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.

Vertical distribution of phytoplankton pigments in the equatorial Pacific

Abundance distribution and cellular characteristics of picophytoplankton were studied in two distinct regions of the equatorial Pacific: the western warm pool (0°, 167°E), where oligotrophic conditions prevail, and the equatorial upwelling at 150°W characterized by high-nutrient low-chlorophyll (HNLC) conditions. The study was done in September-October 1994 during abnormally warm conditions. Populations of Prochlorococcus, orange fluorescing Synechococcus and picoeukaryotes were enumerated by flow cytometry. Pigment concentrations were studied by spectrofluorometry. In the warm pool, Prochlorococcus were clearly the dominant organisms in terms of cell abundance, estimated carbon biomass and measured pigment concentration. Integrated concentrations of Prochlorococcus, Synechococcus and picoeukaryotes were 1.5x10**13, 1.3x10**11 and 1.5x10**11 cells/m**2, respectively. Integrated estimated carbon biomass of picophytoplankton was 1 g/m**2, and the respective contributions of each group to the biomass were 69, 3 and 28%. In the HNLC waters, Prochlorococcus cells were slightly less numerous than in the warm pool, whereas the other groups were several times more abundant (from 3 to 5 times). Abundance of Prochlorococcus, Synechococcus and picoeukaryotes were 1.2x10**13, 6.2x10**11 and 5.1x10**11 cells/m**2, respectively. The integrated biomass was 1.9 g C/m**2. Prochlorococcus was again the dominant group in terms of abundance and biomass (chlorophyll, carbon); the respective contributions of each group to the carbon biomass were 58, 7 and 35%. In the warm pool the total chlorophyll biomass was 28 mg/m**2, 57% of which was divinyl chlorophyll a. In the HNLC waters, the total chlorophyll biomass was 38 mg/m**2, 44% of which was divinyl chlorophyll a. Estimates of Prochlorococcus, Synechococcus and picoeukaryotes cell size were made in both hydrological conditions.

Phytoplankton parameters in the Large Aral Sea in June 2008

Species composition, abundance, and biomass of phytoplankton in the surface water layer were determined at 10 stations in the central part of the Western Basin (WB) and at one station in the Eastern Basin (EB) of the Large Aral Sea. 42 algal species were found. Diatoms had the highest number of species. Similarity of phytoplankton composition in the WB was high, whereas phytoplankton composition in the WB and EB differed significantly. In WB abundance and biomass of phytoplankton varied from 826x10**3 to 6312x10**3 cells/l (aver. 1877x10**3 cells/l) and from 53 to 241 ?g C/l (aver. 95 ?g C/l). In EB the phytoplankton abundance was 915x10**3 cells/l and 93 ?g C/l. Vertical distribution of phytoplankton in upper 35 m was investigated at one station in WB. Maximum values of phytoplankton abundance and biomass were recorded under the thermocline at 20 m depth. Integrated biomass of phytoplankton was 14 g C/m**2.