Strontium-90 concentration in waters of the eastern Carribbean Sea

Vertical structure of the strontium-90 concentration field and its relation to hydrology of waters are described on the basis of investigations in the Caribbean Sea during Cruises 6 and 7 of R/V Akademik Vernadsky (1972-1973). Vertical velocity and the coefficient of vertical turbulent diffusion are calculated for the eastern Caribbean Sea from strontium-90 concentration and salinity data.

(Table 1) Concentration of pollutants in hair of East Greenland polar bears (Ursus maritimus)

Hair sampled from 96 East Greenland polar bears (Ursus maritimus) over the periods 1892-1927 and 1988-2009 was analyzed for cortisol as a proxy to investigate temporal patterns of environmental stress. Cortisol concentration was independent of sex and age, and was found at significantly higher (p<0.001) concentrations in historical hair samples (1892-1927; n = 8) relative to recent ones (1988-2009; n = 88). In addition, there was a linear time trend in cortisol concentration of the recent samples (p< 0.01), with an annual decrease of 2.7%. The recent hair samples were also analyzed for major bioaccumulative, persistent organic pollutants (POPs). There were no obvious POP related time trends or correlations between hair cortisol and hair POP concentrations. Thus, polar bear hair appears to be a relatively poor indicator of the animal's general POP load in adipose tissue. However, further investigations are warranted to explore the reasons for the temporal decrease found in the bears' hair cortisol levels.

(Table 1) Chlorophyll concentration and pigment composition of carotenoids in three heathland bryophytes, northern Sweden

Background and Aims: Anthropogenic depletion of stratospheric ozone in Arctic latitudes has resulted in an increase of ultraviolet-B radiation (UV-B) reaching the biosphere. UV-B exposure is known to reduce aboveground biomass and plant height, to increase DNA damage and cause accumulation of UV-absorbing compounds in polar plants. However, many studies on Arctic mosses tended to be inconclusive. The importance of different water availability in influencing UV-B impacts on lower plants in the Arctic has been poorly explored and might partially explain the observed wide variation of responses, given the importance of water in controlling bryophyte physiology. This study aimed to assess the long-term responses of three common sub-Arctic bryophytes to enhanced UV-B radiation (+UV-B) and to elucidate the influence of water supply on those responses. Results: Responses were species specific: H. splendens responded most to +UV-B, with reduction in both annual growth (-22%) and sporophyte production (-44%), together with increased b-carotene, violaxanthin, total chlorophyll and NPQ, and decreased zeaxanthin and de-epoxidation of the xanthophyll cycle pool (DES). Barbilophozia lycopodioides responded less to +UV-B, showing increased b-carotene and sclerophylly and decreased UV-absorbing compounds. Polytrichum commune only showed small morphogenetic changes. No effect of UV-B on bryophyte cover was observed. Water availability had profound effects on bryophyte ecophysiology, and plants showed, in general, lower growth and ETR, together with a higher photoprotection in the drier site. Water availability also influenced bryophyte responses to +UV-B and, in particular, responses were less detectable in the drier site. Conclusions: Impacts of UV-B exposure on Arctic bryophytes were significant, in contrast to modest or absent UV-B effects measured in previous studies. The impacts were more easily detectable in species with high plasticity such as H. splendens and less obvious, or more subtle, under drier conditions. Species biology and water supply greatly influences the impact of UV-B on at least some Arctic bryophytes and could contribute to the wide variation of responses observed previously.

Fish biometry and concentration of volatile siloxanes in liver of Atlantic cod (Gadus morhua) and shorthorn sculpin (Myxocephalus scorpius) sampled during RV Lance cruise COPOL in 2009

The purpose of this study was to investigate presence and potential accumulation of cyclic volatile methyl siloxanes (cVMS) in the Arctic environment. Octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcy-clohexasiloxane (D6) were analyzed in sediment, Zooplankton, Atlantic cod (Gadus morhua), shorthorn sculpin (Myxocephalus scorpius), and bearded seal (Erignathus barbatus) collected from the Svalbard archipelago within the European Arctic in July 2009. Highest levels were found for D5 in fish collected from Adventfjorden, with average concentrations of 176 and 531 ng/g lipid in Atlantic cod and shorthorn sculpin, respectively. Decreasing concentration of D5 in sediment collected away from waste water outlet in Adventfjorden indicates that the local settlement of Longyearbyen is a point source to the local aquatic environment. Median biota sediment accumulation factors (BSAFs) calculated for D5 in Adventfjorden were 2.1 and 1.5 for Atlantic cod and shorthorn sculpin, respectively. Biota concentrations of D5 were lower or below detection limits in remote and sparsely populated regions (Kongsfjorden and Liefdefjorden) compared to Adventfjorden. The levels of cVMS were found to be low or below detection limits in bearded seal blubber and indicate a low risk for cVMS accumulation within mammals. Accumulation of cVMS in fish appears to be influenced by local exposure from human settlements within the Arctic.

Concentration of total organic carbon in waters of the Atlantic Ocean

In pursuance of previous studies water samples were taken in the Atlantic and Mediterranean during the 12th, 14th and 15th cruises of RV Mikhail Lomonosov in 1962-1964 to determine total and particulate organic carbon and permanganate oxidizability. Preliminary processing of the water samples was carried out in the normal manner in the on-board laboratory immediately after they had been taken: destruction of bicarbonates and carbonates by precise addition of acid (by alkalinity) and evaporation to dryness at 50-60°C. It is quite probable that the corresponding volatile fraction of organic matter is lost under these conditions. In discussion it was demonstrated that it may now be assumed that the carbon of the volatile fraction averages approximately 15% of total carbon, i.e., 15% of the sum of organic carbon of the volatile and nonvolatile fractions. Oxidizability was determined in all samples in the on-board laboratory.