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241.
南沙群岛海区晚第四纪碳酸盐沉积 总被引:1,自引:0,他引:1
本文研究了五个柱状沉积物的碳酸盐沉积。根据沉积物的陆源碎屑和生物骨屑CaCO3沉积作用的特点,把本区沉积物分为五种沉积类;碳酸盐生物组成的门类较多,以有孔虫为主,其次为珊瑚,腹足类等;碳酸盐矿物以低镁方解石为主,还有高镁方解石和文石;与沉积物中CaCO3有关的化学元素10多种。这些元素和稀土元素的含量,比值等,是区分礁相,礁体过渡带和非礁相的标志。所有这些碳酸盐沉积作用的特点表明,区内存在着五种沉 相似文献
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243.
A Stable Carbon Isotope Study of the Food-web in a Freshwater-deprived South African Estuary, with Particular Emphasis on the Ichthyofauna 总被引:1,自引:0,他引:1
The importance of macrophytes as food sources for estuarine nekton is unclear. Previous carbon isotope investigations in the macrophyte-dominated, freshwater-deprived Kariega Estuary showed that the bivalveSolen cylindraceusdid not utilize the dominant estuarine macrophytes found within the estuary as a primary food source. This finding prompted questions as to what the nekton of this estuary utilize as primary energy sources. δ13C analyses of the principal autochthonous and allochthonous primary carbon sources, as well as the dominant invertebrate and fish species, indicate that there are two main carbon pathways within the Kariega Estuary. The littoral community, which incorporates the majority of crustaceans, gobies, mullet and a sparid, utilizes δ13C enriched primary food sources namelySpartina maritima,Zosteracapensis and epiphytes. The channel fauna, which includes the zooplankton, zooplanktivorous and piscivorous fish, utilizes a primary food source depleted in δ13C, which is most likely a mixture of phytoplankton, terrestrial plant debris and C4macrophyte detritus. The C3saltmarsh macrophytesSarcocornia perennisandChenolea diffusa, as well as benthic microalgae, appear to be less important as primary food sources to the nekton of the Kariega Estuary. 相似文献
244.
Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: 3. Secondary Inhabitants
Abstract. Vacated microborings in periostracum of live mussels of the Florida Escarpment redox community (depth of 3266 m) become a habitat for a prolific secondary microbiota consisting of a variety of prokaryotic and a few eukaryotic organisms. Periostracum surface is also colonized by diverse microorganisms, dominated by presumed chemolithotrophic bacteria with stacks of intracellular lamellae. Unlike sheltered microflora within borings, the surface community is heavily grazed upon by numerous archaeogastropods and ciliates. 相似文献
245.
Ecosystem effects of fishing in kelp forest communities 总被引:6,自引:0,他引:6
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247.
In-Seong Han Koichiro Kamio Takeshi Matsuno Atsuyoshi Manda Atsuhiko Isobe 《Journal of Oceanography》2001,57(2):235-249
Relation between internal waves with short time scale and density distribution near the shelf break in the East China Sea is studied utilizing moored current meters, thermometers and conductivity-temperature-depth (CTD) casts. A well developed pycnocline was frequently observed around 150–200 m depth near the shelf break accompanied with the development of internal waves with short time scale. During the cruise in May 1998, the intensified internal wave motion with short time scale and the distinct offshore flow were observed just below the lower pycnocline, which shoaled and extended above the shelf area. It is suggested that vertical mixing generated by amplified internal waves would produce cross-shelf ageostophic density current around the pycnocline. During the cruise in May 1999, on the other hand, the lower pycnocline was located offshore below the shelf break, and the internal wave motion was amplified just above the lower pycnocline. In this case, the offshore flow should be generated above the lower pycnocline, but vertical profiles of current velocity were not obtained because acoustic Doppler current profiler (ADCP) data were not available around the lower pycnocline. 相似文献
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249.
Abstract. Benthic metabolism and standing stocks were investigated in the deep Red Sea between 21o and 27o N, Activity was assessed by the determination of respiration rates with a shipboard method and by calculating oxygen consumption from the activity in the electron transport system. We attempted to compare results from different latitudes within the warm Red Sea and with data from cold Atlantic environments. Our investigations were part of an environmental risk assessment to evaluate future mining of metalliferous sediments from the Atlantis II Deep. 相似文献
250.
烟台市污水处理深海排放工程设计方案研究与选择 总被引:2,自引:0,他引:2
沿海城市污水处理深海排放工程在我国起步较晚,烟台市污水处理深海排放工程我国目前规模最大的同类工程,且已进入施工阶段,本文详细阐述了该工程及水工设计方案,在我国城市污水2深海排放工程领域作了积极有益的探索。 相似文献