Scientific tools to support the practical implementation of ecosystem-based fisheries management   总被引：5，自引：1，他引：5  

Smith  A. D. M.; Fulton  E. J.; Hobday  A. J.; Smith  D. C.; Shoulder  P. 《ICES Journal of Marine Science》2007,64(4):633-639

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Paleomonsoon precipitation deduced from a sediment core from the equatorial Indian Ocean     

M. Tiwari  R. Ramesh  B. L. K. Somayajulu  A. J. T. Jull  G. S. Burr 《Geo-Marine Letters》2006,26(1):23-30

Rapid shifts in past climate recorded in polar ice sheets have elicited various explanations relating to either thermohaline circulation changes by ice-rafting or natural greenhouse gas concentrations modulated by climatic conditions in the tropics. To compare the tropical paleoclimate record with the polar record, one must choose sediment cores from highly productive ocean regions. Necessarily, such regions reflect the wind records in the tropics, because high productivity is associated with upwelling driven by winds. Comparing tropical precipitation records with high-latitude records is, however, a more difficult task because sediments recording paleoprecipitation usually have low sedimentation rates, and offer coarser resolution relative to polar ice cores. Here, we present δ ¹⁸O data of three planktonic species of Foraminifera (a proxy for precipitation) from such a sediment core, spanning the past 35 ka for the equatorial Indian Ocean, which falls under the southwest monsoon (SWM) realm. Results show that minimum SWM precipitation occurred at the Last Glacial Maximum, with a subsequent increase at Termination IA. During the Holocene, SWM precipitation intensified uniformly up to the core top (∼2.2 ka b.p.), as revealed by generally decreasing δ ¹⁸O values. Variations in precipitation are consistent with climate changes recorded in polar ice sheets. Although the different resolutions of the two records preclude a rigorous comparison, abrupt cooling/warming events appear to be accompanied by sudden reduction/enhancement in (SWM) rainfall. Thus, mechanisms with time scales much shorter than a millennium, such as natural greenhouse warming (e.g., CH₄ concentration), controlled by emissions from the tropics, could have played a major role in high-latitude climate change.  相似文献   

The Potential for Environmentally Sound Development of Marine Deposits of Potassic and Phosphatic Minerals Offshore, Southern Africa     

S. K. P. Coles  C. I. Wright  D. A. Sinclair  P. Van den Bossche 《Marine Georesources & Geotechnology》2002,20(2):87-110

Extensive potassium and phosphorous-rich mineralization occurs on the outer continental shelf of the southern and west coasts of South Africa and Nambia. This article reviews the potential of exploiting these deposits in an environmentally sound manner for the manufacture of fertilizer. At present, reserves of potash and phosphate fertilizer are exploited from terresterial deposits, the majority being surface mined. The use of fertilizer in South Africa has shown no growth in the past 13 years, and, in some years, usage has even declined. On average, over the last decade, South Africa has consumed 2 million Mt of fertilizer (including nitrogen) per annum, the vast majority of phosphate fertilizer being produced by FOSKOR from the Phalaborwa Igneous Complex. Potash fertilizer is imported into South Africa. Although fertilizer consumption is expected to decrease in the short-term, there are good future prospects for the domestic and international fertilizer market. Considerable research into both glauconitic (containing K 2 O) and phosphatic deposits along the southern African continental shelf indicate that these sedimentary deposits have a complex genesis and mineralization. Of the total K 2 O reserves of 1300 million Mt on the southern African margin, 1000 million Mt is located off the southern African west coast, and the remainder situated on the Agulhas Bank. The largest glauconite concentration ( ±300 million Mt K 2 O) off southern Africa lies west of Saldanha Bay, South Africa. The distribution of P 2 O 5 off southern Africa is dominated by the vast deposit between Walvis Bay and Luderitz, Nambia. This reserve is estimated to contain 1000 million Mt of greater than 5% P 2 O 5 in a relatively small area of about 10000 km2. The phosphorite deposit south of Saldanha Bay constitutes a reserve of ±3500 million Mt of apatite and the deposit on the Agulhas Bank comprises 5500 million Mt. The phosphate deposit off Saldanha Bay occurs as an extensive, low to medium grade deposit. Although vast resources of potash and phosphatic minerals occur along the southern African outer continental shelf the expensive nature of marine exploitation may render most of these deposits, especially the phosphates, subeconomic. The low price of fertilizer andextensive natureontheonland deposits, although confined to asmallnumber of countries, mean that it will not be financially viable to extract these deposits. Assuming high grade glauconitic sand with the right composition can be located, the high market price indicates good future prospects for these potash deposits.  相似文献   

Fish-farming effects on benthic community structure in coastal sediments: analysis of meiofaunal recovery   总被引：8，自引：0，他引：8  

Mazzola  A.; Mirto  S.; La Rosa  T.; Fabiano  M.; Danovaro  R. 《ICES Journal of Marine Science》2000,57(5):1454-1461

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Frequency dependence of sound backscattering from live individual zooplankton     

Chu  D.; Stanton  T. K.; Wiebe  P. H. 《ICES Journal of Marine Science》1992,49(1):97-106

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The influence of the Sabatayn Evaporites on the hydrocarbon prospectivity of the Eastern Shabwa Basin, Onshore Yemen     

T. Richard Seaborne 《Marine and Petroleum Geology》1996,13(8):963-972

The Shabwa Basin is the northeastern extension of the Marib-Al Jawf-Shabwa system of Mesozoic grabens, located onshore in the Republic of Yemen. An evaporitic sequence with an estimated maximum depositional thickness of 300 metres was deposited during the Tithonian. It is designated the Sabatayn Formation and exerts significant control on most of the play elements in the principal hydrocarbon play systems anticipated in the northeastern part of the basin. Migration of hydrocarbons from pre-salt source rocks into intra-and post-salt reservoirs is restricted by the evaporites. Localised heat flow perturbations introduced by the salt, increase the maturity of post-salt source rocks. Post and intra-salt reservoirs are structured by listric faulting on a salt detachment, salt pillowing due to post-depositional loading, by local salt dissolution and by late folding due to gravity sliding of the post-salt section on a salt detachment. Early dissolution and reprecipitation of salt is responsible for occlusion of porosity in intra-salt clastic reservoirs.  相似文献   

Organo- and lithofacies of glacial-interglacial deposits in the Norwegian-Greenland Sea: Responses to paleoceanographic and paleoclimatic changes     

T Wagner  R Henrich 《Marine Geology》1994,120(3-4):335-364

Based on a multiparameter approach a combined litho- and organofacies concept was developed for glacial and interglacial sediment sections along an E-W transect through the central part of the Norwegian-Greenland Sea (NGS).

Modern and past surface water regimes are clearly displayed by specific litho- and organofacies patterns. Interglacial conditions reveal specific Atlantic water associated lithofacies (A and B3) in the eastern and central sector of the Norwegian-Greenland Sea (NGS). Corresponding interglacial organofacies in general are not well correlated to lithofacies due to strong diagenetic degradation of labile, e.g. autochthonous organic matter (OM). While in near-surface sediments a marine-dominated organofacies (I-1) is preserved under Atlantic water masses, this correlation is not evident for lower Holocene and Isotope Stage 5 deposits. However, during Isotopic Event 5.5.1 increased proportions of marine OM are recorded in a high accumulating core on the Vøring Plateau. Glaciomarine background lithofacies (B and C) indicate minor input of ice rafted debris (IRD) and seasonal variable sea-ice cover. Corresponding organofacies (II-1, non-oxidized and II-2, oxidized) are dominated by allochthonous OM. Most spectacular are glacial diamictons (Lithofacies E and F) evidencing short-term sediment pulses due to a sudden disintegration of far advanced tide water ice margins on the outer shelves. These diamictons bear specific organofacies (III-1 and III-2) with a clear predominance of terrigenous and reworked OM.

Some of the diamictons seem to occur contemporaneous with the so called “Heinrich-layers” H1 and H2, suggesting a common trigger-mechanism for the almost simultaneous disintegration of huge continental ice masses along the shelves of North America and the eastern margin of the NGS.

Application of a combined organo- and lithofacies concept provides essential information on spatial and temporal variations of water mass characteristics, the oceanic effects of ice sheet dynamics and circulation models.  相似文献   

Current and temperature observations in the east Tsushima channel and the Sea of Genkai     

S. Mizuno  K. Kawatate  T. Miita 《Progress in Oceanography》1986,17(3-4)

Data on the Tsushima Current and its neighboring coastal current are analyzed to examine short-term variability of the currents and storm events due to typhoons. A three current-meter array was deployed in a strong current region of the east Tsushima channel during summer in 1983 and 1984, and other two current-meter arrays in the eastern coastal area of the channel (the Sea of Genkai) in the summer and autumn in 1983. The observations of coastal current show that the kinetic energy of the subtidal current component was larger in summer than in autumn by a factor of about 2. A comparison of the wind stresses and the estimated values of mixed layer depth in the summer and autumn season suggest that this seasonal change is closely associated with that of the mixed layer depth rather than with that of the wind stress. The Tsushima Current was greatly influenced by two storm events: its speed increased by a factor of 2 in one event and decreased to nearly zero in the other. Such a large variation of mean current during the storm was observed only for the Tsushima Current and not for the coastal current, suggesting that the Tsushima Current may temporarily change its regular course as a result of a storm.  相似文献   

ICES baseline survey of trace metals in European shelf waters   总被引：1，自引：0，他引：1  

Balls  P.; Cofino  W.; Schmidt  D.; Topping  G.; Wilson  S.; Yeats  P. 《ICES Journal of Marine Science》1993,50(4):435-444

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Impact of offshore oil production installations on the benthos of the North Sea   总被引：3，自引：0，他引：3  

Kingston  P. F. 《ICES Journal of Marine Science》1992,49(1):45-53

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