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91.
福建东山岛西埔湾港养生物资源的开发利用 总被引:2,自引:0,他引:2
在研究东山岛西埔湾港养生物资源及其开发现状的基础上,指出资源种类逐年减少,年渔获量急剧下降,渔获个体趋于小型化,资源已明显衰退。作者认为过度捕捞是导致西埔湾总渔获量下降的最主要因素。为了保护资源和提高渔获量,必须控制捕捞力量,改善港养环境条件,并采取季节性开闸纳苗和放流增殖措施。 相似文献
92.
广州市河涌沉积物及底栖生物体内的重金属含量及分布 总被引:7,自引:0,他引:7
本文报道了广州市河涌沉积物及底栖生物的重金属含量及分布状况。应用 WFX- IF2型原子分光光度计对 2 1个采样点沉积物及底栖生物样品中 Cd、Cu、Zn、Pb、Cr和 Ni的含量进行了测定 ,并使用标准物作了对照分析。结果显示 :沉积物中 Cd、Cu、Zn、Pb、Cr、Ni的平均含量分别为 5.61、30 2 .1 2、72 7.0 3、1 63.37、67.70、84.58μg/ g干重 ;底栖生物中 Cd、Cu、Zn、Pb、Cr、Ni的平均含量分别为 0 .78、2 9.2 0、2 68.38、1 0 .75、3.89、3.44μg/ g干重。结果表明 :广州市河涌已受到不同程度的重金属污染 ,受污染最严重的是赤岗涌、海珠涌和棠下涌。工业活动是造成污染的主要原因。河涌中的水栖寡毛类与沉积物中的重金属含量显著相关 (P<0 .0 1 ,P<0 .0 5) ,可以作为 Cu、Cr、Ni的良好指示生物。本文还探讨了将河涌污泥作为农用的可能性 相似文献
93.
94.
An investigation of the impacts from elevated intertidal Pacific oyster culture in a New Zealand estuary showed enhanced sedimentation
beneath culture racks compared with other sites. Seabed elevation beneath racks was generally lower than between them, suggesting
that topographic patterns more likely result from a local effect of rack structures on hydrodynamic processes than from enhanced
deposition. Compared with control sites, seabed sediments within the farm had a greater silt/clay and organic content, and
a lower redox potential and shear strength. While a marked trend in macrofaunal species richness was not evident, species
composition and dominance patterns were consistent with a disturbance gradient, with farm effects not evident 35 m from the
perimeter of the racks. Of the environmental variables measured, sediment shear strength was most closely associated with
the distribution and density of macrofauna, suggesting that human-induced disturbance from farming operations may have contributed
to the biological patterns. To evaluate the taxonomic sufficiency needed to document impacts, aggregation to the family level
based on Linnean classification was compared with an aggregation scheme based on `general groups' identifiable with limited
taxonomic expertise. Compared with species-level analyses, spatial patterns of impact were equally discernible at both aggregation
levels used, provided density rather than presence/absence data were used. Once baseline conditions are established and the
efficacy of taxonomic aggregation demonstrated, a `general group' scheme provides an appropriate and increasingly relevant
tool for routine monitoring. 相似文献
95.
96.
William T. Mason Jr. 《Environmental monitoring and assessment》1998,50(2):101-130
The macrobenthos in the oligohaline 132 km reach of the Lower St. Johns River, Florida, is an unusual blend of freshwater and marine organisms within the annelid, mollusk, aquatic insect, and crustacean groups. During 1993–1994, the community composition was freshwater-oriented in the 47 km (seg I) and estuarine-dominated in the lower 85 km (seg II). Of the total 146 taxa collected, 89% were euryecious 'eutrophic' and 'pollution-tolerant' organisms. Densities ranged between 5000 and 20 000 individuals/m2 ann av and maximum densities (85 000 individuals/m2) occurred in the muck substrate at the confluence of major tributaries and embayments. Throughout the lake-like seg II, benthic hypoxia existed during much of summer through fall. Biotic index values for grab, artificial substrate, and sled trawl samples reflected greatest stresses to the macrobenthos then. Both low taxonomic diversity and densities of organisms at the most downriver stations nearest the port of Jacksonville indicated that toxic substances also adversely affected the macrobenthos. Maintenance of the narrow band of littoral submerged aquatic vegetation (SAV) and adjacent shoreline riparian vegetation is important to sustain macrobenthic communities and other kinds of aquatic life in the river. 相似文献
97.
采集南京不同水体9个点位的水样,经固相萃取后采用LC-MS/MS方法测定样品中10种抗抑郁类药物,结合风险熵值法评估其对不同营养级水生生物的风险。结果表明,南京水体中存在不同程度的抗抑郁类药物污染,质量浓度范围为未检出~9.4 ng/L;舍曲林、氟伏沙明和西酞普兰的检出率为100%,氟西汀的检出率为44.4%。风险评估结果表明,南京水体中抗抑郁类药物对不同营养级水生生物表现出低—中等风险;舍曲林和氟西汀对总风险的贡献率最高,需要重点关注。 相似文献
98.
99.
Coal-Mine Hollow Fill and Settling Pond Influences on Headwater Streams in Southern West Virginia, USA 总被引:1,自引:0,他引:1
Merricks TC Cherry DS Zipper CE Currie RJ Valenti TW 《Environmental monitoring and assessment》2007,129(1-3):359-378
The influences of coal-mine hollow fills and associated settling ponds in three headwater streams were assessed in southern
West Virginia, USA. Fill drainage waters had elevated conductivities and metal concentrations, compared to a regional reference.
Benthic macroinvertebrate richness was not affected consistently by the hollow fill drainages, relative to a regional reference,
although a more tolerant community, lacking in Ephemeroptera taxa at most locations, was evident. Collector-filterer populations were elevated at monitoring stations directly below the
settling ponds, indicating that the ponds’ presence influenced macroinvertebrate community structure by means of organic enrichment.
Corbicula fluminea growth was enhanced in monitoring locations directly below the settling ponds, also an apparent result of organic enrichment.
Results of acute water column toxicity testing with Ceriodaphnia dubia, sediment chronic toxicity testing with Daphnia magna, and in-situ ecotoxicological assessments with C. fluminea demonstrated no mortality or toxic influence at most of the sites tested below the ponds. The settling ponds appear to serve
as sinks in collecting some, but not all, trace metals. 相似文献
100.
Edward R. Long 《Environmental monitoring and assessment》2000,64(1):391-407
Acute, laboratory toxicity tests were performed by the National Oceanic and Atmospheric Administration (NOAA) on 1543 surficial sediment samples collected during 1991 through 1997 throughout 25 estuaries and marine bays. Selected areas were sampled along the Atlantic, Gulf of Mexico, and Pacific coasts. The toxicity of each sample was determined with 10-day amphipod survival tests performed with solid-phase (bulk) sediments. Collectively, the 1543 samples tested through 1997 represented a total area of approximately 7300 km2. Toxicity was observed with the amphipod survival tests in samples that represented approximately 6% of the combined area. Using similar tests conducted on samples collected in different, but overlapping, study areas, the U.S. Environmental Protection Agency (EPA) estimated that approximately 7% of the combined estuarine area sampled was toxic. Generally, toxicity was most severe in northeastern and southwestern estuaries and least prevalent in southeastern and northwestern areas. However, considerable portions of the Pacific coast have not been tested with the same methods. In tests of CYP1A enzyme induction (n=464), samples were toxic that represented about 5% of the combined study areas. Toxicity was much more widespread, however, when the results of two sub-lethal tests were analyzed. Significant results occurred in samples that represented approximately 25% and 39% of the study areas in tests of sea urchin fertilization (n=1309) and microbial bioluminescence (n=1215), respectively. 相似文献