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1.
对虾养殖生态系中有机碳的初步研究本研究由 总被引:1,自引:0,他引:1
对于围隔养殖对虾生态系中有机碳的变动进行了研究 ,结果表明 :溶解有机碳 (DOC)含量波动在 5 .2 99~ 13.39mg/ L之间 ,平均为 8.5 3mg/ L± 2 .2 5 mg/ L;颗粒有机碳 (POC)含量波动在0 .6 5~ 6 .6 3mg/ L之间 ,平均为 3.2 5 mg/ L± 1.76 mg/ L;总有机碳 (TOC)含量波动在 6 .92~ 2 0 .0 2mg/ L之间 ,平均为 11.78mg/ L± 3.82 mg/ L ;其中 DOC∶ POC∶ TOC为 0 .72∶ 0 .2 8∶ 1。各种有机碳组分的含量明显高于自然海水中各种有机碳的含量 ;各种有机碳组分的含量在养殖期间总体上呈上升的趋势 ;其变化与 DCOD的变化呈显著线性正相关的关系。 相似文献
2.
F. D. Por 《Marine Ecology》1980,1(2):121-131
Abstract. A classification of hypersaline waters is proposed on the basis of the food chain structure of their biota. Four steps of increasing salinity and respective shortening of the food-chains are recognized, respectively named: alpha-, beta-, gamma- and delta-hypersaline waters.
Some general aspects, dealing with cosmopolitism of the biota, production, competition and benthic ecology in hypersaline waters are discussed.
The relevance of ecological studies in hypersaline waters to theoretical ecology and to the new technological uses of saline waters is briefly mentioned. 相似文献
Some general aspects, dealing with cosmopolitism of the biota, production, competition and benthic ecology in hypersaline waters are discussed.
The relevance of ecological studies in hypersaline waters to theoretical ecology and to the new technological uses of saline waters is briefly mentioned. 相似文献
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Frdric Gazeau Stephen V. Smith Bernard Gentili Michel Frankignoulle Jean-Pierre Gattuso 《Estuarine, Coastal and Shelf Science》2004,60(4):673-694
The geomorphic, oceanographic, terrestrial and anthropogenic attributes of the European coastal zone are described and published data on ecosystem function (primary production and respiration) are reviewed. Four regions are considered: the Baltic Sea, Mediterranean Sea, Black Sea and the European Atlantic coast including the North Sea. The metabolic database (194 papers) suffers from a non-homogeneous geographical coverage with no usable data for the Black Sea which was therefore excluded from this part of our study. Pelagic gross primary production in European open shelves is, by far, the most documented parameter with an estimated mean of 41 mmol C m−2 d−1, the lowest value is reported in the Mediterranean Sea (21 mmol C m−2 d−1) and the highest one in the Atlantic/North Sea area (51 mmol C m−2 d−1). Microphytobenthic primary production, mostly measured in shallow areas, is extrapolated to the entire 0–200 m depth range. Its contribution to total primary production is low in all regions (mean: 1.5 mmol C m−2 d−1). Although macrophyte beds are very productive, a regional production estimate is not provided in this study because their geographical distribution along the European coastline remains unknown. Measurements of pelagic community respiration are clearly too sparse, especially below the euphotic zone, to yield an accurate picture of the fate of organic matter produced in the water column. With a mean value of 17 mmol C m−2 d−1, benthic community respiration consumes approximately 40% of the pelagic organic matter production. Estuaries generally exhibit high metabolic rates and a large range of variation in all parameters, except microphytobenthic primary production. Finally, the problem of eutrophication in Europe is discussed and the metabolic data obtained in the framework of the Land–Ocean Interactions in the Coastal Zone (LOICZ) project are compared with available direct measurements of net ecosystem production. 相似文献
6.
The zooplankton of two salt ponds at Aveiro was studied to evaluate its density and diversity. Samples were collected biweekly from the salt ponds Esmolas and Tanoeiras. Samples were first separated into Holoplankton (Copepoda, nauplii,Acartia, Ostracoda and Anostraca) and Meroplankton (Mollusca, Insecta, annelidan larvae and Ichthyoplankton). The Holoplankton was mainly composed of:Acartia tonsa, Acartia sp.,Eurytemora velox, Artemia sp., and harpacticoids and calanoids. In both salt ponds, species diversity was identical, but total zooplankton density was higher in the Tanoeiras salt pond, probably because its physical and chemical characteristics allowed the development of stable communities. 相似文献
7.
泰安市地下水开发利用中的水环境问题及对策 总被引:2,自引:6,他引:2
以泰安市为例,论述了地下水开发利用中出现的区域地下水位下降、地下水资源衰竭、地下水水质恶化、地面沉降、地面裂缝和地面塌陷等水环境问题,并提出了保护对策与建议. 相似文献
8.
The hydraulic and sedimentary characteristics of the spawning habitat of Atlantic salmon (Salmo salar) in tributary and mainstem locations in a river system in north-east Scotland are described. Salmon used spawning sites with a relatively wide range in sediment characteristics, although measures of central tendency were all in the gravel (2–64 mm) size-class. The dominant factor differentiating the sediment characteristics of study sites was the level of fine sediment, which accounted for significant differences between tributary and mainstem samples. The ranges of depth and velocity in areas used for spawning by salmonids were found to be similar in all tributary study sites. However, due to the interdependence of depth and velocity, major differences were observed between tributary and mainstem study sites in that spawning in larger streams tended to be associated with deeper, faster flowing water. Spawning locations were shown to have similar Froude number, despite different sized streams and species of salmonid. Due to its dimensionless nature and significance in characterising flow hydraulics, the Froude number is proposed as a potentially useful variable for describing the habitat of aquatic organisms. 相似文献
9.
青藏公路铁路沿线生态系统特征及道路修建对其影响 总被引:36,自引:2,他引:36
根据2001—08和2002—08月野外调查数据及2001年1:100万中国植被图、1996年1:400万青藏高原植被区划图和2000年青藏铁路沿线自然保护区分布及功能区界调整图,以青藏公路铁路沿线植被生态系统为研究对象,运用ARCVIEW和ARC/INFO软件研究青藏公路铁路建设对沿线生态系统结构的影响,结论如下:①青藏公路铁路南北跨越9个纬度,东西跨越12个经度,共穿越青东祁连山地草原地带、柴达木山地荒漠地带、青南高寒草甸草原地带、羌塘高寒草原地带、果洛那曲高寒灌丛草甸地带和藏南山地灌丛草原地带6个自然区,对植被类型的统计结果显示了地带性。②青藏公路铁路的建设对生态系统产生直接的切割,使景观更加破碎。③青藏公路铁路的建设直接破坏沿线植被生态系统(主要为50m缓冲区内),年损失总净初级生产量为30504.62t,损失总生物量432919.25~1436104.3t/a。损失总净初级生产量占1km缓冲区年净初级生产量535005.07~535740.11t/a的百分比为5.70%,占10km缓冲区年净初级生产量3408950.45~3810480.92t/a的0.80~0.89%;损失生物量占1km缓冲区生物总量7502971.85~25488342.71t/a的5.70%,占10km缓冲区总生物量43615065.35~164150665.37t/a的0.80%~0.89%。 相似文献
10.
Floodplains are ecotones that form a transition between aquatic and terrestrial environments. These important ecosystems can be described as dynamic spatial mosaics in which water plays an important role in connecting various patches on the floodplain surface. Hydrological connections facilitate the exchange of carbon and nutrients between the river channel and the floodplain and therefore influence the productivity of the entire river system. This paper examines the influence of hydrological connections on the potential exchange of dissolved organic carbon between a large Australian floodplain to a river channel, and the effects of land and water developments on these exchanges. The paper proposes that an understanding of floodplain ecosystems requires an interdisciplinary approach—a recognition of the importance of the three disciplines hydrology, geomorphology and ecology. Large-scale water-resources and floodplain development has significantly altered the spatial and temporal patterns of hydrological characteristics in the Lower Balonne floodplain, Australia. The magnitude, frequency and duration of flooding events have all been reduced. The construction of levees and water storages has also reduced the reactive floodplain surface area. The presented data show the impacts of these changes on the potential supply of dissolved organic carbon from the floodplain surface during periods of inundation. Annual reductions of up to 1293 tonnes of dissolved organic carbon supply were noted and reductions were especially significant for floods with an average recurrence interval of 2 years or less. Some small flood events no longer facilitate the potential supply of dissolved organic carbon from the floodplain to the river channel because of water-resources and floodplain developments. 相似文献