Effects of tributyltin at environmental levels on monooxygenase system of digestive gland in hard clam Meretrix meretrix

The effects on ethoxyresorufin O-deethylase （EROD）, NADPH-cytochrome c reductase and NADH cytochrorne b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin （TBT） at environmental levels （0.1,1.0,10.0 ng/dm as stannum concentration）,in experimental condition, were evaluated. The EROD, NADH cytochrorne b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm^3 TBT for 8 and 20 d, the NADPH cytochrorne c reductase activities were significantly inhibited after exposure to 0.1,1.0 and 10.0 ng/dm TBT for 8 d and to 1.0 and 10.0 ng/dm for 20 d, as compared with the matched control, while NADH cytochrorne b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10.0 ng/dm^3 TBT for 2 d. The EROD activity in the 10 ng/dm^3 group,and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm groups, were significantly induced when transferred to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time.     

围垦的社会经济价值及其对海洋环境影响的评估

从围垦滩涂与保护湿地的关系着手,针对浙江省的滩涂围垦现状,讨论了沿海滩涂实施围垦工程所创造的社会经济价值,分析了湿地生态的环境特征及其对自然界的贡献,指出并探讨了海岸带资源开发与海岸工程建设所带来的问题,从湿地保护和经济可持续发展的角度提出了相关的建议。     

赤点石斑鱼(Epinephelus akaara)精子超微结构及环境因子对精子活力的影响

为揭示赤点石斑鱼精子的超微结构及环境因子对其精子活力的影响,利用扫描电镜和透射电镜观察赤点石斑鱼精子的超微结构,设置不同梯度的温度、盐度、pH值及不同浓度的NaCl、KCl、CaCl₂、MgCl₂、EDTANa₂溶液,探究这些因子对赤点石斑鱼精子活力的影响。结果表明:赤点石斑鱼成熟精子的结构特点是细胞核圆形或卵圆形,核内染色质致密,没有核泡(核空隙)。精子尾部细长,横切面为典型的"9+2"微管结构。温度、盐度、pH值等环境因子对精子活力的影响表明,精子活力的适宜温度范围为23~31℃,27.5℃时精子寿命最长为37min;适宜的盐度范围为15~35,盐度15时精子寿命最长为50min;适宜的pH范围为7~9,pH为9时精子的运动时间最长为33min。赤点石斑鱼精子在EDTANa₂溶液中呈抑制状态,在400~700 mmol/L的NaCl溶液、400~600mmol/L的KCl溶液和500 mmol/L的CaCl₂溶液中精子均具有较好的活动能力。在MgCl₂溶液中赤点石斑鱼精子的活动能力不佳。赤点石斑鱼精子的最适温度范围与繁殖季节的最适水温范围符合,适宜盐度范围较广,对pH值的变化适应性较强。赤点石斑鱼精子在NaCl、KCl、CaCl₂溶液中活力较佳,在MgCl₂溶液和EDTANa₂溶液中呈抑制状态。     

海岸工程中海浪数值模拟和环境参数选取的进展

主要介绍了我国近的来在海岸工程设计，建设中有关海浪数值模拟及环境参数选取方面的研究进展。     

Seasonal use of coastal resources by otters: Comparing sandy and rocky stretches

Seasonal patterns of use of coastal resources by otters have been studied, simultaneously performing diet analyses and spraint counts (expressed as marking intensity, MI). In spite of the small size of the study area, two different sectors could be clearly identified, a sandy and a rocky one. The origin (freshwater or coastal) of most prey types could also be determined. Surveys were performed bimonthly and classified as autumn–winter (A–W) or spring–summer (S–S).In the sandy sector, eels, flatfish and grey mullets were more frequently consumed in A–W, while crayfish was more frequently consumed in S–S. None of the identified prey types in the rocky sectors showed different frequency of occurrence values between the two periods. In this sector otter fed mainly on coastal prey throughout the year, while in the sandy one there was a clear shift from coastal prey to freshwater ones in S–S. The decrease of coastal prey consumption in S–S in the sandy sector coincided with the lowest MI values, showing that in this period otters use coastal areas less intensely. Though shifts in otter diet and use of space in the sandy sector are probably influenced by the population dynamics of estuarine fish species and crayfish, the increased tourist disturbance during spring and summer in the sandy sector could be an important determinant of the observed patterns. Finally, the results show that MI can be used as a reliable measure of habitat use by otters, at least in small areas.     

厦门筼筜港区环境地震地质的若干问题

本文研究了厦门筼筜港区的工程地质条件与分区特征,讨论了该区环境地质的若干问题。