Mud and fluid migration in active mud volcanoes in Azerbaijan   总被引：7，自引：2，他引：7  

S. Planke  H. Svensen  M. Hovland  D. A. Banks  B. Jamtveit 《Geo-Marine Letters》2003,23(3-4):258-268

Mud volcanic eruptions in Azerbaijan normally last for less than a few hours, and are characterized by vigorous extrusion of mud breccias, hydrocarbon gases, and waters. Recent fieldwork and mapping on four active mud volcanoes show that dormant period activity ranges from quiet to vigorous flow of mud and fluids. Geochemical analyses of expelled waters show a wide range in solute concentrations, suggesting the existence of a complex plumbing system. The mud and fluids have a deep origin, but are sometimes stored in intermediate-depth mud chambers. A mixing model between deep-seated saline waters and shallow meteoric water is proposed.  相似文献   

Atmospheric forcing of fine-sand transport on a low-energy inner shelf: south-central Louisiana,USA     

David A. Pepper  Gregory W. Stone 《Geo-Marine Letters》2002,22(1):33-41

Hydrodynamic and sediment transport measurements from instrumentation deployed during a 54-day winter period at two sites on the Louisiana inner shelf are presented. Strong extratropical storms, with wind speeds of 7.8 to 15.1 m s^-1, were the dominant forcing mechanism during the study. These typically caused mean oscillatory flows and shear velocities about 33% higher than fair weather (averaging 12.3 and 3.2 cm s^-1 at the landward site, and 11.4 and 2.7 cm s^-1 at the seaward site, respectively). These responses were coupled with mean near-bottom currents more than twice as strong as during fair weather (10.3 and 7.5 cm s^-1 at the landward and seaward sites, respectively). These flowed in approximately the same direction as the veering wind, causing a net offshore transport of fine sand. Weak storms were responsible for little sediment transport whereas during fair weather, onshore sand transport of approximately 25-75% of the storm values appears to have occurred. This contradicts previous predictions of negligible fair-weather sediment movement on this inner shelf.  相似文献   

Thermal fluxes and stability of the upper boundary of deep near-bottom layer in the Black Sea     

V. M. Kushnir 《Physical Oceanography》1997,8(1):29-38

Experimentally-derived data are used to scrutinize structural peculiarities of the upper boundary of deep near-bottom layer in the Black Sea. Thermal fluxes through the layer’s upper boundary have been evaluated and compared with the geothermal fluxes. Although there is significant divergence between the individual evaluations, the quantities at issue generally agree with one another. It is shown that in evaluating thermal fluxes, it is necessary to consider fine structure of the differential-diffusive type. Stability of the upper boundary of the deep near-bottom layer has been examined, and diagrams of stability/instability resulting from the development of convection have been plotted. Translated by Vladimir A. Puchkin.  相似文献   

Primary production and plankton stocks in the Pacific Ocean and their seasonal variation according to remote sensing and field observations     

M.E. vinogradov  E.A. Shushkina  V.I. Vedernikov  N.P. Nezlin  V.I. Gagarin 《Deep Sea Research Part II: Topical Studies in Oceanography》1997,44(9-10)

Data collected from 20 years of observations by the P. P. Shirshov Institute of Oceanology (about 250 comprehensive ecosystem stations) are summarized to evaluate the primary production and biomass of the principal groups of plankton in the Pacific Ocean. The stations were classified into geographical regions according to satellite determined criteria. The areas of these regions were evaluated according to CZCS data from 1978 to 1986. The total value of primary production was evaluated as 26·9 Gt C year⁻¹. Taking the “bottle effect” correction into account, this value may be as high as 45.6 Gt C year⁻¹. Total biomass values of phytoplankton (134 Mt C), bacteria (86 Mt C), protozoa (26 Mt C) and mesoplankton (184 Mt C) were also calculated. Seasonal variabilities of all these values were remarkably insignificant.  相似文献   

Simulation ABC Model of Consumption of Natural Resources     

Timchenko  I. E.  Igumnova  E. M. 《Physical Oceanography》2002,12(4):209-219

The problem of simulation of possible scenarios of the development of processes running in ecological economic systems is studied as a part of the general problem of control over natural economic complexes. The consumption of mineral, food, and ecological resources is regarded as credits given by the society to the producer and then refunded as a part of his gains. If this nature-protective tax does not compensate the damage to the environment caused by production, then the debt of the producer (called accumulated credit) appears and, finally, the process of consumption of the resources is terminated. A universal simulation model is constructed by using a new method of adaptive balance of causes (ABC method). We present basic concepts of this method and some examples of application of the simulation model to the analysis of various scenarios of consumption of marine bioresources under variable economic conditions for a marine environment with variable assimilation capacity.  相似文献   

Vertical and lateral transport of organic carbon and the carbon budget in Santa Monica Basin, California     

M.I. Venkatesan  I.R. Kaplan 《Progress in Oceanography》1992,30(1-4)

The flux and compositions of solvent-extractable lipid fractions were measured in particulate matter collected periodically by moored sediment traps in the Santa Monica Basin from 1985–1988. The purpose was to assess the compositional changes during settling, the carbon dynamics in the basin and to estimate the impacts of energy-related by-products on the surface sediments. Sediment traps recorded consistently high lipid fluxes in the eastern slope relative to the central basin, reflecting elevated terrigenous carbon inputs possibly from land-based human activities. Generally, lipid fluxes decrease offshore but increase vertically with water depth below 500m, implying lateral transport of particles. The steep decline of flux in the top 500m of the water is related to the rapid decomposition and mineralization of the marine-derived cellular carbon compounds. Less than 5% of the marine lipid components reach the seabed. In contrast, preferential preservation of terrigenous lipid is clearly evident from the chemistry of deeper traps and surface sediments.The lateral transport of particles is reflected in the presence of higher plant-derived lignin phenols and sewage-derived coprostanol and epicoprostanol in the deep trap material as well as in surface sediment throughout the basin. Petroleum triterpanes characteristic of natural seepage also permeates through the entire basin. Based on the data collected from both the trap particulte matter and surface sediments, a carbon budget for the Santa Monica Basin has been constructed.  相似文献   

The Growth Rates of Raja Brachyura, R. Clavata and R. Montagui as Determined From Tagging Data     

Holden  M. J. 《ICES Journal of Marine Science》1972,34(2):161-168

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Lower Eocene red-clay sedimentation on the George Bligh/Rockall Channel     

A. Ferragne  C. Latouche  M. Parra 《Geo-Marine Letters》1984,4(2):77-82

Core 7710, recovered on the George Bligh/Rockall Channel, is composed of fine grained ocher-colored sediments rich in ferriferous smectite (montmorillonite, beidellite). These sediments were deposited during early Eocene in a shallow marine environment. Their mineralogic, chemical and isotopic constituents indicate subaerial weathering of lower Eocene intermediate igneous rocks (ferrodiorite, marscoiite) eroded from the still-emergent George Bligh and Rockall Banks. Lack of any post Eocene Sediments may be due to major morphologic and hydrologic changes forming sedimentation gaps.  相似文献   

Freezing as a method of sample preservation for the analysis of dissolved inorganic nutrients in seawater   总被引：1，自引：0，他引：1  

John E. Dore  Terrence Houlihan  Dale V. Hebel  Georgia Tien  Luis Tupas  David M. Karl 《Marine Chemistry》1996,53(3-4)

It is often desirable or necessary to store collected seawater samples prior to analysis for dissolved inorganic nutrients. It is therefore important to establish preservation and storage techniques that will ensure sample integrity and will not alter the precision or accuracy of analysis. We have performed a series of experiments on the storage of nutrient samples collected at the oligotrophic North Pacific benchmark Station ALOHA, using both standard autoanalyses and low-level techniques. Our results reveal that for oligotrophic oceanic waters, the immediate freezing of an unfiltered water sample in a clean polyethylene bottle is a suitable preservation method. This procedure is simple, it avoids potentially contaminating sample manipulations and chemical additions, and it adequately preserves the concentrations of nitrate + nitrite, soluble reactive phosphate, and soluble reactive silicate within a single water sample.  相似文献   

Comparison of cytochrome P450 in three butterflyfish species: Ecological implications of elevated CYP2B and CYP3A in Chaetodon capistratus     

Nicholas H. Vrolijk  Nancy M. Targett  Bruce R. Woodin  John J. Stegeman 《Marine environmental research》1995,39(1-4)

The relationship between cytochrome P450 and feeding on terpenoid-rich gorgonian corals was investigated in a species of tropical butterflyfish and compared with two other sympatric congeners that do not feed on gorgonians. Fish were collected from non-polluted waters in Belize and the levels of two cytochrome P450 isozymes (CYP2B and CYP3A) were immunoquantitated in addition to quantification of total P450. Chaetodon capistratus regularly feeds on gorgonian corals and has higher levels of total hepatic microsomal cytochrome P450 than C. ocellatus or C. striatus. The content of hepatic P450 (0.588–0.794 nmol mg⁻¹) in C. capistratus is among the highest ever reported in teleosts from non-polluted waters and is significantly greater than detected in C. ocellatus or C. striatus. Chaetodon capistratus also had a larger hepatic index (g liver per g fish) and more microsomal protein (mg protein per g liver), factors that translate into 3.3- to 8-fold more total P450 per g fish. Sexual differences in total P450 were observed between male and female C. capistratus, but not among the other species. The contents of proteins detected by immunoassay with polyclonal anti-scup P450B (CYP2B) and anti-human P4503A (CYP3A) were 2- to 10-fold and 2- to 20-fold greater, respectively, in C. capistratus than in the congeneric species. CYP2 and CYP3 gene families in mammals are thought to have evolved partially in response to dietary allelochemicals. These results suggest that these P450 isozymes may also be important in marine teleosts that feed on terpenoid-rich prey.  相似文献