Marine environmental monitoring in the shelf zone of the Black Sea: Assessment of the current state of the pelagic ecosystem

Арашкевич, Е. Г.; Louppova, N. E.; Никишина, А. Б.; Паутова, Л. А.; Часовников, В. К.; Drits, A. V.; Подымов, О. И.; Romanova, N. D.; Stanichnaya, R. R.; Зацепин, А. Г.; Куклев, С. Б.; Флинт, М. В.

doi:10.1134/s0001437015060016

Cited by 15 publications

(5 citation statements)

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“…Biomass values were standardized to units of milligrams of dry weight per cubic meter (mg DW m −3 ) or milligrams of dry weight per square meter (mg DW m −2 ). The intensity of the echo signal strongly depends on the material properties of the organism's tissue (Stanton et al, 1994); therefore, when comparing the pattern of the scattering signal intensity with the pattern of zooplankton distribution in a community containing different taxa, it was reasonable to express zooplankton biomass as DW or carbon (Flagg and Smith, 1989;Heywood et al, 1991;Ashjian et al, 1998). For a graphical presentation of the results, six components of zooplankton were considered: copepods Calanus euxinus and Pseudocalanus elongatus, small crustaceans (Acartia clausi, Paracalanus parvus, Oithona similis and cladocerans), heterotrophic di- noflagellate Noctiluca scintillans, chaetognaths Parasagitta setosa, and varia (ctenophores Pleurobrachia pileus, appendicularians, meroplankton, decapod larvae, Pisces ova).…”

Section: Measurementsmentioning

confidence: 99%

“…The inclusion of diapause (or dormant stage) in the life cycle of all Calanidae species living in high-latitude and temperate environments is well known (e.g., see review in Baumgartner and Tarrant, 2017). Having accumulated a large amount of lipids, diapausing copepods descend into deeper ocean layers, where they can exist for several months at the expense of energy reserves.…”

Section: The Ssls Validated From the Stratified Net Samplingmentioning

confidence: 99%

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Seasonal variation of the sound-scattering zooplankton vertical distribution in the oxygen-deficient waters of the NE Black Sea

et al. 2021

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Abstract. At the northeastern Black Sea research site, observations from 2010–2020 allowed us to study the dynamics and evolution of the vertical distribution of mesozooplankton in oxygen-deficient conditions via analysis of sound-scattering layers associated with dominant zooplankton aggregations. The data were obtained with profiler mooring and zooplankton net sampling. The profiler was equipped with an acoustic Doppler current meter, a conductivity–temperature–depth probe, and fast sensors for the concentration of dissolved oxygen [O2]. The acoustic instrument conducted ultrasound (2 MHz) backscatter measurements at three angles while being carried by the profiler through the oxic zone. For the lower part of the oxycline and the hypoxic zone, the normalized data of three acoustic beams (directional acoustic backscatter ratios, R) indicated sound-scattering mesozooplankton aggregations, which were defined by zooplankton taxonomic and quantitative characteristics based on stratified net sampling at the mooring site. The time series of ∼ 14 000 R profiles as a function of [O2] at depths where [O2] < 200 µm were analyzed to determine month-to-month variations of the sound-scattering layers. From spring to early autumn, there were two sound-scattering maxima corresponding to (1) daytime aggregations, mainly formed by diel-vertical-migrating copepods Calanus euxinus and Pseudocalanus elongatus and chaetognaths Parasagitta setosa, usually at [O2] = 15–100 µm, and (2) a persistent monospecific layer of the diapausing fifth copepodite stages of C. euxinus in the suboxic zone at 3 µm < [O2] < 10 µm. From late autumn to early winter, no persistent deep sound-scattering layer was observed. At the end of winter, the acoustic backscatter was basically uniform in the lower part of the oxycline and the hypoxic zone. The assessment of the seasonal variability of the sound-scattering mesozooplankton layers is important for understanding biogeochemical processes in oxygen-deficient waters.

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Section: Measurementsmentioning

confidence: 99%

Section: The Ssls Validated From the Stratified Net Samplingmentioning

confidence: 99%

Seasonal variation of the sound-scattering zooplankton vertical distribution in the oxygen-deficient waters of the NE Black Sea

et al. 2021

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“…К такому же выводу приходят и [26], установившие, что даже в годы своего максимального развития (1980-е) A. aurita могли потреблять лишь 5-7 % биомассы зоопланктона в сутки, или 50-70 % его суточной продукции. Отсутствие корреляции между биомассой желетелых хищников и биомассой мезопланктона и его отдельных таксономических групп [12]…”

Section: материал и методыunclassified

“…Среднегодовая биомасса A. aurita составляла около 400 г•м -2 . Близкие среднегодовые величины (340 г•м -2 ) обнаружены в северо-восточной части Чёрного моря в 2011-2012 гг [12]…”

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Пространственная Вариабельность И Пищевые Характеристики Популяций Желетелых В Акватории Крыма В Летний Период

Финенко

Datsyk

Игнатьев

et al. 2019

mbj

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The existence of two alternative points of view on the long-term dynamics of gelatinous macroplankton populations in the World Ocean determines the need for long-term monitoring as a basis for assessing their condition. The accumulation of long-term series of data on the development of gelatinous predators in the Black Sea makes it possible to assess their role in the functioning of the pelagic ecosystem in connection with climatic variability. The abundance, biomass, the size structure of the gelatinous predators (jellyfish Aurelia aurita; ctenophores Mnemiopsis leidyi and Pleurobrachia pileus) and the feeding intensity of the two species (A. aurita and M. leidyi) were investigated in the early summer period (June) of 2016 at 45 stations covering the shelf zone off the coast of Crimea from Cape Tarkhankut to Kerch, as well as at 3 stations of the deepwater area with the coordinates 44°23′N–45°5′N and 32°22′E–36°36′E. The material was collected from the bottom (10–100 m) up to the surface at the inshore stations and from the depth with σt = 16.2 to the surface – in deepwater by vertical trawls with modified Bogorov – Russ net with an inlet diameter of 80 cm, a mesh of 300 μm. The nutritional spectrum and its quantitative composition were determined under a microscope in the laboratory immediately after the catch of animals, followed by the calculation of diurnal rations and the rate of ingestion of zooplankton. Spatial differences in abundance of gelatinous species were observed: the maximum biomass of A. aurita, prevailing in all regions, was observed in the Yevpatoriya – Sevastopol region and was due to large accumulations of middle-sized specimens of new generation. Ctenophora P. pileus dominated in the abundance in the halistatic zone. The food spectrum of jellyfish was very diverse and included various stages of Copepoda, Tunicata, Cladocera, and also the meroplankton – the Bivalvia and Gastropoda veligers. The halistatic zone with great depths was characterized by the widest species composition of planktonic Copepoda in A. aurita food. The average daily rations of jellyfish varied from one region to another, being the lowest in the Karkinitsky Bay [(0.113 ± 0.10) mg C−1·day−1, or (1.6 ± 2.18) % of C body] with most of the food being algae C. granii. The most intensive feeding was in the halistatic zone [(56.2 ± 23.7) % of C body] with a predominance of Calanus euxinus and Pseudocalanus elongatus in the diet. In no region A. aurita can compensate the respiration requirements by the consumption of mesozooplankton. The highest impact on zooplankton was provided by jellyfish population in the Karkinitsky Bay and in the Yevpatoriya – Sevastopol region, although along all the shelf its impact was very low and did not lead to a dramatic reduction in the zooplankton community abundance.

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“…Results of long-term studies of the phytoplankton taxonomic composition in different parts of NE Black Sea, the spatial distribution of the phytoplankton abundance and biomass, seasonal dynamics, and influence of anthropogenic pressures and climate change are summarized and presented in reviews [1,[25][26][27][28]. Recent studies covered phytoplankton of the NE shelf and adjacent deepwater basin of the Black Sea [29][30][31][32][33][34][35]. These studies have analyzed seasonal and interannual variability of the hydrophysical, hydrochemical, and biological parameters and have identified long-term trends in the relationship between abiotic factors and the variability of phytoplankton communities.…”

Section: Introductionmentioning

confidence: 99%

Response of the Coastal Phytoplankton Community to the Runoff from Small Rivers in the Northeastern Black Sea

et al. 2023

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River runoff is an important source of nutrients as well as suspended and dissolved organic matter that in coastal zones and on the shelf are transformed due to local production cycles. River runoff affects the hydrological regime, salinity, temperature, and irradiance in river–seawater mixing zone. Our study focuses on the response of phytoplankton to the impact of small Caucasian rivers in the Northeastern (NE) Black Sea, as one of the most sensitive components of marine ecosystems with respect to the changes in abiotic factors. The leading role of marine species of diatoms, dinoflagellates, and coccolithophores in the structure and functioning when impacted by runoff from small rivers is demonstrated in comparison to the freshwater community. Variability of the taxonomic composition and quantitative and productive characteristics of marine phytoplankton communities impacted by small rivers were comparable to or exceed the seasonal and interannual variability on the NE Black Sea shelf. This indicates the significant role of runoff from small Caucasian rivers in maintaining of a high production level of phytoplankton overall and of the coccolithophore Emiliania huxleyi in particular in the coastal zone.

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Marine environmental monitoring in the shelf zone of the Black Sea: Assessment of the current state of the pelagic ecosystem

Cited by 15 publications

References 4 publications

Seasonal variation of the sound-scattering zooplankton vertical distribution in the oxygen-deficient waters of the NE Black Sea

Seasonal variation of the sound-scattering zooplankton vertical distribution in the oxygen-deficient waters of the NE Black Sea

Пространственная Вариабельность И Пищевые Характеристики Популяций Желетелых В Акватории Крыма В Летний Период

Response of the Coastal Phytoplankton Community to the Runoff from Small Rivers in the Northeastern Black Sea

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