412 research outputs found
Physical oceanography and chlorophyll in surface water along ship track profile JARE29B
No full textData should be used only with permission from the PI
Report on Japan-Australia collaborative research on marine biology in the Prydz Bay area, Antarctica in 1992
No full textA three-year research collaboration with biologists in the Australian Antarctic Division, on the variability in the Antarctic marine environment and its effects on the biological processes has started from the 1991/92 austral summer season. For the first year, a joint proposal of H. MARCHANT (Australian Antarctic Division) and M. FUKUCHI (National Institute of Polar Research) to investigate biological processes in the Prydz Bay and the coastal ice-covered areas, titled "The production and fate of biogenic particles in the Antarctic marine ecosystem" was submitted and carried out during the voyage 6 of the Australian Antarctic research ship, AURORA AUSTRALIS from January 9 to March 27,1992. Main objectives of this research were; 1) to investigate seasonal variations in the primary and secondary productions and sinking processes of the products throughout the year with moored instruments and 2) to estimate the contribution of different components to the production and sinking processes of lower trophic organisms. For these objectives, time-series sediment traps with an in-situ chlorophyll recorder and current meters were deployed and water collections, plankton-net samplings and incubation experiments were carried out in the Prydz Bay area. The feeding selectivity of the antarctic krill (Euphausia superba), a dominant primary consumer in the Southern Ocean, was preliminarily investigated with a simple electrophysiological method
Bromoform concentrations in slush-layer water in Antarctic fast ice
No full textBromoform concentrations in water of the slush layer that developed at the interface between snow and sea ice were measured during the seasonal warming in Lützow-Holm Bay, East Antarctica. Mean bromoform concentration was 5.5 ± 2.4 pmol l-1, which was lower than that of the under-ice water (10.9 ± 3.5 pmol l-1). Temporal decrease in bromoform concentrations and salinity with increasing temperature of the slush water suggest that the bromoform concentrations were reduced through dilution with meltwater input from the upper surface of sea ice. In contrast, bromoform concentrations in the under-ice water increased during this period while the salinity of the under-ice water decreased. It is speculated that the sea ice meltwater input contained high bromoform concentrations from the brine channels within the sea ice and from the bottom of the ice that were contributed to the increased bromoform concentrations in the under-ice water
Chlorophyll-α content in the surface water along the course of the FUJI to from Antarctica in 1976-1977
No full textDuring the relief cruise of the FUJI to Syowa Station, Antarctica, from November 1976 to April 1977, the chlorophyll-α contents in the surface water were measured at 150 stations as a part of the routine observations of marine biological program of the 18th Japanese Antarctic Research Expedition. The chlorophyll-α distributions were generally similar to those noticed in the previous observations. The maximum value was observed in the pack ice area of Prince Olav Coast, Antarctica (2.40 mg chl-α/m^3). The high values were also seen in the Celebes Sea, Makassar and Malacca Straits
Incorporation of nitrogen compounds into sea ice from atmospheric deposition
No full textTemporal measurements of temperature, salinity, water–oxygen isotopic ratio and nutrient concentrations at Saroma-ko Lagoon, southern Sea of Okhotsk, were made in February–March 2008 to examine the processes by which nitrogen compounds from the atmosphere were incorporated via snowfall into sea ice. Granular ice made up more than half the ice thickness, and the mass fraction of snow in the snow-ice layer on top of the ice ranged from 0.8% to 46.9%. The high concentrations of NO3− + NO2− and NH4+ observed in the snow and snow-ice throughout the study period were likely due to the proximity of the study site, in northern Japan, to the east coast of the Asian continent. Pollutants containing high NO3−and NH4+ concentrations are transported from East Asia and deposited in snowfall over the sea ice in the southern part of the Sea of Okhotsk. Compared with NO3− + NO2− and NH4+ concentrations, PO43− concentrations in the snow and snow-ice were low. The strong correlation between the NO3− + NO2− and NH4+ concentrations in the snow-ice and the mass fraction of snow indicates that the nitrogen compounds on top of the sea ice were controlled mainly by the snow contribution to the sea ice when snow-ice predominated. Our results indicate that chemical cycles in sea ice can be affected by polluted precipitation (snow) originating from a nonpolar sea
DMSP and DMS in coastal fast ice and under-ice water of Lützow-Holm Bay, eastern Antarctica
No full textThe combined concentration of total dimethylsulfoniopropionate and dimethylsulfide (DMSP+DMS) were measured in Antarctic fast ice on the coast of Lützow-Holm Bay, eastern Antarctica. High bulk-ice DMSP+DMS and chlorophyll a concentrations were found at the bottom of the sea ice, and these concentrations were higher than those in the under-ice water. The bulk-ice DMSP+DMS and chlorophyll a concentrations were highly correlated (r2=0.68, P<0.001), suggesting that the high bulk-ice DMSP+DMS concentrations were caused mainly by the presence of algae assemblages in the ice. The calculated brine DMSP+DMS concentrations were as high as 1100 nM in the bottom ice layer, and the vertical profile patterns of brine DMSP+DMS concentrations were almost the same as for the bulk ice, mainly because of the small amount of variability in the vertical brine volume fraction. DMSP+DMS and chlorophyll a concentrations in the under-ice water increased, whereas the salinity of the under-ice water decreased, during the sampling period. These results reflect the supply of freshwater containing high levels of DMSP+DMS to the water just under the ice as the ice melted. These results suggest that sea-ice melting could be important to sulfur cycling in coastal ice-covered regions of the polar oceans
Xth SCAR International Biology Symposium on “Antarctic Biology in the 21st Century—Advances in and beyond IPY—”: A brief overview
No full textAbstractThe Xth SCAR International Biology Symposium was held under the theme of “Antarctic Biology in the 21st Century—Advances in and beyond IPY—“ at the Conference Hall, Hokkaido University, between July 26 and 31, 2009. A total of 113 oral presentations and 122 poster presentations were given under six sub-themes. This special issue was edited by six guest editors under the Editor-in-Chief of “Polar Science”, in accordance with the editorial system of “Polar Science” and contains one overview paper and five review papers and 18 research papers
Phytoplakton and Zooplankton Standing Stocks and Downward Flux of Particulate Material around Fast Ice Edge of Lutzow-Holm Bay,Antarctica
No full textP(論文)Phyto- and zooplankton standing stocks in the fast ice and in the water column under the ice and downward flux of particulate material through the water column were investigated in Liitzow-Holm Bay, Antarctica, during the austral summers, i.e., in January 1977 and February 1979. Chlorophyll a standing stock integrated through the ice was 0.38-0.80 mg/m^2 and that in the water column beneath the ice down to 150 m was 3.06 mg/m^2. Microdistribution of zooplankton beneath the ice was observed by the pumping collections and the dense populations were found just beneath the ice. Zooplankton density was in a range of 12-60 indiv/m^3 and the zooplankton stocks integrated through the 150 m water column ranged from 6000 to 7675 indiv/m^2. By the sediment trap operation, the fecal materials were found to comprise a large proportion of the collected particles. The maximum daily vertical flux of particulate organic carbon (POC) was found at the 100m depth (103 mg C/m^2/day) and concentration of POC in the water column was in a range of 24-56 mg C/m^3. These data on standing stocks of phyto- and zooplankton and vertical flux of POC in the icecovered Liitzow-Holm Bay were compared with those in the other sea areas.departmental bulletin pape
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