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1.
The seasonal circulation in the southeastern Huanghai Sea has been studied with hydrographic data,which were observed in February and June 1994 and bimonthly during 1970-1990,and numerical model results.Horiwntal distributions of temperature and salinity in 1994 are quite different due to strong tidal mixing so that we need a analysis to see the real distributions of water masses.The mixing ratio analysis with the data of 1970-1990 shows the connection of the waters in the west coasts of Kotea Peninsula with warm and saline waters from the south in summer,which means northward inflows along the west coasts of Korea Peninsula in summer.With this flow,the seasonal circulations,which are deduced from the seasonal change of water mass distributions in the lower layer,are warm inflows in winter and mld outflows in summer in the central Huanghai Sea,and cold outflows in winter and warm inflows in summer along the west coasts of Korea Peninsula.The seasonally changed inflows might be the Huanghai Sea Warm Current.The monsoon winds can drive such circulations.However,summer monsoon winds are weak and irregular.As one of other possible dynamics,the variation of Kuroshio transport is numerically studied with allowing sea level fluctuations.Although it should be studied more,it possibly drives the summer circulations.The real circulations seem to be driven by both of them.  相似文献   
2.
In situ primary production data collected during 1978–1981 period and 1997–2000 period were combined to improve understanding of seasonal and spatial distribution of primary production in the southeastern Bering Sea. Mean daily primary production rates showed an apparent seasonal cycle with high rates in May and low rates in summer over the entire shelf of the southeastern Bering Sea except for oceanic region due to lack of data. There was also an increasing trend of primary production rates in the fall over the inner shelf and the middle shelf. There was a decreasing trend of primary production rates between late April and mid-May over the inner shelf while there was an abrupt increase between late April and mid-May over the middle shelf and the outer shelf. In the shelf break region, there was an increasing pattern in late May. These suggest that there was a gradual progression of the development of the spring phytoplankton bloom from the inner shelf toward the shelf break region. There was also a latitudinal variability of primary production rate over the middle shelf, probably due to either spatial variations of the seasonal advance and retreat of sea ice or horizontal advection of saline water in the bottom layer. Annual rates of primary production across the southeastern Bering Sea shelf were 121, 150, 145, 110, and 84 g C m−2 yr−1 in the inner shelf, the middle shelf, the outer shelf, the shelf break, and oceanic region, respectively. High annual rates of primary production over the inner shelf can be attributed to continuous summer production based on regenerated nitrogen and/or a continuous supply of nitrogen at the inner front region, and to fall production. There were some possibilities of underestimation of annual primary production over the entire shelf due to lack of measurement in early spring and fall, which may be more apparent over the shelf break and oceanic region than the inner shelf, the middle, and the outer shelf. This study suggests that the response of primary production by climate change in the southeastern Bering Sea shelf can be misunderstood without proper temporal and seasonal measurement.  相似文献   
3.
Kim  Suk Hyun  Ra  Kongtae  Kim  Kyung-Tae  Jeong  Hyeryeong  Lee  Jihyun  Kang  Dong-Jin  Rho  Taekeun  Kim  Intae 《Ocean Science Journal》2019,54(4):673-684
Ocean Science Journal - Trace elements (Mn, Fe, Co, Ni, Cu, Zn, etc.) are essential micronutrients for marine organisms and are thus related to major issues in the ocean, such as climate change,...  相似文献   
4.
Ocean Science Journal - This study sought to examine the characteristics and patterns of marine algae community changes in Wangdol-cho in order to establish a theoretical basis for the development...  相似文献   
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6.
During most of the vegetation season from late May to early September, the large-sized diatom alga Proboscia alata forms local patches with high abundances and biomasses in different oceanographic domains of the eastern Bering Sea shelf. The average abundance and biomass of the species in these patches amounts to 0.7 × 106 cells/l and 5 g WW/m3, respectively, for the layer of 0–25 m, while the corresponding estimates for the layer of the maximal species concentrations are 4.0 × 106 cells/l and 38 g WW/m3 (1.6 g C/m3). These levels of abundance and biomass are typical of the spring diatom bloom in the region. The outbursts of P. alata mass development are an important element of carbon cycling in the pelagic zone of the shelf area in the summer season. The paradox of the P. alata summertime blooms over the middle shelf lies in their occurrences against the background of the sharp seasonal pycnocline and the deficiency in nutrients in the upper mixed layer. The duration of the outbursts in the P. alata development is about two weeks and the size of the patches with high abundances can be as large as 200 km across. Degradation of the P. alata summertime outbursts may occur during 4–5 days. The rapid sinking of the cells through the seasonal pycnocline results in an intense transport of organic matter to the bottom sediments. One of the possible factors responsible for the rapid degradation of the blooms is the affect on the population by ectoparasitic flagellates. At the terminal stages of the P. alata blooms, the share of infected cells may reach 70–99%.  相似文献   
7.
A new species of free-living marine draconematid nematode, Dracograllus trukensis sp. nov., is described based on the specimens collected from the sediments of a intertidal seagrass bed from Chuuk Islands, Micronesia. Dracograllus trukensis sp. nov. differs from other species of the genus by the combination of the following characteristics: the presence of numerous minute spiny ornamented body cuticular annules in both sexes, eight cephalic adhesion tubes inserted on the head capsule in both sexes, the presence of stiff posteriorly directed setae anterior to posterior adhesion tubes in both sexes, the shape (large, elongated, open loop-shaped in male and large, elongated, closed loop-shaped in female) and position (longer ventral arm extending to the first body annule in male) of amphideal fovea, shorter spicule length (34–42 μm), the presence of sexual dimorphism in shape and length of the non-annulated tail terminus, and number of posterior sublateral adhesion tubes (10 in male and 13–15 in female) and posterior subventral adhesion tubes (8–10 in male and 9–11 in female). A comparative table on the biogeographical and ecological characteristics of the species of Dracograllus is presented. This is the first taxonomic report on the genus Dracograllus from Chuuk Islands, Micronesia, central western Pacific Ocean.  相似文献   
8.
In this study we describe measures taken in our laboratory to improve the long-term precision of nitrate and ammonia analysis in seawater using a microflow segmented-flow analyzer. To improve the nitrate reduction efficiency using a flow-through open tube cadmium reactor (OTCR), we compared alternative buffer formulations and regeneration procedures for an OTCR. We improved long-term stability for nitrate with a modified flow scheme and color reagent formulation and for ammonia by isolating samples from the ambient air and purifying the air used for bubble segmentation. We demonstrate the importance of taking into consideration the residual nutrient content of the artificial seawater used for the preparation of calibration standards. We describe how an operating procedure to eliminate errors from that source as well as from the refractive index of the matrix itself can be modified to include the minimization of dynamic refractive index effects resulting from differences between the matrix of the samples, the calibrants, and the wash solution. We compare the data for long-term measurements of certified reference material under two different conditions, using ultrapure water (UPW) and artificial seawater (ASW) for the sampler wash.  相似文献   
9.
Stable carbon and nitrogen isotopic composition of zooplankton, suspended particulate organic matter (SPOM), and sinking particles collected using sediment traps were measured for samples obtained from the southeastern Bering Sea middle and outer shelf during 1997–1999. The quantity of material collected by the middle shelf sediment trap was greater in both spring and late summer and fall than in early and mid-summer. The δ15N of SPOM, sinking material and zooplankton showed greater inter-annual variability at the middle shelf site (M2) than at the outer shelf site (M3). Zooplankton and sinking organic matter collected by M2 sediment traps became more depleted in 15N from 1997 through 1999, associated with a change from unusually warm to unusually cold conditions. Suspended and sinking organic matter and zooplankton collected from M3 decreased only slightly in δ15N from 1998 to 1999. SPOM, zooplankton, and sediment trap samples collected at M2 were usually enriched in δ15N and δ13C over those from M3. However, in 1999 sediment trap samples from the middle shelf were enriched in 13C over M3 material, but the δ15N of samples from the two sites was similar. The geographic pattern could be explained greater productivity over the middle shelf, associated with either isotopically heavy nitrogen being regenerated from sediments, or with utilization of a greater fraction of the available inorganic nitrogen pool during most years.  相似文献   
10.
This study was carried out as part of a baseline long-term environmental project in the proposed mining areas for an environmental impact assessment of future mining in the Clarion-Clipperton Fracture Zone (CCFZ). The community structure and distributional pattern of meiobenthos were investigated in the deep-sea bottom of the Clarion-Clipperton Fracture Zone of the northeastern Pacific in July 1998, 1999, 2001, 2003 and August 2004, 2005. Twenty one meiobenthic groups were found at the stations in the study area. The most abundant meiobenthos comprised nematodes followed by benthic foraminiferans and harpacticoid copepods. The maximum density of meiobenthos was 306 ind/10 cm2 at the station located at 11°N (water depth, 4833 m), and the minimum density was 6 ind/10 cm2 at the station located at 14°N (water depth, 5037 m). Oligotrophic conditions in the CCFZ seem to directly reflect the lower standing stocks of meiobenthos in the CCFZ compared to other deep-sea plains of similar depth. The latitudinal distribution pattern of meiobenthos in the study area seemed to be related with surface water primary productivity, which was connected to the water circulation pattern of the Pacific Ocean near the Equator, diverging at 8ºN latitude and converging at 5°N. The horizontal distribution of meiobenthic organisms in the study area showed high densities at the stations within 135–136°W. The densities of meiobenthic organismas within the CCFZ were high at stations with few manganese nodules on the sediment surface at low-latitude sites. In 1998, the observed relative high values of meiobenthic abundance were at stations from 5° to 6°N. Other stations from 7° to 10°N showed no significant fluctuations during the interannual sampling periods. It is considered that the inter-annual fluctuation of meiobenthos abundance is intimately related with a regime shift that may have occurred in the north Pacific between 1998 and 1999, the El Niño period. Vertical distribution of meiobenthic organisms showed the highest individual numbers in the surface sediment layers of 0~2 cm depth and a steep decreasing trend as sediment becomes deeper at the stations of high latitude located in 16~17°N. Size distribution analyses showed that organisms that fit into the sieve mesh size of 0.063 mm were abundant.  相似文献   
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