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1.
The relationship between Cd and PO4 in the Kuroshio and Oyashio regions and the Okhotsk Sea was examined. The resultant equations are as follows: Cd (ng l–1)=37.0 PO4 (M)+2.6; Cd(ng l–1)=32.1 PO4 (M)+1.2 and Cd (ng l–1)=34.1 PO4 (M)+7.9, respectively. These results are in good agreement with previously reported studies, and indicate that during removal from surface waters to deeper waters by biological assimilation and regeneration in deeper waters Cd and PO4 maintain the same ratio in the open ocean. The relationship between Cd and PO4 in coastal waters, however, differed from that in the open ocean.  相似文献   

2.
Primary productivity off Enshu-nada was measured by the13C method in September 1989. Primary productivity was estimated in a cold water mass developed off Enshu-nada for the first time. The obtained value was 469 mgC·m–2·d–1 and higher than those in the pelagic area of Kuroshio, but equivalent to those in the neritic and the Oyashio areas. It was indicated that cold water mass is the place where organic matter is produced actively. Extremely high chlorophylla of more than 5g·l–1 were found in the cold water mass. The high productivity was due to high standing crop of phyoplankton. Furthermore, calculated light efficiency and quantum yield showed consistent increase with depth and showed a maximum at 10% light level. Both were larger on the coastal side than those on the oceanic side of the Kuroshio current.  相似文献   

3.
Dissolved copper concentrations in surface waters of the Bering Sea ranged from 106 to 882 ngl–1. Higher concentrations were found in continental shelf waters. In the northwestern North Pacific dissolved copper ranged from 54 to 140 ngl–1. Particulate copper concentrations varied regionally and seasonally from 6 to 79 ngl–1. Regionally averaged particulate copper concentrations decreased from 175 to 33g g–1 against an increase in suspended materials because of the dilution effects of biological fractions. Apparent sporadic increases in copper concentrations were found in the mixing area of the Kuroshio and the Oyashio waters. The feature is attributed to the lateral distribution of different water types rather than to the upwelling of deeper waters by eddies. In the same area west of 160E, waters with high concentrations of dissolved copper (96±9 ngl–1) were found. Their origin appears to be the continental shelf of the Bering Sea. In spite of intensive biological activity, a considerable fraction of copper added to shelf waters was transported to the area off Japan via the circulation in the Bering Sea and the Oyashio current.  相似文献   

4.
Mercury, cadmium, arsenic, and antimony were analyzed in cores sampled on the Azores-Iceland Ridge. High values of 780 g · kg–1 for Hg, 1.7 g · g–1 for Cd, 87 g · g–1 for As, and 8.1 g · g–1 for Sb occur in the rift valley and transform faults. These enrichments, strictly linked to the ridge, could not have an allochtonous origin. A local hydrogenous flux may explain this phenomenon. These metallic enrichments may be connected to a hydrothermal activity extended between 43° N and 47° N.  相似文献   

5.
Surface temperature, salinity, concentrations of silicate (Si) and nitrate + nitrite (N), and in vivo fluorescence (Fluor) were investigated in the marginal ice zone (MIZ) and the seasonally open oceanic zone (SOOZ) (32–40°E, 64–69°S) from February 23 to 28 1992. In the MIZ the mean Si and N were 67.8 ± 2.2 M and 32.5 ± 1.7 M, respectively. There was a trend that low N values coincided with high Fluor values. Observation conducted at one point (64°S, 38°E) revealed a diel variation pattern in Fluor. Applying this pattern of deviation from noon value, all Fluor data were normalized to value at local noon. In the MIZ a significant negative correlation was observed between the normalized Fluor and N but not Si. On the other hand, Si decreased continuously from south to north in the SOOZ and was negatively correlated with the normalized Fluor. Difference in Si concentration was about 30 M between the sea around 64°S and the MIZ, while the difference in N concentration was estimated as less than 10 M. If diatoms take up silicate and nitrogen at an approximate ratio of 1:1, additional nitrogenous nutrients other than nitrate and nitrite (e.g. ammonia, urea etc.) would be required. In this case, an f-ratio of lower than 33% is obtained. It is suggested that in the MIZ abundance of phytoplankton community dominated by non-diatom increases utilizing nitrate while in the SOOZ abundance of phytoplankton community dominated by diatoms increases consuming Si and regenerated nitrogen.  相似文献   

6.
Responding to the recommendation at the first Meeting of the International Coordination Group for the Cooperative Study of the Kuroshio and Adjacent Regions (CSK) 1965, a series of nitrate standard solutions consisting of eight different concentrations ranging from 0 to 50g-at NO3-N/l in 30.5 sodium chloride solution with the highest purity was prepared for nitrate-N determination in seawater. The solutions have been proved to be stable at least 520 days after preparation.The best way of handling and conditioning the copper-cadmium column was studied for securing the perfect and reproducible conversion of nitrate to nitrite for the procedure as proposed byWood et al. (1967).It was also shown that the method can be applied to freshwater samples by the addition of sodium chloride and adjusting pH properly.  相似文献   

7.
Sedimentation rates were determined with the210Pb technique in six sediment cores from Harima Nada (Harima Sound), Seto Inland Sea. The rate of deposition varies from 0.11 g cm–2y–1 in the northern part to 0.33 g cm–2 y–1 in the southern part of the basin. A marked increase in copper and zinc content was observed above a depth in the core corresponding to about 1900 A.D. as a result of increasing human activities. Anthropogenic input of copper and zinc decreased slightly after 1970. Natural background levels of copper and zinc in the sediment in this sound are 11–16 ppm and 100–120 ppm, respectively. The total amounts of anthropogenic copper and zinc in the sediments were estimated to be 110–180g cm–2 and 610–1,280g cm–2, respectively. These values constitute 40–50% of the total sedimentary input of copper and zinc in the sediments since about 1900 A.D.  相似文献   

8.
Chlorophylla concentrations (Chla) of size-fractionated phytoplankton samples were measured in the western North Pacific Ocean, the Bering Sea, and the Gulf of Alaska during the summer of 1986. Among samples collected in the upper 100 m (total of 210 samples), 207 samples were dominated by micro- (>10 m) or picoplankton (<2 m) and only three samples were represented by nanoplankton (2–10 m). These 207 samples were classified based on the total Chla content into three types: Type H (>1.0 g l–1), Type M (0.5–1.0 g l–1), and Type L (<0.5 g l–1). These types further divided into two subtypes (-p and-m), depending upon dominancy of pico (-p) and microplankton (-m). The phytoplankton community was represented by Type L-p in the Gulf of Alaska, where 80% of the samples fell into this type. It was represented by Type M-p in the western North Pacific and the Oceanic Domain in the Bering Sea, where 53 and 41% of samples were identified as this type, respectively. In the Middle Domain of the Bering Sea, 68% of samples collected below the nitracline was Type H-m, which indicates blooms of microplanton. This type was also observed in the neritic waters near the Aleutian Islands. These types described above are consistent with a general trend that an increase in phytoplankton abundance is attributed to the growth of microplankton. An unusual type occurred above the nitracline of the Middle Domain, where microplankton prevailed, although the total Chla was less (Type L-m). This type represents a feature of late phase of an ice edge bloom. Another unusual type was found mainly in the Outer Domain of the Bering Sea, where the total Chla was high and picoplankton prevailed (Type H-p). The predominance of picoplankton seems to result from the heavy grazing intensity of large calanoid copepods upon microplankton but not upon picoplankton  相似文献   

9.
The effects of irradiance on the excystment of tintinids from marine sediments were examined by incubating sediment samples in filtered seawater under various light levels. The total incidence of tintinnid excystment over five days was significantly less at low irradiance at and less than 2.5 E m–2sec–1 comparing to that at higher irradiance, at and more than 6.9 E m–2sec–1 (p<0.01), indicating that excystment of tintinnids is inhibited under low irradiance conditions. These results imply that water depth, disturbance of surface sediments and vertical mixing of water influence the excystment of tintinnids in coastal areas because these factors determine the light levels to which the tintinnid cysts are exposed.  相似文献   

10.
A method of obtaining the operative sea surface temperature (SST)t using satellite scanner observations in the spectral ranges 3.53–3.94 m and 10.3–11.3 m is realized. The method represents a combination of McClainet al.'s formula (1983) and expressions suggested by the authors which describe the universal angular structures of the radiation temperature fields. The RMS error of reconstructingt at scanning angles of 0–55o is equal to 0.2–0.3°C for atmospheric states corresponding to the SST variation within the limit 6–28°C. An atlas of temperature maps on the grid 0.5×0.5o with temporal averaging from 5 days to 1 month is compiled using the data obtained on board the RVAkademik Vernadsky in the Atlantic Ocean in 1987–1989.Translated by Mikhail M. Trufanov.  相似文献   

11.
The winter water mass distributions in the western Gulf of Mexico, affected by the collision of a Loop Current anticyclonic ring, during January 1984 are analyzed. Two principal modes of Gulf Common Water (GCW) formation, arising from the dilution of the Caribbean Subtropical Underwater (SUW), are identified. Within the western gulf continental slope to the east of Tamiahua, the GCW is formed by the collision of anticyclonic rings. During these collision events, the SUW, entrapped at the core (200 m depth) of these features, is diluted by low salinity (36.1S36.3) water from the uppermost layer of the main thermocline. The end product of this mixture is GCW, which is further diluted by low salinity coastal water within the western gulf continental shelf. The second GCW formation mode is associated to the northerly wind stress which propagates over the western gulf during winter. During January, 1984, this wind stress gave rise to a 175 m mixed layer. This convective mixing destroyed the static stability of the summer thermocline and allowed for the partial dilution of the SUW with low salinity (S36.3) water from the western gulf continental shelf. Within the western gulf's upper 2000 m, the following water masses were identified to be present: GCW, SUW, Tropical Atlantic Central Water and associated dissolved oxygen minimum stratum, Antarctic Intermediate Water remnant, a mixture of the Caribbean Intermediate Water and the upper portion of North Atlantic Deep Water (NADW), and the NADW itself. The topographic distribution of these water masses' strata was dictated by the cyclonic-anticyclonic baroclinic circulation that evolved from the anticyclone's collision to the east of Tamiahua. Between the cyclonic and anticyclonic domains, the maximum pressure differential of these water masses' core occurrences was 150 to 280 dbar. The topographic transition zone defined by these strata occurred between the cyclonic and anticyclonic domains and coincided unambiguously with the anticyclone's collision zone. Within the continental shelf, we identified low temperature (12°C) and low salinity (31) coastal waters contributed by river runoff. Driven by the northerly wind stress, these coastal waters were advected toward the south hugging the coastline. The coastal and continental shelf waters demarcated a sea surface temperature, salinity, and dissolved oxygen discontinuity region that coincided with the horizontal baroclinic flow transition zone associated to the anticyclone's collision.  相似文献   

12.
Five heat flow measurements were made in the Asiatic Mediterranean Sea; two in the Celebes Sea and three in the Sulu Sea. The mean of all five values of 2.0 cal/cm2 sec is significantly greater than the over-all mean heat flow value for the oceans and is close to the mean value for marginal seas. The measurement indicate that there may be a difference in the flow of heat through the two seas.Contribution of the Scripps Institution of Oceanography, new series.  相似文献   

13.
The primary productivity in coastal water adjacent to the Kuroshio off Shimoda was measured as part of the International Biological Program. The total amount of chlorophylla in the euphotic zone varied widely from 20 mg/m2 to 60 mg/m2 throughout the year and the maximum values were measured in early summer. These values were higher than those in the Kuroshio but agreed with those in the Oyashio. Vertical differentiation of photosynthetic characteristics was well developed and it was strongly related to the stratification of the water column. The light-saturated photosynthetic rate of surface phytoplankton varied from 5.8 mg C/(mg chl.h) in May to 2.0 mg C/(mg chl.h) in January. These rates were higher than those in the Kuroshio. The daily primary production was estimated by the chlorophyll method. Highest value was 0.5–1.5 g C/(m2day) in early summer and the lowest was 0.2 g C/(m2day) in winter. The primary productivity in the coastal water studied accorded fairly well with that in the Oyashio.Contribution No. 239 from Shimoda Marine Biological Station. This study is part of JIBP project entitled Studies on the Dynamic Status of the Biosphere, a Special Research Project supported by the Ministry of Education.  相似文献   

14.
Over 20 occurrences of discontinuous limestone blocks, locally called calcari aLucina, were mapped in the Tuscan—Romagna region of the northern Italian Apennines. The limestones, consisting of a variable mixture of authigenic carbonates (calcite, dolomite, and aragonite), sulfides (primarily pyrite), and allogenic silicates, occur in association with turbidite and hemipelagite units that were deposited in foredeep basins during early to late Miocene times. The limestone blocks are interpreted to represent relicts of carbonate buildups formed around methane-rich fluid vents on the basis of their (1) striking petrographic similarities to carbonates from cold vents in the modern oceans; (2) unique chemosynthetic-like fauna, and (3) anomalously negative 13C values ( 13C = – 16 to – 58 PDB). The contemporaneous tectonism of the Apennine orogeny is likely to be the primary cause for the expulsion of the methane-rich fluids to the seabed in a manner analogous to the fluid-flow processes occurring at modern accretionary prisms.  相似文献   

15.
Chlorophyll a concentrations of net (retained on 30 m mesh net) and total plankton in surface waters were determined along cruise tracks in an area of the northern North Pacific Ocean and the adjacent Bering Sea and the Gulf of Alaska from summer to autumn. Total chlorophyll a concentrations were high with a great areal and temporal variations in the western northern North Pacific compared to the eastern part. Chlorophyll a concentrations of netplankton varied from 0.001 to 0.230 g chl a l–1 (average, 0.029 ± 0.040 g chl a l–1), and showed a positive relation but a weak regression coefficient (r 2 = 0.551) against the "average total chlorophyll a" (average of total chlorophyll a at the beginning and at the end during sampling of netplankton). However there were several data points showing high "average total chlorophyll a" but low netplankton and vice versa. Average percentage share of netplankton in the total chlorophyll a was estimated to be as large as 4.26%.  相似文献   

16.
Primary productivity in the East China Sea and its adjacent area was measured by the13C tracer method during winter, summer and fall in 1993 and 1994. The depth-integrated primary productivity in the Kuroshio Current ranged from 220 to 350 mgC m−2d−1, and showed little seasonal variability. High primary productivity (above 570 mgC m−2d−1) was measured at the center of the continental shelf throughout the observation period. The productivity at the station nearest to the Changjiang estuary exhibited a distinctive seasonal change from 68 to 1,500 mgC m−2d−1. Depth-integrated primary productivity was 2.7 times higher in the shelf area than the rates at the Kuroshio Current. High chlorophyll-a specific productivity (mgC mgChl.-a−2d−1) throughout the euphotic zone was mainly found in the shelf area rather than off-shelf area, probably due to higher nutrient availability and higher activity of phytoplankton at the subsurface layer in the shelf area.  相似文献   

17.
The Mackenzie River estuary serves as an avenue for suspended particles to pass seaward. The horizontal distribution of surface suspended particles is compartible with the distribution of low-salinity surface waters. The water structure in the shelf area is highly stratified in summer due to a thin upper layer of low-salinity which has a high concentration of suspended particles. The concentration of suspended particles decreases with depth, but near the bottom a turbid layer had often been observed. It is likely that bottom current energy high enough to erode and maintain in suspension the bottom sediments below 15m in diameter does occur over this shelf area.  相似文献   

18.
The vertical distributions of suspended particles in Osaka Bay were measured by using anin situ beam attenuation meter. The concentration of suspended particles near the bottom increases rapidly toward the bottom where size of sediment is in a range of silt. The settling velocity of suspended particles near the bottom was measured with the use of a settling tower in the laboratory. The settling velocity of the suspended particles with diameter from 10 to 100m is 2×10–3cm s–1 to 5×10–2cm s–1. The density of the particles ranges from 2.0 to 1.1 and decreases with increasing particle diameter.  相似文献   

19.
Information on the distribution of dissolved Folin phenol active substances (FPAS) such as tannin and lignin in the seawater along the west coast of India is provided. Notable amounts of FPAS (surface concentrations: 80 g/l to 147 g/l and bottom concentrations: 80 g/l to 116 g/l) were detected in the seawater along the coast. The distribution pattern brings about a general depth-wise decrease. A seaward decrease was observed in the southern stations whereas reverse was the case in northern stations. A significant negative correlation was observed between FPAS concentration and dissolved oxygen in sub-surface samples. The appreciable amounts of FPAS detected in the coastal waters indicate the presence of organic matter principally originating from terrestrial (upland and coastal marsh) ecosystems in the marine environment. In this context, they may be used as tracers to determine the fate of coastalborn dissolved organic matter in the ocean and to determine directly the relationship between allochthonous and autochthonous organic matter.  相似文献   

20.
Significant fluctuations of the currents of the tidal frequencies have been detected in the Kuroshio Current northeast of Taiwan and in the Tokara Strait, with total amplitudes comparable to the mean surface current (about 4050 cm s−1). At the continental shelf the tidal signal varies considerably with distance from the axis of the Kuroshio. Tidal ellipses on the continental shelf consistently have major axes in the northwest-southeast direction. Because tidal signals in the Kuroshio regions have very small spatial scales, they may not be caused by the barotropic tide but the baroclinic tide. It is inferred that the Kuroshio interacts with the baroclinic tides over the continental slope.  相似文献   

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