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1.
A bottom station (lander) was installed onto the bottom at station 6214 during cruise 86 of R/V Professor Shtokman. Resulting from this installation, all the systems of the lander functioned within the predicted regimen. The potentialities
of the chamber experiment technique (the lander) seem to be preferable compared to those of the studies by means of the method
of interstitial waters, especially for the elements of variable valence. 相似文献
2.
With a view to a more complete understanding of the role of phyto-and zooplankton in biogeochemical cycles, the spatial distributions of Fe, Mn, Co, Ni, Cr, Cu, Cd, Pb, Zn, As, Hg, and C org in the White Sea seston (21 samples) collected in August 2004 during cruise 64 or R/V Professor Shtokman were studied. It was shown that the elements studied are accumulated in plankton with enrichment coefficients from 10 2 for Hg to 10 5 for Fe, as compared to seawater. The spatial distribution of microelements is determined by the sources of their supply and correlates with the distribution of the primary production and biomass of zooplankton. The increased values of microelement contents (excluding As) are characteristic of Dvina Bay, whereas the highest As concentrations were found in Kandalaksha Bay. 相似文献
3.
During a cruise aboard the R/V Hakuho-maru in the northwestern North Pacific in the summer of 1998 the particle number concentrations
and the major ionic components of size fractionated aerosols were measured to investigate the aerosol produced by marine biological
activity. Continuous low concentrations of nitrate (<1.8 nmol m −3), similar to the marine air background level, were found over the northwestern North Pacific (40–45°N) and the Sea of Okhotsk
(44–45°N). Over the Sea of Okhotsk, a high concentration of chlorophyll-a (5.4 mg m −3) in seawater was observed, and atmospheric concentrations of non sea-salt (nss-) sulfate (44 nmol m −3), methane sulfonic acid (MSA) (1.8 nmol m −3) and particle number in the size range of 0.1 < D < 0.5 μm (199 cm −3) were found to be 9, 7, and 2 times, respectively, higher than those in the background marine air. The increase in particle
number concentrations mainly in the size range of 0.2 < D < 0.3 μm was likely caused by the increase of biogenic sulfate over the high productive region of the Sea of Okhotsk. In
humid air conditions (R.H. > 96%), the increased biogenic sulfate that condensed the large amount of water vapor would not
have sufficient solute mass to activate as cloud condensation nuclei (CNN) and would remain as aerosol particles in the marine
air with frequent sea-fogs over the high productive region. Biogenic sulfate originating from dimethyl sulfide (DMS) would
gradually grow into the CCN size and continuously supply a great number of CCN to the marine air in the northwestern North
Pacific.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Nutrient regeneration and oxygen consumption after a spring bloom in Funka Bay were studied on monthly survey cruises from
February to November 1998 and from March to December 1999. A high concentration of ammonium (more than 4 μmol l −1) was observed near the bottom (80–90 m) after April. Phosphate and silicate gradually accumulated and dissolved oxygen decreased
in the same layer. Salinity near the bottom did not change until summer, leading to the presumption that the system in this
layer is semi-closed, so regenerated nutrients were preserved until September. Nitrification due to the oxidation of ammonium
to nitrate was observed after June. Nitrite, an intermediate product, was detected at 4–7 μmol L −1 in June and July 1999. Assuming that decomposition is a first order reaction, the rate constant for decomposition of organic
nitrogen was determined to be 0.014 and 0.008 d −1 in 1998 and 1999, respectively. The ammonium oxidation rate increased rapidly when the ambient ammonium concentration exceeded
5 μmol L −1. We also performed a budget calculation for the regeneration process. The total amount of N regenerated in the whole water
column was 287.4 mmol N m −2 in 4 months, which is equal to 22.8 gC m −2, assuming the Redfield C to N ratio. This is 34% of the primary production during the spring bloom and is comparable to the
export production of 25 gC m −2 measured by a sediment trap at 60 m (Miyake et al., 1998). 相似文献
5.
We have analyzed the specific features of the mineralogical composition of bottom sediments of Blagopoluchiya, Tsivol’ki, and Abrosimov bays and soils on Cape Zhelaniya and the coasts of Abrosimov and Stepovoi bays. The data were obtained during two scientific expeditions of the R/V Professor Shtokman in 2014 (cruise 128) and R/V Akademik Mstislav Keldysh in 2015 (cruise 63). These investigations revealed patterns in the transportation of terrigenous material in the coastal zone of the bays: a decrease in the share of nonclay minerals and an increase in that of clay minerals with distance from shore. The increase in kaolinite and smectite content in soil horizons is related to biochemical weathering, while illite is mainly formed as a result of physical weathering. 相似文献
6.
An analysis is presented of data on chlorophyll a concentrations of the total and the netplankton (>10 μm), determined either in April to June or in August to September from
48°N to 15°S along 175°E in the Pacific Ocean during 6 years by the NOPACCS (Northwest Pacific Carbon Cycle Study). Particular
attention was given to the variability of absolute concentrations of the netplankton chlorophyll a and their percentage shares of the total chlorophyll a concentration. Below 0.2 μg l −1 of surface total chlorophyll a, the netplankton chlorophyll a showed low percentage shares (such as 12.7% on average) with a large variation, but above 0.2 μg l −1 it was 35.9% on average with less variation, showing an accelerated increase at high total chlorophyll a concentrations. High netplankton chlorophyll a concentrations in surface waters were observed at high latitudes, in waters having high chlorophyll a concentrations at sub-surface depth, and in equatorial upwelling. The percentage shares of netplankton in the total chlorophyll
a in the euphotic zone were 8.5% and 25.9% above and below 0.2 μg l −1, respectively, although the data points scattered over a wide range (from 7.2% to 53.8%) depending on differences in water
masses, depths and seasons. High chlorophyll a concentrations and high percentage shares of netplankton corresponded to high ambient nitrate plus nitrite concentrations.
Integrated netplankton chlorophyll a concentrations in the euphotic zone varied from 0.7 to 19.5 mg m −2 in waters below 0.2 μg l −1 of surface total chlorophyll a, and from 2.0 to 29.5 mg m −2 above 0.2 μg l −1, and the percentage shares of netplankton for the former were 7.4% on average and 23.7% for the latter.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Using time series of hydrographic data in the wintertime and summertime obtained along 137°E from 1971 to 2000, we found that
the average contents of nutrients in the surface mixed layer showed linear decreasing trends of 0.001∼0.004 μmol-PO 4 l −1 yr −1 and 0.01∼0.04 μmol-NO 3 l −1 yr −1 with the decrease of density. The water column Chl-a (CHL) and the net community production (NCP) had also declined by 0.27∼0.48
mg-Chl m −2 yr −1 and 0.08∼0.47 g-C-NCP m −2 yr −1 with a clear oscillation of 20.8±0.8 years. These changes showed a strong negative correlation with the Pacific Decadal Oscillation
Index (PDO) with a time lag of 2 years (R = 0.89 ± 0.02). Considering the recent significant decrease of O 2 over the North Pacific subsurface water, these findings suggest that the long-term decreasing trend of surface-deep water
mixing has caused the decrease of marine biological activity in the surface mixed layer with a bidecadal oscillation over
the western North Pacific. 相似文献
8.
The optimum conditions were selected for the chromatographic separation of model mixtures of C 12–C 40
n-alkanes. For one of the samples of hydrothermal deposits, the extraction conditions of the hydrocarbons were studied and
a sample preparation procedure was selected. A procedure is proposed to determine the n-alkanes in samples of hydrothermal deposits by means of gas chromatography-mass spectrometry (GC-MS). The detection limit
for the n-alkanes amounted to 3 × 10 −9 to 10 −8% depending on the components. On the basis of the procedure proposed, the composition of the n-alkanes was studied in the samples of hydrothermal deposits collected at the Mid-Atlantic Ridge (the Broken Spur, Lost City,
and Rainbow fields). The analysis performed showed that the samples treated contained C 14-C 35
n-alkanes. The concentrations of the n-alkanes considered were rather low and varied from 0.002 to 0.038 μg/g. Hypotheses concerning the genesis of the n-alkanes identified were formed. 相似文献
9.
As a part of the JGOFS synthesis and modeling project, researchers have been working to synthesize the WOCE/JGOFS/DOE/NOAA
global CO 2 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.
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 O 2 (mg protein) −1 h −1 at 10°C] as compared with mixed copepods from 0 to 200 m depths [5.93 ± 1.66 μl O 2 (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 O 2 (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
11.
The δ 18O, δ 13C and trace element composition of pearls collected from Ago Bay, Japan, were investigated in order to evaluate biomineralization
in the cultured pearl oyster ( Pinctada fucata martensii). The oxygen isotopic data suggest that the pearls were produced around 23–24°C, mainly in June to early July, which is consistent
with their occurrence in the field. Therefore the pearls were produced under or close to isotopic equilibrium conditions,
although they showed high calcification rates (higher than 0.2–1.0 g cm − 2yr −1) under which, for example, coral skeletons (calcification rate ∼0.28 g cm − 2yr −1) often show non-equilibrium isotope partitioning. The δ 13C values were ∼− 2.9‰ lower than those calculated for offshore waters under equilibrium conditions. This may be due to low-δ 13C bottom waters resulting from the degradation of organic matter (OM) or to a contribution of low-δ 13C food. In the latter case, a simple mass balance calculation gives a respiration component of 14%. Twelve trace elements
of bulk pearl samples were classified into four groups on the basis of their enrichment/depletion patterns relative to seawater
and inter-element relationships: group 1, Co, Cr, Pb; group 2, Ba, Cs, U; group 3, Cu, Sn, V, and group 4, Mn, Rb, Mo. Comparison
with coral skeletons suggests that Ba and Mn (groups 2 and 4) were definitely much enriched in proteinaceous OM relative to
aragonite crystals in pearls and that V (group 3) in pearls showed only slight enrichment in the organicrich layer. By contrast,
the other elements showed small differences between both layers (enrichment factor of <3), suggesting that these elements
occur largely in aragonite crystals. 相似文献
12.
Ocean acidification damages calcareous organisms, such as calcifying algae, foraminifera, corals, and shells. In this study,
we made a device equipped with a Clark-type oxygen electrode and a pH-stat to examine how the most abundant calcifying phytoplankton,
the coccolithophorid Emiliania huxleyi, responded to acidification and alkalization of the seawater medium. When E. huxleyi was incubated at pH 8.2, close to oceanic pH, the medium was alkalized during photosynthesis, and the alkalization rate [determined
as μmol HCl added (mg Chl) −1 h −1] was identical to the activity of photosynthesis [determined as μmol O 2 evolved (mg Chl) −1 h −1]. When pH was maintained at 7.2 by the pH-stat, alkalization activity was stimulated and exceeded photosynthetic activity,
resulting in an increase in the ratio of alkalization to photosynthesis (Alk/PS). On the other hand, no alkalization and photosynthesis
were observed at pH 9.2. In contrast, acidification of seawater was observed in the dark because of the release of respiratory
CO 2 from cells at pH 8.2–9.2, but not at pH 7.2. When orthophosphate was rapidly depleted within a day in the batch culture,
intracellular calcification gradually increased, and both photosynthesis and alkalization decreased gradually. During the
period the Alk/PS ratio also decreased gradually. These results indicate that E. huxleyi possesses an ability to compensate for the acidification of seawater when photosynthesis is more actively driven than respiration.
These results suggest that the E. huxleyi cells may not be severely damaged by oceanic acidification during photosynthesis because of their homeostatic function to
avoid negative effects on cellular activity. Finally, we concluded that E. huxleyi cells possess a buffering ability to reduce acidification effects when photosynthesis is actively driven. 相似文献
13.
We present high-resolution isotopic records and cathodoluminescence studies of recently dead and live bivalve specimens from
cold seeps, in an attempt to reconstruct environmental conditions during organism growth, and thereby the possible variability
of fluid-venting activity at the seafloor. Shells of the burrowing lucinid Myrtea aff. amorpha were collected at three localities near actively venting methane seeps in the Eastern Mediterranean deep sea, using the Nautile
submersible during two French oceanographic cruises: from the Kazan mud volcano, in the vicinity of the Anaximander mounts
(MEDINAUT cruise, 1998), and from the central pockmark province and the Amon mud volcano of the Nile deep-sea fan (NAUTINIL
cruise, 2003). The oxygen and carbon isotope compositions of 18 shells from the various localities, and also from different
sites at the same locality show a rather strong scatter (1.8 < δ
18O‰ < 3.4; −10.2 < δ
13C‰ < 2.2), and values lower than those expected for carbonate precipitated at equilibrium with present-day bottom waters.
This means that warm methane-rich fluids were mixed with bottom seawater during precipitation of shell carbonates. We have
tried to determine ontogenetic age of two shells by using cathodoluminescence as a sclerochronological proxy, because the
direct counting of carbonate increments was not possible in these specimens. There is a relatively good correspondence between
cathodoluminescence trends and oxygen isotope profiles that might support the link between manganese incorporation during
growth and temperature. Eight specimens of lucinid shells were selected for high-resolution isotopic profiling. A few shells
exhibit decreasing δ
18O and δ
13C values from the umbo to the actively growing ventral shell margin, which can be attributed to the commonly observed physiologically
controlled deceleration of growth with increasing organism age, this metabolic effect corresponding to the increase of incorporation
of respiratory CO 2. A few shells exhibit high-frequency δ
18O variations with an amplitude of about 1.5‰ that might be related to temperature variations controlled by fluid-venting activity.
One shell from the pockmark province of the Nile deep-sea fan records a strong, sharp δ
13C decrease of about 9‰, and extending over a 5-mm interval in the shell that can be related to a major methane release event.
Another shell from the Kazan mud volcano exhibits a progressive increase of δ
13C values from −10‰ to 0‰ with age, which might indicate decreasing methane flow throughout the organism’s life. This study
has demonstrated that bivalve shells from deep-sea cold seeps represent good indicators of variability in seepage activity
of methane-rich fluids, at various scales in both space and time. Although the precise chronology of the observed events was
not established, because shell growth rate is not known in this case, this remains a priority for future studies in such environments. 相似文献
14.
Trawling of the bottom in the northeastern Kara Sea during cruise 125 of the R/V Professor Shtokman in 2013 recovered a block of cavernous, partly phosphatized carbonate rock consisting of biogenic carbonate material and partly crystallized diagenetic calcite. The fauna remains are mainly Oligocene–Pliocene planktonic and benthic foraminifers, with less common Oligocene–Miocene coccoliths and single wormlike organisms. Part of the phosphatized material in caverns is impregnated by manganese and iron oxides and enriched in heavy and trace metals. According to the oxygen isotopic composition, this rock formed under moderate temperature conditions. In terms of morphology, mineralogy, and the abundance of organic remains, the block is comparable to methanogenic carbonates found in other parts of the ocean, but shows no isotopically light carbon signatures typical of methane activity. This indicates the diversity of the carbon isotope composition of the Arctic carbonates. 相似文献
15.
The Coriolis effect on frontogenesis in the transitional region between the inner bay and the outer ocean is studied by running
several three-dimensional numerical experiments. The aim is to clarify what external parameters, including the transverse
scale of the basin, control the phenomena. The characteristics of the front in each case are described by defining three diagnostic
quantities, namely, the sharpness of the front, the intrusion of the front, and the buoyancy difference between the minimum
buoyancy region and the surrounding part, as the existence of the minimum buoyancy region is closely related to frontogenesis.
The three quantities are shown to depend on two nondimensional numbers, R
of (= f
−1
L
−2/3
F
b
1/3
: defined as flux Rossby number) and R
ef (= ν
v
−1
L
−2/3
F
b
1-3
H
2: defined as flux Reynolds number). 相似文献
16.
The light-saturated maximum value ( P
B
max) and initial slope (α) of the photosynthesis-irradiance (P-E) curve were examined in a warm streamer, a cold streamer and
a warm core ring off the Sanriku area in the subarctic western North Pacific Ocean during an ADEOS/OCTS Sanriku field campaign
in early May 1997. Both P
B
max and α were within the ranges of temperate populations. A regional difference was apparent in P
B
max: populations in the warm streamer tended to show higher value ranging between 1.92 and 4.74 mgC (mgChl a) −1h −1 than those in the cold streamer and the warm core ring (1.35–2.87 mgC (mgChl a) −1h −1). A depth variation was also observed in α in both the warm streamer and the warm core ring: shallow populations tended to
have lower α than deep populations. The depth variations in both P
B
max and α resulted in a lower light intensity of the light saturation in a deeper population than that of a shallower one. These
depth-related variations in the P-E parameters were likely a manifestation of “shade-adaptation” of photosynthesis. Photoinhibition
was not observed over in situ surface light intensity varying below ca 1600 μmol photon m −2s −1. Water-column primary productivity was biooptically estimated to be 233 to 949 mgC m −2d −1 using vertical distributions of the P-E parameters, chlorophyll a, phytoplankton light absorption and underwater irradiance. Applicability of surface data sets for estimation of water-column
productivity is discussed. 相似文献
17.
The summer distributions of planktonic microbial communities (heterotrophic and phtosynthetic bacteria, phtosynthetic and
heterotrophic nanoflagellates, ciliate plankton, and microphytoplankton) were compared between inner and outer areas of Lake
Sihwa, divided by an artificial breakwater, located on the western coast of Korea, in September 2003. The semienclosed, inner
area was characterized by hyposaline surface water (<17 psu), and by low concentrations of dissolved oxygen (avg. 0.4 mg L 1) and high concentrations of inorganic nutrients (nitrogenous nutrients >36 μM, phosphate <4 μM) in the bottom layer. Higher
densities of heterotrophic bacteria and nanoflagellates also occurred in the inner area than did in the outer area, while
microphytoplankton (mainly diatoms) occurred abundantly in the outer area. A tiny tintinnid ciliate, Tintinnopsis nana, bloomed
into more than 10 6 cells L 1 at the surface layer of the inner area, while its abundance was much lower (10 3-10 4 cells L 1) in the outer area of the breakwater. Ciliate abundance was highly correlated with heterotrophic bacteria (r = 0.886, p <
0.001) and heterotrophic flagellates (r = 0.962, p < 0.001), indicating that rich food availability may have led to the T. nana bloom. These results suggest that the breakwater causes the eutrophic environment in artificial lakes with limited flushing
of enriched water and develops into abundant bacteria, nanoflagellates, and ciliates. 相似文献
18.
Determinations of Chlorophyll a (Chl a) in eutrophic coastal marine waters were compared using N, N-dimethylformamide (DMF) and 90% acetone techniques. Measured
Chl a concentrations ranged from 0.89 to 10.65 μg l −1 for 90% acetone extracts and from 0.97 to 12.92 μg l −1 for DMF extracts, respectively, for 24 surface water samples from the Harima-nada, Seto Inland Sea, Japan. Chl a concentrations using DMF as a solvent were consistently higher than those found using 90% acetone ( p < 0.001, n= 24). Chl a is thus likely to be underestimated (by 13%) when 90% acetone is used for eutrophic waters.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
In stably stratified media with a Prandtl number Pr ≫ 1, vertical scales of the density ( ℓ) and horizontal velocity variation ( L) are quite different, ℓ/L = O(Pr −1/2) ≪ 1, and this influences the flow stability. In particular, shear flows without inflection points on the velocity profile
are unstable even in an ideal incompressible fluid. The maximum instability growth rate for sufficiently small ℓ/L is of the same order as in homogeneous mixing layers, with mainly three-dimensional rather than two-dimensional oscillations
increasing in a wide range of parameters. This paper focuses on the three-dimensional instability of such flows. It is shown
that the spectrum of unstable oscillations is essentially anisotropic in the case of a relatively weak stratification when
the bulk Richardson number J ≤ O[( ℓ/L) 3/2]. The results of the asymptotic analysis are illustrated by calculations for a model flow in a two-layer medium ( ℓ = 0) as well as for flows with values of ℓ/L corresponding to a temperature or salinity stratification of the water. 相似文献
20.
The determination of dissolved Mn in sea water was carried out using a Chelex 100 resin and graphite furnace atomic absorption
spectrophotometer. The nearshore surface layer waters off the Straits of Kii had the highest Mn concentration of 6.40 n mol
kg −1 at these stations. Mn concentration of intermediate and deep water off the Straits of Kii ranged between 0.18 and 1.42 n
mol kg −1. Mn concentration in deep and bottom waters at the Mariana Trough were between 0.71 and 2.48 n mol kg −1. Sharp increases of Mn concentration near the bottoms were observed at two stations near the hydrothermal vents of the central
ridge of the Mariana Trough. 相似文献
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