• Journal of the korean society of oceanography
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• v.38 no.1
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• pp.1-10
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• 2003

A time-series sediment trap was deployed at a depth of 1034 m in the eastern Bransfield Strait from December 25, 1998 to December 24, 1999. Particle fluxes showed large seasonal variation; about 99% of the annual total mass flux (49 g m/sup -2/) was collected during the austral summer and fall (January-March). Settling particles consisted primarily of biogenic silica, organic carbon, calcium carbonate, and lithogenic material. Biogenic silica and lithogenic material predominated settling particles, comprising 36% and 30% of the total mass flux, respectively, followed by organic carbon, 11% and calcium carbonate, merely 0.6%. The annual organic carbon flux was 5.4 g C m/sup -2/ at 1000 m in the eastern Bransfield Strait, which is greater than the central Strait flux. The relatively lower flux of organic carbon in the central Bransfield Strait may be caused by a stronger surface current in this region. Organic carbon flux estimates in the eastern Bransfield Strait are the highest in the Southern Ocean, perhaps because of the fast sinking of fecal pellets, which leads to less decomposition of organic material in the water column. Approximately 5.8% of the organic carbon produced on the surface in the eastern Bransfield Strait is exported down to 1000 m; this percentage exceeds the maximum EF/sub 1000/ values observed in the Atlantic and Southern Oceans. The eastern Bransfield Strait appears to be the most important site of organic carbon export to the deep sea in the Southern Ocean.

• Ocean and Polar Research
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• v.24 no.2
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• pp.153-166
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• 2002

Particle fluxes were measured by using time-series sediment traps in the Bransfield Strait from December 27th, 1999 to December 26th, 2000. Total mass fluxes showed distinct seasonal variations with high fluxes in the austral summer and low fluxes in the austral winter at a 678m water depth in the eastern Bransfield Strait, while they were high only in January and fairly low in other months at a 960m water depth in the central Bransfield Strait. The reason that total mass fluxes occurred only in January at a 960m water depth in the central Bransfield Strait seems to be the strong current in the surface waters, which leads to a substantial amount of terrestrial materials and locally produced organic matter being advected away from the mooring site. Total mass fluxes were very high from January to October at a 1678m water depth in the eastern Bransfield Strait, while they were high only in January and February at a 1860m water depth in the central Bransfield Strait. The fact that total mass fluxes were higher at the deep water in the both sites than at the intermediate water depth may reflect that a substantial amount of terrestrial and organic materials are laterally transported by strong tidal current from the shallow environments to the deep basins.

• Ocean and Polar Research
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• v.24 no.3
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• pp.301-311
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• 2002

We used diatom and porewater data of two piston cores from the central subbasin and one from the western subbasin in the Bransfield Strait in the northern Antarctic Peninsula to elucidate the depositional mechanism of the layered diatom ooze. The layered diatom ooze is characterized by an abundance of organic carbon, biogenic silica, sulfde sulfur, and lower porewater sulfate concentration. This lack of pore-water sulfate concentration in the diatom ooze interval may reflect development of reducing micro-environment in which bacterially mediated sulfate reduction occurred. The negative relationship between the total organic carbon and sulfate contents, however, indicates that sulfate reduction was partly taking place but does not control organic carbon preservation in this unit. Rather, well-preserved Chaetoceros resting spores in the layered diatom ooze indicate a rapid sedimentation of the diatom as a result of repetitive iceedge blooms on the Bransfield shelf during the cold period (around 2500 yrs BP) when the permanent seaice existed on the shelf, During this period, it is expected that the downslope-flowing cold and dense water was also formed on the Bransfield shelf as a result of sea ice formation, playing an important role for the formation of layered diatom ooze in the Bransfield subbasins.

• Journal of the Korean Geophysical Society
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• v.8 no.4
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• pp.173-185
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• 2005

This study examines the relationships among sea ice concentration, surface air temperature, surface wind, and SST (Sea Surface Temperature) in Bransfield Strait to understand the climatic characteristics and its related sedimentary process there. In analyses of the monthly data, during the austral autumn (Mar., Apr., and May), the frequency of southeasterlies is correlated positively with the sea ice concentration and negatively with the surface air temperature, whereas that of northwesterlies is reverse. These relationships are explained by the process that the southeasterlies of the cold air from the Antarctic Continent affect the ocean current around Bransfield Strait. And then the ocean current makes the sea ice generated in the Weddell Sea drift into the strait. During the spring (Sep., Oct., and Nov.), sea ice concentration and surface air perature are closely correlated with the frequency of northwesterlies with warm air mass. In the some parts of the northern boundary region, the sea ice concentration in Bransfield Strait is positively correlated with the SST during the autumn and spring. Such relationship may rather propel the sea ice melting in proportion to the sea ice concentration during the autumn.

• Journal of the Korean Geophysical Society
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• v.2 no.4
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• pp.241-250
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• 1999

Reflection coefficients of the seafloor have been calculated from the amplitude ratio of secondary to primary water bottom reflection in seismic data obtained from Bransfield Strait, Antarctic Peninsula. Test processing for the coefficients shows that moving average is effective to reduce severe fluctuation of the coefficient measured at each point. Relationship between the coefficients and the properties of water bottom is analyzed to illuminate geological environment. In the central Bransfield Basin, the magnitude of reflection coefficients decreases as it is distant from the sedimentary sources. Reflection coefficients range from 0.12 to 0.2 near the continental slope of the basin, and from 0.1 to 0.12 in the basin floor. In the western Bransfield basin, reflection coefficients between 0.2 to 0.3 are obtained from the area eroded by glacial movement. On the volcanic structures near Deception Island, the coefficients show relatively high values more than 0.2. Paleo-geological structures uplifted by tectonic movement and outcropped by glacial erosion have relatively high coefficients.

• Ocean and Polar Research
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• v.23 no.4
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• pp.395-400
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• 2001

A time-series sediment trap was deployed at 1,034 m water depth in the eastern Bransfield Strait from December 25, 1998 to December 24, 1999. About 99 % of total mass fluxes were observed during the austral summer and fall (January, February, and March). The annual total mass flux was $49.2g\;m^{-2}$. Biogenic materials including biogenic silica, organic matter, and carbonate accounted for about 67% of total particle flux, and lithogenic materials contributed about 29%. Biogenic silica was the most dominant (42% of the total flux) in these components. The next most important biogenic component was organic matter, comprising 24% of total mass flux. Calcium carbonate contributed a small fraction of total mass flux, only 0.6%. The annual organic carbon flux was $5.2g\;C\;m^{-2}$ at 1,034m water depth. The annual primary production was estimated to be $21.6g\;C\;m^{-2}$ at the sediment trap site, which seems to be highly underestimated. About 5.5% of the surface water production of organic carbon sinks below 1,034m water depth.

• Ocean and Polar Research
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• v.25 no.1
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• pp.41-52
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• 2003

Sediment trap samples were collected to find out characteristic behaviors of metals in the settling particles by using time-series sediment traps at 678m and 1678m water depths in the Bransfield Strait from December 27th, 1999 to December 26th, 2000. Total mass fluxes at the intermediate water depth (678m water depth) were high in the austral summer and low in the austral winter, whereas at the deep water depth (1678m water depth) they showed high values in both the summer and winter. Total mass fluxes were generally higher in the deep water depth than in the intermediate water depth, which indicates that a substantial amount of sediments are laterally transported by strong currents into the deep basin from the shallow water depths. Aluminium contents also showed large seasonal variations with high values in the winter and low values in the summer. On the contrary, organic carbon contents were high in the summer and low in the winter. Al contents were negatively correlated with organic carbon contents, which may be ascribed that detrital particles are diluted by organic matter produced by phytoplankton in the surface waters. Metals measured in this study exhibited three characteristic behaviors; 1) a positive correlation with Al-Ti, Fe, Mn, V, Co, and Ba, 2) a negative correlation with Al-Cd and Zn, 3) no relationship with Al-Sr, Cu, Cr, Ni. Terrestrial materials may act as a major source fer metals that are positively correlated with Al, and organic matter may be a major source for metals that are negatively correlated with Al. Enrichment factor (EF) of Fe, Mn, Ba, Vi Co, Sr, Cr, and Ni ranged from 0.5 to 1.5, whereas EF of Zn, Cu, and Cd showed much higher values than 1.

• 한국해양학회지
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• v.27 no.3
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• pp.250-258
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• 1992

The oxygen isotope composition of surface waters in the Bransfield Strait was determined as one extra state variable in order to characterize water masses in the region, since salinity is significantly modified due to the freezing and ice-melting in the polar region. The salinity, temperature, and $\delta$/SUP 18/O values vary from 34.0 to 34.5$\textperthousand$, -.05 to 2.1$^{\circ}C$ and -0.50 t -0.26$\textperthousand$, respectively. The combined effects of evaporation, precipitation, freezing, ice-melting are reflected in the widely scattered data. Although it is small, the distribution of $\delta$/SUP 18/O of the Bransfield Strait is strongly affected by the freezing-ice melting rather than the evaporation-precipitation. The ice melted fresh water which has higher temperature, depleted salinity and nutrients may be injected to the Bransfield Strait from the north. The concentrations of nutrients are decreasing gradually from the north to the south. The waters were characterized by two groups of higher (about 19.4) and lower N/P ratio (about 16.7). The lower N/P ratio is found in the northern part where ice-melted fresh water is injected. and the higher N/P ratio is found in the southern part of the Bransfield Strait. Although more precise work is needed, the deference of N/P ratio can be an evidence of the ice melted water injection to the Bransfield Strait. Chlorophyll a concentrations, in general, increase from northwest (Waddell Sea) to the southeast (Smith and Hosseason Islands). Probably the injection of nutrient depleted fresh water from the ice melting reduce the chlorophyll a concentration.

• Ocean and Polar Research
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• v.26 no.4
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• pp.607-618
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• 2004

Zooplankton community was surveyed during the Seventh Korea Antarctic Research Program, from 28 December 1993 to 11 January 1994. Zooplankton samples were collected at 40 stations from the waters around the South Shetland Islands with a Bongo net and a MOCNESS. A total of 14 taxa of zooplankton were identified. Zooplankton abundances varied at each station as well as with the sampling gears. Zooplankton abundances were higher in the Western Weddell Sea than those in the Bransfield strait. Zooplankton collected with MOCNESS showed a different vertical distribution depending on its depths at selected stations. Copepods were the major components of zooplankton contributing 72.84% (mesh size $333{\mu}m$) and 68.36% (mesh size $505{\mu}m$) of total zooplankton abundance from the Bongo samples. Salps were the second most abundant group comprising 7.92% $(333{\mu}m)$ and 11.99% $(505{\mu}m)$ of total zooplankton abundance. Euphausiids, chaetognaths, polychaetes, pteropods and ostracods occurred more than 1% of total zooplankton. Copepods were not abundant at stations salps and euphausiids were dominant. Salpa thompsoni, Euphausia superba, Calanoides acutus, Metridia gerlachei and Calanus propinquus were dominant depending on the stations. The hierarchical UPGMA cluster analysis of dissimilarities between sampling stations is displayed with clusters identified similar habitats. Copepods rarely appeared in the clusters 4 and 5, and they appeared a ffw in the cluster 3 (or salps were numerous), while copepods were abundant in the clusters 1 and 2. As in the results of cluster analysis, the distributions of dominant taxa have a well identified correspondence to the geological positions included physical factors.

• Ocean and Polar Research
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• v.23 no.2
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• pp.77-95
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• 2001

Temperature, salinity, nutrients, chlorophyll-a, and primary production were measured within the upper 200 m water column in the area around the South Shetland Islands in January, 2000. Surface temperature was relatively high in the Drake Passage north of the South Shetland Islands and low in the northeastern area of the Antarctic Peninsula. In contrast, surface salinity was low in the Drake Passage and increased toward the Antarctic Peninsula, reaching the maximum value in the northeastern area of the Antarctic Peninsula. Surface nutrients were low in the Drake Passage and high in the area near the South Shetland Islands. Surface chlorophyll-a was also low in the Drake Passage and near the Antarctic Peninsula and high in the area of the northern King George Island. The study area could be classified as four geographical zones based on the characteristic shape of the T/S diagrams;the Drake Passage, the Bransfield Strait, the mixed zone, and the Weddell Sea. Each geographical zone showed apparently different physical, chemical, and biological characteristics. Phytoplankton biomass was relatively low in the Drake Passage and the Weddell Sea and high in the Bransfield Strait and the mixed zone. The low phytoplankton biomass in the Weddell Sea could be explained by the low water temperature and deep surface mixing down to 200 m. The high grazing pressure and low availability of iron could be responsible for the low phytoplankton biomass in the Drake Passage.