MISKEVITCH I.V., ZELENKOV V.M. Northern Branch of the Polar Research Institute of Marine Fisheries and Oceanography, Russia

Since 2001 after having purchased two scientific research ships Northern Branch of the FSUE PINRO (SevPINRO) has performed complex ecological monitoring researches of the condition of the Pechora Sea annually every summer period.

Monitoring researches according to the standard network of oceanographic stations consist of:
• Hydrologic observations (water temperature, salinity, transparency, turbidity and content of the suspended matter)
• Hydrochemical observations (oxygen, biochemical oxygen demands, biogenetic substances, oil hydrocarbons)
• Hydrobiological observations (phytoplankton, zooplankton, zoobenthos)

Furthermore, complex of performed researches is being completed by ichthyological examinations based on the drag-net and stationary net fishing in the littoral region.

Besides standard monitoring observations of the area of water of the Pechora Sea special ecological researches of the local areas containing technogenic objects and of the regions of theirs suspected construction are being performed. During the workout of such investigations the list of the studying parameters may noticeably enlarge. In particular, there is an extra measurement of the content of the polyaromatic hydrocarbons and heavy metal in the water, bottom sediments, macrozoobenthos and in fish.

The analysis of the data of the monitoring researches performed during 2001-2005 allows to make some conclusions. The Pechora Sea in general is considered to be the relatively mild polluted part of the global water budget. The level of the toxic substances content of different elements of it's ecosystem is essentially lower in comparison with the White Sea, which is considered to be one of the purest seas of the Russian Federation. The concentration medians of pollutant substances in entire area of water do not overstep the limits of the maximum allowable concentration.

Repetition of the quantity of oil hydrocarbons in the water over the maximum allowable concentration usually no higher than 10-20%. The concentration of oil hydrocarbons in bottom sediments out of distance of the technogenic influence generally vary in a range of 1-10 mg/kg. Biochemical oxygen demands often higher maximum allowable concentration (2 mg Ог/L), but it is due to increased content of easy oxidable organic natural caused substances in the water of the Pechora Sea. Concentrations of the critical nitrogen and phosphorus salts, phenols, benzpyrene and heavy metals in open area of water doesn't overstep the limits of the maximum allowable concentration. Content of the oxygen from the ecological point of view is rather well, so there is no oxygen deficiency even in bottom sediments of deep-see areas.

Characteristics of the condition of aquatic life of the Pechora Sea in general, including field bioresources, vary in a range of long-term changeableness. It's quantity and density determines mostly by cycling of meteorological (climatic) conditions and by variations of the water flow of Pechoraa river. It is necessary to mention that during recent 30 years there is a strong tendency to warming in the superficial area of water of the Pechora Sea in the autumn period. Increase of duration of the vegetative period, taking place in this situation, doesn't exclude noticeable changes in functioning of the sea ecosystem in subsequent years.

Space distribution analysis of the controlled quantity of pollutant substances shows that there are two factors of influence on it's background content as a source of entering the water of the Pechora Sea - water rotation with adjacent areas of the Barents Sea and water flow of Pechoraa river. In this case technogenic sources have only local influence within the spatial scale ranging from hundreds of meters to hundreds of kilometers.

Situation of the aquatic ecosystems pollution in the shore area near tanker terminals, regions of the coastal oil production and in the rivers' creek may vary from situation described for open areas of the Pechora Sea. In this case there is a noticeable increase of pollutant substances content in the bottom sediments. For oil hydrocarbons including polyaromatic hydrocarbons it's surely due to technogenic influence, as for heavy metals it's due to complex of influence of technogenic and natural agents. Nature factor is conditioned by the higher natural content of such a heavy metals as iron, zinc, manganese and copper in waters of the tundra rivers with waterlogged columbine. There is also a slight repetition of the concentration of oil hydrocarbons, several per cent higher in comparison with open areas of the Pechora Sea. It is necessary to mention that high level of sea waters" hydrodynamics, generated by high and low tide and the wind-induced flow prevent from the forming of constant pollution of the sea waters.

Mild technogenic influence on phytoplankton and zooplankton is due to absence of constant chronic pollution of the sea waters and to presence of strong currents. It's not possible to distinguish technogenic influence on a background of high natural space-time changeableness of characteristics of the plankton associations in a costal areas of the Pechora Sea even in the direct nearness to the industrial objects. Over limit content of toxic substances in the bottom sediments near these objects very slightly influences on the bottom associations. According to the investigations of the SevPINRO negative influence on the quantity and biomass of the macrozoobenthos starts within the concentration of the oil hydrocarbons over 120 mg/kg of soil. Such a level doesn't exist in the Pechora sea in comparison with the White Sea.

Thus, economical activity of workouts concerning search, production and transportation of the hydrocarbon material in the area of water of the Pechora sea during current moment of time doesn't influence noticeably on the condition of the ecosystem and on industrial biosourses, even not taking into consideration fishery. It is believed that there is no threat to the Pechora Sea ecosystem in general during the full-scale development of it's hydrocarbon material deposit, but only with realization of the standard environmental protection measures. With the exception of development of emergency conditions with release of great amount of oil into sea waters. As practice shows, the presence of oil in the Pechoraa river's columbine during last years damaged seriously the ichthyofauna, including anadrom and half-anadrom species of white-fishes.

The most important, according to our point of view, is organization of the highly adjusted network system of the ecological monitoring in the conditions of further intensification of the industrial shelf and costal development of the Pechora Sea. Network system should produce researches of entire areas of water in general and its particular regions near functioning industrial objects in particular. Realization of a such monitoring allows to lock in appearance of negative trends on the background of natural changeableness of various elements of the sea ecosystem and to develop discontinuance measures for its further evolution.

The second moment is the development of high effective emergency conditions preventive measures and measures for efficient breakdown elimination. Solution of this problem must be founded with taking into concern inclement natural conditions of the Pechora sea and absence of developed system of transport communications along its costal area. Formal transfer of the experience obtained for southern seas (Caspian Sea, Black Sea, Sea of Azov, Baltic Sea) can lead to serious mistakes. Another important factor is development of the complex of compensatory measures for restoration of resource potential, increase of bioproduction and biovariety of the sea ecosystem in regions, suffered from oil spill by accident. Such measures must be supported by true working technologies of aquaculture adapted for Pechora Sea's conditions.

OIL AND GAS OF ARCTIC SHELF 2006 (PROCEEDINGS OF INTERNATIONAL CONFERENCE)