FEDOROV A.S., MOSKVINA M. I., ZELENKOV V.M., MISKEVICH I. V., LYKYANOV YU. S.
Peter Gaz, Russia, Econeftegaz, Russia, Northern Branch of the Polar Research Institute of Marine Fisheries and Oceanography, Russia,
State Oceanografical Institute, Russia

In August of 2005, environmental surveys were carried out over the Baidaratskaya Bay water area of the Kara Sea, in the area of the projected undersea gas pipeline route.

The route of the four-arm undersea gas pipeline will serve as a connecting unit between the terrestrial sites of the undersea cross of Yamal Peninsula and Yugorski Shar (Ural). The overall length of the offshore site will be 66.77 kilometers.

Observations were conducted from board the R/V Poisk (SevPMRO). In the course of expedition and laboratory works, experts from the organizations such as ZAO IETs Econeftegaz, SevPINRO, РШЖ), GOIN, MGU, 10 RAS, and GU NPO Taifun took part. Thirty-seven oceanographic and hydrochemical stations, including 29 complex stations (hydrochemistry, plankton, and benthos) were carried out at two depths. For determination of the contaminant concentrations, 15 water samples, 43 samples of the bottom sediments, 11 ichthyological samples, and 7 benthic samples were taken. In addition, for determination of radioactive pollution, 29 samples of the bottom sediments and 4 ichthyological samples were collected. In the littoral zone, for examination of microphyto- and meiobenthic organisms, 25 stations (18 samples) were carried out. Seven trawls and 2 net set-ups were implemented for analysis of ichthyofauna; at the area of 130 square kilometers, ornithological and teriological observations were performed. Layout of stations for sampling water and bottom sediments, and sites of fishing is shown in Fig. 1.

The area of Baidaratskaya Bay remains little investigated; first of all, this concerns the examinations of its hydrobiological properties, including fishery characteristics.

A low fishery potential of Baidaratskaya Bay and the absence of perspectives for its industrial development, low abundance of marine animals, lack of the populated localities in the inner part of the bay, and relative remoteness of this area from the principal navigable Arctic routes, all determined the low degree of scientific interest to its natural conditions.

When comparing previous environmental studies in this area, mainly in the 1990s of the last century, the observations of 2005, differ in a high degree of complexity, namely: at the same time, properties of the water and biota, from microorganisms to mammals, in the range of all depths, i.e. from overwashes to the maximum depths. Meiobenthic and microphytobenthic organisms and bacterioplankton as well were pioneered. The surveys were carried out both with the use of sea vessels and with divers. In addition, the surveys of 2005 were implemented in accordance with the requirements of the normative documents accepted in the Yamalo-Nenets Autonomous Area. These documents came into force during the foregoing period.

The data obtained and the analysis of the stock information have made possible an assessment of the background conditions of the test area ecosystem, the qualitative prediction of the environmental changes due to the cross construction, and recommendations for conducting industrial monitoring and control at the stage of its construction and operation. This information can serve as a basis for optimization of the project decisions regarding to construction of the undersea cross of the main gas pipeline over Baidaratskaya Bay. Based on the results of the surveys of 2005, ornithological and teriological surveys (observations and counts along the coastal and terrestrial routes, complex aerial surveys over the bay water area from board of an AN-26 Arktika specially-equipped airplane-laboratory) were suggested to be conducted during
the period after ice thawing in the coastal zone. In addition, a complex of marine studies (including ichthyological) in the areas of dredging works, ground dumping, and it’s taking for backfilling.

Very significant interannual variability of hydrological conditions and, respectively, variability of chemical properties of the water column and a pelagic component of the biota characterize Baidaratskaya Bay. The bottom (benthic) communities are markedly more resistant in time. As macrophytes being important phytocoenosis for coastal areas is absent that was confirmed by surveys of 2005, the main attention was given to examination of zoobenthos (macro- and meiobenthos), as well as to microphytobenthos as a main source of primary production (Ekspeditsii..., 1992).

The analysis of the data gained and their correlation with the previous studies has showed that no essential changes in the test ecosystem occurred.

For example, it has been shown that:

• In Baidaratskaya Bay, saline waters belonging to the chloride class of the sodium group are present. Here, sodium occupies a dominant position among cations; it is followed by magnesium. Among anions, chlorides prevail, and sulfates are of secondary importance;

• The range of Eh variability found (532-540 mV) shows that in the bay waters, the oxidizing type of chemical activity is observed. This type is characterized by the presence of high concentrations of free oxygen and metals, which were in the highest form of their valence;

• The median (the most characteristic) BOC5 value for the surface level was 1.65 mg02/m3 and 3.10 mg02/m3 for the near- bottom depth, at the maximum value equal to 4.66 mg02/m3 and the minimum value equal to 0.66 mg02/m3. The higher content of organic matter is noted in the near-bottom layers of Baidaratskaya Bay. It should be noted that this phenomenon is mostly typical for the deep-water areas with the low water temperature if a well-pronounced layer of density discontinuity is present. Here, the exceed of the maximum permissible concentration (MPC, 2 mg02/m3) is observed; however, this is connected just with natural processes, in particular, with sedimentation of suspended particles, which contain readily organic matter;

• A low extent of pollution of the marine environment is noted, and no human-induced impact on the environment in reference to chemical properties is followed;

• As a whole, the content of heavy metals in the bottom sediments matched the conditions representative of the Arctic coastal zone;

• Plankton living in Baidaratskaya Bay is a very characteristic complex of the sea and neritic species of the Arctic seas;

• The phytoplankton of the test area is characterized by comparatively low biomass values, especially in the central areas of the bay. The species composition, the proportion of the main phyla of plankton algae (Cyanophyta, Bacillariophyceae, and Dinophyta), ecological, and phytogeographical taxa, all have a considerable degree of resistance;

• During the period of observations, zooplankton from the central part of Baidaratskaya Bay differed by the relatively high biomass and marked biodiversity. In the coastal areas, all the quantitative zooplankton properties are markedly lowered;

• The zoobenthos living in the bay is fairly diverse; its biomass and abundance correspond to the middle level representative for the coastal areas of the western section of the Russian Arctic when highly productive areas are absent;

• When surveying, no fish eggs in the water column were noted that is likely to be determined by the late period of observations;

• During the period of surveying, the composition of ichthyofauna in trawl and net catches differed in the low biodiversity. Altogether, in trawl catches, 11 fish species belonging to 7 families were found. In the net coastal catches, 5 fish species belonging to 5 families were encountered. Among them, a diadromous whitefish species such as an arctic cisco (omul) was found. The most abundant species in the catches were representatives of the Cotidae family, namely, three species, and those of the family Osmeridae (two species); all the rest families are presented by one species each. Of the industrial species, except for omul, navaga, arctic cod, eel-back flounder, and "arctic herring" were encountered.

During the period of surveying of 2005, the following results were also obtained:

• A well-pronounced zone of thermocline was observed; its upper boundary varied in the range of depths (6-11 m) and was directly dependent on the depth of the point of measurements;

• The bottom sediments and marine biota are not radiation-dangerous and correspond to the background values;

• In reference to microbiological characteristics, the water area of Baidaratskaya Bay is characterized as a typical bay in one of the northern seas of Russia, which is affected by slight human-induced impact;

• High ability of microbiological population to adapt to utilization of hydrocarbons;

• In the ichthyoplankton, larvae and fries of 11 fish species belonging to 8 families of boreal-arctic (60%) and arctic (40%) faunistic complexes were found that is almost a double level of properties observed before;

• Microphytobenthos involves 255 taxa that is not too high value for the marginal seas of the Arctic region. The characteristics of abundance, biomass, and diversity are rather high over the area as a whole, except for separate deep-water and littoral stations;

• The test area is extremely heterogeneous in terms of the meiobenthos composition and abundance, the maximum values of meiofauna are very high;

• No aggregations of fowl birds and marine mammals were observed.

The greatest negative effect can be caused by hydrotechnical works, which are implemented for laying the gas pipeline. These works are related to removing and dumping ground and to disturbing the wholeness of the bottom sediments of Baidaratskaya Bay. In addition, hydrotechnical works can generate the increase in turbidity of the water column. EES of 2005-2006 will allow giving the well-substantiated recommendations for selection of the most optional sites of ground dumping.

When constructing and operating the gas pipeline, different characteristics of the Baidaratskaya Bay ecosystem are expected to be varied in the frame of natural variability. In realizing the projected economic activity, technogenic impact on the bay ecosystem will very low. During the period of construction of the undersea gas pipeline cross at the section of the gas pipeline route, adverse phenomena can be noted in the areas of ground dumping and its taking for backfilling. However, these phenomena will be of local character.

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