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1.
The global VDM database, which was later supplemented by new determinations published in the world literature (a total of 3194 determinations), is used as the basis for addressing the VDM behavior in the Phanerozoic (0–542 Ma) and up to 580 Ma. The results revealed a positive linear trend to higher VDM values from 3.5 × l022 Am2 to 5.7 × l022 Am2. Against this background, fluctuations of the mean VDMs occur with a periodicity of about 40 Myr. In the Phanerozoic, prominent minima of the intensity are found in the time intervals of 510–520, 420–460, 340–370, 290–300, 240–270, 190–210, 165–140 Ma (chrons M17–M43), 130–120 Ma (chrons M2–M10), 100–110 Ma (chron C34), 75–85 Ma (chrons C33 and the beginning of chron C34), 70–60 Ma (chrons C31–C27), and 40–15 Ma (chrons C18–C5AD). The distribution of the VDMs appears to reflect the paleomagnetic field behavior and may be taken into account in a magnetization model for the reversely magnetized oceanic crust.  相似文献   

2.
两类La Nia季节演变过程的海气耦合特征对比   总被引：5，自引：4，他引：1  
利用1951—2010年逐月的HadISST海表温度资料、SODA次表层海温资料和NCEP/NCAR再分析资料等,对比分析了东太平洋(EP型)La Nia和中太平洋(CP型)La Nia的海气耦合特征在季节演变过程中的差异。EP La Nia海表温度异常中心在发展年夏季出现于南美沿岸,随后向西移动,盛期最大海表温度异常中心位于赤道东太平洋,而CP La Nia海温异常中心少动,基本维持在160°W附近,其强度更强,持续时间更长。受海温分布形态影响,热带大气对两类La Nia的响应非常不同,成熟期间CP型在中太平洋偏旱的强度和范围比EP型大,且略偏西。发展年夏、秋季,北半球位势高度响应较弱;冬季,负PNA位相易伴随两类La Nia出现,但异常活动中心的位置和强度不同,在北大西洋其大气响应几乎相反,这些差异会引起显著不同的区域气候异常。  相似文献   

3.
The petrophysical properties of sediment drill core samples recovered from the Sardinian margin and the abyssal plain of the Southern Tyrrhenian Basin were used to estimate the downhole change in porosity and rates of deposition and mass accumulation. We calculated how the deposited material has changed its thickness as a function of depth, and corrected the thickness for the compaction. The corresponding porosity variation with depth for terrigenous and pelagic sediments and evaporites was modelled according to an exponential law. The mass accumulation rate for the Plio-Quaternary is on average 4.8×104 kg m−2 my−1 on the Sardinian margin and for the Pliocene in the abyssal plain. In the latter area, the Quaternary attains its greatest thickness and a mass accumulation rate of 11–40×104 kg m−2 my−1. The basement response to sediment loading was calculated with Airy-type backstripping. On the lower part of the Sardinian margin, the basement subsidence rate due to sediment loading has decreased from a value of 300 m my−1 in the Tortonian and during the Messinian salinity crisis (7.0–5.33 Ma) to about 5 m my−1 in the Plio-Quaternary. In contrast, on the abyssal plain this rate has changed from 8–50 m my−1 during the period 3.6–0.46 Ma, to 95–130 m my−1 since 0.46 Ma, with the largest values in the Marsili Basin. The correlation between age and the depth to the basement corrected for the loading of the sediment in the ocean domain of the Tyrrhenian Basin argues for a young age of basin formation.  相似文献   

4.
 A 2D numerical thermal model for transform continental margin evolution is presented that calculates thermally driven uplift and subsidence profiles across the margin, for any margin segment assuming both regional and local isostasy. Lateral variations in the magnitude of continental uplift along the transform are predicted. For a margin with a length of 900 km, with a spreading rate of 1 cm yr-1, maximum continental uplift of 1300–1400 m is calculated, assuming local isostasy. Using a regional isostatic approximation, maximum uplift is reduced substantially to 335–470 m, and the exact magnitude, location, and timing of the maximum effect depends strongly on the assumption of a coupled or decoupled continent–ocean boundary. The length of time a margin point experiences continent–ocean shearing prior to ridge passing is also shown to be very significant. Received: 23 February 1995 / Revision received: 17 August 1995  相似文献   

5.
中西太平洋金枪鱼围网高产渔区年间变化及其原因分析   总被引：1，自引：1，他引：0  
金枪鱼类是中西太平洋海域重要的经济鱼种,其中鲣产量约占到总产量的50%。本研究利用1995-2010年16年的中西太平洋（20°S~20°N,120°E~155°W）鲣围网生产统计数据和Niño3.4海区（5°S~5°N,120°~170°W）海表温度异常数据,对这16年鲣产量最高的十大渔区（5°×5°）进行时空格局分析,讨论渔场分布差异及CPUE与ENSO指数的关系。结果表明:16年间十大作业渔区主要分布在5°S~5°N、130°~175°E区域,这十大渔区产量占总产量的比重达47.5%,其中5°S~0°、155°~160°E,0°~5°N、130°~135°E,0°~5°N、135°~140°E及5°S~0°、160°~165°E等4个渔区产量占高产渔区产量的比重均超过10%,是中西太平洋重要的鲣产区。高产渔区的分布受海表温度影响较大,在厄尔尼诺时期,高产渔区分布明显偏东,主要分布在155°~180°E海域;在拉尼娜时期,高产渔区分布明显偏西,主要分布在130°~160°E海域。  相似文献   

6.
We make an attempt to answer the following question: how a natural stationary system formed by a layer and an interface “selects” a unique set of governing parameters from a great number of possible collections under the conditions of double-diffusion layer convection (e.g., for the bottom boundary layer in the Black Sea)? As the “rule of selection,” we use the principle of minimum entropy production for systems close to the state of thermodynamic equilibrium. In the process of solution of the problem, the system is regarded as a heat engine. The proposed approach is reduced to a simple procedure of application of the principle of minimum entropy production to the analyzed case. The combined analysis of the theoretical results, the data of deepwater field measurements in the Black Sea, and the results of laboratory experiments leads us to the conclusion that, most likely, the stationary system “selects” its governing parameters according to the Prigogine–Glansdorff principle. The density ratio (approximately equal to three for the stationary case) proves to be the key parameter of the system. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 16–25, January–February, 2009.  相似文献   

7.
The considered area of the Russian sector of the Arctic Basin was characterized in August–September of 2008 by the wide horizontal and vertical variability of the concentrations of dissolved and particulate organic matter (OM), as well as of its elemental and biochemical composition. The concentration ranges amounted to 51.6–434 and 2.2–18.6 μM, respectively, for the dissolved and particulate Corg; up to 1.9–30.2 μM for Norg; and up to 0.08–1.53 μM for Porg. The maximum values were characteristic for the Russian Arctic shelf. The analysis of the authors’ and published data showed that a pronounced accumulation of OM, mainly in the dissolved form, took place in the Arctic Basin within the past 12 years. The concentrations of dissolved OM were higher in the western sector of the Russian Arctic than those in the eastern sector. The main biochemical components in all the waters constituting the Arctic Ocean are carbohydrates and lipids for dissolved OM and proteins and carbohydrates for particulate matter.  相似文献   

8.
 Near-surface sediment geoacoustic and physical properties were measured from a variety of unconsolidated carbonate sediments in the Lower Florida Keys. Surficial values of compressional and shear speed correlate with sediment physical properties and near-surface acoustic reflectivity. Highest speeds (shear 125–150 m s-1; compressional 1670–1725 m s-1) are from sandy sediments near Rebecca Shoal and lowest speeds (shear 40–65 m s-1; compressional 1520–1570 m s-1) are found in soft, silty sediments which collect in sediment ponds in the Southeast Channel of the Dry Tortugas. High compressional wave attenuation is attributed to scattering of acoustic waves from heterogeneity caused by accumulation of abundant shell material and other impedance discontinuities rather than high intrinsic attenuation. Compared to siliciclastic sediments, carbonate sediment shear wave speed is high for comparable values of sediment physical properties. Sediment fabric, rather than changes due to the effects of biogeochemical processes, is responsible for these differences.  相似文献   

9.
Based on the scatterometer QuickScat wind data and the water-leaving radiances from the ocean color scanner SeaWiFS data for 2000–2004, we composed a pair of mean annual images of a testing site in the South Caspian Sea under conditions of west-bound and east-bound winds corresponding to the offset and onset state of the shallows in the east of the testing site. It was established that both the “offset” and “onset” radiances grow shorewards, but the former becomes about twice as large as the latter in the middle of the shallows with 10–15 m of water, while their difference tends to zero at the seaward and coastal boundaries of the shallow. These and other findings are hypothetically attributable to the inclination of the sea floor of the shallows, due to which the surfacing of bottom sediments resuspended by the drift current takes less time under the “offset” wind conditions than under the “onset” ones. The study’s results indicate that the effect of the bottom sediments resuspension upon the structure of the images of the marine shallows is universal in character and needs to be taken into account to improve the bio-optical algorithms for estimating the admixtures in the thickness of the shallows from the satellite data.  相似文献   

10.
Activities of the naturally occurring radium nuclides 228Ra, 226Ra, 224Ra and 223Ra were determined in waters of the open German Bight and adjacent nearshore areas in the North Sea, in order to explore the potential use of radium isotopes as natural tracers of land–ocean interaction in an environment characterised by extensive tidal flats, as well as riverine and groundwater influx. Data collected at various tidal phases from the Weser Estuary (228Ra: 46.3 ± 4.6; 226Ra: 17.1 ± 1.1; 224Ra: 26.1 ± 8.2 to 36.5 ± 6.1; 223Ra: 1.8 ± 0.1 to 4.0 ± 0.4), tidal flats near Sahlenburg (228Ra: 39.3 ± 3.8 to 46.0 ± 4.5; 226Ra: 15.5 ± 1.5 to 16.5 ± 1.7; 224Ra: 34.3 ± 2.2 to 85.3 ± 6.3; 223Ra: 3.6 ± 0.5 to 8.0 ± 1.2), freshwater seeps on tidal flats near Sahlenburg (228Ra: 42.1 ± 4.1; 226Ra: 21.3 ± 2.2; 224Ra: 5.1 ± 0.9; 223Ra: 2.6 ± 1.3) and also in permanently inundated parts of the North Sea (228Ra: 23.0 ± 2.3 to 28.2 ± 2.8; 226Ra: 8.2 ± 0.8 to 11.8 ± 1.2; 224Ra: 3.1 ± 1.0 to 10.1 ± 0.9; 223Ra: 0.1 ± 0.02 to 0.9 ± 0.05; units: disintegrations per minute per 100 kg water sample) reveal that, except for the fresh groundwater, the potential end-members of nearshore water mass mixing have quite similar radium signatures, excluding a simple discrimination between the sources. However, the decreasing activities of the short-lived 224Ra and 223Ra isotopes recorded towards the island of Helgoland in the central German Bight show a potential to constrain fluxes of land-derived material to the open North Sea. The largest source for all radium isotopes is generally found on the vast tidal flats and in the Weser Estuary. Future work could meaningfully combine this so-called radium quartet approach with investigations of radon activity. Indeed, preliminary data from a tidal flat site with fresh groundwater seepage reveal a 222Rn signal that is clearly lower in seawater.  相似文献   

11.
On the basis of processing of the oceanographic data accumulated for the water area of the North Atlantic in 1950–1999 (∼500,000 stations), we study seasonal and interannual variations of the principal characteristics of pycnocline within the range of σt = 25.5–27.5 conventional density units. It is shown that the interannual oscillations of these characteristics in the entire analyzed layer can be regarded as a superposition of fluctuations with periods from 2–3 to 10–12 yr. The typical ranges of these fluctuations for the depths of occurrence of isopycnic surfaces and the corresponding temperature and salinity are equal to 20–25 m, 1–1.5°C, and 0.25‰, respectively. The intensification of atmospheric circulation at middle latitudes is accompanied by the simultaneous deepening of the pycnocline and its heating in the central part of the North Subtropical Anticyclonic Gyre. At the same time, the process of weakening of the atmospheric circulation leads to the rise of the pycnocline and its cooling. The complete cycle of interaction of the North-Atlantic Oscillation with the anomalies of isopycnic characteristics (with regard for the period of their advection) is equal to ∼6–8 yr. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 29–48, March–April, 2007.  相似文献   

12.
An analysis is presented of snapshot data (eastward and northward velocity components: u and v; tracer such as potential temperature: τ) from an eddy-resolving (Rgrid: 1/12°) ocean model experiment, in order to explore a method for improving eddy-permitting model performance. Horizontal 3 × 3 R-grid averages give the eddy-permitting grid (P-grid: 1/4°) variables: 〈u〉, 〈v〉, and 〈τ〉, where 〈〉 denotes the spatial P-grid scale average. The difference between the horizontal tracer flux across the boundary face of a P-grid and that across the corresponding faces of R-grids is estimated as F2E. It is found that the correlations among the gradients of u, v, and τ give a good approximation F2C to the estimated flux F2E. The approximated flux is a function of these gradients and the grid size. A method is presented for implementing the F2C for density to an eddying ocean model as an additional advection. Practical experiments were conducted with a realistic configuration. It is shown that the zonal mean isotherms in the Kuroshio extension region are more flattened in the run using the proposed method than in another run using the conventional horizontal biharmonic operator, suggesting that the additional flux correction leads to an enhancement of sub-basin scale mixing.  相似文献   

13.
The first empirical orthogonal functions (EOF1s) of surface-air temperature fluctuations for Russia and its neighboring states within the period 1950–2005 are analyzed. The spatial distribution of the EOF1, the first principal components (PC1s) of the observed air temperature (averaged over the summer, July, December–March, and individual winter months), and their time variations (including trend parameters, some spectral characteristics, and the quantitative indices of relation to circulation indices (on the basis of multiple step-by-step regression)) are considered. Significant seasonal differences have been revealed: the winter air-temperature fluctuations are characterized by a higher (when compared to summer) spatial coherence, especially in the latitudinal direction. The EOF1 of the winter air temperature (averaged over December–March) describes its fluctuations for almost all of Russia; in this case, no less than 70% of the PC1 variability is due to variations in several circulation indices; the main contribution (60%) is made by both the North Atlantic Oscillation (NAO) and Scandinavian (SCAND) indices. On the whole, over the periods 1951–2005 and 1971–2005, the NAO contribution exceeds the SCAND contribution to the winter temperature variability; the NAO is associated with a more rapid increase in air temperature in 1968–1997 and with the 1971–2005 trend. In 1951–1970 the main contribution to air temperature fluctuations was made by SCAND; the SCAND contribution exceeds the NAO contribution in the periods 1951–2005 and 1971–2005. The 1971–2005 and 1968–1997 temperature trends are completely described by variations in the NAO (70%) and SCAND (30%) indices for January and February.  相似文献   

14.
The underwater vocalizations of the beluga whale summering in Onega Bay (64°24′N, 35°49′E) were recorded in June–July of 2008. The vocalizations were classified into five major whistle types, four types of pulsed tones, click series, and noise vocalizations. To determine the relationship between the behavioral activity and the underwater vocalizations, a total of fifty-one 2 minute-long samples of the audio records were analyzed in the next six behavioral contexts: directional movements, quiet swimming, resting, social interactions, individual hunting behavior, and the exploration of hydrophones by beluga whales. The overall vocalization rate and the percentage of the main types of signals depend on the behavior of the belugas. We suggest that one of the whistle types (the “stereotype whistle”) is used by belugas for long-distance communications, while other whistle types (with the exception of “squeaks”) and three types of pulsed tones (with the exception of “vowels”) are used for short distance communication. The percentage of “squeaks” and “vowels” was equally high in all the behavioral situations. Thus, we assume that “squeaks” are contact signals. “Vowels” have a specific physical structure and probably play a role in identification signals. A high rate of the click series was observed in the process of social interactions.  相似文献   

15.
印度洋鲣鱼围网资源渔场时空变化及其与ENSO的关系   总被引：1，自引：0，他引：1  
鲣鱼是印度洋重要的金枪鱼种类之一,其资源丰度与海洋环境关系密切。本研究根据1980-2010年印度洋鲣鱼围网生产统计数据以及海洋环境与厄尔尼诺-南方涛动（ENSO）指数等,对印度洋鲣鱼围网资源渔场时空分布,以及厄尔尼诺年和拉尼娜年等不同尺度气候条件下鲣鱼资源渔场时空变动及其与海洋环境因子的关系进行分析。研究结果表明,1980-2010年印度洋鲣鱼围网渔获量基本保持不断增加的趋势,但CUPE值变化幅度较大,最低仅为0.68 t/d（1997年）,最高达到1.58 t/d（2002年）。同时鲣鱼资源丰度（CPUE）与Ni?o3.4区指数存在显著的负相关关系,即厄尔尼诺年,鲣鱼CPUE 随之下降,拉尼娜年,CPUE 随之上升。ENSO现象对鲣鱼渔场时空分布也有显著影响,厄尔尼诺发生时,鲣鱼围网作业渔场重心会向东、向北移动,而拉尼娜年则向西、向南移动。  相似文献   

16.
Compared to oxygen isotopes, the carbon isotope composition of biogenic carbonates is less commonly used as proxy for palaeoenvironmental reconstructions because shell δ13C is derived from both dissolved inorganic (seawater) and organic carbon sources (food), and interactions between these two pools make it difficult to unambiguously identify any independent effect of either. The main purpose of this study was to demonstrate any direct impact of variable food supply on bivalve shell δ13C signatures, using low/high rations of a 13C-light mixed algal diet fed to 14-month-old (adult) cultured Japanese Crassostrea gigas under otherwise essentially identical in vitro conditions during 3 summer months (May, June and July 2003, seawater temperature means at 16, 18 and 20 °C respectively) in experimental tanks at the Argenton laboratory along the Brittany Atlantic coast of France. At a daily ration of 12% (versus 4%) oyster dry weight, the newly grown part of the shells (hinge region) showed significantly lower δ13C values, by 3.5‰ (high ration: mean of −5.8  ± 1.1‰, n = 10; low ration: mean of −2.3  ± 0.7‰, n = 6; ANOVA Scheffe’s test, p < 0.0001). This can be explained by an enhanced metabolic activity at higher food supply, raising 13C-depleted respiratory CO2 in the extrapallial cavity. Based on these δ13C values and data extracted from the literature, and assuming no carbon isotope fractionation between food and shell, the proportion of shell metabolic carbon would be 26  ± 7 and 5  ± 5% for the high- and low-ration C. gigas shells respectively; with carbon isotope fractionation (arguably more realistic), the corresponding values would be 69  ± 14 and 24  ± 9%. Both groups of cultured shells exhibited lower δ13C values than did wild oysters from Marennes-Ol éron Bay in the study region, which is not inconsistent with an independent influence of diet type. Although there was no significant difference between the two food regimes in terms of δ18O shell values (means of 0.1  ± 0.3 and 0.4  ± 0.2‰ at high and low rations respectively, non-significant Scheffe’s test), a positive δ13C vs. δ18O relationship recorded at high rations supports the interpretation of a progressive temperature-mediated rise in metabolic activity fuelled by higher food supply (in this case reflecting increased energy investment in reproduction), in terms not only of δ13C (metabolic signal) but also of δ18O (seawater temperature signal). Overall, whole-shell δ18O trends faithfully recorded summer/winter variations in seawater temperature experienced by the 17-month-old cultured oysters.  相似文献   

17.
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 CO2. 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   

18.
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   

19.
To date, coral proxy studies have proved largely unsuccessful in reconstructing temporal variability of the Indian monsoon system in the NW Indian Ocean. In a recent publication in this journal, Storz and Gischler demonstrated that extension rates in corals can be used to fill this gap. Those authors found a link between decadal and interannual variations of the SW monsoon current velocities and Porites lutea extension rates in the lagoon of Rasdhoo Atoll (4°N/73°W) in the central Maldives for the period 1917–2007. This sister paper shows that this extension-rate record can be used to reconstruct decadal variations of summer monsoon rainfall over peninsular India and adjacent areas. The amount of monsoon rainfall and current velocities during summer are both affected by the strength of the Indian monsoon system. Assessments of coral extension rates and the mean May–September All India Monsoon Rainfall index, a measure of monsoon strength over the Indian subcontinent, revealed a significant spectral coherence within periods of 18–19 and 6–7 years. Almost 92% of variance is shared between both time series in the former band, and 85% in the latter. A correlation between the 5-year running mean extension rate and rainfall records from the Western Ghats (grid of 73–76°E/13–15°N) is significant especially for 1958–2006 (r = −0.82, p < 0.05). These findings imply that coral growth characteristics can serve as a new marine archive to reconstruct past variations of the Indian monsoon system on interannual to decadal timescales.  相似文献   

20.
Deep-water experiments on the transportation of collected samples of methane hydrates from a lake’s bottom to a support container were carried out as part of the MIRY na Baikale (2008–2009) expedition run by the Russian Academy of Sciences. High pressures and low temperatures are necessary for gas hydrates stability. As a sample of the hydrate is lifted to the water’s surface, it intensively decomposes into water and methane gas. To reduce the decomposition, we used a container in which the hydrate’s sample occurs in a gas medium rather than in water, which results in a substantial reduction in the rate of the heat exchange. At that, the gas for the container’s filling was supplied by the hydrate itself due to its partial decomposition. To estimate the method’s efficiency, we observed the hydrate’s decomposition during lifting from a depth of 1400 m using different transportation techniques such as gas- or water-filled containers or fixing the sample in the manipulator’s arm of the submersible. The sample in the gaseous medium was the only one that was safely delivered on board the support container, while the two others completely decomposed during the transportation. It is remarkable that all the samples started to decompose simultaneously at a depth of 380 m but their decomposition occurred at different rates.  相似文献   

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