Presentability of the Utrish Nature Reserve's benthic communities for the North Caucasian Black Sea Coast

An assessment of the presentability of the biotopes and benthic communities of the northwestern part of the Utrish Nature Reserve marine area for the Caucasian Black Sea coast has been conducted. The literary and original data on the state of benthos in the area from the Kerch Strait to Adler were examined. The studied area of the Utrish Natural Reserve included habitats that are common along the coast (an active cliff, a narrow pebble beach, boulder deposits, rock bench and soft sediments). Only two of the three well-known Black Sea belt macrozoobenthic biocoenoses were observed along the northeastern Black Sea coast: the shallow-water «venus sand» and the deep-water «phaseolina silt». The third biocoenosis («mussel mud») was not noted neither in the reserve's area nor in the studied part of the shelf to the south of Novorossiysk. Of these three belts only «venus sand» was found in the Utrish Nature Reserve's marine area. The absence of the mussel belt in the studied area of the reserve is typical for the southern part of the North Caucasian coast in the current period and thus does not affect the presentability of the reserve's benthic ecosystem. The biocoenosis of the bivalves Pitar rudis – Gouldia minima was common at the muddy sand with shells in both reserve's and reference sites' middle-depths complex instead of the mussel belt which was typical for the 20th century. Its boundary was 10 m deeper in the reserve compared to the reference sites. The absence of the Modiolula phaseolina belt in the area of the reserve could be explained by the insufficient width of the protected marine area (up to 52 m depth); due to this the deep-water complex in the reserve is actually represented by a narrow strip. Extension of the reserve's boundary over the depth of 70 m will include this biocoenosis into the Protected Area, which would significantly increase the presentability of the reserve's marine part for the North Caucasian coast. The biogeographical composition of the reserve's flora, its species diversity and structure in general corresponds to that of the whole region. The macrophyte zone consists of four belts: upper (0–2 m, Dictyota fasciola f. repens + Polysiphonia opaca + Ceramium ciliatum + Ulva compressa), upper mid (2–12 m, Cystoseira crinita + Cystoseira barbata – Cladostephus spongiosus – Ellisolandia elongata), lower mid (12–18 m, Phyllophora crispa, Codium vermilara and Bonnemaisonia hamifera), and the lower belt (below 18 m) formed by a recent invader, B. hamifera. The majority of species found in the reserve's marine area are common species of the Black Sea macrophytobenthos. However, the Utrish Nature Reserve includes more favourable habitats for macrophytes than most of the North Caucasian coast, because the typical macrophyte Cystoseira spp. have been noted at greater depths in the reserve, in comparison to the remaining shelf

HAUSGARTEN: Multidisciplinary investigations at a deep-sea, long-term observatory in the Arctic Ocean

The marine Arctic has played an essential role in the history of our planet over the past 130 million years and contributes considerably to the present functioning of Earth and its life. The global cycles of a variety of materials fundamental to atmospheric conditions and thus to life depend to a signifi cant extent on Arctic marine processes (Aargaard et al., 1999). The past decades have seen remarkable changes in key Arctic variables. The decrease of sea-ice extent and sea-ice thickness in the past decade is statistically signifi - cant (Cavalieri et al., 1997; Parkinson et al., 1999; Walsh and Chapman, 2001; Partington et al., 2003; Johannessen et al., 2004). There have also been large changes in the upper and intermediate layers of the ocean, which have environmental implications. For instance, the deep Greenland Sea has continued its decadal trend towards warmer and saltier conditions, with a corresponding decrease in oxygen content, refl ecting the lack of effective local convection and ventilation (Dickson et al., 1996; Boenisch et al., 1997). Changes in temperature and salinity and associated shifts in nutrient distributions will directly affect the marine biota on multiple scales from communities and populations to individuals, consequently altering food-web structures and ecosystem functioning (Benson and Trites, 2002; Moore, 2003; Schumacher et al., 2003; Wiltshire and Manly, 2004; Perry et al., 2005). Today, we do not know whether the severe alterations in abiotic parameters represent perturbations due to human impacts, natural long-term trends, or new equilibriums (Bengtson et al., 2004). Because Arctic organisms are highly adapted to extreme environmental conditions with strong seasonal forcing, the accelerating rate of recent climate change challenges the resilience of Arctic life (Hassol, 2004). The entire system is likely to be severely affected by changing ice and water conditions, varying primary production and food availability to faunal communities, an increase in contaminants, and possibly increased UV irradiance. The stability of a number of Arctic populations and ecosystems is probably not strong enough to withstand the sum of these factors, which might lead to a collapse of subsystems. To detect and track the impact of large-scale environmental changes in the transition zone between the northern North Atlantic and the central Arctic Ocean, and to determine experimentally the factors controlling deep-sea biodiversity, the German Alfred Wegener Institute for Polar and Marine Research (AWI) established the deepsea, long-term observatory HAUSGARTEN, representing the fi rst, and by now only, open-ocean, long-term station in a polar region

Meiofauna in the Gollum Channels and the Whittard Canyon, Celtic Margin—How Local Environmental Conditions Shape Nematode Structure and Function

The Gollum Channels and Whittard Canyon (NE Atlantic) are two areas that receive high input of organic matter and phytodetritus from euphotic layers, but they are typified by different trophic and hydrodynamic conditions. Sediment biogeochemistry was analysed in conjunction with structure and diversity of the nematode community and differences were tested between study areas, water depths (700 m vs 1000 m), stations, and sediment layers. The Gollum Channels and Whittard Canyon harboured high meiofauna abundances (1054–1426 ind. 10 cm−2) and high nematode diversity (total of 181 genera). Next to enhanced meiofauna abundance and nematode biomass, there were signs of high levels of organic matter deposition leading to reduced sedimentary conditions, which in turn structured the nematode community. Striking in this respect was the presence of large numbers of ‘chemosynthetic’ Astomonema nematodes (Astomonema southwardorum, Order Monhysterida, Family Siphonolaimidae). This genus lacks a mouth, buccal cavity and pharynx and possesses a rudimentary gut containing internal, symbiotic prokaryotes which have been recognised as sulphur-oxidising bacteria. Dominance of Astomonema may indicate the presence of reduced environments in the study areas, which is partially confirmed by the local biogeochemical environment. The nematode communities were mostly affected by sediment layer differences and concomitant trophic conditions rather than other spatial gradients related to study area, water depth or station differences, pointing to small-scale heterogeneity as the main source of variation in nematode structure and function. Furthermore, the positive relation between nematode standing stocks, and quantity and quality of the organic matter was stronger when hydrodynamic disturbance was greater. Analogically, this study also suggests that structural diversity can be positively correlated with trophic conditions and that this relation is tighter when hydrodynamic disturbance is greater

Ecology and Biogeography of Free-Living Nematodes Associated with Chemosynthetic Environments in the Deep Sea: A Review

Background: Here, insight is provided into the present knowledge on free-living nematodes associated with chemosynthetic environments in the deep sea. It was investigated if the same trends of high standing stock, low diversity, and the dominance of a specialized fauna, as observed for macro-invertebrates, are also present in the nematodes in both vents and seeps. Methodology: This review is based on existing literature, in combination with integrated analysis of datasets, obtained through the Census of Marine Life program on Biogeography of Deep-Water Chemosynthetic Ecosystems (ChEss). Findings: Nematodes are often thriving in the sulphidic sediments of deep cold seeps, with standing stock values ocassionaly exceeding largely the numbers at background sites. Vents seem not characterized by elevated densities. Both chemosynthetic driven ecosystems are showing low nematode diversity, and high dominance of single species. Genera richness seems inversely correlated to vent and seep fluid emissions, associated with distinct habitat types. Deep-sea cold seeps and hydrothermal vents are, however, highly dissimilar in terms of community composition and dominant taxa. There is no unique affinity of particular nematode taxa with seeps or vents. Conclusions: It seems that shallow water relatives, rather than typical deep-sea taxa, have successfully colonized the reduced sediments of seeps at large water depth. For vents, the taxonomic similarity with adjacent regular sediments is much higher, supporting rather the importance of local adaptation, than that of long distance distribution. Likely the ephemeral nature of vents, its long distance offshore and the absence of pelagic transport mechanisms, have prevented so far the establishment of a successful and typical vent nematode fauna. Some future perspectives in meiofauna research are provided in order to get a more integrated picture of vent and seep biological processes, including all components of the marine ecosystem

Amphimonhystera molloyensis Tchesunov et Mokievsky, sp. n.

<i>Amphimonhystera molloyensis</i> Tchesunov et Mokievsky sp. n. <p>(Figures 4 A–E, 5 A–D & 6A–E)</p> <p> <b>Type material:</b> Holotype male, three paratype males and two paratype females mounted in glycerin on glass slides. Type specimens is deposited in the collection of the P. P. Shirshov Institute for Oceanology, Russian Academy of Sciences, Moscow.</p> <p> <i>Labels</i>: (Holotype male ref #1­1/4): RV Polarstern, ARK XVII st. 125, B(0 – 1 cm), 63 µm, 1/44; (Paratype male 1 and paratype female 1 ref # M­1/6): RV Polarstern, ARK XVII, st. 125, C (0–1 cm), 250 µm, 2/2; (Paratype male 2, ref # M­1/5): RV Polarstern, ARK XVI, St. 251, MD 316 (0–1 cm), 125 mkmµm, 1/13; (Paratype male 3, ref # M­1/3): RV Polarstern, ARK XVI, St. 251, MD 316 (0–1 cm), 125 mkm; (Paratype female 2, ref # M­1/7): RV Polarstern, ARK XVII, st. 125, C (0–1 cm), 125 µm, 2/44.</p> <p> <b>Type locality</b>: Arctic Ocean, area between Greenland and Svalbard. Holotype: st.125, 79°12.0' N 02°34.5' E, 5416 m, (Molloy Deep), silt, 13 July, 2001; Paratypes: St.251, 79°8.2' N & 02°53.6' E, depth 5569 m (Molloy Deep), silt, 16 August, 2000; and st.125, 79°12.0' N 02°34.5' E, 5416 m, (Molloy Deep), silt, 13 July, 2001.</p> <p> <b>Etymology:</b> The species name refers to the area of its findings, Molloy Deep. <b>Morphometric data:</b> Table 5.</p> <p>Specimens Holotype Paratypes</p> <p>Label Male 1 Male 2 Male 3 Male 4 Female 1 Female 2 dist. tail portion (%) 28 34 29 36 32 28</p> <p> termin s. 6.5 6.0 5.0 6.5 7.5 6.0 <b>Description:</b> Body slender, elongated spindle­shape, near cylindrical. Cuticle rather thin and finely transversely striated. In one specimen (ɗ2), subcuticular hypodermis yellow­brownish granules irregularly distributed throughout the body; pigment granules concentrated in preneural region (especially densely just posterior to the amphidial fovea) and thereafter less densely in posterior body region and tail, predominantly in ventral position. In other specimens, males and females as well, there are no conspicuous pigment granules in the anterior hypodermis. Labial region dome­shaped and slightly set off from the rest of the body. Inner labial sensilla not observed. Six outer labial sensilla and four cephalic sensilla setiform, and united with two additional lateral setae in one circle of twelve slender setae situated at the level of the stoma base. ɗ2 distinguished with shorter outer labial setae equal to cephalic setae and lacking additional setae. Amphidial fovea very large, longitudinally oval, with distinct cuticular edging; amphidial fovea of ɗ2 with a convex central spot. The cuticular edging marked with a slight break posteriorly in some specimens. The amphidial fovea situated relatively close to the anterior end. Somatic setae scarce and short, mostly in sublateral position. Buccal cavity small, with very weakly sclerotised walls. The cheilostoma forming the major part of the buccal cavity. The posterior stoma region or esophastoma very short, narrow and slightly asymmetrical. Esophagus uniform and weakly muscular, very slender, gradually widening to the cardia. Cardia internal. There is a thick dense internal lining in the midgut lumen. No indication of a renette cell. Anterior part of the female genital branch with germinal zone and smaller oocytes in two rows situated left of the intestine. Posterior part of the female branch with larger oocytes in one row folded ventrally to the right side of the intestine. The posteriormost part of the branch filled with small rounded spermatozoa. Vagina slanting and encircled by a strong sphincter. There are two sets of granular vulvar glands associated with the vagina, the anterior vulvar glands being much smaller than posterior ones. Five transparent ejaculatory glands visible at the left side of the ejaculatory duct of ɗ1. Spicules short, twice bent, distally acute and proximally cephalated. No gubernaculum.</p> <p>Tail consisting of a proximal conical and a distal slender cylindrical part. Tail tip slightly widened and provided with two subterminal setae.</p> <p> <b>Remark:</b> ɗ2 (paratype) is noticeably distinguished from other males and females by slightly shorter outer labial setae of the cephalic circle and intensive subcuticular pigmentation in the anterior body region (Fig. 6 B–C). These differences may be connected with the locality of ɗ2, i.e. remote from the sites of other specimens.</p> <p> <b>Diagnosis</b>: Body length 810–975 µm. Outer labial and cephalic setae 4.0–8.5 µm long. Amphidial fovea large, 15.5–18.0 µm long; ratio length to width of the amphidial fovea 1.55–1.67; distance from cephalic apex to anterior rim of the amphidial fovea rather short, 9.0–11.5 µm. Spicules 27.0–32.5 µm long. Terminal caudal setae 5.0–7.5 µm long.</p> <p> <b>Differential diagnosis</b>: The new species shares with <i>A. galea</i>, <i>A. marisalbi</i> and <i>A. pallida</i> a relatively small body length (<1 mm) and tail shape with slender cylindrical portion bearing terminal setae. <i>A. molloyensis</i> sp. n. distinctly differs from both <i>A. galea</i> and <i>A. pallida</i> by very short setae of the cephalic circle and by proximal position of the amphidial fovea.</p>Published as part of <i>Tchesunov, Alexei V. & Mokievsky, Vadim O., 2005, A review of the enus Amphimonhystera Allgén, 1929 (Monhysterida: Xyalidae, Marine Freeliving Nematodes) with description of three new species, pp. 1-20 in Zootaxa 1052</i> on pages 12-16, DOI: <a href="http://zenodo.org/record/170014">10.5281/zenodo.170014</a&gt

Amphimonhystera pallida Tchesunov et Mokievsky, sp. n.

<i>Amphimonhystera pallida</i> Tchesunov et Mokievsky sp. n. <p>(Figure 7)</p> <p> <b>Type material:</b> Holotype male 1 (ref # M­1/1), paratype male 2 (ref # M­1/2) and paratype female 1 (ref # M­1/8) mounted in glycerin on glass slides. Type specimens are deposited in the collection of the P. P. Shirshov Institute for Oceanology, Russian Academy of Sciences, Moscow.</p> <p> <b>Type locality</b>: Arctic Ocean, area between Greenland and Svalbard, 79°8.2' N & 02°53.6' E, depth 5569 m (Molloy Deep), silt, 16 August, 2000.</p> <p> <b>Etymology</b>: The species name reflects the pale colouration of the species in comparison with some other brownish <i>Amphimonhystera</i> species.</p> <p> <b>Morphometric data:</b> Table 6.</p> <p> <b>Description:</b> Small nematodes with slender, near fusiform to cylindrical body. Cuticle thin, with fine transverse annulation. Subcuticular yellow­brownish granulation weakly developed (mainly in pre­amphidial and amphidial regions) in males or nearly absent in female. Pre­amphidial region more or less narrowed. Labial region slightly set off. Inner labial sensilla as poorly visible tiny papillae. Outer labial and cephalic sensilla united in one circle of ten setae of moderate length. Amphidial fovea large, longitudinally oval, with distinct unbroken cuticular edging and without a visible central spot. Somatic sensilla short, scarcely distributed laterally along the body; nearly absent in midgut region.</p> <p> Buccal cavity small; cheilostoma hemispherical; esophastoma narrow, funnel shaped, with sclerotised walls. Esophagus slender, weakly muscular, gradually widening to the posterior end. Cardia small, triangular, internal. Midgut with distinct internal lumen and peritrophic membrane. At a short distance posterior to the cardia, the midgut shifted dorsally by a cell body which may be a pseudocoelomocyte or cell body of a rudimental renette cell. Anterior portion of the female branch situated left of the intestine, posterior portion right of the intestine. Uterus with two ripe eggs. Vulva as a small transversal slit. No vulval glands discernible. Anterior strait testis poorly discernible; posterior testis not visible at all. Two ejaculatory glands left of the <i>vas deferens</i> and intestine in the paratype male. Spicules short and slender, sharply bent in the middle, distally acute and proximally cephalated. No gubernaculum. Tail with a proximal conical and a distal slender cylindrical portion. Tail tip slightly inflated, with two or three terminal setae. No other somatic setae visible in tail region.</p> <p> <b>Diagnosis:</b> Body pale, 655–740 µm long. Outer labial and cephalic setae 3.0–7.0 µm long. Amphidial fovea, 11–12 µm long; ratio length to width of the amphidial fovea 1.2– 1.4 µm; distance from cephalic apex to anterior rim of the amphidial fovea 14–21 µm. Spicules 24–26 µm long. Terminal caudal setae 4.0–9.0 µm long.</p> <p> <b>Differential diagnosis:</b> <i>Amphimonhystera palida</i> sp. n. is similar <i>to A. galea</i>, <i>A. marisalbi</i> and <i>A. molloyensis</i> in body size. However, <i>A. pallida</i> differs from <i>A. galea</i> by having a much shorter cephalic setae length and shorter spicules; from <i>A. marisalbi</i> by a greater distance apex­amphidial fovea and longer terminal caudal setae; and from <i>A. molloyensis</i> by a greater distance apex­amphidial fovea.</p>Published as part of <i>Tchesunov, Alexei V. & Mokievsky, Vadim O., 2005, A review of the enus Amphimonhystera Allgén, 1929 (Monhysterida: Xyalidae, Marine Freeliving Nematodes) with description of three new species, pp. 1-20 in Zootaxa 1052</i> on pages 16-19, DOI: <a href="http://zenodo.org/record/170014">10.5281/zenodo.170014</a&gt