Nelli G. Sergeeva

Meiobenthos of the Oxic/Anoxic Interface in the Southwestern Region of the Black Sea: Abundance and Taxonomic Composition

The Black Sea contains the World’s largest body of anoxic water. Based on new and published data, we describe trends among selected protozoan and metazoan meiofaunal taxa at water depths of 120–240 m in the northwestern part of the Black Sea near the submarine Dnieper Canyon. This transect spans the transition between increasingly hypoxic but non-sulfidic bottom water and the deeper anoxic/sulfidic zone, the boundary between these two domains being located at approximately 150–180 m depth. This transition zone supports a rich rose-Bengal-stained fauna. Among the protozoans, gromiids are common only at 120 and 130 m. All other groups exhibit more or less distinct abundance maxima near the base of the hypoxic zone. Foraminifera peak sharply at ∼160 m while ciliates are most abundant at 120, 160–190, and 240 m, where they are possibly associated with concentrations of bacterial cells. The three most abundant metazoan taxa also exhibit maxima in the hypoxic zone, the nematodes and polychaetes at 160 m, and the harpacticoid copepods at 150 m. Most of the polychaetes belong to two species, Protodrilus sp. and Vigtorniella zaikai, the larvae of which are widely distributed in severely hypoxic water just above the anoxic/sulfidic zone of the Black Sea. Both protozoans and metazoans are usually concentrated in the 0–1 cm layer of the sediment, except at the shallowest (120–130 m) site where deeper layers may yield a substantial proportion of the assemblage. The concentration of nematodes in the 3–5 cm layer at 120 m is particularly notable. Our data suggest that some benthic species can tolerate anoxic/sulfidic conditions in the Black Sea. An important caveat is that anoxia or severe hypoxia may lead to the corpses of nonindigenous organisms being preserved in our samples. However, we argue that the morphological integrity of specimens, the high population densities (associated with high bacterial concentrations in the case of ciliates), the presence of taxa often found in hypoxic settings, and the presence of all life stages (including gravid females) among nematodes and harpacticoids, suggests that at least some of the organisms are indigenous. Further comparative studies of shallow- and deep-water meiobenthic communities in the Black Sea are necessary in order to establish which species are characteristic and indicative of hypoxic/anoxic conditions.

The monothalamous foraminiferan Tinogullmia in the Black Sea

INTRODUCTION The organic-walled allogromiid genus Tinogullmia was established by Nyholm (1954) based on a single species, T. hyalina, from the Gullmar Fjord on the Swedish west coast. This distinctive species is characterized by an elongate, smoothly curved test with two terminal apertures located at the ends of tubular extensions. A similar species occurs in Kongsfjord, Svalbard (Gooday et al., 2005). Several other organic-walled allogromiids have been assigned to the genus Tinogullmia but are distinctly different from T. hyalina. A deep-water species from the NE Atlantic, described as Tinogullmia riemanni by Gooday (1990), has a relatively short, asymmetrical test and possibly represents a distinct genus. An undescribed sausageshaped species from Explorers Cove, Antarctica, assigned to Tinogullmia by Gooday et al. (1996), has a less elongate shape than T. hyalina and a thinner wall. The purpose of this note is to report the first record of this distinctive genus from the Black Sea. OBSERVATIONS During the 45th cruise of the Research Vessel Professor Vodyanitsky in 1994, three core samples were obtained using a multiple corer (Barnett et al., 1984) as part of an investigation of a methane seep area southwest of the Crimean peninsula (Station 5186; 44° 46.342′N, 31° 35.342′E, 78 m water depth). The sampling area bottom-water temperature is 8–10°C, rising to 13–15°C in summer; salinity is 17–18‰. The bottom sediment is phaseolinic silt (i.e. an alevrit silt associated live molluscs and dead molluscan shells). Each core was sub-sampled using a plastic tube, diameter 9.5 cm, length 5 …

Transformation of Gulf Sivash (the Sea of Azov) in Conditions of Growing Salinity: Changes of Meiobenthos and Other Ecosystem Components (2013-2015)

Nickolai V. Shadrinа,*, Nelli G. Sergeevaа, Aleksandr A. Latushkinb, Еlena А. Kolesnikovaа, Laura M. Kipriyanovac, Elena V. Anufriievaа and Anna A. Chepyzhenkob aA.O. Kovalevsky Institute of Marine Biological Research RAS 2 Nakhimov, Sevastopol, 299011, Russia bMarine Hydrophysical Institute RAS 2 Kapitanskaya Str., Sevastopol, 299011, Russia cInstitute for Water and Environmental Problems SB RAS 2 Morskoy, Novosibirsk, 630090, Russia