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731.
综述了目前国内外对二甲基硫(DMS)的海一气通量的研究状况,指出了DMS的海一气通量受很多因素的影响。运用不同的模型计算值相差很大。此外本文着重论述DMS进入大气后被OH和NO3等自由基的氧化机化及其氧化产物对酸雨酸雾的贡献以及DMS、凝云结核(CCN)、气候 系统之间的关系。 相似文献
732.
733.
于2019年3月和7月对连云港主要入海河流着生藻类群落结构进行了调查,并基于水生态环境质量综合指数对15条入海河流水质进行评价。结果表明,良好以上的断面占总数的66.7%,调查共发现硅藻、绿藻、蓝藻、裸藻、黄藻及金藻共计106种着生藻类,其中春季60种,夏季80种;硅藻为全年优势种。着生藻类全年平均密度为42 266.7 个/cm2,各断面密度差异较大。Shannon-Wiener多样性指数(H’)为1.46~392,平均值为2.93,其中夏季H’平均为3.07,高于春季的2.80,总体呈放置7 d样品多样性高于14 d样品的趋势。 相似文献
734.
Arsenic, cadmium, chromium, lead, manganese, mercury, selemium,and tin concentrations were measured in the feathers of Capecormorant (Phalacrocorax capensis), Hartlaubs gull(Larus hartlaubii), kelp gull (Larus dominicanus), andlesser flamingo (Phoeniconaias minor) from the coast ofNamibia in southern Africa. Metal concentrations in feathers represent the concentrations in the blood supply at the time offeather formation. Cape Cormorants are piscivores; kelp gullsare primarily piscivores; Hartlaubs gull is an omnivore; and lesser flamingos eat primarily blue-green algae and invertebrates filtered from the water and sediment ofhypersaline lagoons. We predicted that metal concentrationswould reflect these trophic level differences. There weresignificant species differences in the concentrations of allmetals, with flamingos having the lowest levels, and cormorantshaving the highest levels of 4 metals but not mercury. The gulls hadthe highest levels of mercury, perhaps reflecting their morescavenging behavior. 相似文献
735.
本文介绍一个简单而灵敏的催化分光光度法,用于测定环境样品中微量碘,本法系基于亚硝酸根存在时微量碘离子催化还原硫氰酸铁络含物,并以分光光度计测量该红色络合物的减弱强度,在一定温度时,该络合物的分解速度正比于磺的含量.在给定的实验条件下,磺离子的浓度在0.001-0.024毫克/升之间服从比尔定律. 本法已成功地应用于天然水、土壤、海底泥和海生物中微量磺的测定,结果良好. 相似文献
736.
A long-term study of temperature, pH, turbidity, suspended solid, salinity, dissolved oxygen, biochemical oxygen demand and ammonia nitrogen has been performed in a port and harbour region in India for four years from December 1996 to November 2000. Marine water quality results showed no regular trend. The mean monthly values of temperature, pH, turbidity, suspended solid, salinity, dissolved oxygen, biochemical oxygen demand and ammonia nitrogen were in the range of 22.64 ± 0.4 to 29.05 ± 1.37 °C; 7.65 ± 0.04 to 7.81 ± 0.13; 28.8 ± 14.7 to 64.2 ± 32.0 NTU; 283.5 ± 81.8 to 356.0 ± 159.7 mg/L; 29.78 ± 7.18 to 29.78 ± 1.04 ppt; 4.67 ± 0.50 to 6.01 ± 1.02 mg/L; 5.41 ± 1.92 to 7.56 ± 2.1 mg/L; and 0.25 ± 0.07 to 0.63 ± 0.49 mg/L, respectively. The results of correlation analysis showed that biochemical oxygen demand (BOD) was inversely correlated dissolved oxygen (DO) and poorly correlated with all other parameters. Turbidity and suspended solid were moderately correlated with each other while salinity was moderately correlated with other water quality parameters. In factor analysis, four factors were drawn out of the eight variables, which represented 74% of the variance of the original data. Factor I was related to suspended solid and turbidity. Factor II represented mainly temperature and DO showing inverse relation between these two. Factor III implied the degree of pollution at any monitoring station. Factor IV included pH and salinity. It could be concluded that the factor model represented almost all the variables. 相似文献
737.
Efficiency,costs and trade-offs in marine reserve system design 总被引:1,自引:0,他引:1
Romola?R.?StewartEmail author Hugh?P.?Possingham 《Environmental Modeling and Assessment》2005,10(3):203-213
With marine biodiversity conservation the primary goal for reserve planning initiatives, a site's conservation potential is
typically evaluated on the basis of the biological and physical features it contains. By comparison, socio-economic information
is seldom a formal consideration of the reserve system design problem and generally limited to an assessment of threats, vulnerability
or compatibility with surrounding uses. This is perhaps surprising given broad recognition that the success of reserve establishment
is highly dependent on widespread stakeholder and community support. Using information on the spatial distribution and intensity
of commercial rock lobster catch in South Australia, we demonstrate the capacity of mathematical reserve selection procedures
to integrate socio-economic and biophysical information for marine reserve system design. Analyses of trade-offs highlight
the opportunities to design representative, efficient and practical marine reserve systems that minimise potential loss to
commercial users. We found that the objective of minimising the areal extent of the reserve system was barely compromised
by incorporating economic design constraints. With a small increase in area (<3%) and boundary length (<10%), the economic
impact of marine reserves on the commercial rock lobster fishery was reduced by more than a third. We considered also how
a reserve planner might prioritise conservation areas using information on a planning units selection frequency. We found
that selection frequencies alone were not a reliable guide for the selection of marine reserve systems, but could be used
with approaches such as summed irreplaceability to direct conservation effort for efficient marine reserve design. 相似文献
738.
Ranasinghe JA Montagne DE Weisber SB Bergen M Velarde RG 《Environmental monitoring and assessment》2003,81(1-3):199-206
Studies designed to measure anthropogenic impacts on marine benthic communities depend on the ability of taxonomists to consistently discriminate, identify, and count benthic organisms. To quantify errors and discrepancies in identification and enumeration, 20 samples were completely reprocessed by another one of four participating laboratories. Errors were detected in 13.0% of the data records, affecting total abundance by 2.1%, numbers of taxa by 3.4%, and identification accuracy by 4.7%. Paired t-tests were used to test for differences in the Benthic Response Index (BRI), total abundance, numbers of taxa, and the Shannon-Wiener index between the original and the reanalysis data. Differences in the BRI were statistically insignificant. Although statistically significant differences were observed for numbers of taxa, total abundance, and the Shannon-Wiener index, the differences were small in comparison to the magnitude of differences typically observed between anthropogenically affected and reference sites. 相似文献
739.
叙述了海洋大气环境下装备典型金属材料的腐蚀与防护研究进展。介绍了高强钢、不锈钢和铝合金等装备材料在高温、高湿、高盐雾和强辐射等海洋大气环境下的腐蚀特征和主要腐蚀形式,总结了海洋大气腐蚀防护技术的研究进展。最后,提出了海洋大气环境下装备防护需从装备选材与结构环境适应性设计、有效表面防护、环境控制、加强维护保养等方面着手,在充分利用现有防腐技术的基础上,加强金属涂/镀层与有机涂层的技术组合;大力开发研制海洋环境下长期有效、绿色环保的表面处理技术和涂层技术;针对铝合金等易腐蚀材料,开展腐蚀结构修复技术研究。采用系统工程方法来解决海洋大气环境中装备的腐蚀问题,进而提高舰载武器、船舶、海岸工程、近海工程等服役装备的安全性、寿命和可靠性。 相似文献
740.
R.L. Flitcroft I. Arismendi M.V. Santelmann 《Journal of the American Water Resources Association》2019,55(2):430-441
Long‐term conservation planning for diadromous fishes would benefit from a better understanding of both the role of connectivity among environments and habitat variability in the expression of life‐history diversity. Most of the scientific knowledge on habitat fragmentation and connectivity has been developed in terrestrial systems in the discipline of landscape ecology. Research on habitat connectivity in aquatic systems (e.g., salmonid research that spans the spectrum of habitats from freshwater to the sea) is uncommon and largely focused on barriers to fish passage. Here, we present a review of the literature characterizing current research patterns on habitat connectivity within and among environments for Pacific salmon. We found this topic is still incipient: the literature is dominated by studies of freshwaters, with few articles focusing on habitat needs in estuary and marine systems. Pan‐environment studies are rare, pointing to a gap in our understanding of complex habitat relationships that might be significant in the development of long‐term conservation and restoration plans for Pacific salmon, particularly in light of the potential impact of climate change. 相似文献