Chlorophyll a concentration in plankton, biomass of different taxonomic phytoplankton groups, dominating algae species, and some parameters of coastal surface waters of the Black Sea

Based on data obtained at three stations in coastal waters of the Black Sea off Sevastopol in 2000 and 2001, we present seasonal dynamics of the carbon to chlorophyll a ratio in nano- and microphy-toplankton. This parameter varied approximately tenfold throughout the year. Its maximum values (442-500) were obtained in summer (July), when Pyrrophyta dominated in phytoplankton. Minimum values (36-56) were observed in winter (December),when diatomaceous species predominated. We derive a regression relating the carbon to chlorophyll a ratio to proportion of Pyrrophyta in total phytoplankton biomass, doing so separately for warm and cold seasons. Regression equations demonstrate coupled action of irradiance, temperature, and nutrient availability on the carbon to chlorophyll a ratio. For Pyrrophyta phytoplankton assemblage R**2 = 0.95, and for diatomaceous one R**2 = 0.87.

(Table 4) Concentrations of radionuclides in waters of the Barents and Kara Seas in August 2003

A methodology of experimental simulation of state of spent nuclear fuel that occurs on the sea floor due to some catastrophes or dumping is developed. Data on long-term (more than 2000 days) experiments on estimation of 85Kr and 137Cs release rate from spent nuclear fuel (fragments of irradiated UO2 pellets) were firstly obtained; these estimates prove correctness of a hypothesis offered by us in early 1990s concerning to earlier 85Kr release (by one order of magnitude higher than that of 137Cs) as compared to other fission fragments in case of loss of integrity of fuel containment as a result of corrosion on the sea floor. A method and technique of onboard 85Kr and 137Cs sampling and extraction (as well as sampling of tritium, product of triple 235U fission) and their radiometric analysis at coastal laboratories are developed. Priority data on 85Kr background in bottom layers of the Barents and Kara Seas and 137Cs and 3H in these seas (state of 2003) are presented. Models necessary for estimation of dilution of fission products of spent nuclear fuel and their transport on the floor in accident and dumping regions are developed. An experimental method for examination of state of spent nuclear fuel on the sea floor (one expedition each 2-3 years) by 85Kr release into environment (a leak tracer) is proposed; this release is an indicator of destruction of fuel containment and release of products of spent nuclear fuel in case of 235UO2 corrosion in sea water.

Argon concentration in waters of the Atlantic Ocean

Neutron activation analysis was used to determine content of dissolved argon at five points in the Atlantic Ocean at depths of 2 m.

Concentration of hydrogen sulfide in waters of the Black Sea in the layer of its coexistence with oxygen

About 100 parallel determinations of hydrogen sulfide by the volumetric and photometric methods were made in the layer of coexistence of oxygen with hydrogen sulfide (C layer). Thiosulfates were determined simultaneously. Regardless of locations of the stations, determinations by two methods coincided for the entire range of depths of occurrence of the C layer upper boundary. Within the C layer hydrogen sulfide readings obtained by these two independent methods agreed; thiosulfates were not found by direct measurements. Difference in the readings appears at the lower boundary of the C layer and below it, accompanied by appearance of thiosulfates. It is therefore concluded that it is correct to determine the upper boundary of the C layer by the iodometric method and to use concentration of hydrogen sulfide obtained by this method in the C layer to calculate rate of chemical oxidation of hydrogen sulfide in quasistationary processes.