共查询到20条相似文献,搜索用时 31 毫秒
1.
A. G. Zatsepin E. G. Morozov V. T. Paka A. N. Demidov A. A. Kondrashov A. O. Korzh V. V. Kremenetskiy S. G. Poyarkov D. M. Soloviev 《Oceanology》2010,50(5):643-656
During cruise 54 of the R/V Akademik Mstislav Keldysh to the southwestern Kara Sea (September 6 to October 7, 2007), a large amount of hydrophysical data with unique spatial resolution
was obtained on the basis of measurements using different instruments. The analysis of the data gave us the possibility to
study the dynamics and hydrological structure of the southwestern Kara Sea basin. The main elements of the general circulation
are the following: the Yamal Current, the Eastern Novaya Zemlya Current, and the St. Anna Trough Current. All these currents
are topographically controlled; they flow over the bottom slopes along the isobaths. The Yamal Current begins at the Kara
Gates Strait and turns to the east as part of the cyclonic circulation. Then, it turns to the north and propagates along the
Yamal coast over the 100-m isobath. The Eastern Novaya Zemlya Current (its core is located over the eastern slope of the Novaya
Zemlya Trough) flows to the northeast. Near the northern edge of Novaya Zemlya, it encounters the St. Anna Trough Current,
separates from the coast, and flows practically to the east merging with the continuation of the Yamal Current. A strong frontal
zone is formed in the region where the two currents merge above the threshold that separates the St. Anna Trough from the
Novaya Zemlya Trough and divides the warm and saline Arctic waters from the cooler and fresher waters of the southwestern
part of the Kara Sea. This threshold, whose depth does not exceed 100–150 m, is a barrier that prevents the spreading of the
Barents Sea and Arctic waters to the southwestern part of the Kara Sea basin through the St. Anna Trough. 相似文献
2.
S. A. Mosharov 《Oceanology》2010,50(6):884-892
The studies were performed from September 10 to 29 of 2007 in the Kara Sea in transects westward of the Yamal Peninsula, near
the St. Anna Trough, in the Ob River’s estuary, and on the adjacent shelf. The concentration of chlorophyll a in the euphotic layer changed from 0.02 to 4.37 mg/m3, amounting on the average to 0.76 mg/m3. The primary production in the water column varied from 10.9 to 148.0 mg C/m2 per day (the mean was 56.9 mg C/m2 per day). It was shown that frontal zones divided the Kara Sea into distinct areas with different productivities. The maximum
levels of the primary production were measured in the deep part of the Yamal transect (132.4 mg C/m2 per day) and the shallow Kara Sea shelf near the Ob River’s estuary (74.9 mg C/m2 per day). The characteristics of these regions were the low salinity of the surface water layer (19–25 psu) and the elevated
silicon content (12.8–28.1 μg-atom Si/l), which is explainable by the river water inflow. The frontal zones of the Yamal Current
in the Yamal and Ob transects displayed high values of the assimilation numbers, amounting to 2.32 and 1.49 mg C/mg of chlorophyll
per h, respectively (the maximal for the studied regions). 相似文献
3.
The research was performed along a transect from the Yamal Peninsula coast towards the outer shelf of the southwestern part
of the Kara Sea in September 2007. 130 phytoplankton species have been identified, among which 63 were found in the area for
the first time. The total phytoplankton numbers varied within the range of 0.2 to 11.3 × 109 cells/m2, while biomass within the range of 43 to 1057 mgC/m2. A well pronounced cross-shelf zoning in the phytoplankton communities was ascertained. The inner shelf zone about 30 km
wide with depths down to 30 meters was characterized by the predominance of diatoms (up to 80% of the total algae numbers
and biomass). The second group by value was dinoflagellates. Seaward in the area of the depth increase from 30 to 140 m, the
zone of the Yamal Current was located, which was 40 km wide and notable for its active water dynamics. The total cell numbers
in the zone reached a maximum for the entire investigated area: up to 11.3 × 109 cells/m2. The leading group in the phytoplankton was autotrophic flagellates, whose share in the total numbers reached 56–82%. Further
than 70 km from the shore, the outer shelf zone was found with the water column rigidly stratified. The highest for the whole
area phytoplankton biomass was identified here (up to 1.06 gC/m9), 80% of which was concentrated above the halocline. Diatoms dominated in the phytoplankton numbers (up to 92%) and biomass
(up to 90%), which was related to the mass development of two species: Chaetoceros diadema and Leptocylindrus danicus. 相似文献
4.
The quantitative characteristics and spatial distribution of the meiobenthos in Baidaratskaya Bay (Kara sea) were analyzed based on data collected in 1994–2007. The extremely high density of the meiobenthos (up to 8121 ind/10 cm2, average 2318 ind/10 cm2) makes it possible to consider Baidaratskaya Bay among the most productive Arctic regions. The spatial distribution of the meiobenthos was mostly determined by the depth and sediment properties in the subtidal zone of the bay. The density of meiobenthic organisms decreased with depth, and with the increase of the small sediment fraction. The difference in the meiobenthic densities between the two coastal areas of the bay (Yamal and Jugora CAs) is also revealed. Such difference caused by the combined effects of small-scale and mesoscale factors, mainly by the grain size. Opposite changes in the meio- and macrobenthic biomass with depth is shown. 相似文献
5.
Isotope parameters (δD, δ<Superscript>18</Superscript>O) and sources of freshwater input to Kara Sea
The isotope characteristics (δD, δ18О) of Kara Sea water were studied for quantitative estimation of freshwater runoff at stations located along transect from Yamal Peninsula to Blagopoluchiya Bay (Novaya Zemlya). Freshwater samples were studied for glaciers (Rose, Serp i Molot) and for Yenisei and Ob estuaries. As a whole, δD and δ18O are higher in glaciers than in river waters. isotope composition of estuarial water from Ob River is δD =–131.4 and δ18O =–17.6‰. Estuarial waters of Yenisei River are characterized by compositions close to those of Ob River (–134.4 and–17.7‰), as well as by isotopically “heavier” compositions (–120.7 and–15.8‰). Waters from studied section of Kara Sea can be product of mixing of freshwater (δD =–119.4, δ18O =–15.5) and seawater (S = 34.9, δD = +1.56, δ18O = +0.25) with a composition close to that of Barents Sea water. isotope parameters of water vary significantly with salinity in surface layer, and Kara Sea waters are desalinated along entire studied transect due to river runoff. concentration of freshwater is 5–10% in main part of water column, and <5% at a depth of >100 m. maximum contribution of freshwater (>65%) was recorded in surface layer of central part of sea. 相似文献
6.
A. S. Savvichev E. E. Zakharova E. F. Veslopolova I. I. Rusanov A. Yu. Lein M. V. Ivanov 《Oceanology》2010,50(6):893-908
The results of microbiological, biogeochemical, and isotope geochemical studies in the Kara Sea are described. The samples
for these studies were obtained during the 54th voyage of the research vessel Akademik Mstislav Keldysh in September 2007. The studied area covered the northern, central, and southwestern parts of the Kara Sea and the Gulf of
Ob. The quantitative characteristics of the total bacterial population and the activity of the microbial processes in the
water column and bottom sediments were obtained. The total population of the bacterioplankton (BP) varied from 250000 cells/ml
in the northern water area to 3000000 cells/ml in the Gulf of Ob. The BP population depended on the content of the water suspension.
The net BP production was minimal in the central water area, amounting to 0.15–0.2 μg C/(l day), and maximal (0.5–0.75 μg
C/(l day)) in the Gulf of Ob. The organic material at the majority of the stations in the Ob transect predominantly contained
light carbon isotopes (−28.0 to −30.18‰) of terrigenous origin. The methane content in the surface water layer varied from
0.18 to 2.0 μl CH4/l, and the methane oxidation rate changed in the range of 0.1–100 nl CH4/(l day). The methane concentration in the upper sediment layer varied from 30 to 300 μl CH4/dm3; the rate of the methanogenesis was 44 to 500 nl CH4/(dm3 day) and that of the methane oxidation, 30 to 2000 nl CH4/(dm3 day). The rate of the sulfate reduction varied from 4 to 184 μg S/(dm3 day). 相似文献
7.
Twenty-nine benthic invertebrate species were registered for the Gudauta Bank in the depth range of 8–32 m in 1990. The shallow-water
biocenose was defined for the depths of less than 10 m, the biocenoses of Anadara inaequivalvis and A. inaequivalvis-Upogebia pusilla occupied the depths of 10–30 m; and the biocenosis of Pitar rudis was found for the depths of more than 30 m. The highest biodiversity and abundance of benthos was registered for the Anadara biocenoses, while the lowest, for the shallow-water ones. It was found that significant changes in the benthic communities
took place in the forty years after the predator gastropod Rapana venosa was introduced into the Black Sea. The oysters became extinct on Gudauta Bank, and the species composition of the benthic
community has been significantly depleted. Alien species of Anadara and Rapana became the most abundant by biomass, comprising more than 80% of the total biomass of the benthos. The population density
of Rapana constituted 12 ind./m2 and was the highest ever registered for the studied areas of the Black Sea. Insufficient nutrition preconditioned the small
size of the mollusks. 相似文献
8.
Biomass and primary productivity of benthic microalgae (BMA) and planktonic algae in Suo Nada, the western part of the Seto
Inland Sea, Japan were compared in terms of unit area with regard to their seasonal and spatial distribution in 2002. Judging
from light compensation depth and water depth, the southwestern part of Suo Nada was considered to be a potential habitat
for BMA. Whereas the contribution of sedimented planktonic algae was high in biomass at the sediment surface, BMA was obviously
significant both in biomass and primary production in the shallow southwestern part. However, the contribution of BMA to the
total biomass in the entire water column was 7% in winter and 2% in summer. The primary production of BMA varied between 4.0
and 74.0 mg C m−2 d−1 in the southwestern part, accounting for 2–12% of the whole water column primary production. The ecological roles of BMA
in the Suo Nada ecosystem are discussed, such as reduction of benthic nutrient flux, oxidation of surface sediments and feed
for higher animals. 相似文献
9.
A. G. Zatsepin P. O. Zavialov V. V. Kremenetskiy S. G. Poyarkov D. M. Soloviev 《Oceanology》2010,50(5):657-667
An area of about 40000 km2 of desalinated upper layer waters with a salinity of less than 25 psu was found during cruise 54 of the R/V Akademik Mstislav Keldysh in the southwestern part of the Kara Sea (September 2007). Close to the boundary of this region located near the eastern
coast of Novaya Zemlya, the salinity was less than 16 psu. The thickness of the desalinated layer was about 10 m. The results
of the chemical analysis revealed that the observed desalination of the sea water was produced, first of all, by the Yenisei
River, while the contribution of the Ob River’s waters was secondary. However, the most desalinated region near the eastern
coast of Novaya Zemlya was separated from the Ob-Yenisei estuary and corresponded to a quasi-isolated lens. It is likely that
the formation of this lens, as well as the major part of the desalinated upper layer waters, occurred in June when the flood
of the Yenisei was maximal, while the further drift of the desalinated waters to the west of the Ob-Yenisei estuary was forced
by the prevailing northern wind. The additional desalination (by 2–3 psu and even more) of the upper layer waters near the
eastern coast of Novaya Zemlya might be related to the melting of the Novozemelskiy ice massif. The regularities of the temporal
evolution of the upper desalinated layer, as well as the influence of this layer on the hydrological structure and dynamics
of the southwestern Kara Sea, are discussed. 相似文献
10.
In seven cruises on benthic organisms in the nearshore waters(>50 m) to the west of the Taiwan Strait(23°20''-25°54''N,117°11''-119°58''E) in 1961-1964,altogether 189 stations of quantitative grabbing and 33 stations of qualitative trawling were made.
Altogether 392 species of benthic organisms have been identified.The composition was dominated by nearshore shallow water species,with tropical and subtropical species absolutely dominant.The total average of biomass was 38.0 g/m2 and average density,116.0 ind./m2.The communities of benthic organisms in the area can be classified into five communities namely,(1) Amphiura sp.-Acaudina molpadioides Community;(2) Protankyra asymmetrica-Arnphioplus pracstans-Murex trapa Community;(3) Modiolus meicalfei-Phyllophorus liuwutiensis-Armandia letocirris-Nephtys sinensis Community;(4) Branchiostoma belcheri-Solenr oseomaculatus-Marphysa sinensis- Onuphis eremita Community;(5) Iconomtra japonica-Barbatia decussata Community. 相似文献
Altogether 392 species of benthic organisms have been identified.The composition was dominated by nearshore shallow water species,with tropical and subtropical species absolutely dominant.The total average of biomass was 38.0 g/m2 and average density,116.0 ind./m2.The communities of benthic organisms in the area can be classified into five communities namely,(1) Amphiura sp.-Acaudina molpadioides Community;(2) Protankyra asymmetrica-Arnphioplus pracstans-Murex trapa Community;(3) Modiolus meicalfei-Phyllophorus liuwutiensis-Armandia letocirris-Nephtys sinensis Community;(4) Branchiostoma belcheri-Solenr oseomaculatus-Marphysa sinensis- Onuphis eremita Community;(5) Iconomtra japonica-Barbatia decussata Community. 相似文献
11.
P. N. Makkaveev P. A. Stunzhas Z. G. Mel’nikova P. V. Khlebopashev Sh. Kh. Yakubov 《Oceanology》2010,50(5):688-697
Hydrochemical studies of the Kara Sea were included into the program of the integrated expedition during cruise 54 of the
R/V Akademik Mstislav Keldysh (September 9–30, 2007). In several sea areas quite different in their weather conditions, a large set of hydrochemical analyses
was carried out, including the determination of the primary nutrients (silicon and different forms of nitrogen and phosphorus),
the dissolved oxygen content, and the total alkalinity and pH values. The report presents the hydrochemical conditions in
the southwestern part of the Kara Sea and the most striking results from the authors’ viewpoint. The data were compared to
those of the integrated oceanographic expedition of cruise 49 of the R/V Dmitry Mendeleev in 1993. 相似文献
12.
The benthic fauna was studied in the Blagopoluchiya Bay (Kara Sea, Novaya Zemlya Archipelago) during an expedition of the R/V Professor Shtokman in autumn 2013. The inner basin of the bay, with depths of around 150 m, is separated from the outer slope of Novaya Zemlya by a shoal 30 m in depth. Six macrobenthic communities were described at nine stations (25 bottom grab samples) taken along a transect from the inner part of the bay to the outer part of the slope. The depths, position on the transect axis and sediment types were the major factors influencing the distribution of the communities. The benthic abundance and biomass in the inner and outer parts of the bay did not differ significantly. The diversity of macrobenthic organisms (α-diversity as the number of species in the sample and β-diversity as the rate of increase in species number in the area) was lower in the inner part of the bay. The intertidal zone (littoral) has been described. The littoral fauna was very poor; it comprised only the amphipods Gammarus setosus inhabiting the near-surface area. 相似文献
13.
To explore the spatial pattern of macrobenthic communities and their response to environmental factors in the Prydz Bay,samples were collected using a 0.25-m2 box corer at 10 stations from November 2012 to April 2013.A total of 50 species of macrobenthos belonging to 8 phyla and 33 families were identified,of which polychaetes(e.g.,Maldane sarsi)and sponges(e.g.,Halichondria sp.and Leucosolenia sp.)were the most prominent groups.The macrobenthos in study area were categorized into five functional groups based on the feeding type,and the detritivorous group represented by polychaetes showed the highest average abundance,while the planktophagous group represented by sponges showed the highest average biomass.Macrobenthos abundance(0–592 ind./m2)and biomass(0–1155.5 g/m2)in the Prydz Bay were relatively lower than those of other Antarctic shelf soft-bottom waters,although the compositions of the dominant species and functional feeding groups were similar.The results of the Spearman rank correlation analysis indicated that the average biomass of the macrobenthos and the biomass of the planktophagous group in the study area were negatively correlated with the water depth,sediment grain size and silt percentage.However,these variables were clearly not strong determinants of macrobenthos assemblage structure.Many factors not measured in the study,e.g.,sediment organic matter and iceberg interference,have probably influenced the spatial distribution of macrobenthic community structure in the Prydz Bay. 相似文献
14.
Data on the bacterial and primary production, which were obtained simultaneously for the same water samples, are presented
for three regions of the Kara Sea. The samples were collected for the transect westwards of the Yamal Peninsula, along the
St. Anna Trough, and the transect in Ob Bay. Direct counts of the DAPI-stained bacterial cells were performed. The bacterial
production and grazing rates were determined using a direct method when metabolic inhibitors vancomycin and penicillin were
added. The primary production rates were estimated using the 14C method. 相似文献
15.
Evidence of microphytobenthic roles on coastal shallow water of the Seto Inland Sea,Japan 总被引:1,自引:0,他引:1
This study describes the temporal variation of microphytobenthic biomass and its controlling factors, as well as the impact
of microphytobenthic activities on coastal shallow sediment in the eastern Seto Inland Sea, Japan. The chlorophyll a (Chl a), phaeopigments and sedimentary biophilic element (C, N, P and Si) contents in surface sediments, as well as nutrient concentrations
at the sediment-water interface (overlying water and pore water) were observed monthly during November 2003 to May 2005 at
one site in Shido Bay (water depth ca. 7 m) and at one site in Harima-Nada (35 m). No correlation was observed between the sedimentary biophilic elements and other
parameters. The maximum chlorophyll a content of 48.2 μg g–1 was found in surface sediments under the photon flux reaching the seafloor of 537 μmol photon m–2 s–1 during the winter period when water transparency was the highest at station S (Shido Bay). Our results suggest that higher
chlorophyll a content in surface sediment was due to the fresh microphytobenthic biomass (mainly benthic diatom). We also found a significant
negative correlation between Chl a and inorganic nutrients in pore water during the low temperature period, especially silicic acid. This result suggests that
the silicic acid was assimilated largely during the increase of microphytobenthic biomass in surface sediment. This study
suggests that the microphytobenthic roles may have a great effect on nutrient budgets during the large supply of irradiance
(winter periods) for their photosynthetic growth in shallow coastal waters. 相似文献
16.
The distribution of the suspended particulate matter concentration in the Kara Sea is analyzed based on ship and satellite
data. The statistical relationships between the suspended matter concentration and the optical characteristics were revealed.
Charts of the distribution of the suspended matter concentration in the Kara Sea were plotted, which confirmed that the application
of optical methods for analyzing the spatial distribution of the suspended matter is effective. The most turbid waters were
observed in the Ob Gulf, Yenisei Bay, the Baidaratskaya Gulf, and the adjacent regions. The smallest concentrations of suspended
matter were observed in the central and western parts of the Kara Sea. 相似文献
17.
18.
A. I. Chava A. A. Udalov A. A. Vedenin M. I. Simakov S. A. Shchuka V. O. Mokievsky 《Oceanology》2017,57(1):144-153
Benthic fauna in Tsivolki Bay (Novaya Zemlya Archipelago, Kara Sea) has been studied during the voyage of the R/V Professor Shtokman in 2013 and 2014. A peculiar feature of the bay is the presence of the Serp i Molot glacier in its inner part, which determines the extremely high content of suspended particles in the water column. The bay is divided into three parts: the inner part (close to the glacier), the middle basin, and the outer slope. These parts are separated from each other by several rises. Benthic communities changed gradually from the inner part of the bay towards the outer slope. Three communities were described from the data of nine grab stations (26 samples). The apex of the bay is occupied by the depleted community dominated by the isopod Saduria sabini and the bivalve Yoldiella lenticula, which can successfully survive the increased mineral sedimentation. In the middle basin, it is replaced by the transitional community with Ennucula tenuis and Portlandia arctica being the main dominants. Finally, the outer slope is inhabited by the community typical for the open parts of the Kara Sea. It is dominated by Astarte crenata, Ophiacantha bidentata, and Ophiopleura borealis. The main reason for macrobenthic distribution in the studied region is the content of mineral particles in the water column and bottom layers. 相似文献
19.
Late Pleistocene-Holocene Paleoceanography and Ventilation of the Gulf of California 总被引:1,自引:0,他引:1
Lloyd D. Keigwin 《Journal of Oceanography》2002,58(2):421-432
Sediment cores collected in 1990 from the Gulf of California have been studied using stable isotope and radiocarbon techniques
to reconstruct the climate and ventilation histories since the last glacial maximum. Benthic foraminiferal δ18O from core tops in a water depth range of 145 to 1442 m increases by about 2% with increasing depth. This is consistent with
a composite temperature profile constructed from several hydrocasts in the various gulf basins. However, the δ18O water/salinity relationship is not sufficiently linear in gulf locations or in nearby open Pacific Geochemical Ocean Sections
Study (GEOSECS) stations to be useful in solving paleotemperature equations. Of the most common benthic foraminifera, only
Planulina ariminensis has δ13C that is consistent with the measured δ13C of ΣCO2. Several cores in the depth range 500 to 900 m have the laminated Holocene and Bolling/Allerod sediments, and the nonlaminated
glacial age and Younger Dryas sediments that are typical of the gulf and other locations such as Santa Barbara Basin. The
best of those, Jumbo Piston Core (JPC) 56 from 818 m water depth on the western margin of Guaymas Basin, was sampled for intensive
study. Oxygen isotope ratios in benthic and planktonic foraminifera show little evidence for deglacial temperature oscillations.
Carbon isotope ratios are generally lower during warm epochs, but the most striking result is strongly lowered benthic and
planktonic δ13C about 9500 years ago. This may reflect water column oxidation of locally released methane. Neither benthic δ13C in depth section nor paired benthic and planktonic 14C data in JPC56 are consistent with increased intermediate water ventilation during the glacial maximum and Younger Dryas.
Likewise, 14C data from 5 pairs of foraminifera from the Okhotsk Sea fail to support better ventilation in that basin during the last
glacial maximum.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
渤海小型底栖动物生物量的初步研究 总被引:15,自引:1,他引:15
主要以线虫、桡足类、双壳类、多毛类和动吻5个类群对渤海小型底栖动物的生物量进行了估算,并对其水平分布进行了研究.结果表明,3个航次平均,渤海小型底栖动物年生物量为(干重)0.404g/(m2·a);1998年9~10月和1999年4~5月2个航次中小型底栖动物生物量的水平分布主要表现为渤海中东部和海峡口站位的生物量明显高于其他站位,但在1999年航次,海峡口靠近海岸的站位生物量下降,位于莱洲湾B1站位生物量明显上升.依据小型底栖动物的年生产力P=9B,估算渤海小型底栖动物的年平均生产力为(干重)3.636g/(m2·a).还对渤海小型底栖动物生物量与世界其他海域的进行了比较,认为渤海小型底栖动物生物量的数值与其他海域生物量的数值接近,但略偏低.就不同学者研究所得的线虫平均个体干重进行了比较研究. 相似文献