different (N=57, t=0.99, p<0.05). Spatial distribution of P. jenkinae among sampling stations (S1, S2 and S3) showed significant differences (N=57, t=0.99, p<0.05). Freshwater stations (S1) within the river showed higher density and biomass (112.1±64.8 ind m-2 and 0.082±0.035g m-2) than semi-brackish stations (S2) within the estuary (18.8±10.3 ind m-2 and 0.013±0.005g m-2). Semi-brackish stations (S2) showed higher density and biomass than brackish stations (S3) within the sea (0±0 ind m-2 and 0±0g m-2). Density and biomass of this species in Cheshmehkileh River and estuary was more than Sardabrood. A significant correlation (N=57, r=Pearson, p<0.05) between density and biomass of P. jenkinaewith environmental variables was found.

Biological traits of benthic macrofauna show sizebased differences in response to bottom trawling intensity

Bottom trawling results in widespread impacts to the structure and composition of benthic communities. Although an ecosystem approach to fisheries management aims to conserve marine biodiversity and ecosystem function, there remains a lack of empirical evidence regarding the effects of trawling on benthic functional properties. Here, we examined the sensitivity of benthic macrofauna communities to trawling using their biological traits, and compared trait responses across size-categories and survey types. We collected 84 benthic soft-sediment samples by Van Veen grab (0.1 m2) in the Kattegat in 2016, and complemented with 827 Haps cores (0.0143 m2) gathered over a long-term monitoring programme between 2006 and 2013. By analysing trait response in 3 size categories (small: 1-4 mm fraction; large: ≥4 mm fraction; full community: all individuals combined), we demonstrate a size-dependent effect of trawling on benthic trait composition, where the traits of large-bodied fauna (≥4 mm) were more sensitive. Specifically, larger sessile, deep-living, suspension-feeding, tube-dwelling, subsurface deposit-feeding, burrow-dwelling, and long-lived (≥10 yr) individuals were among the most affected. Our results based on large fauna were largely in agreement with trait responses observed in the multi-year monitoring data, suggesting that trait data gathered from a targeted one-time sampling event can convey information on both acute (short-term) and chronic (long-term) trawling impacts. Given that most trawling impact assessments do not consider size-based effects, we outline how size-separating the community can be used to improve the detectability of trawling impacts, and provide new insights into the functional impacts of fishing on the seabed.

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The aim of this study was to describe and analyze the structure, distribution, and temporal variation in the composition of benthic polychaeta and their relation to abiotic characteristics in marine sediments along the continental shelf of Bahia de Todos Santos, Baja California, Mexico. Benthic macrofauna and environmental variables were collected to coordinated with a long-term ocean monitoring project known as the Southern California Bight Regional Monitoring Program. A total of nineteen stations were collected in September 1998, twenty stations in November 2003, fifteen stations in December 2013 and sixteen stations in September 2018. These data were compared to assess the response of benthic polychaete assemblages to natural and human induced changes in sediment characteristics. All stations were sampled using a Van Veen grab (0.1 m2) at depths between 15 to 206 m. Sites were selected using a multiple density nested random-tessellation stratified design. Environmental parameters measured included depth (m), sediment grain size &lt;63µm (%), organic carbon (%), and concentration of metals: Co, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. A total of 11,854 polychaetous annelids were identified in 43 families, with the numerically dominant families for all years (Spionidae, Chaetopteridae, Cirratulidae, Maldanidae, Onuphidae, and Ampharetidae) accounting for 52.95% of individuals. The best represented families in 1998 were Spionidae, Maldanidae, Ampharetidae and Cirratulidae. In 2003 the best represented families were Spionidae, Maldanidae, Cirratulidae, and Onuphidae; in 2013 Chaetopteridae and Spionidae; and in 2018 Spionidae, Ampharetidae, Syllidae and Cirratulidae. The Bio-Env multivariate analysis showed that the factors that most correlated with the abundance and richness of families and had the greatest influence over spatial distribution trends for community structure were %Organic carbon and Cu concentration during 1998, % Organic carbon and depth in 2003 and Pb concentration in 2013.

Optimizing Costs to Collect Local Infauna through Grabs: Effect of Sampling Size and Replication

Most ecological studies require a cost-effective collection of multi-species samples. A literature review unravelled that (1) large-sized grabs to collect infauna have been used at greater depths, despite no consistent relationship between grab size and replication across studies; and (2) the total number of taxa and individuals is largely determined by the replication. Then, infauna from a sedimentary (sandy) seabed at Gran Canaria Island was collected through van Veen grabs of three sizes: 0.018, 0.042 and 0.087 m2 to optimize, on a simple cost-benefit basis, sample size and replication. Specifically, (1) the degree of representativeness in the composition of assemblages, and (2) accuracy of three univariate metrics (species richness, total infaunal abundances and the Shannon-Wiener index), was compared according to replication. Then, by considering mean times (a surrogate of costs) to process a sample by each grab, (3) their cost-efficiency was estimated. Representativeness increased with grab size. Irrespective of the grab size, accuracy of univariate metrics considerably increased when n &gt; 10 replicates. Costs associated with the 0.087 m2 grab were consistently lower than costs by the other grabs. In conclusion, because of high representativeness and low cost, a 6.87 L grab appears to be the optimal sample size to assess infauna at our local site.

Structure and composition of the macrobenthic community associated to shallow mangrove-seagrass habitat along the southern Red Sea coast, Saudi Arabia

Macrobenthic communities in shallow mangrove-seagrass habitat at the southern portion of Saudi Arabia, Red Sea were explored to (i) characterize their diversity and abundance; (ii) examine the variability among outer, middle and inner stations; and (iii) evaluate the catch performance of scoop (bulldozer) and Van Veen grab. Fifteen sampling collections (9 scoop and 6 grab) captured 4,491 individuals encompassing 18 taxonomic groups. Polychaetes predominated the samples, followed by pelecypods, gammarids, gastropods, and isopods. The species richness did not differ among stations. The density of macrobenthos was significantly (ANOVA, F = 5.51, p = 0.020) higher in the outer and middle stations than the inner station. Moreover, the difference of macrobenthos abundance was seemingly associated with the sediment type and the presence and absence of seagrass. The proportion of non-shared groups over the total number of groups increases from the outer to the inner stations (30.7 to 57.1%), which revealed a degree of difference in the community. The exclusive presence of stomatopods in the inner station suggests their territorial behavior. As well, Van Veen grab captured higher taxonomic groups than scoop; the difference in abundance was not significant. Grab was more pragmatic with ease to operate and thus higher catch efficiency.

MACROFAUNA BENTÔNICA SOB EFEITO DA PISCICULTURA DE TANQUE-REDE NO RIO SÃO MATEUS, SUDESTE DO BRASIL

A piscicultura no Brasil vem crescendo em ritmo acelerado e isto se deve ao alto grau de lucratividade e retorno de investimento rápido. Entretanto, a escolha de local não favorável para a implantação de tanques-rede pode resultar na produção de efluente de baixa qualidade, baixa concentração de oxigênio dissolvido, altas concentrações de matéria orgânica, nutrientes e sólidos em suspensão, os quais afetam os ambientes aquáticos. Dessa forma, o monitoramento da comunidade bentônica pode ser usado como uma ferramenta de avaliação ambiental, refletindo mudanças nas condições físicas, químicas e ecológicas do local. Assim, o objetivo deste estudo foi avaliar a comunidade macrobentônica sob tanques rede em um trecho do rio São Mateus, ES, a fim de detectar possíveis alterações decorrentes dessa atividade. As amostras foram coletadas cinco vezes entre fevereiro de 2011 e maio de 2012, em quatro pontos de amostragem: sob o tanque de peixes, na margem oposta, cerca de 500m a montante e 500m a jusante. As amostras foram coletadas com um coletor Van Veen, quantificadas e identificadas em laboratório. Foram encontrados 195 indivíduos distribuídos em cinco táxons, com Oligochaeta e Chironomidae sendo os mais abundantes. Apenas variações temporais foram detectadas. O índice BMWP’ deixa claro que a qualidade ambiental de toda a área de estudo é muito crítica, demonstrando que a degradação ambiental do rio causada por diversos fatores, incluindo a descarga de efluentes orgânicos, parece comprometer muito mais a fauna bentônica do local do que a própria piscicultura.

Metal Concentrations in Sediments of the Alinsaog River, Santa Cruz, Zambales, Central Luzon, Philippines.

Background.Efforts are needed to evaluate heavy metal concentrations in aquatic sediments which serve as repositories and as sources of contamination of other habitats.Objectives.The present study assessed temporal changes in the pH, particle size and concentration of metals in sediments of a mining-affected river in Zambales, Philippines.Methods.Sediment samples were collected at different periods in four stations along the river using a modified Van Veen grab. The samples were subjected to quartering, air-drying, and sieved through a mesh of 40 mm prior to X-ray fluorescence spectroscopy analysis using Thermo Scientific Niton XL3t to determine metal concentrations. The sediment particle size was analyzed by the sieve method and soil pH by the electrode method.Results.Measured metal concentrations in the sediment were as follows: iron (Fe)> calcium (Ca)> chromium (Cr)> nickel (Ni)> manganese (Mn) with averages of 174.6 mg/g, 7.89 mg/g, 6.54 mg/g, 4.82 mg/g, and 2.75 mg/g dry matter (DM), respectively. The mean pH of riverine sediments was generally neutral, except for Station 4. In terms of particle size, silt and clay fractions increased in the upstream station but decreased in the midstream and downstream stations across the sampling periods. The flooding brought by Typhoon Koppu resulted in lowered concentrations of Fe, Mn, Cr, and Ni and an upsurge in Ca and potassium levels.Discussion.Most of the heavy metals (Fe, Ni, Cr, Mn) exceeded the probable effect level (PEL) for inorganics in sediments, suggesting that the adverse effects of these metals on the environment and aquatic organisms are expected to occur frequently. In comparison with Station 4, which was less affected by siltation, there was a sign of metal enrichment in the area. This indicates that soil erosion and runoff, which might have been triggered by vegetation loss, mineral extraction, and agricultural activities, had a significant impact on the quality of river sediments.Conclusions.The findings of the study point to the need for the formulation and implementation of appropriate regulatory measures for the protection and rehabilitation of the heavy metal-loaded river.Competing Interests.The authors declare no competing financial interests.

Bathymetrical and temporal variations in soft-bottom molluscan assemblages in the coastal area facing the Sarno River mouth (Mediterranean Sea, Gulf of Naples)

Molluscan assemblage of coastal area facing the very polluted Sarno River estuary to offshore (Gulf of Naples, Italy) was studied, focusing on temporal and depth-related distribution of species diversity, quali-quantitative composition and trophic guilds structure. A total of 9 stations, at depths ranging between 7 and 95m, were sampled in triplicate by means of a 0.17 m 2 Van Veen grab in four sampling occasions (2 seasons, winter and summer, during 2 years, 2015 and 2016). A total of 1,744 individuals, belonging to 78 species and 3 classes (Bivalvia, Gastropoda and Scaphopoda), was recorded. Bivalves, followed by gastropods, qualitatively and quantitatively dominated the mollusc assemblages and both these taxonomic groups showed the highest values in the shallower stations down to about 25 m depth. In the deeper stations, only the bivalve taxon was dominant, even though exhibiting a much lower species richness and abundance. On the overall, the molluscan species were ascribed to 6 feeding guilds: Suspension and deposit feeders were the dominant trophic groups, occurring at all stations along the bathymetrical gradient, while predators, detritus feeders, ecto-parasites and scavengers were poorly represented and mainly occurred in the shallowest stations. The mollusc composition and distribution pattern along the bathymetrical gradient over time show signs of structural stability that might be mainly due to the continuous supply of organic matter from the river mouth expanding to all area. These results are of primary importance for filling the knowledge gaps on benthic biodiversity over a still poorly known and very fragile coastal area under continuous anthropogenic pressures mainly through the runoff of a very polluted river.

Spatial and temporal variations in the species composition and abundance of benthic macroinvertebrates along the coast of the Eastern Black Sea

ABSTRACT The species composition and abundance of benthic macroinvertebrates in the Eastern Black Sea were determined seasonally, between May 2013 and February 2014. Sediment was collected using a Van Veen grab, at different depths: 5–15 m, 15–25 m, 25–35 m and >35 m. A total of 320 hauls were undertaken at 80 stations, and 90 species were identified, from seven phyla and 47 families. Overall, Mollusca was the most diverse phylum, with 32 species, followed by Annelida (32) and Arthropoda (13). The most abundant species was Chamelea gallina, which accounted for 37% of the total number of individuals, followed by Gouldia minima (25%) and Pitar rudis (10%). Based on seasonal variations, 62 species were identified in winter, 59 in summer, 54 in spring and 46 in autumn. The highest abundance was recorded in summer, representing 37.8% of the total abundance, followed by spring (25.2%). The species with the highest abundance in all four seasons was C. gallina followed by G. minima. Also, C. gallina followed by G. minima was the most abundant species in Samsun, Ordu, Giresun and Trabzon, whereas in Rize and Artvin, the most abundant species was G. minima followed by C. gallina. The results of this study should provide baseline data for future monitoring, to understand the consequences of natural or anthropogenic disturbance on the species composition and abundance pattern of the benthic macroinvertebrate community along the coast of the Eastern Black Sea.

Data on the microplastics contamination in water and sediments along the Haraz River estuary, Iran.

The type and extent of microplastic contamination in water and sediment of Haraz River were evaluated. Water and sediment samples were collected using a planktonic trawl with a mesh size of 300 µ and a Van Veen grab, from February to May 2017. The morphology and elemental compounds of microplastic particles were analysed using SEM/EDX. Moreover, differential scanning calorimetry (DSC) was done for polymers identification; so that the data could be used for comparative analyses. The number of pieces per kg dry weight in sediments and per cubic meter sampled water was determined. Last but not least, plastic types were also distinguished.

Source apportionment and associated potential ecological risk assessment of heavy metals in coastal marine sediments samples in Ondo, Southwest, Nigeria

Heavy metals are released into the sediments in aquatic environment from both natural and anthropogenic sources and they are considered as worldwide issue due to their deleterious ecological risks and food chain disruption. In this study, sediments samples were collected at three major sites (Awoye, Abereke and Ayetoro) along Ondo coastal marine area using VanVeen grab sampler. The concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn were determined by employing Atomic Absorption Spectroscopy (AAS). The combined concentrations data were subjected to Positive Matrix Factorization (PMF) receptor approach for source identification and apportionment. The probable risks that might be posed by heavy metals in the sediment were estimated by potential and integrated ecological risks indices. Among the measured heavy metals, Fe had the average concentrations of 20.38 ± 2.86, 23.56 ± 4.16 and 25.32 ± 4.83 µg/g at Abereke, Awoye and Ayetoro sites, respectively. The PMF resulted in identification of four sources of heavy metals in the sediments. The resolved sources and their percentage contributions were oil exploration (39%), industrial waste/sludge (35%), detrital process (18%) and Mn-sources (8%). Oil exploration activities and industrial wastes are the major sources that contribute heavy metals into the coastal sediments. The major pollutants that posed ecological risks to the local aquatic ecosystem are As, Pb, Cr and Cd (40 ≤ $$E_{r}^{i}$$ < 80) classifying the sites as moderate risk. The integrate risks values of Awoye, Abereke and Ayetoro are 231.2, 234.0 and 236.4, respectively suggesting that the study areas had a moderate ecological risk. The study showed the suitability of PMF receptor model for source identification of heavy metals in the sediments. Also, the intensive antropogenic activities and natural sources could largely discharged heavy metals into the study area, which may increase the heavy metal contents of the sediments and further contribute to the associated ecological risk, thus affecting the local aquatic ecosystem.