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.

Composition of sedimentary rocks from the Mountainous Crimea and the Northwestern Caucasus

Detailed data obtained on chemistry of sedimentary rocks from the Mountainous Crimea and the Northwestern Caucasus that were dated at the Cenomanian/Turonian boundary and formed during Oceanic Anoxic Event 2 make it possible to calculate dissolved oxygen concentration in bottom waters of the sedimentation basin. Enrichment factors of trace elements in black shales are revised and an explanation is suggested for genesis of the rocks with regard for unusual climatic changes.

Biomass of seston in the benthic layer of the Southwestern Indian Ocean

At stations to 1530 m depth in the Mozambique Channel and on the Saya-de-Malha and Walters banks seston biomass 2 m above the bottom was lower than at 30 m. Above the Walters shoal this difference was 13.2 mg/m**3 and was not equal to zero for P < 0.001. These results contradict previous ideas of biomass increase in benthic layers. The most likely cause of the observed impoverishment of plankton may be predominant consumption of living zooplankton component of seston by bottom and near-bottom predators. In the area of the Walters shoal this consumption is estimated as being about 300 mg/m**2 per day. Animals inhabiting this area live mainly on plankton brought in by horizontal advection, so that existence of faunal assemblages even on shallow-water submarine elevations is supported not mainly by local photosynthesis, but by primary production of surrounding waters.

Geometric parameters of shoreface profiles of Laptev Sea erosion coast (Table 1)

Field investigations of the Laptev Sea shoreface morphology were carried out (1) off erosional shores composed of unconsolidated sediments, (2) off the modern delta shores of the Lena River, and (3) off rocky shores. It was found that profiles off erosional shores had a concave shape. This shape is not well described by commonly applied power functions, a feature, which is in disagreement with the generally accepted concept of the equilibrium shape of shoreface profiles. The position of the lower shoreface boundary is determined by the elevation of the coastal lowland inundated during the last transgression (at -5 to -10 m) and may easily be recognized by a sharp, an order of magnitude decrease in the mean inclination of the sea floor. The mean shoreface inclination depends on sediment grain-size and ranges from 0.0022 to 0.033. The concave shape of the shoreface did not change substantially during the last 20-30 years, which indicates that shoreline retreat did not slow down and hence suggests continued intensive coastal erosion in the 21st century. The underwater part of the Lena River delta extends up to 35 km offshore. Its upper part is formed by a shallow and up to 18-km wide bench, which reaches depths of 2-3 m along the outer edge. The evolution of the delta was irregular. Whereas some parts of the delta are advancing rapidly (58 m/year), other parts are eroding. Comparison of measured profiles with older bathymetric data gave an opportunity to evaluate the changes of the underwater delta over past decades. Bathymetric surveys of the seabed around the delta can thus contribute towards a quantification of the sediment budget of the river-sea system. In addition, some sections of the Laptev Sea coast are composed of bedrock that has a comparatively low resistance to wave erosion. These sections may supply a considerable amount of sediment, especially if the cliffs are high. This source must therefore also be taken into account when assessing the contribution of shore erosion to the Laptev Sea sediment budget.