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121.
海洋和海岸带生态系统价值的科学评估对海洋与海岸带开发决策起着重要的支撑作用.目前盛行的生态系统服务价值评估是从生态系统对人类的效用的角度衡量生态系统的价值,而缺乏从生态系统自身的角度进行客观评估.首先分析了生态系统内在价值的内涵,提出基于能值和ecoexergy两种系统生态学方法的价值评估框架,建立了一套海洋生态系统内在价值较为有效的评估方法.该框架先通过能值计算将生态系统的生物成分、非生物成分及物种多样性转换为能值货币价值,再通过eco-exergy来体现生态系统的结构与功能过程,并转换为eco-exergy货币价值.最后将该评估框架应用于厦门湾海洋生态系统内在价值的评估.结果显示,2010年厦门湾海洋生态系统的本底内在价值为1.16×10^11CNY,全年创造内在价值为9.24×10^10CNY,总计2.09×10^11CNY,远高于生态系统服务价值7.27×10^9CNY和厦门海洋产业GDP 2.47×10^10CNY. 相似文献
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Mahmoud M. El Banna 《Environmental Geology》2007,52(1):41-49
Beach profile data, covering the coast of Ras El Bar, northeast Nile Delta, collected during the years from 1990 to 2002 combined
with landsat images for the area and sedimentological investigation have been used to identify beach and nearshore seafloor
sediment changes. Along the coast of Ras El Bar, two accretion sectors and one of erosion have been recognized. The first
accretion sector is located west of Damietta harbour, where the harbour jetties have halted the littoral transport, while
the second one is behind a system of detached breakwaters protecting Ras El Bar resort. Both the two sectors are characterized
by growing shoreline with maximum rates ∼15 and 10 m/year, respectively. Also, they have maximum nearshore seafloor accretion
rates of ∼18 and 22 cm/year, respectively. The erosion sector is located east of Damietta port and has a maximum rate of shoreline
retreat ∼−10 m/year. Erosion of its nearshore seafloor is indicated recording a maximum rate of ∼−20 cm/year. The rate of
net sediment volume change in the area indicates shifting of the accretion sector (II) westward, responding to installation
of the new breakwaters unit. The two accretion sectors are characterized by dominance of moderately sorted fine sands in their
shore area which change seaward into less sorting very fine sands. Beach sands of the eroded sector are poorly sorted medium
grain size. The dominant constituents of heavy mineral species in beach and sea-bottom sands are the characteristic assemblages
of the Nile deposits. The sands of the eroded zone are relatively enriched in monazite, zircon, tourmaline, garnet, and rutile. 相似文献
126.
Nick Marriner 《Quaternary Research》2006,65(1):164-171
Chrono-stratigraphic data from Tyre's ancient northern harbour delineate extensive dredging practices during the Greco-Roman and Byzantine periods. Radiocarbon dates from four cores consistently cluster between ca. 500 B.C. and 1000 A.D. and indicate rapid rates of sedimentation in the basin, namely ∼10 mm/yr during the Greco-Roman and Byzantine periods, compared to 0.5-1 mm/yr for the period 6000-4000 B.C. Absence of strata between 4000 B.C. and 500 B.C. is not consistent with a natural base-level sediment sink and cannot be interpreted as a depositional hiatus in the high-stand systems tract. Ancient dredging is further corroborated by persistent age-depth inversions within the fine-grained harbour facies. These data support removal of Middle Bronze Age to Persian period sediment strata, with deliberate overdeepening of the harbour bottom by Greco-Roman and Byzantine societies. 相似文献
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Samples of green lipped mussels (Perna viridis) were collected from three sites (Huoshao, I’Maluan and Tong’an) around Xiamen coastal waters, where levels of various trace organic pollutants have been studied. Samples were also collected at a “cleaner” reference site near Dongshan Island for comparison. Clearance rate, absorption efficiency and oxygen consumption of the mussels were measured under controlled laboratory condition; organic pollutants in their tissues were also analyzed. Scope for growth (SFG) was employed as a general biomarker to evaluate the stress of pollutants. Specimens from Tong’an site had the lowest SFG values (1.14 J/h/g); while specimens from the I’Maluan site and Huoshao site had SFG values of 5.01 and 6.72 J/h/g, respectively. Specimens from Dongshan (reference site) had a relatively high SFG value of 10.96 J/h/g. There was a significant negative correlation between the SFG of the different populations of green lipped mussels and the concentration of DDT in their tissues. 相似文献
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我国东南沿海3港口有机锡污染的调查 总被引:14,自引:1,他引:13
利用顶空固相微萃取与气相色谱表面发射火焰光度检测法于2001年11月至2002年8月对我国东南沿海厦门、汕头和惠阳3个大型港口21个站位的水样、底泥和生物样的有机锡污染现状进行调查.结果表明,绝大多数样品的一丁基锡(MBT)含量最高,三丁基锡(TBT)次之,二丁基锡(DBT)大多低于检测限.水样的TBT含量实测值从低于检测限至9.8ng/dm3,泥样的为0.3~174.7ng/g(干重),生物样的为2.1~23.0ng/g(湿重).水样TBT含量均值以惠阳港的为最高,泥样和生物样的均以厦门港的最高.影响有机锡含量及其空间分布的主要因素有港口船舶吞吐量、水文状况、季节和与大型码头的距离.关联的海产腹足类性畸变调查结果发现,我国沿海有机锡污染比较普遍和严重,已对生态系统产生实质性的负面生态效应. 相似文献