塔玛亚历山大藻和赤潮异弯藻对黑褐新糠虾和卤虫的急性毒性作用

以黑褐新糠虾和卤虫为实验材料,研究了两种典型有毒有害赤潮藻,塔玛亚历山大藻和赤潮异弯藻的毒性.结果表明塔玛亚历山大藻和赤潮异弯藻都能影响糠虾的存活,在9 h内塔玛亚历山大藻和赤湖异弯藻对糠虾的半致死浓度分别约为7000和450 000个/cm3;在24 h内塔玛亚历山大藻和赤潮异弯藻对卤虫存活没有显著影响,而赤潮异弯藻能对卤虫的活力产生强烈的抑制作用,0.1,1.5,5和24 h的半抑制浓度分别为15 000,7500,4500,3000个/cm3,但在赤潮异弯藻较低浓度为3000个/cm3时,经过48 h卤虫的运动能力能够恢复到正常水平.结果表明,这两种有害藻对同一种生物的毒性大小存在差异,而这两种甲壳类生物对同一种有害藻的反应也不相同.     

不同盐度对文蛤(Meretrix meretrix)呼吸代谢及体内酶活性的影响

为研究不同盐度对文蛤呼吸代谢的影响,本实验设置5个盐度(‰)梯度(11、18、25、32、39),检测不同盐度对文蛤(Meretrixmeretrix)耗氧和排氨的影响,以及文蛤的外套膜、鳃、肝胰腺三种组织中乳酸脱氢酶和Na+/K+-ATP酶活性的变化。结果表明:随着盐度的不断升高,文蛤耗氧率先升后降再升,在盐度18时达到最大值;排氨率先升后降,在盐度32时达到最大值。随着盐度不断升高和胁迫时间延长,文蛤的肝胰腺中乳酸脱氢酶活力总体呈先升高后下降再升高的趋势(P0.05),酶活力在盐度39时为最高;随着盐度不断升高和胁迫时间延长,文蛤的外套膜中Na+/K+-ATP酶活力总体呈先下降再升高后下降的趋势(P0.05),在盐度32时为最高;文蛤的外套膜和鳃中乳酸脱氢酶活力以及鳃和肝胰腺中Na+/K+-ATP酶活力受盐度影响不显著(P0.05),酶活力变化也多呈现"W"形的变化趋势。研究结果为文蛤的人工养殖提供参考。     

Impacts of maintenance channel dredging in a northern Adriatic coastal lagoon. I: Effects on sediment properties,contamination and toxicity

Conservation and management of coastal lagoons envisage direct human intervention. To prevent siltation and to preserve the hydrodynamics features of the lagoon system, the inner channels undergo regular maintenance dredging.     

镉和汞两种重金属离子对四角蛤蜊的急性毒性

采用毒理学实验方法,比较研究了Cd~(2+)和Hg~(2+)对四角蛤蜊(Mactra veneriformis Reeve)急性毒性效应的差异,以期为进一步评价重金属离子对四角蛤蜊的毒性效应和作用机理等提供理论依据.死亡概率单位和实验液浓度对数的线性回归分析表明,Cd~(2+)对四角蛤蜊在24、48和96 h的半致死浓度(LC_(50))分别为15.961、5.149和2.383 mg/L,Hg~(2+)的LC_(50)分别为3.714、0.607和0.207 mg/L;Cd~(2+) 和Hg~(2+) 对四角蛤蜊的安全质量浓度分别为0.023 8 mg/L和0.002 1 mg/L,分别是我国渔业水质标准(GB11607-89)限定量的4.76倍和4.02倍.     

Fluoride enrichment in aquifers of the Thar Desert: controlling factors and its geochemical modelling

The groundwater is the only source of drinking water in the Jaisalmer district of Rajasthan, India. The study area is a part of the Thar Desert. It has low and scattered population and no industries; hence, the possibility of anthropogenic input of fluoride is almost negligible. Thus, the enrichment of fluoride is only possible due to geochemical processes taking place in the groundwater of the region. A total of 100 groundwater samples, 34 samples from Jaisalmer and 66 samples from the Pokharan administrative blocks, were collected. It was observed that the concentration of fluoride ranged from 0.08 mg/l to 4.56 mg/l in the groundwater of Jaisalmer and from 0.56 mg/l to 6.60 mg/l in the samples of the Pokharan block. The alkaline condition (average pH, 7.7 ± 0.22 and 8.01 ± 0.25 in Jaisalmer and the Pokharan administrative block, respectively) in the region favours fluorite dissolution. Ion exchange, dissolution of calcite, semi‐arid climate, alkaline conditions and weathering are responsible for fluoride enrichment in the groundwater of the study area. Copyright © 2012 John Wiley & Sons, Ltd.     

The acute and chronic effects of wastes associated with offshore oil and gas production on temperate and tropical marine ecological processes

A review of the acute and chronic effects of produced formation water (PFW), drilling fluids (muds) including oil-based cutting muds, water-based cutting muds, ester-based cutting muds and chemical additives, and crude oils associated with offshore oil and gas production was undertaken in relation to both temperate and tropical marine ecological processes. The main environmental effects are summarized, often in tabular form. Generally, the temporal and spatial scales of these studies, along with the large levels of inherent variation in natural environments, have precluded our ability to predict the potential long-term environmental impacts of the offshore oil and gas production industry. A series of critical questions regarding the environmental effects of the offshore oil and gas production industry that still remain unanswered are provided for future consideration.     

发光细菌在渔业水域污染物急性毒性快速检测中的应用

以明亮发光杆菌为指示生物,对渔业水域中污染物的急性毒性进行了检测,同时研究了PH值、温度对试验结果的影响。研究表明,发光细菌毒性试验是一种快速、简便的毒性测试方法,在温度20～30℃,pH6.0～9.0条件下所进行的测试,其结果与鱼类毒性试验可以互相替代。     

Carbonatation processes at the El Berrocal natural analogue granitic system (Spain): inferences from mineralogical and stable isotope studies

The El Berrocal granite/U-bearing quartz vein system has been studied as a natural analogue of a high-level radioactive waste repository. The main objective is to understand the geochemical behaviour of natural radionuclides occurring under natural conditions. In this framework, the carbonatation processes have been studied from a mineralogical and isotopic ( and ) point of view, since carbonate anions are powerful complexing agents for U(VI) under both low-temperature hydrothermal and environmental conditions. The carbonatation processes in the system are identified by the presence of secondary ankerite, with minor calcite, scattered in the hydrothermally altered granite, and Mn calcite in fracture filling materials. The isotopic signatures of these carbonates lead us to conclude that ankerite and calcite from the former were formed at the end of the same hydrothermal process that altered the granite, at a temperature range of between 72° and 61°C for ankerite, and between 52° and 35°C for calcite. The effect of edaphic CO₂ on both carbonates, greater on calcite than on ankerite, is demonstrated. Calcites from fracture fillings are, at least, binary mixtures, in different proportions, of hydrothermal calcite, formed between 25° and <100°C, and supergenic calcite, formed at ≤25°C. According to their signatures, the effect of edaphic CO₂ in both calcites is also evident. It is assumed that: (i) hydrothermal calcite from fracture fillings and ankerite from the hydrothermally altered granite are the result of the same hydrothermal process, their chemical differences being due to the intensity of the water/rock interaction which was stronger in the altered granite than in the fractures; and (ii) all of these carbonatation processes are responsible for ancient and recent migration/retention of uranium observed in the hydrothermally altered granite and fracture fillings.     

A homogeneous model of the Deacon cell in a circumpolar ocean

Dynamics of the three-dimensional structure of the wind-driven Deacon cell in a β-plane channel are discussed in a homogeneous model in the presence of a sufficiently high ridge. The emphasis is on the water mass balance: how the northward surface Ekman drift is returned. It is demonstrated that a sufficiently high ridge can break up the geostrophic constraint and a net geostrophic volume flux across the open latitude band is allowed. It is found that: (1) the Deacon cell is a fundamentally three-dimensional structure, (2) wind forcing can drive an inter-basin water mass exchange in the Southern Ocean, and (3) zonal through-channel transport in the circumpolar ocean varies at different longitudes.     

Effect of land–ocean contrast on the structure of anomaly tropical circulation

While the important role of land–ocean contrast (LOC) in the mean atmospheric circulation is well-known, an intriguing question remains as to whether LOC can also significantly influence the anomaly circulation. This question is particularly important in the tropics, where a large part of the variabilities is known to be due to convective internal dynamics, which in turn can be significantly affected by LOC. In the present work, we investigate this question using a model of convectively driven anomaly circulation in the tropics. Emphasizing the lower tropospheric flow, we adopt a model describing the horizontal dynamics of the first baroclinic mode on an equatorial β-plane, in the presence of moist feedbacks. We introduce LOC in both latitudinal and longitudinal directions. Land surface dryness is taken into account in the moisture budget through the control of evaporative flux. A constant non-latent heating term is used over land in order to represent radiative and sensible heating effects. First, a control run is performed, numerically, without any LOC using random initial perturbations. The gravest mode that emerges from the control run, which is a wave-2 feature with a period around 20 days, is then used as the initial field for the model runs with LOC. The results show that LOC can significantly influence even the tropical variabilities. A latitudinal LOC, with a land mass in the northern hemisphere (north of 10°N), tends to shift the region of maximum precipitation slightly north of the equator with accompanying steeper gradients near the land–ocean boundary. The implications of this result for our understanding of Asian summer monsoon conditions are discussed. When LOC is only in the longitudinal direction, the dominant wave structure that emerges from the model run has wavenumber one and a period of about 35 days, very similar to the observed 30–60 day oscillation. In our final experiment, which is nearer to the realistic land–ocean configuration in the tropics, it is found that both latitudinal and longitudinal effects of LOC are important aspects of the tropical anomaly circulation. It is suggested that some of the patterns in the precipitation distribution, observed in the tropics and simulated using general circulation models are results of convectively induced internal dynamics, modulated by LOC.