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1.
水环境腐殖质的光化学研究进展   总被引:3,自引:0,他引:3  
1腐殖质的研究概况 腐殖质是动植物残体在水体、土壤中经过长期的物理、化学、生物作用等过程转化而成的一种高分子化合物,是存在于海底或湖底淤泥中有机物的主要形式。据估计,腐殖质占天然水体系统中溶解有机碳(DOC)的50%~90%。一般说来,腐殖质是无定型,棕色或黑色,呈酸性和多分散性,其分子质量从几百到几万。  相似文献   

2.
中国近岸海域潜在性富营养化程度的评价   总被引:105,自引:6,他引:105  
根据近岸海域的富营养化普遍受营养盐限制的特征,提出了潜在性经的概念,并在此 提出了一种新的富营养化分级标准及相应的评价模式,运用该模式分别评价了厦门海域及中国近海的富养化程度。结果表明,厦门东海域敞 于贫营养水平,而西海域则为磷限制潜在性营养水平;与厦门西海域相近,中国近海主要河口、海湾总体上处于磷限制或磷中等限制潜在性富营养水平。  相似文献   

3.
山东半岛南部近岸海域富营养化状况的多元评价研究   总被引:8,自引:0,他引:8  
周斌  王悠  王进河  刘泳  唐学玺 《海洋学报》2010,32(2):128-138
于2006年至2007年分四个季度月对山东半岛南部近岸海域(35.5°~36.7°N,119.8°~121.3°E)的营养盐和叶绿素a进行了设站调查,分析了该海域上述因子时空分布特征,同时应用主成分分析(PCA)和潜在富营养化评价方法对该海域的富营养化状况进行了分析,初步确定了影响该海域富营养化状况的主要驱动因子。结果表明:(1)在时间分布上,总氮、总磷、活性磷酸盐、溶解态氮与总无机氮和活性硅酸盐的季节变化类似,均表现出秋冬季浓度较高而春夏季较低的趋势,而总磷、溶解态磷的浓度则在冬季最高,在夏秋季较低,叶绿素a浓度的季节变化趋势为春夏季较高,而冬季最低;该海域营养盐与叶绿素a浓度空间分布以胶州湾和丁字湾为中心,总体呈现出由近岸向离岸海域逐渐递减的趋势;(2)应用主成分分析对调查结果进行分析,结果显示10项调查指标(营养盐与叶绿素a)可以转换提取4个主成分,解释82.00%的结果。主成分综合得分可以作为富营养化程度的评价指标,据此得到调查海域富营养化状况的季节变化趋势由高到低依次为秋季、冬季、春季、夏季,总体呈现出以胶州湾和丁字湾为中心,沿岸及北部海域富营养化程度较高的格局;分析结果还表明总无机氮是该海区富营养化形成的主要驱动因子;(3)利用潜在富营养化评价方法对调查海域富营养化状况进行了初步分析,结果表明该海区仅于秋季表现为总体中度营养,在其他季节总体趋势均为贫营养,胶州湾与丁字湾附近海域在春秋季表现为磷限制潜在富营养化。主成分分析法较潜在富营养化评价方法更敏感,不仅能够定量表述海区富营养化状况,而且能够有效确定富营养化驱动因子。  相似文献   

4.
海岸河口泥沙数学模型研究进展   总被引:25,自引:0,他引:25  
李孟国 《海洋工程》2006,24(1):139-154
对海岸河口泥沙运动的基本方程、数值方法、边界条件、参数选取等进行了归纳总结和评述,以期对本学科的发展起到一定的引导和促进作用。  相似文献   

5.
6.
海岸河口潮流数值模拟的研究与进展   总被引:45,自引:2,他引:45  
李孟国  曹祖德 《海洋学报》1999,21(1):111-125
对海岸河口地区潮流场的数值模拟方法进行了较为系统的归纳总结和评述,对潮流数值模拟的发展趋势进行了分析.  相似文献   

7.
参考目前国际上被广泛应用的第2代富营养化评价方法体系,结合我国近岸海域生态环境特点和监测资料现状,建立了一种以压力-状态-响应模式为基本框架、以富营养化症状为主的第2代近岸海域富营养化评价体系。实际应用结果表明,应用本方法得出的长江口海域富营养化状况评价结论,与目前国外主流评价方法的评价结论一致,而且本方法具有评价指标代表性强、数据资料易得、评价标准有据、方法简便易行等优点。  相似文献   

8.
我国近岸海域富营养化评价新方法及应用   总被引:3,自引:1,他引:3  
参考目前国际上被广泛应用的第2代富营养化评价方法体系,结合我国近岸海域生态环境特点和监测资料现状,建立了一种以压力-状态-响应模式为基本框架、以富营养化症状为主的第2代近岸海域富营养化评价体系。实际应用结果表明,应用本方法得出的长江口海域富营养化状况评价结论,与目前国外主流评价方法的评价结论一致,而且本方法具有评价指标代表性强、数据资料易得、评价标准有据、方法简便易行等优点。  相似文献   

9.
The effects that man has on coastal waters are enumerated and what needs to be known to evaluate those effects is considered. Instruments and techniques are described for measuring and sampling the physical, chemical, and biological situation in the sea. Some suggestions are offered for improvement in the existing instrumentation. Also noted are certain limitations in present capabilities including the inability to satisfactorily determine the effects on the environment of fisheries, of oil spills, or of changes in ocean conditions.  相似文献   

10.
Studies on the early life history of fish in New Zealand started during the 1950s off the Northland coast. Since then taxonomy, seasonality in abundance, and vertical and horizontal distribution patterns have been described as well as aspects at the level of individuals, such as age, growth, and condition. I discuss the findings and issues that have developed from these studies and illustrate three undescribed presettlement reef fish. Results indicate that different taxonomic groups typically have different vertical and horizontal distribution patterns as well as different temporal patterns of abundance. This implies that general models of how “larval fish” behave are unrealistic. As a result, the importance of physical and biological processes that may influence the distribution and survival of ichthyoplankton will vary among categories of fish (such as pelagic and reef fish) and taxonomic groups within these. Based on knowledge of the distribution pattern of some species, there is considerable scope for focusing future research on specific groups offish in terms of ontogenetic changes in morphology, sensory abilities, growth, diet, condition, interrelationships with other plankters, and, in the case of reef fish, onshore transport.  相似文献   

11.
Both water and suspended particulate matter in the deep water of the Gulf of St. Lawrence are greatly enriched in manganese. Maximum dissolved manganese concentrations are encountered close to the sediment-water interface whereas the particulate matter with highest manganese content occurs 30–100 m above the bottom. The elevated concentrations are attributed to the diagenetic release of dissolved manganese from the underlying fine-grained sediments and its subsequent precipitation in the water column. The rate of manganese precipitation is rapid compared to the rates of diffusion and mixing in the bottom water. Part of the manganese-enriched particulate matter becomes mixed throughout the water column by advection and diffusion. Thus, particles enriched in manganese can ultimately be carried into the open ocean by prevailing currents. This process, which appears to be widespread in eastern Canadian coastal waters, enables manganese originally associated with rapidly settling terrigenous particles to be transferred to slowly settling fine-grained suspended particles entering the ocean from coastal environments. In this way, riverborne manganese of terrigenous origin may well account for a major proportion of the excess manganese in pelagic sediments.  相似文献   

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