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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 ...

The occurrence of micro- (25mm) was investigated in seven commercial fish species of the Black Sea. Plastics were found in gastrointestinal track of all species analysed: Engraulis encrasicolus, Trachurus mediterraneus, Sarda sarda, Belone belone, Pomatus saltatrix, Merlangius merlangus and Mullus barbatus. A total of 352 plastic particles were removed from 190 individuals (29% of all individuals examined). The mean number of plastic particles per fish was 0.81±1.42 par.ind-1 (considering all fish analysed, n=650) and 2.06±1.09 par.ind-1 (considering only the fish that ingested plastic, n=190). The most common types of plastics were fibres (68.5%), followed by films (19%), fragments (11.9%), foams (0.3 %) and microbeads (0.3%). The most common plastic colour was black (39.3%) followed by blue (19.5%) and transparent (18.1%). The length of plastics ranged from 0.05 to 26.5 mm with an average of 1.84±2.80 mm. 93.2% of plastics were microplastics, 6.5 % as mesoplastics and 0.3% macroplastics. Plastic occurrence was higher in S. sarda (plastic in 70% of the analysed individuals) and lower in M. merlangus (plastic in 9% of the analysed individuals). The main synthetic polymers identified by Fourier-transform infrared (FTIR) spectroscopy were polypropylene (29.8%), polyester (17.5%), acrylic (15.8%), polyethylene (14%) and polystyrene (1.8%) and 21.1% of polymers were cellulosic. Results show that commercial fish of the Black Sea is contaminated by plastics. This might affect vital functions of fish and pose a risk to ecosystem and human health. The study contributes to a better understanding of the status of plastic pollution in the fish from different habitats of the Black Sea and provides baseline data to implement the Marine Strategy Framework Directive in the basin.

Marine litter, especially plastic, is the fastest growing environmental problem in the Black Sea. Rivers are recognized as the major sources of litter in the basin, but information on the transport of litter by rivers is still limited. This study presents the first estimates of riverine floating macro-litter in the SE Black Sea (Turkey), based on monthly visual counting in three relatively small rivers between January and August of 2020. Plastic represented 99 % of the identified items with fragments (2.5–50 cm) (40.3 %) and shopping bags (26.2 %) being the most abundant items. Riverine litter fluxes median values varied between 35 and 96 items/hour in three rivers. Results show that small rivers can carry a considerable amount of plastic to the SE Black Sea. This calls for increased monitoring of riverine litter transport to develop effective prevention and removal strategies for tackling the problem of plastic pollution in the Black Sea.

Ingestion and egestion of microplastics by copepods in the Black Sea was assessed for the first time. Composition and concentration of microplastics in the water column was also evaluated. Samples were collected from three stations (river mouth, coastal and open water) in the Southeastern Black Sea over the course of one year. Microplastic concentration in the water column ranged between 0.12 and 7.62 mp·m−3 (mean 2.04 ± 1.05 mp·m−3) with significantly higher concentrations in the river mouth. The most common types of microplastics were fibres, followed by films and fragments. A total of 11 colours of microplastics were found, being blue the most common colour. Analysis of 1126 C. euxinus and 1065 A. clausi, resulted in 26 and 9 microplastics being detected, respectively. This resulted in a microplastic ingestion of 0.024 ± 0.020 mp. Calanus−1 and 0.008 ± 0.006 mp. Acartia−1. Analysis of 351 faecal pellets, resulted 4 microplastics being found. The average size of ingested microplastics was greater in C. euxinus (0.100 mm ± 0.153 mm) than in A. clausi (0.062 mm ± 0.056 mm). Size of ingested microplastics was in the size range of natural preys of these copepods. Fragments were the most common type of ingested microplastics, followed by films and fibres. The colour of ingested particles was black, blue and red. Our results show that the copepods and the pelagic environment of the Black Sea are contaminated by microplastics. Critical functions of zooplankton in this degraded ecosystem are under risk and zooplankton are likely to act as a vector for the transfer of microplastics and associated toxic chemicals to upper trophic levels including humans in the Black Sea.

The near-surface layer of the ocean is a habitat in which plankton are subjected to very different stresses to those in deeper layers. These include high turbulence and illumination, allowing increased visibility to predators, and exposure to harmful UV radiation. To provide insights into stress caused by UV, we examined the occurrence of protective UV-absorbing compounds called mycosporine-like amino acids (MAAs) in seston and zooplankton along an Atlantic Meridional Transect (AMT) between 45°S and 50°N. Seston contained most MAAs per unit phytoplankton carbon in the northern Atlantic gyre and equatorial region and this coincided with distribution of the nitrogen fixing cyanobacterium Trichodesmium spp. and increased UV transparency but not irradiance. Asterina-330 was the most abundant MAA in the seston. MAAs were detected in a third of the zooplankton tested and these taxa varied greatly both in the amount and diversity of the MAAs that they contained with copepods in temperate regions containing highest concentration of MAAs. Most commonly found MAAs in zooplankton were palythine and shinorine. Juvenile copepods were found not to contain any MAAs. We determined abundance and richness of zooplankton inhabiting the top 50 cm of the ocean. Zooplankton abundance and genera richness was low in the surface waters in contrast to the dome-shaped latitudinal trend in genera richness commonly found from depth-integrated zooplankton sampling. The lack of any measurable MAA compounds in nauplii across the whole transect was concomitant with their severe (3–6-fold) reduction in nauplii densities in the near-surface layer, as compared to the underlying water column. Overall we suggest that the UV stress on life near the surface, particularly in the warmer, oligotrophic and brightly-lit low latitudes, imposes radically different pressures on zooplankton communities compared to the rest of the epipelagic.

Agirbas, Ertugrul/0000-0001-7987-9668; Aytan, Ulgen/0000-0002-6530-3083 WOS: 000405241000008 Phytoplankton community, diatom to dinoflagellate ratio and pigment composition in surface waters with nutrient data from April 2013 to March 2014 were monitored in the southeastern (SE) Black Sea using high performance liquid chromatography (HPLC) and microscopic analyses. Microscopic examination revealed a total of 71 species that consist of dinoflagellate (58%), diatoms (25%) and other groups (17%). Microscopy and HPLC- based pigment analyses revealed almost similar results which suggest that the phytoplankton community is mainly composed of diatoms, dinoflagellates and coccolithophores. Fucoxanthin (mean 0.35 +/- 019 mu g L-1), peridinin (mean 0.18 +/- 0.14 mu g L-1) and 19- hexanoyloxyfucoxanthin (mean 0.24 +/- 0.15 mu g L-1) are prominent pigments which showed significant correlation with Diatom-C (r(2) = 0.63-0.71, p < 0.05), Dinoflagellate-C (r(2) = 0.49-0.80, p < 0.05) and Coccolithophore-C (r(2) = 0.72-0.82, p < 0.05), respectively. Mean carbon biomass of diatoms (36.50 perpendicular to 9.72 mg L-1) was higher than that of dinoflagellates (33.32 +/- 9.05 mu g L-1). Significant differences were also observed in nutrient ratio (N:P and Si:N) (One-way ANOVA, p < 0.05). Results illustrate that HPLC-based pigment approach can be used for taxonomic characterisation of phytoplankton groups in the SE Black Sea. Moreover, relatively high dinoflagellate species dominancy and significant correlations between Phyto-C and marker pigments indicate that phytoplankton community composition is shifting towards much smaller groups in SE coasts of the Black Sea. (C) 2017 the Authors. Production and hosting by Elsevier Sp. z o. o. on behalf of Institute of Oceanology of the Polish Academy of Sciences. Scientific Research Project council of Recep Tayyip Erdogan University [2013.103.01.02] We sincerely thank the officers and crew of R/V RIZE SUAR for their assistance during the cruises. Authors also thank to Dr. Serkan KORAL for HPLC analyses and Serkan SERDAR for nutrient analyses. This work was funded by Scientific Research Project council of Recep Tayyip Erdogan University (Project No: 2013.103.01.02).

Seasonal and spatial distribution of Noctilucoid dinoflagellates collected from three stations (river mouth, coastal and offshore waters) were investigated between May 2015 and April 2016 in the SE Black Sea. Noctilucoid dinoflagellates were represented with four species, Noctiluca scintillans (Macartney) Kofoid & Swezy, 1921, Scaphodinium mirabile Margalef, 1963, Spatulodinium pseudonoctiluca (Pouchet) J.Cachon & M.Cachon, 1968 and Pronoctiluca pelagica Fabre-Domergue 1889. The abundance of Noctilucoids ranged between 0 and 575 cells l−1 in the first 100 m of the water column during study. Noctilucoid dinoflagellates comprised 0.0–48.5% of total dinoflagellate abundance in the study area with the highest percentages occurring in May 2016. Noctiluca scintillans was the most abundant species being associated with 45.6% of total Noctilucoids followed by P. pelagica (30.8%), S. mirabile (13.3%) and S. pseudonoctiluca (5.9%). There were no significant differences on Noctilucoid distribution between stations (p > 0.05, one-way ANOVA), however significant differences were found between sampling dates with the highest in May (p 0.05, t-test). S. mirabile and S. pseudonoctiluca were reported for the first time from the Southeastern Black Sea.

Summary: We investigated biomass and composition of the pico-, nano- and microplankton communities in a coastal station of the southeastern Black Sea during 2011. We also examined trophic interactions within these communities from size-fractionated dilution experiments in February, June and December. Autotrophic and heterotrophic biomasses showed similar seasonal trends, with a peak in June, but heterotrophs dominated throughout the year. Autotrophic biomass was mainly comprised by nanoflagellates and diatoms in the first half of the year, and by dinoflagellates and Synechococcus spp. in the second half. Heterotrophic biomass was mostly dominated by heterotrophic bacteria, followed by nanoflagellates and microzooplankton. Dilution experiments suggest that nano- and microzooplankton were significant consumers of autotrophs and heterotrophic bacteria. More than 100% of bacterial production was consumed by grazers in all experiments, while 46%, 21% and 30% of daily primary production were consumed in February, June and December, respectively. In February, autotrophs were the main carbon source, but in December, it was heterotrophic bacteria. An intermediate situation was observed in June, with similar carbon flows from autotrophs and heterotrophic bacteria. Size-fraction dilution experiments suggested that heterotrophic nanoflagellates are an important link between the high heterotrophic bacterial biomass and microzooplankton. In summary, these results indicate that nano- and microzooplankton were responsible for comprising a significant fraction of total microbial plankton biomass, standing stocks, growth and grazing processes. This suggests that in 2011, the microbial food web was an important compartment of the planktonic food web in the coastal southeastern Black Sea. Keywords: Phytoplankton, Microzooplankton, Carbon biomass, Microbial food web, Grazing, Black Sea

Guneydogu Karadeniz’de Mikrozooplankton komunite komposzisyonu, bollugu ve iliskili oldugu dusunulen cevresel parametreler nehir agzi ve acik istasyonunda Haziran 2015-Agustos 2015 tarihleri arasinda arastirildi. Mikrozooplankton komunitesi protozoa ve mikrometazoadan olustu. Ancak protozoa mikrozooplanktonun baskin grubu oldu. Her iki ornekleme istasyonunda da protozoa komunitesi heterotrofik dinoflagellatlar ve siliyatlar tarafindan temsil edildi. Bu calismada sarkodinlere rastlanmadi. Mikrozooplankton bollugu nehir agzinda 332- 845 hucre/l ve acik istasyonunda 203- 604 hucre/l arasinda degisti ve Haziran’dan Agustos’a dusus egilimi sergiledi. Istasyonlar arasinda toplam mikrozooplankton bollugu bakimindan istatistiki acidan onemli bir farklilik bulunmamistir (t-test, p< 0.05). Onceki yapilan calismalarla karsilastirmalar, mikrozooplanktonun termal tabakalasma doneminde ust besinsel seviyeler icin onemli bir enerji kaynagi olabilecegini gosterdi. Anahtar Kelimeler : Heterotrofik dinoflagellat, siliyat, mikrometazoa, mikrozooplankton, Karadeniz Abstract Microzooplankton community composition, abundance and related environmental parameters were assessed in estuarine and offshore stations during June to August 2015 in the South Eastern Black Sea. The microzooplankton community was composed of protozoa and metazoa, however, microzooplankton were dominated by protozoa. Protozoan community comprised of heterotrophic dinoflagellates and ciliates in both stations. No sarcodines were observed. Microzooplankton abundance ranged from 332 to 845 cells/l and 203 to 604 cells/l in the estuarine and off-shore stations, respectively. Microzooplankton abundances tended to decrease from June to August. No significant differences were found between sampling stations in terms of microzooplankton abundance (t-test, p< 0.05). Comparison with previous studies showed microzooplankton could be an important energy source for higher trophic levels during thermal stratification. Keywords : Heterotrophic dinoflagellate, ciliate, micrometazoa, microzooplankton, Black Sea