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1.
L. S. Zhitina 《Oceanology》2011,51(6):1004-1011
The species composition, cell concentration, and biomass in the surface layer were determined at 10 stations in the central
part of the Western Basin (WB) and one station in the Eastern Basin (EB) of the Large Aral Sea. A total of 42 algae species
were found. Diatoms had the highest number of species. The similarity of the phytoplankton composition in the WB was high,
whereas the phytoplankton composition in the WB and EB differed significantly. In the WB, the cell concentration and biomass
of the phytoplankton varied from 826 × 103 to 6312 × 103 cells/l (the mean value was 1877 × 1586 × 103 cells/l) and from 53 to 241 μgC/l (the mean value was 95 × 56 μgC/l). In the EB, the phytoplankton abundance was 915 × 103 cells/l and 93 μgC/l. The vertical distribution of the phytoplankton in upper 35 m was investigated at one station in the
WB. The maximum values of the algal cell concentration and biomass were recorded under the thermocline at the 20 m depth.
The integrated biomass of the phytoplankton was 14 gC/m2. 相似文献
2.
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
3.
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
4.
In the southwestern Okhotsk Sea off Hokkaido we observed chemical components related to the carbonate system for 1 year from
August 1997 to June 1998. Using the conservative components salinity and water temperature, we confirmed the existence of
two water masses flowing into the intermediate layer of the Okhotsk Sea, the East Sakhalin Current Water (ESCW) which becomes
denser by mixing of brine water, and the Forerunner of Soya Warm Current Water (FSWW) which becomes denser due to cooling
of the saline Kuroshio water. The ΔNTCx values were calculated by comparing the ESCW and the FSWW with the Pacific Deep Water (PDW). The ΔNTCx values obtained are 100–110 μmol/kg and 70–100 μmol/kg for the ESCW and the FSWW off Hokkaido, respectively, which are considerably
larger than that of the Kuroshio water. These large ΔNTCx values may be due to both low DIC concentration in the surface water and intense gas exchange under the cold and stormy winter
conditions for the ESCW and the cooling of the FSWW as it flows northward. Since the flow rates of dense waters concerned
with the ESCW and the FSWW have previously been estimated as 0.9 Sv and 0.2 Sv, respectively, the amount of atmospheric CO2 absorbed and transported to the intermediate layer turns out to be 3.9−4.1 × 1013 gC/yr. This flux is small on a global scale, but the flux divided by the surface layer of the Okhotsk Sea is 30 gC/m2/yr, which is 5 times greater than the mean absorption flux of anthropogenic CO2 in the world's oceans. It is thus considered that atmospheric CO2 is efficiently absorbed in the Okhotsk Sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Yu. I. Sorokin 《Oceanology》2011,51(6):969-977
The rate of the hydrogen sulfide oxidation in the redox zone of the Black Sea and the rate of the hydrogen sulfide formation
due to bacterial sulfate reduction in the upper layer of the anaerobic waters were measured during the period of February–April
1991. The measurements were made using a sulfur radioisotope under conditions close to those in situ. It was established that
the hydrogen sulfide is oxidized in the layer where oxygen and hydrogen sulfide coexist, which is under the upper boundary
of the hydrogen sulfide layer. The maximum rate of the hydrogen sulfide oxidation was recorded within the limits of the density
values δτ of 16.20–16.30, while varying in the layer from 2 to 4.5 μM/day. The average rate of the hydrogen sulfide oxidation
was 1.5–3 times higher than that during the warm season. Sulfide formation was not observed at most of the stations in the
examined lower portion of the pycnocline layer (140 to 400 m depths). Noticeable sulfate reduction was detected only at one
station on the northwestern shelf. A probable reason for such noticeable changes in the sulfur dynamics in the water mass
of the Black Sea may be the intensified hydrodynamics in the upper layers of the water mass during the cold season. The data
suggesting that hydrogen sulfide oxidation proceeds under the hydrogen sulfide boundary indicate the absence of the so called
“suboxic zone” in this basin. 相似文献
6.
Akihiro Shiomoto Katsuyuki Sasaki Toru Shimoda Satsuki Matsumura 《Journal of Oceanography》1994,50(2):209-222
Primary productivity was measured byin situ method using13C in the offshore Oyashio region in the spring (May) and summer (September) of 1990. Most of the values were within the range of 0.1 to 4 gC 1–1 h–1 although a very large value, 7.96 gC l–1 h–1, was observed in summer. Most daily primary production fell within the range of 372 to 633 mgC m–2 d–1 although a very large value, 2,109 mgC m–2 d–1, was observed around the frontal area in summer. Chlorophylla (Chl.a) exceeded 1 g l–1 in many cases, and the maximum was 4.61 g l–1 in spring and 7.53 g l–1 in summer. Most primary productivity per unit Chl.a (photosynthetic assimilation ratio) was within the range of 0.1 to 3 gC gChl.a
–1 h–1 although higher values, 3–6 gC gChl.a
–1 h–1, were observed where small-size phytoplanktons (<2 m) were dominant. These results were compared with results obtained until now in the Oyashio region. The values beyond the range obtained so far in the offshore region were also observed in this study. Furthermore, it was pointed out that the size composition of phytoplankton community has significant influence on the results of Chl.a and photosynthetic assimilation ratio in the Oyashio region. 相似文献
7.
Kuninao Tada Koji Monaka Masakazu Morishita Toshiya Hashimoto 《Journal of Oceanography》1998,54(4):285-295
Standing stocks and production rates of phytoplankton and abundance of bacteria were investigated at 39 stations in the Seto
Inland Sea, Japan during four crulses in October 1993, January, April and June 1994. Primary productivity was measured by
the13C tracer method. Photosynthetic rate varied from 0.41 to 32.1 μgC/1/h with an average value of 4.67 μgC/l/h. Annual primary
production was estimated to be 218 gC/m2/year. Annual primary production in this study was 1.8 times as high as the values which were previously reported at same
area. The reason for the disagreement between our primary production value and previous values is not thought to be due to
the difference of methods used for measuring primary production or the different Chl.a concentrations but to the method of estimating the primary production in the euphotic zone from thein vitro measurements. The distribution of bacterial cells in surface seawater was examined during the same cruises. Bacterial cell
density ranged from 0.32 to 3.4×106 cells/ml. The density was relatively high in the eutrophic regions of Hiroshima Bay and Osaka Bay In addition, a high density
of bacteria was also observed in an area within Suo Nada where Chl.a was relatively low. The disparity between Chla and bacterial density in Suo Nada suggests that bacterial abundance can be controlled by the availability of substrates other
than phytoplankton exudate. 相似文献
8.
The intensity of the processes of organic matter (OM) destruction in the deep-water part of the Arctic Basin is considered
in terms of the activities of hydrolytic enzymes (alkaline phosphatase and proteases) and of redox enzymes of the electron
transport system (ETS). High concentrations of mineral phosphorus are shown to cause low phosphatase activity (0.000–0.005
μM P/l h). The average time of the phosphate recycling amounted to about 240 h. The ranges of the total and specific activity
of protease are 0.000–0.192 mg of azocasein/(l h) and 0.00–3.57 mg of azocasein/h mg of protein, respectively. It is found
that the microplankton production of exo- and endopeptidase in the Arctic Basin is controlled by the concentration of nitrates
in the water. The values of the total and the specific activities of the ETS enzymes vary within 0.27–8.96 μl O2/(l h) and 8.4–583 μl O2/mg of protein h, respectively. It is shown that the maximum values of the total activities of the hydrolytic and redox enzymes
are characteristic for the photic layer. The vertical fluxes of organic carbon from the photic layer, being calculated by
the activity of the ETS enzymes, amounted to 220–600 g of Corg/year m2. The presence of ice intensifies the redox processes by factors of 2–15. 相似文献
9.
Richard A. Feely Christopher L. Sabine Reiner Schlitzer John L. Bullister Sabine Mecking Dana Greeley 《Journal of Oceanography》2004,60(1):45-52
As a part of the JGOFS synthesis and modeling project, researchers have been working to synthesize the WOCE/JGOFS/DOE/NOAA
global CO2 survey data to better understand carbon cycling processes in the oceans. Working with international investigators we have
compiled a Pacific Ocean data set with over 35,000 unique samples analyzed for at least two carbon species, oxygen, nutrients,
chlorofluorocarbon (CFC) tracers, and hydrographic parameters. We use these data here to estimate in-situ oxygen utilization
rates (OUR) and organic carbon remineralization rates within the upper water column of the Pacific Ocean. OURs are derived
from the observed apparent oxygen utilization (AOU) and the water age estimates based on CFCs in the upper water and natural
radiocarbon in deep waters. The rates are generally highest just below the euphotic zone and decrease with depth to values
that are much lower and nearly constant in water deeper than 1200 m. OURs ranged from about 0.02–10 μmol kg−1yr−1 in the upper water masses from about 100–1000 m, and averaged = 0.10 μmol kg−1yr−1 in deep waters below 1200 m. The OUR data can be used to directly estimate organic carbon remineralization rates using the
C:O Redfield ratio given in Anderson and Sarmiento (1994). When these rates are integrated we obtain an estimate of 5.3 ±
1 Pg C yr−1 for the remineralization of organic carbon in the upper water column of the Pacific Ocean.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
The shortwave radiative forcings of smoke aerosol in the cloudless atmosphere during the summer fires of 2010 in European
Russia were quantitatively estimated for the land surface and the atmospheric upper boundary from measurement data obtained
at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics (OIAP ZSS), Russian Academy of Sciences.
Variations in the temperature of the surface air layer due to the smoke-induced attenuation of incoming solar radiation were
estimated. The most intensive smoke generation in the atmosphere was observed on August 7–9, 2010, when the maximum aerosol
optical thickness amounted to more than 4.0 at a wavelength of 550 nm. In this case, the albedo of single aerosol scattering
amounted to ∼0.95–0.96 and the asymmetry factor amounted to ∼0.69–0.70. The maximum shortwave radiative forcing of aerosol
amounted to about −360 W/m2 for the land surface and almost −150 W/m2 for the atmospheric upper boundary. During the period of intensive smoke generation, the cooling of the atmospheric surface
layer over daylight hours (12 h) amounted, on average, to ∼6°C. The power character of the dependence of the shortwave radiative
forcing of aerosol for the land surface on aerosol optical thickness up to its values exceeding 4.0, which was revealed earlier
on the basis of data on aerosol optical thickness (up to 1.5) obtained at the OIAP ZSS during the summer forest and peatbog
fires of 2002 in the region of Moscow, was supported. 相似文献
11.
Chiho Sukigara Toshio Suga Toshiro Saino Katsuya Toyama Daigo Yanagimoto Kimio Hanawa Nobuyuki Shikama 《Journal of Oceanography》2011,67(1):77-85
A profiling float equipped with a fluorimeter, a dissolved oxygen (DO) sensor, and temperature and salinity sensors was deployed
in the subtropical mode water (STMW) formation region of the North Pacific. It acquired quasi-Lagrangian, 5-day-interval time-series
records from March to July 2006. The time-series distribution of chlorophyll showed a sustained and sizable subsurface maximum
at 50–100 m, just above the upper boundary of the STMW, throughout early summer (May–July). The DO concentration in this lower
euphotic zone (50–100 m) was almost constant and supersaturated in the same period, becoming more supersaturated with time.
On the other hand, the DO concentration at 100–150 m near the upper boundary of the STMW decreased much more slowly compared
with the main layer of STMW below 150 m, even though oxygen consumption by organisms was expected to be larger in the former
depth range. The small temporal variations of DO in the lower euphotic zone and near the upper boundary of the STMW were reasonably
explained by downward oxygen transport because of large diapycnal diffusion near the top of the STMW. Assuming that the oxygen
consumption rate at 100–150 m was the same as that in the main layer of STMW and compensated by the downward oxygen flux,
the diapycnal diffusivity was estimated to be 1.7 × 10−4 m2 s−1. Nitrate transport into the euphotic zone by the same large diffusion was estimated to be 0.8 mmol N m−2 day−1. All of the transported nitrate could have been used for photosynthesis by the phytoplankton; net community production was
estimated to be 5.3 mmol C m−2 day−1. 相似文献
12.
Tsutomu Ikeda 《Journal of Oceanography》2011,67(6):785-790
This study demonstrates reduced electron transfer system (ETS) activity of mixed copepods collected from 5,000 to 7,000 m
depths [3.21 ± 1.25 μl O2 (mg protein)−1 h−1 at 10°C] as compared with mixed copepods from 0 to 200 m depths [5.93 ± 1.66 μl O2 (mg protein)−1 h−1 at 10°C] of the western subarctic Pacific. At the in situ temperature of 1.5°C, the 5,000–7,000 m ETS data, in terms of wet
mass (WM)-specific respiration rates (R), is equivalent to [0.052 ± 0.021 μl O2 (mg WM)−1 h−1] which is similar to or greater than those reported for selected copepods or mixed mesozooplankton from <5,000 m depth by
previous workers. 相似文献
13.
I. A. Nemirovskaya 《Oceanology》2010,50(5):716-728
Data are presented on the content of aliphatic and polycyclic aromatic hydrocarbons (AHC and PAH, respectively) in the interstitial
waters and bottom sediments of the Kara Sea compared to the distribution of the particulate matter and organic carbon. It
was found that the AHC concentrations within the water mass (16 μg/l on average) are mainly formed by natural processes. The
AHC distribution represents the variability of the hydrological and sedimentation processes in different regions of the sea.
The widest ranges of the concentrations were registered in the Ob Bay-Kara Sea section: in the water (10–310 μg/l for the
AHC and 0.4–7.2 ng/l for the PAH) and in the surface layer of the bottom sediments (8–42 μg/l for the AHC and 9–94 ng/g for
the PAH). The differentiation of the hydrocarbons (HC) in the different media follows the marginal filter’s regularities;
therefore, no oil and pyrogenic compounds are supplied to the open parts of the sea. In the sediment mass, the HC content
is determined by the variations in the oxidative conditions in the sediment and its material’s composition. 相似文献
14.
《Marine Chemistry》1991,32(2-4)
Before the onset of wind in the Krka Estuary, a sharp halocline extends from 2.5 to 4 m below the surface, separating the upper brackish water layer from the lower marine layer. Strong wind (20 m s−1) induces a tilt of the halocline surface so that downwind (5-km wind fetch) the halocline is pushed to 4.6 m below the surface. Wind-driven surface currents induce a vertical gyre within the upper layer and a gyre in the opposite direction in the lower marine layer. As a consequence, the halocline close to the coast on the downwind side is not only deeper but is also steepened. The entrainment of marine water into the upper brackish water layer is intensified on the windward side. The possible role of wind in oxygenating the bottom layer is discussed. 相似文献
15.
I. N. Sukhanova M. V. Flint E. Ju. Georgieva E. K. Lange M. D. Kravchishina A. B. Demidov A. A. Nedospasov A. A. Polukhin 《Oceanology》2017,57(1):75-90
Studies have been performed on a transect along 130°30′ E from the Lena River delta (71°60′ N) to the continental slope and adjacent deepwater area (78°22′ N) of the Laptev Sea in September 2015. The structure of phytoplankton communities has distinct latitudinal zoning. The southern part of the shelf (southward of 73°10′ N), the most desalinated by riverine discharge, houses a phytoplankton community with a biomass of 175–840 mg/m2, domination of freshwater Aulacoseira diatoms, and significant contribution of green algae (both in abundance and biomass). The northern border for the distribution range of the southern complex of phytoplankton species lies between the 8 and 18 psu isohalines (~73°10′ N). The continental slope and deepwater areas of the Laptev Sea (north of 77°30′ N), with a salinity of >27 psu in the upper mixed layer, are populated by the community prevalently composed of Chaetoceros and Rhizosolenia diatoms, very abundant in the Arctic, and dinoflagellates. The phytoplankton number in this area fall in the range of 430–1100 × 106 cell/m2, and the biomass, in the range of 3600 mg/m2. A moderate desalinating impact of the Lena River discharge is observed in the outer shelf area between 73°20′ and 77°30′ N; the salinity in the upper mixed layer is 18–24 psu. The phytocenosis in this area has a mosaic spatial structure with between-station variation in the shares of different alga groups in the community, cell number of 117–1200 × 106 cells/m2, and a biomass of 1600–3600 mg/m2. As is shown, local inflow of “fresh” nutrients to the euphotic layer in the fall season leads to mass growth of diatoms. 相似文献
16.
V. V. Knysh G. K. Korotaev S. G. Demyshev V. N. Belokopytov 《Physical Oceanography》2005,15(3):142-160
We compare the thermohaline and dynamic characteristics of the Black Sea reconstructed by using two versions of climatic temperature
and salinity fields:old (1903–1982)and new (1903–2003). The fields are reconstructed with the help of continuous assimilation
of the climatic temperature and salinity in the model. It is shown that the climatic thermohaline fields constructed with
regard for the data of observations for the last 20 yr are characterized by an insignificant elevation of the halocline (pycnocline)in
the winter-spring period and the elevation of the upper boundary of the cold intermediate layer in the spring-summer period.
The intensity of surface geostrophic currents is greater than the same quantity computed on the basis of the old climatic
data for the whole year. The horizontal currents in the sea computed according to the new climatic data are more intense.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 11–30, May–June, 2005. 相似文献
17.
Hirotaka Otobe Keisuke Taira Shoji Kitagawa Tomio Asai Kimio Hanawa 《Journal of Oceanography》2003,59(5):619-627
The heat balance of the surface layer in the vicinity of the former Ocean Weather Station “Tango” (OWS-T; 29°N, 135°E), where
a large amount of heat is transported by the Kuroshio and transferred to the atmosphere, was studied by during Ocean Mixed
Layer Experiment (OMLET) as an oceanographic component of the Japanese World Climate Research Program (1987–1991). Temperature
and velocity in the upper ocean measured using a surface moored buoy system deployed by the Ocean Research Institute, the
University of Tokyo, in total 668 days of four time series namely the periods of April 1988–November 1988 (OMELET-88), August
1989–February 1990 (OMLET-89), April 1990–September 1990 (OMLET-901) and September 1990–January 1991 (OMLET-902). We have
analyzed the moored buoy data of the upper 100 m for the latter three time series (OMLET-89, -901 and -902) and here we discuss
the heat balance of the upper 100 m, in combination with surface heat flux and oceanographic data provided by the Japan Meteorological
Agency. A large fluctuation of oceanic heat convergence/divergence of 200–300 W/m2 in amplitude with predominant period of 20–30 days occurred in the first half of OMLET-89 period, which was just the early
stage in the formation process of a large meander path of the Kuroshio. A large amount of heat convergence of 71 and 79 W/m2 on average was detected in observation period of OMLET-89 and -901, respectively. During OMLET-902, relatively small heat
convergence of 13 W/m2 was obtained. It is suggested that these variations of oceanic heat convergence in this region were closely related to the
fluctuation of the Kuroshio axis to the south of Japan.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
We perform the experimental verification of the applicability of the theory of similarity to the wave boundary layer and the
assessment of wave-induced perturbations of the air flow depending on various conditions of stratification of the atmosphere
and the state of the sea. The measurements were carried out from a stationary platform located in the coastal part of the
Black Sea. The experimental procedure is based on the simultaneous measurements of the profile and fluctuations of the wind
speed at 5–6 levels in the 1.3–21-m layer, the elevations of the sea surface, the directions of waves and winds, and the mean
gradients of temperature and humidity of air. The structure of the boundary layer in the region of measurements depends on
the direction of the wind. For weak and moderate onshore winds (< 9 m/sec), the approximate balance is preserved between the
production and dissipation of turbulent energy in the cases of unstable and neutral stratification. On the average, the estimates
of friction velocity according to the profiles are higher than the dissipative estimates by 10% mainly due to the deficiency
of dissipation near the surface. For the offshore wind, the structure of the boundary layer abruptly changes and is determined
not by the local parameters but by strong turbulent eddies formed over the dry land. The intensity of low-frequency turbulent
fluctuations and the gradient of wind velocity near the surface in the coastal zone are 1.5–2 times higher than for the open
sea.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 42–61, May–June, 2007. 相似文献
19.
In three sections in the Kara Sea, the contents of the dissolved and particulate organic carbon (the DOC and POC, respectively),
as well as of the organic carbon of the bottom sediments (Corg) were determined. The contents of varied from 6.3 to 2400 μg/l for the DOC and from 0.84 to 12.2 mg of C/l for the POC. The
average concentrations for all the samples tested amounted to 200 μg/l for the DOC (n = 78, σ = 368) and 2.7 mg/l for the POC (n = 92, σ = 2.7). The concentrations of Corg in the samples of the upper layer of the bottom sediments of the area treated
varied from 0.13 to 2.10% of the dry substance at an average value of 0.9% (n = 21, σ= 0.49%). It is shown that the distribution of the different forms of organic matter (OM) is an indicator of the supply
and spreading of the particulate matter in the Kara Sea and that the DOC and POC of the Kara Sea are formed under the impact
of the runoff of the Ob and Yenisei river waters. It is found that the distribution of the OM of the bottom sediments in the
surveyed area of the Kara Sea is closely related to their grain-size composition and to the structure of the currents in the
area studied. The variations in the Corg content in the bottom sediment cores from the zone of riverine and marine water mixing
represent the variability of the OM burial. 相似文献
20.
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