Interannual Variations of Phytoplankton, Zooplankton and Chlorophyll a in the Arctic Seas and Their Relations to ENSO and AO

To study effects of variations in climate-marine environment in the Arctic Ocean on ecology,based on the actual and reestablished data by biomarkers of algae in sediment in 1997,1999,2003,2008,and 2010,the interannual and spatial variations of phytoplankton,zooplankton and chlorophyll a concentration in the Chukchi Sea and the Bering Sea as well as their relations to El Nino-Southern Oscillation( ENSO) and Arctic Oscillation( AO) were analyzed. The results show that there were spatial and temporal anomalies in the phytoplankton community structure reestablished by biomarkers of algae in the Chukchi Sea and the Bering Sea in 1999 and 2010. The total content of biomarkers( brassicasterol,dinosterol,C37 alkenones and chlesterol) in sediment collected in 2010 was far lower than that in 1999,but brassicasterol was dominant in the two years,that is,diatom was dominant,which was consistent with the actual structure and distribution of phytoplankton community in 1999 and 2010; there were great changes in the dominant species of plankton in the two seas in 1999 and 2010,which could be regarded as the ecological response of the North Pole under the background of global warming. Chlorophyll a concentration in the water of the Bering Sea was 0. 720 μg/dm^3 at 0 m and 0. 765μg/dm^3 at 10 m in 1997 and 0. 723 μg/dm^3 at 0 m and 0. 731 μg/dm^3 at 10 m in 2003,and the concentration was very close to each other,which was affected by El Ni1 o and the negative phase of AO. It was 0. 395 μg/dm^3 at 0 m in 1999 and 0. 399 μg/dm^3 at 0 m and 0. 357 μg/dm^3 at 10 m in 2008,which was influenced by La Ni1 a and the positive phase of AO. The phases and intensity of AO and ENSO had various effects on the quantity and dominant species of phytoplankton and zooplankton in the Chukchi Sea and the Bering Sea. During the period of AO with positive or negative phase and El Ni1o( in 1997 and 2003),their combination was favorable to the growth of phytoplankton and zooplankton,while the combination of negative phase of AO and La Nina( in 2010) had adverse effects on the growth of phytoplankton. The combination of AO with positive phase and strong La Nina( in 1999 and 2008) had small effects on phytoplankton community.

Occurrence of organochlorine pollutants in the eggs and dropping-amended soil of Antarctic large animals and its ecological significance

Persistent organochlorine pollutants (POPs) are analyzed for the dropping-amended soils from the habitats of Antarctic seabirds and seals in Fildes Peninsula and Ardley Island. The concentration ranges are 0.21 to 3.85 ng/g for polychlorinated biphenyls (ΣPCBs),0.09 to 2.01 ng/g for organochlorine pesticides (ΣDDT),and 0.06 to 0.76 ng/g for hexachlorocyclohexanes (HCHs). Among these,hepata-chlorobiphenyls,hexachlorobiphenyls,p,p′-DDE and α-HCH compounds are dominant. The concentra-tion ranges of ΣPCB,DDT and HCH in the eggs of skuas were 91.9―515.5 ng/g,56.6―304.4 ng/g and 0.5―2.0 ng/g respectively; those in the eggs of penguins were 0.4―0.9 ng/g,2.4―10.3 ng/g and 0.1― 0.4 ng/g; and those in the eggs of giant petrel were 38.1―81.7 ng/g,12.7―53.7 ng/g and 0.5―1.5 ng/g respectively. The dominant POP compounds in the eggs are PCB180,PCB153,p,p′-DDE and hexa-chlorobenzene (HCB). The present study shows that the concentration of POPs in the sea-bird-inhabited-dropping-amended soil varies with the extent of predation and nest occupancy of dif-ferent seabird populations. Statistical analysis on the POP concentrations from the different seabird eggs implies that the difference in the bio-concentration levels of the birds depends on the bio-habits of the species,such as the range of activity,distance of immigration,feeding pattern,and nest occupation. Among these,the most important factor is the location of the seabirds in the food chain and their feeding pattern. This shows that POPs accumulated in the seabirds resulted from the bio-concentration through the food chain. In addtion,210Pb dating for the dropping-amended soils (AD1-a and AD2) was performed,which provided the POP accumulation rate and the historic record for the soil profile. It indicates that POP will continuously affect the Antarctic ecosystem for a long time.