Volume 37 (2008): Issue 1 (March 2008)

The effect of exogenous traumatic acid, (2E)-dodecene-1,12-dioic acid (TA), at concentrations of 10^-6 - 10^-3 M on the growth and development of the unicellular green alga Chlorella vulgaris was examined over 7 days. TA plays an important role in algal growth and development. Treatment with 10^-5 M TA resulted in the greatest increase in cell numbers, by 77%, chlorophyll a content, by 126%, chlorophyll b, by 45%, total carotenoids, by 65%, monosaccharides, by 111%, and water-soluble proteins, by 37%, in relation to the control. After three days of treatment with 10^-5 M TA cultures were analysed by SDS-PAGE, which showed the presence of new polypeptides with molecular weights 13-103 kDa.

58 species of decapod crustacean were identified (1 Dendobranchiata, 14 Caridea, 5 Thalassinidea, 14 Anomura, 24 Brachyura) on soft substrates of the Aegean Sea coast of Turkey. Samples were collected from 60 sampling sites along the Turkish Aegean shore (eastern Aegean Sea) between July 2000 and September 2000 with dredge and a van Veen grab at bottom depths of 7 to 150 m. Different species dominated in each ecological zone with the anomuran squat lobster, Galathea intermedia Lilljeborg, 1851, being the most dominant species across the whole sampling area, comprising 11.71% of the individuals collected. This report represents the first published investigations into soft-sediment decapod communities in the coastal waters of the Turkish Aegean Sea.

Studies on the fauna of water beetles inhabiting anthropogenic water bodies were conducted on 44 clay-pit and gravel-pit ponds. A total of 125 water beetle species were identified. The dominant species were Scarodytes halensis and Laccobius minutus, representing the argillophilous component. Eurytopic, lake and riverine, and peatland species were also identified. Among the environmental factors determining the diversity of the water beetle fauna in particular types of habitats, the most significant role was played by the substratum and succession stage.

Polychaetes of the northwestern Black Sea (NWBS) were sampled in January 2005 at 4 sites comprising 32 stations. The 4 sites have different anthropogenic loads, different depths (<10 m, 11-20 m, 21-30 m, >30 m) and different substrates (shelly, silty). The species composition of polychaetes in Black Sea meiobenthic communities has not previously been studied. Twenty polychaete species belonging to 11 families, the Phyllodocidae, Nephtyidae, Polynoidae, Sigalionidae, Nereidae, Syllidae, Hesionidae, Protodrilidae, Spionidae, Capitellidae and Ampharetidae, were recorded. The polychaete density varied with depth and type of substrate from 500 ind. m^-2 to 66,000 ind. m^-2.

Lake Ostrowite is a mesotrophic lake in Northern Poland 280.7 ha in area and 43 m deep at its deepest point. To study vendace (Coregonus albula L.) diet in the lake, fish and zooplankton were sampled at two stations on 28-29 April, 15-16 May (fish only), 28-29 July and 15-16 August 2004. Fish were caught by gill netting, while zooplankton was collected from the whole water column by means of a Ruttner sampler (5 x 2 dm³). In total 91 vendace specimens were analysed, of which 64.8% had non-empty alimentary tracts. In the April and May samples Copepoda were the most numerous prey, while Daphnidae dominated the diet in the July- and September-caught fish. Planktonic Chironomidae pupae were also an important dietary item in the April-caught fish. Cladocerans, especially from Daphnidae family, were positively selected by vendace whilst copepods were not. Large predatory cladocerans, Leptodora kindtii, and the non-indigenous Bythotrephes longimanus were consumed in substantial quantities by the July- and September-sampled fish, with the vendace feeding more intensively on the L. kindtii than on the B. longimanus.

Salmonella enterica serovar typhimurium was stressed by incubation in seawater microcosms for seventeen years. The microcosms were prepared in such a way as to allow progressive evaporation of the water. Despite being introduced into the sterile seawater at very high concentrations, the Salmonella rapidly declined to levels undetectable by plate counts on nutrient agar. After two years of starvation, about half of the seawater volume had evaporated from each microcosm, and salt crystals appeared. Inoculation of the salty suspension did not result in any culturable strains in selective and non-selective media. However, incubation of samples in nutrient-rich broth, without supplemental growth factors, allowed resuscitation of stressed cells, yielding colonies that remained viable for extended periods of time. After three years the total volume of water had evaporated from each microcosm, and only salt crystals remained. These microcosms were then incubated at room temperature for seventeen years. Resuscitation of VBNC Salmonella from the salt crystals was conducted in vitro and in vivo; recovery occurring after incubation in both nutrient broth and in mice. Recovery occurred in the Salmonella administered orally into the mice, but not in those administered by intra-peritoneal injection. The identity of initial, stressed and revived strains was confirmed by DGGE analysis and sequencing of 16S RNA gene fragments.

The density and biomass of planktonic ciliates significantly differed between sample sites in a deep, mesotrophic lake, with the lowest numbers in the hypolimnion and the highest in the epilimnion. The community composition varied greatly with depth. Oligotrichs dominated in the epilimnion, where prostomatids and peritrichs were also important components of the community. The density of oligotrichs and peritrichs decreased in the metalimnion, and they were absent from the hypolimnion. In the deep metalimnion the most abundant groups were prostomatids, haptorids and scuticociliates. In the hypolimnion, the ciliate community was dominated by scuticociliates and heterotrichs. In the epilimnion and metalimnion a significant positive correlation was observed between ciliate numbers, chlorophyll a and heterotrophic flagellate density. In all three zones the number of ciliates was most strongly correlated with water temperature, concentrations of total organic carbon (TOC), total phosphorus (P_tot) and bacterial density, whilst in the hypolimnion there was a significant correlation between ciliate numbers and the dissolved oxygen concentration.