Time-course evaluation of ROS-mediated toxicity in mussels, Mytilus galloprovincialis, during a field translocation experiment

Harbours can be considered as model environments for developing and validating field monitoring procedures and to investigate mechanistic relationships between different biological responses. In this study several biomarkers were investigated in marine mussels caged for 4 weeks (June-July 2001) into an industrialized harbour of NW Italy. Organisms were collected at different time-intervals to better characterize the sensitivity, temporal variations and interactions of analysed responses. Besides single antioxidants the total oxyradical scavenging capacity (TOSC) assay was used to analyse the capability of the whole antioxidant system to neutralize specific forms of radicals: these data were further integrated by measurement of DNA integrity, oxidized bases and the impairment of lysosomal membrane stability in haemocytes. Results showed a biphasic trend for single antioxidants and TOSC, with an increase during the first 2 weeks of exposure to the polluted site followed by a progressive decrease up to a severe depletion in the final part of the experiment.     

Trace metal uptake by the Chinese mitten crab Eriocheir sinensis: the role of osmoregulation

Changes in salinity affect the bioavailability and consequent uptake of trace metals by euryhaline invertebrates. In many cases, salinity-related effects on metal uptake can be explained by changes in chemical speciation but salinity may also influence uptake indirectly through its action on osmoregulatory mechanisms. Specifically, it can be hypothesised that trace metal uptake may be reduced at salinities approaching the isosmotic point of a species because, at this point, there is reduced activity of ionic exchange pumps. The present study tested this hypothesis using the Chinese mitten crab, Eriocheir sinensis, a hyper-hypoosmoregulator with an isosmotic point around 33 per thousand. Crabs were exposed to radio-labelled cadmium and zinc at 23, 33 and 43 per thousand for 4 days. To eradicate speciation effects, crabs were exposed to the same concentration of the radio-labelled free metal ion (estimated using MineQL computer software) at each salinity. Haemolymph samples were taken daily and radio-labelled metal concentrations were estimated from radioactivity counts and used to provide relative measures of metal uptake. Neither cadmium nor zinc uptake was lowest at the isosmotic point. The uptake of cadmium increased significantly with increase in salinity, while the uptake of zinc showed no significant change with increased salinity. Thus changes in trace metal uptake rates in E. sinensis do not appear to be controlled only by changes in free metal ion concentrations. The different effects of salinity change on the uptake of cadmium and zinc (in the absence of free metal ion change) also indicate that physiological responses to osmotic change alone do not control metal uptake rates for this species.     

Tributyltin and triphenyltin induce spermatogenesis in ovary of female abalone,Haliotis gigantea

Two-month flow-through exposure experiments of tributyltin (TBT) and triphenyltin (TPhT) were conducted with abalone, Haliotis gigantea. Nominal concentrations of 100 ng TBT/l and 100 ng TPhT/l caused significant spermatogenesis in ovaries of exposed females. There were also significantly more contracted primary oocytes observed in females exposed to either TBT or TPhT than controls. The incidence of two types of unknown cells was also significant in females exposed to TPhT. No significant histological changes were observed in testis of exposed males. This ovarian spermatogenesis caused by TBT and/or TPhT resembles gastropod imposex. Remarkably high concentrations of TBT and TPhT were observed in the head (including central nervous system ganglia), compared to muscles concentrations. Accumulation of TBT and TPhT in the head may disturb reproductive hormonal regulators through neuropeptides released from ganglia. This, as well as possible aromatase inhibition, may be one of the inducers for spermatogenesis in the abalone ovaries.     

重量稀释的和浓缩的标准海水的电导率同盐度和温度的函数关系

在-2℃至35℃的整个海洋温度范围和0至42‰S盐度范围内测量准确已知盐度的海水样品电导率和同温度下标准海水电导率的比值R_(s.t.o)。盐度S<35‰的海水样品是由蒸馏水准确重量稀释标准海水制备的,快速蒸发标准海水制备高盐度海水样品继而重量稀释到已经确定的<35‰S范围。推导出了非常准确地表示1～42‰S和全部温度范围内的S与R_(s.t.o)关系式,即 S=f_1(R_(s.t.o)) f_2(R_(s.o,t.)t)=sum from n=0 to 5 a_1R~(a/2) △t/(1 k△t)sum from n=0 to 5 b_nR~(n/2)式中△t=t-15℃,R=R_(s.t.o),只有第一项f_1要求15℃。也确定了温度对标准海水电导率的影响,用t的四次方程非常准确地表示温度t时的电导率的比值的r_(tt)(C_(35.t.o)/C_(35.15.o)),即:(?)_t=sum from n=0 to 4 C_nt~n 这两个方程足以满足常压下所有盐度测量。     

两种涡鞭毛藻生长特性的研究

运用单种培养的方法研究了分别于１９８７年和１９８９年采自葡萄牙沿海和德国湾的两种赤潮涡鞭毛藻Ａｌｅｘａｎｄｒｉｕｍ ｌｕｓｉｔａｎｉｃｕｍ（Ａ．Ｌ．）和Ｙ－１００在不同光、温、盐条件下的生长特性，结果表明，在较低温度条件下，藻的生长在较低的光照强度时就显示了光饱和现象；在较高温条件下，藻的生长随光照增加而加快，两种藻生长的最适温度随光照强度增加而增加，在低于最适温度条件下生长速率都随温度升高而加快     

晚弗拉斯期缺氧事件——弗拉斯-法门阶动物危机的原因？

弗拉斯-法门期(晚泥盆世)动物灭绝事件是显生宙五次主要生物事件中的一次，在此事件中，大约有21％的海洋生物科和50％的生物属消亡，低纬度热带生物礁生态系和浅水海洋动物所受影响最为严重，而高纬度生态系，深水生物和陆地动、植物群仅受到微弱影响，对于该事件的持续时期和最终原因存在广泛分岐。     

美国公众参与理论与实践及其对中国土地整治的借鉴

采用文献分析、对比分析等方法研究美国公众参与理论与实践,以期为中国土地整治公众参与提供借鉴。结果表明:美国公众参与理论比较成熟,联邦及州政府法律要求公众参与规划、决策等,部门、协会等制定了公众参与手册,公众参与技术方法多样且有针对性。中国可借鉴美国公众参与做法,加强土地整治公众参与理论研究,建立健全土地整治公众参与法律制度,编制土地整治公众参与手册,采用多样的公众参与技术方法,从而完善中国土地整治理论,提高土地整治科学性和综合效益。     

Analytic element modeling of embedded multiaquifer domains

An analytic element approach is presented for the modeling of multiaquifer domains embedded in a single-aquifer model. The inside of each domain may consist of an arbitrary number of aquifers separated by leaky layers. The analytic element solution is obtained through a combination of existing single-aquifer and multiaquifer analytic elements and allows for the analytic computation of head and leakage at any point in the aquifer. Along the boundary of an embedded multiaquifer domain, the normal flux is continuous everywhere; continuity of head across the boundary is met exactly at collocations points and approximately, but very accurately, in between. The analytic element solution compares well with an existing exact solution. A hypothetical example with a river intersecting two embedded domains illustrates the practical application of the proposed approach.     

亚洲第四系的主要划分及其岩性和生物地层学意义

这个专题讨论会是作为INQUA亚太地区地层分委员会的第四次国际专题讨论会举办的。1985年,国际地层委员会(ISC)批准了意大利南部Vrica地区的上新世-更新世界线。此后,1987年在渥太华召开的Ⅻ届INQUA大会通过了更新世地层划分分委员会(主席G.M.Richmond)的建议,即把下更新统-中更新统界线暂定在松山-布容极