Поиск по автору "Kemp, R. B."
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Материал Annual dynamics of abundance, biomass and survival of meroplankton in Sevastopol Bay, Black Sea(2007) Pavlova, E. V.; Murina, V. V.; Kemp, R. B.; Wilson, J. G.; Parchevsky, V. P.The first comprehensive data on species composition, abundance, biomass and survival (living/dead ratio) of meroplankton in Sevastopol Bay (Black Sea) are presented. Marked differences were observed between the years 1998 and 1999, and these could be attributed to the hydrology and the eutrophication status of the different parts of the Bay. Shannon index and selected community parameters (number of species, biomass, numbers of individuals) indicated that South Bay was the worst affected part of the Bay with the greatest eutrophication impact on the meroplankton. The early larval stages of the barnacle Balanus improvisus and of the polychaete Polydora sp. were the most sensitive to presumed environmental stresses. It is suggested that the mortality of certain ontogenetic stages of the meroplankton can be used as sensitive indicators of ecosystem health with good spatial discrimination. The canonical correlations between biological and environmental variables ranged from 86 – 87 %. Discriminant functions defined two well-defined subecosystems in the Bay. Long-term comparison with 1989/90 data for the Bay outlet showed that molluscan larval mortality had remained unchanged, while that of Polychaete and Cirripedia had more than doubled, suggesting that they could be sensitive to increased eutrophication in Sevastopol Bay.Материал Microcalorimetry of the smallest plankton fraction: in search for the sources of heat dissipation(2005) Mukhanov, V. S.; Kemp, R. B.Heat production by the plankton pico (0.2 to 2 μm) and femto (<0.2 μm) fractions was measured in the dark using a microcalorimetric method. It was surprisingly found that the femtofraction (FF) produced more heat per seawater volume (48 ± 24 (95% Cl) μW l-1) than the picofraction (25 ± 14 μW l-1). Consequently, we tested two hypotheses which could explain the phenomenon through a differentiation between the potential sources of heat in FF: (i) metabolism of ultramicrobacteria, the only living component in the fraction besides the non-metabolizing virioplankton which are unable to produce heat; (ii) extracellular chemical processes in aquatic environments. Results of micro-calorimetry and respirometry combined with the use of antimicrobial agents (ciprofloxacin, glutaraldehide, sodium azide), and microscopical examination (counts and sizing of bacteria in the measuring ampoules) showed that both sources contributed to the overall heat flow by FF but the non-living component was responsible for the bulk of it. Hydrolysis of high molecular weight organic substances dissolved in seawater, associated with bacterial extracellular enzyme activity, is considered the most probable source of the heat. If so, microcalorimetry has great prospective in aquatic microbial ecology and biochemistry as a powerful unspecific analytical method.Материал ДИССИПАЦИЯ ЭНЕРГИИ, ПРОДУКТИВНОСТЬ И СКОРОСТЬ ОБОРОТА БИОМАССЫ В СООБЩЕСТВЕ БАКТЕРИОПЛАНКТОНА: СРАВНИТЕЛЬНОЕ ИССЛЕДОВАНИЕ ДВУХ ВОДНЫХ ЭКОСИСТЕМ(Севастополь: ЭКОСИ-Гидрофизика, 2000) Муханов, В. С.; Рылькова, О. А.; Лопухина, О. А.; Кемп, Р. Б.В Севастопольской бухте Черного моря (СБ), и в прибрежье Аберистуита, залив Кардиган, проведены сравнительные исследования обилия и функциональной активности бактериопланктона. Продукцию энтропии и траты сообщества на энергетический обмен оценивали по его теплопродукционным характеристикам с помощью микрокалориметрии. Средние in situ продукционные показатели, скорость оборота и величина бактериальной биомассы были выше (в 2-6 раз) в акватории СБ, тогда как значения удельной диссипативной функции (ψ) в обеих экосистемах оказались сходными. На "грязных" станциях в СБ интенсивность теплопродукции и, соответственно, значение ψ-функции ниже.Материал Состояние икры пелагических рыб в прибрежных водах Черного моря у г. Севастополя(2004) Гордина, А. Д.; Цыцугина, В. Г.; Овсяный, Е. И.; Романов, А. С.; Кемп, Р. Б.