A field-based population model for the sediment toxicity test organism Leptocheirus plumulosus: I. Model development     

Spencer M  McGee BL 《Marine environmental research》2001,51(4):327-345

We describe the development of a stage-structured population matrix model for the estuarine amphipod Leptocheirus plumulosus, a sediment toxicity test organism, based on regular sampling of a natural population for approximately 2 years. Annual population dynamics were characterized by abundance peaks in the spring and fall, and low densities in the summer and winter. We use a sequence of seasonal projection matrices to capture these qualitative patterns in population dynamics. We compare two methods for estimating transition probabilities: multiple regression and truncated singular value decomposition (SVD). Overall, SVD gave more realistic parameter estimates than regression, although fecundity estimation was problematic. There were predictable trends in growth, survival and fecundity within years. The SVD-derived model provides a framework for assessing the population-level effects of contaminants on Leptocheirus.  相似文献   

Seasonal and annual variations of marine sinking particulate flux during 1993~1996 in the central South China Sea   总被引：1，自引：0，他引：1  

CHEN Ronghu  WIESNER M G  ZHENG Yulong  CHENG Xinrong  JIN Haiyan  ZHAO Qingying  ZHENG Lianfu 《海洋学报(英文版)》2007,26(3):33-43

A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993~1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species (Globigerinoides sacculifer, G. ruber, Globigerinita glutinata, Neogloboquadrina dutertrei) and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution.  相似文献   

Contamination of organotin compounds and imposex in molluscs from Vancouver,Canada     

Horiguchi T  Li Z  Uno S  Shimizu M  Shiraishi H  Morita M  Thompson JA  Levings CD 《Marine environmental research》2004,57(1-2):75-88

Gastropods and bivalves were collected at 15 sites at Vancouver and Victoria, Canada between 24 May and 7 June, 1999, to establish tissue concentrations of butyltin and phenyltin compounds, to record imposex symptoms in gastropods, and to assess the present status of organotin contamination around Vancouver. No neogastropods (such as Nucella lima) were found around Vancouver. Neogastropod populations could have been extirpated by severe TBT contamination in Vancouver, as relatively high concentrations of TBT were detected in tissues of Mytilus trossulus from Vancouver, and the neogastropods distributed in Vancouver might be sensitive to TBT. Recovery from imposex, however, was observed in neogastropod populations from three sites at Victoria and Mission Point. TBT contamination has continued around Vancouver, arising from continuous use of TBT in antifouling paints for vessels larger than 25 m in length; however, TBT has decreased around Victoria and Mission Point. Different patterns of TBT accumulation in tissue were observed among the bivalve species from Vancouver. The highest TBT concentration detected in Tresus capax suggested some possible adverse effects. TBT was the most predominant butyltin component in almost all bivalve specimens surveyed, suggesting a low rate of TBT metabolism. Phenyltin compounds were not detected in any molluscan specimens in this study.  相似文献   

Variations of antioxidant efficiency and presence of endosymbiotic diatoms in the Antarctic porifera Haliclona dancoi     

Regoli F  Nigro M  Chierici E  Cerrano C  Schiapparelli S  Totti C  Bavestrello G 《Marine environmental research》2004,58(2-5):637-640

The role of endosymbiotic diatoms as pro-oxidant stressors in porifera has been investigated in the Antarctic sponge Haliclona dancoi in which the presence of diatoms is influenced by marked seasonal variations during the austral summer. Both chlorophaeopigments and frustules were absent in sponge tissues sampled in early November at the beginning of the summer and increased from the mid of December with slightly shifted temporal trends. The efficiency of antioxidant defenses in the sponge showed a marked response to symbionts with clearly enhanced values corresponding to the peak of diatoms.  相似文献   

Cytochrome P450 differences in normal and imposex-affected female whelk Buccinum undatum from the open North Sea     

Santos MM  ten Hallers-Tjabbes CC  Vieira N  Boon JP  Porte C 《Marine environmental research》2002,54(3-5):661-665

Normal and imposex-affected female Buccinum undatum were sampled from the open North Sea at three locations, one with low, and two with high shipping densities. Cytochrome P450 components and P450 aromatase activity were determined in the microsomal fractions isolated from pooled digestive gland/gonads. Cytochrome P450 aromatase activity was significantly higher (P < 0.05) in normal females collected in the low shipping density area (1,325 +/- 295 fmol/h/mg protein) than levels from imposex animals from a high shipping density area (620 +/- 287 fmol/h/mg protein). A negative correlation was found between aromatase activity and organotin body burden (r = -0.99). Levels of CYP450, cytochrome b5 and NADPH cytochrome c reductase activity did not show differences among groups. This is the first field evidence of depressed aromatase activity in imposex affected females, although additional research under laboratory controlled conditions is required to fully understand the mechanisms underlying the development of imposex in this species.  相似文献   

通过对重力波曳力的参数化来减小数值天气预报和大气环流模式中的系统性误差     

N.Mcfarlane  D.Wshantz  C.Girard 《海洋预报》1988,(Z1)

一、引 言 由于地形性激发的中尺度重力波的中断,在加拿大气候中心大气环流谱模式中有时候采用了波的曳力效应的参数化。这一参数化的细节以及它在大气环流模式气候模拟中影响的讨论,可见Boer等人(1985)的工作。 最近,人们利用激发重力波次尺度地形的更好的描绘,来修改这一参数化方案。还有,使用Lindzen(1981)的波饱和概念来描述曳力效应。这一关于地形重力波曳力参数化的作法已在加拿大气候中心的大气环流谱模式中广泛试验,在加拿大气象中心的业务的谱数值预报模式中也正在普遍进行试验。本文的目的所在于概述在这些模式中正在普遍使用的波的曳力方案,并且证明这一方案在消除中期预报和大气环流模拟的系统性误差方面的用处。  相似文献   

应用C¹⁴测定浮游生物初级生产力的方法     

M.S.Doty  M.Oguri 《海洋与湖沼》1964,6(3):297-308

本文从单位时间和单位体积内通过光合作用转变为有机碳的重量出发,介绍了一个测定有机物初级生产力的新的海洋学方法。为了使对此感兴趣的人都能够参照他们各自的需要来应用或改进这一同位素定量方法,我们简短地对操作方法和历史作了一般的评价之后,还作了相当详尽的叙述。  相似文献   

北海盆地第三纪深海扇的定量分析     

T．Reynolds何拥军  刘健 《海洋地质前沿》1995,(3):12-13

北海盆地第三纪深海扇的定量分析Ｔ．Ｒｅｙｎｏｌｄｓ深海扇内富存有大量的碳氢化合物。因此，无论是从扇容积作为石油储层还是在生产期提供水的补给方面来说，它们的规模、几何形态、砂的体积、纯砂体积与总体积之比以及砂的连通性都是石油工业的关键问题。但是，至今深...  相似文献   

海洋底质图     

M.B.克利诺娃  范时清  徐经 《海洋与湖沼》1958,1(1):243-251

根据第一个五年国民经济发展计划所拟定的关于扩大巴伦支海工业渔捞场的计划,在三十年代初期给苏维埃海洋地质学提供了编制底质图的任务。同时,为了支援我国的工业及保证航海的需要,也提出了控制苏联富饶的海洋资源的任务。 还在上古时代、在航海的早期,就萌发了对海底成分和特性的兴趣。我国在十八世纪、开始编制标有底质特性的原始航行图。以后,在所有国家的航行图上,通常注明底质的名称和它的颜色、或者其它特点的标记;这种底质标记的方法,目前还在采用,但它的缺  相似文献   

Oxidative stress in ecotoxicology: from the analysis of individual antioxidants to a more integrated approach     

Regoli F  Gorbi S  Frenzilli G  Nigro M  Corsi I  Focardi S  Winston GW 《Marine environmental research》2002,54(3-5):419-423

An integrate approach will be discussed for investigations on oxidative stress in xenobiotic toxicity. While the analysis of individual antioxidants is useful for their sensitivity and to understand the mode of action of a stressor, the integration with the analysis of the total antioxidant capacity provides a more holistic assessment of the overall biological significance of such variations. TOSC has a greater predictive value on the health condition of the organisms and allows to discriminate the different role of specific ROS in oxidative stress syndrome.  相似文献