Plankton biomass in the Mamala Basin (Oahu Island, Hawaii Islands) under antropogenic influence in August-September of 2002-2004

Anthropogenic impact on biomass of coastal plankton communities caused by submerged disposal of urban sewage waters (dumping) was studied. Observations were carried out in August-September of 2002-2004 in the Mamala Bay (Oahu Island, Hawaii Islands) using satellite and straight sea measurements. An analysis of variability of integral indicators of the water column determined on the basis of on-board measurements allowed us to divide them into two groups: elements most sensitive to pollution (heterotrophic bacteria (H-Bact), phototrophic cyanobacteria Synechococcus spp. (SYN), and chlorophyll a (CHLa)) and elements that manifested episodic positive dependence on inflow of polluted waters (heterotrophic unicellular eukaryotes, small unicellular algae, phototrophic green bacteria Prochlorococcus spp., as well as total biomass of microplankton). It was shown that submerged waste water disposal in the region of the diffuser of the dumping device led to insignificant (aver. 1.2-1.4 times) local increase in integral biomass of H-Bact, SYN, and in concentration of CHLa. Similar but sharper (aver. 1.5-2.1 times) increase in these parameters was found in water layers with maximal biomasses. Possible pathways of disposed waters (under the pycnocline, at its upper boundary, and in the entire mixed layer) were analyzed on the basis of studying vertical displacement of biomasses of H-Bact, SYN, and prochlorophytes. Possibility of using optical anomalies distinguished from satellite data as markers of anthropogenic eutrophication caused by dumping was confirmed. Application of such markers depends on water transparency and on shapes of curves of vertical distribution of autotrophic organisms.

Carbon isotopic compositions and concentrations of major fatty acids in the Beggiatoa covered sediment core at the crest of southern Hydrate Ridge

Membrane fatty acids were extracted from a sediment core above marine gas hydrates at Hydrate Ridge, NE Pacific. Anaerobic sediments from this environment are characterized by high sulfate reduction rates driven by the anaerobic oxidation of methane (AOM). The assimilation of methane carbon into bacterial biomass is indicated by carbon isotope values of specific fatty acids as low as -103 per mill. Specific fatty acids released from bacterial membranes include C 16:1 omega 5c , C 17:1 omega 6c , and cyC 17:0 omega 5,6 , all of which have been fully characterized by mass spectrometry. These unusual fatty acids continuously display the lowest d13 C values in all sediment horizons and two of them are detected in high abundance (i.e., C 16:1 omega 5c and cyC 17:0 omega 5,6 ). Combined with microscopic examination by fluorescence in situ hybridization specifically targeting sulfate-reducing bacteria (SRB) of the Desulfosarcina/Desulfococcus group, which are present in the aggregates of AOM consortia in extremely high numbers, these specific fatty acids appear to provide a phenotypic fingerprint indicative for SRB of this group. Correlating depth profiles of specific fatty acid content and aggregate number in combination with pore water sulfate data provide further evidence of this finding. Using mass balance calculations we present a cell-specific fatty acid pattern most likely displaying a very close resemblance to the still uncultured Desulfosarcina/Desulfococcus species involved in AOM.

Seawater carbonate chemistry, primary production, biomass and calcification of plankton and bacteria, 2009

Production (abundance and biomass) and net calcification rates of the coccolithophorid Pleurochrysis carterae under different partial pressures of CO2 (pCO2) were examined using short (15, 24 and 39 h), long (7 d) and dark (7 d) incubation experiments. Short incubations were conducted at ambient, 500 and 820 ppm pCO2 levels in natural seawater that was enriched with nutrients and inoculated with P. carterae. Long incubations were conducted at ambient and 1200 ppm pCO2 levels in natural seawater (0.2 µm filtered as well as unfiltered) that was enriched with nutrients and inoculated with P. carterae. Dark incubations were conducted at ambient and 1200 ppm pCO2 in unfiltered seawater that was inoculated with P. carterae. The abundance and biomass of coccolithophorids increased with pCO2 and time. The abundance and biomass of most noncalcifying phytoplankton also increased, and were hardly affected by CO2 inputs. Net calcification rates were negative in short incubations during the pre-bloom phase regardless of pCO2 levels, indicating dissolution of calcium carbonate. Further, the negative values of net calcification in short incubations became less negative with time. Net calcification rates were positive in long incubations during blooms regardless of pCO2 level, and the rate of calcification increased with pCO2. Our results show that P. carterae may adapt to increased (~1200 ppm) pCO2 level with time, and such increase has little effect on the ecology of noncalcifying groups and hence in ecosystem dynamics. In dark incubations, net calcification rates were negative, with the magnitude being dependent on pCO2 levels.