Bioaccumulation of heavy elements by Armadillidium vulgare (Crustacea,Isopoda) exposed to fallout of a municipal solid waste landfill

This paper reports the response of isopods exposed to fallout of a municipal solid waste landfill located in central Italy. Soil samples and specimens of Armadillidium vulgare were collected at different distances from the landfill and analyzed to determine the concentrations of heavy elements such as As, Cd, Co, Cr, Cu, Ni, Pb, Sb, V and Zn. The isopod analysis was performed on unpurged and purged specimens. Analytical data indicate that the soil contents of heavy elements were quite uniform and within the respective local geochemical background. Slight enrichments of Cu and Pb were found in some soils collected within the solid waste. Purged isopods showed an accumulation of As, Co, Cr, Ni, Sb and V whose body levels decreased as the distance from the landfill increased. Cd, Cu, Pb and Zn concentrations in purged specimens were rather uniform and no significant variation trend occurred. This result probably was due to the fact that the isopods are provided with physiological mechanisms of regulation for these heavy elements. Analytical data also indicate the ability of A. vulgare to adsorb differently the heavy elements according to the following order: As > Co > Ni > Pb > V. The contents of heavy elements in unpurged specimens were higher than in purged ones. This finding suggested that the defecation has marked effects on the tissue levels of heavy elements in isopods. This study indicates that the isopods provide useful information about environmental quality in areas characterized by low and discontinuous emission of heavy elements and their low accumulation in soil.     

长江中下游湖泊软体动物的多样性及分布现状

长江中下游流域是我国淡水贝类多样性最为集中的地区,然而由于人类活动的影响,淡水贝类已成为高度濒危的类群。为有效保护淡水贝类的多样性,我们于 2003 年 6 月-2005 年 5 月对长江中下游流域 13 个水体软体动物的多样性及分布进行了调查。共采集到软体动物 69 种(中国特有种 42 种),隶属于腹足类 9 科 14 属 29 种和瓣鳃类 5 科 17 属 40 种。其中,蚌科和田螺科是种类数最多的两个科,分别占总种类数的 50.7%和 14.5%。不同类型湖泊软体动物种类数的差别较大。通江湖泊所占种类数相对丰富,尤其是适应流水的种类,如河螺属、短沟蜷属及蚌科的种类。大型通江湖泊鄱阳湖和洞庭湖软体动物的种类数和特有种数分别 66 种和 40 种,分别占总种类数和总特有种数的 95.7%和 95.2%。阻隔水体所占种类数相对较少,种类数为 4-19种。与历史资料相比,长江中下游湖泊软体动物的种类数和特有种数均减少 50%左右,且多数种类的分布范围也明显缩小。造成贝类资源衰退的可能原因主要是江湖阻隔所引起的整个江湖复合系统栖息地和水文情势的改变,其他的人为活动如过度捕捞、围垦及废污水的过度排放等也可能是其中的重要原因。     

River-reef connectivity in the Meso-American Region

The accumulation and seasonal impact of riverine discharge on coral reefs of the Meso-American Region (MAR) were estimated using a numerical simulation of river runoff dispersion. River-reef connectivity, or source-sink dynamics of terrestrial runoff was further assessed from more than 400 watersheds of the region onto discrete coral reef areas. Using land use for 2003 and 2004 in the MAR, this work builds upon a Regional Ocean Modeling System simulation of the MAR validated by ocean color satellite data, and on the monthly river nutrient and sediment load and discharge provided by the World Resources Institute using the N-SPECT model. Analysis of the variability of simulated runoff transport to the reefs showed that reefs of the Mesoamerican Barrier Reef System (MBRS) were mostly impacted from June to September, following the peak time of river discharge. At that time, the coastal and oceanic circulations contribute quickly to expel the runoff from the MBRS. High runoff concentration waters leaving the eastern coast of Honduras during the months of October to December return to the southwestern MAR in March as they are entrained in a cyclonic gyre. Coral reefs of the MAR are thus impacted twice, first from the coastal side with runoff of local origin and later from the oceanic side with runoff from mixed origin. High probability of connectivity between rivers and remote reefs is established as this study revealed that river runoff from the north shore of Honduras has a wide-spread impact on most of the coral reefs of southern Belize, while watersheds on the Gulf of Honduras are mostly connected to coral reefs in the northern shore of Honduras. Although the level of remote influence (or runoff concentration reaching the reef) is lower than the local, the cumulative effect of numerous remote river-reef connections remains significant. Communicated by Biology Editor Michael Lesser     

An overview of indexes to evaluate terrestrial plants for phytoremediation purposes (Review)

This paper reviews the various factors, coefficients and indexes developed to evaluate terrestrial plant performance in respect to phytoremediation.A brief list of indexes includes the Accumulation factor, Bioabsorption coefficient, Bioaccumulation coefficient, Bioaccumulation factor, Bioconcentration, Bioconcentration coefficient, Bioconcentration factor, Biological absorption coefficient, Biological accumulation coefficient, Biological concentration factor, Biological transfer coefficient, Concentration factor, Enrichment coefficient, Enrichment factor, Extraction coefficient, Index of bioaccumulation, Mobility index, Shoot accumulation factor, Soil host transfer factor, Soil-plant transfer coefficient, Soil-plant transfer factor, Transfer factor and Translocation factor.These indexes represent the result of a ratio calculation between element concentrations in plant parts to that of substrata. In other cases indexes arise from the ratio calculation of element concentrations in two distinct plant parts.In the literature different terms have been attributed to the same ratio and this often represents an overlap in terminology. On the other hand the same term corresponds to several different ratios and this could create confusion and misinterpretation in data comparison.Furthermore, the evaluation of hyperaccumulation, phytostabilization or phytoextraction of plant species is not always performed in the same way. Different plant parts are considered as well as different extraction procedures for both plant and substrata element assessment. As a consequence, a direct comparison between obtained data is not always reliable and possible.In this paper the various available indexes are reviewed, highlighting both the similarity and differences between them with the aim of helping the community in choosing the appropriate term for both data evaluation and comparison. In this author’s opinion there is no need of new terms to define indexes. I would stress the need for conformity to the original definitions and criteria.     

Determination of food sources of marine invertebrates from a subtidal sand community using analyses of fatty acids and stable isotopes

The fatty acid compositions and stable isotope ratios of carbon, nitrogen, and sulfur were analyzed in the bivalve mollusks Mactra chinensis, Pandora pulchella, Felaniella usta, and Megangulus zyonoensis, the polychaete Chaetopterus cautus, and the main sources of organic matter in a subtidal sand bottom community in Vostok Bay (Sea of Japan). The fatty acid composition and stable isotope ratios of some bivalves is likely to be indicative of substantial inputs from benthic microalgae and an important role of microbial food chains. Only the filter-feeding polychaete C. cautus showed similarity in these characteristics to suspended particulate organic matter synthesized by phytoplankton. It is suggested that the contribution of benthic microalgae to the diet of a consumer organism, inferred solely from the carbon stable isotope analysis, can be significantly overestimated.     

Concentrations of Selected Trace Elements in Marine Bivalves and the Dietary Risk to Residents of Dalian City,Northern China

To assess the potential health risks associated with selected trace elements due to consumption of bivalves, a screening-level risk assessment was conducted through consideration of internationally accepted dietary guidelines and the calculation of hazard quotients. Seventeen edible bivalve species were collected from a local market in Dalian City, China. The ranges obtained for the trace elements analyzed in mg/kg dry weight were as follows: Cu (1.8–133), Zn (56–693), Mn (5.7–150), Se (0.2–3.8), Ni (0.56–7.67), Cd (0.04–10.3), Cr (0.48–2.23), Pb (0.01–1.63), Hg (0.07–0.35), and As (0.22–4.00). The estimated daily intake (EDI) of bivalves was 15.0–255.1 times lower than the RfD guidelines for all the trace elements studied. Further, the calculated hazard quotients (HQs) of the trace elements analyzed were well less than 1. Therefore, there were no potential human health risks to Dalian City consumers of marine bivalves.     

陆地生态系统磷素循环及其影响因素

 磷是生命系统的重要组成成分,其在生态系统内的迁移转化是生态系统结构和功能的决定性因素之一。近20年来,磷在陆地生态系统内的重要性受到越来越多的关注。该文总结了国内外磷循环研究的成果,从磷的来源、在土壤中的存在形态和固定特性、影响因素的复杂性等方面分析了磷素循环的特点;系统阐述了磷在陆地生态系统各库之间及其内部,主要是植被-土壤亚系统内的迁移转化规律及影响因素。陆地生态系统磷素循环主要是系统内部的生物化学循环,由植物自身的遗传特性和土壤的生物、理化性质共同控制,不同控制因素的相对重要性因生态系统类型、时间和空间尺度而异。文章简述了磷循环研究方法的发展及存在的局限性;另外,分析了干旱、半干旱地区磷循环研究的重要性和意义;干旱区生态系统的脆弱性及其植被、土壤特性决定了其磷素循环有其自身的特点及研究的必要性。最后指出了当前陆地生态系统磷循环研究的发展趋势。     

Population Dynamics of the Japanese Scallop <Emphasis Type="Italic">Mizuhopecten yessoensis</Emphasis> (Bivalvia) Under Conditions of Enhanced Hydrodynamics

A population of the Japanese scallop, Mizuhopecten yessoensis, found in the open area of Peter the Great Bay (Sea of Japan), which was not protected against southeastern summer monsoons, has been studied. Specimens of different ages, from 1 year old to 11 years old, were found in the population. According to a provisional estimation, the total reserve of the Japanese scallop in the population reached 30 000 specimens. After strong typhoons, up to 6 000 specimens were stranded along the shoreline. Even after repeatedly occurring typhoons observed during one particular summer season, the population of M. yessoensis remained rather stable, although its age structure demonstrated both uneven annual recruitment in the population and different survival rates in different generations. Specimens of the highly productive generation of 1999 constituted the bulk of the bottom population and coastal wreckage. At older ages, the probability for the Japanese scallop to be stranded during a storm decreases significantly.Original Russian Text Copyright ¢ 2005 by Biologiya Morya, Silina, Latypov.     

菌根真菌对土壤呼吸以及凋落物分解的影响

土壤呼吸是植物固定的碳由陆地生态系统进入大气的主要途径之一; 凋落物分解是养分循环的重要环节。陆地植物的90%以上可同菌根真菌形成共生关系, 菌根真菌对于植物获取环境中的养分具有重要的作用。然而, 其对土壤呼吸和凋落物分解的影响却经常在生态系统对环境变化的响应研究中被忽视。本文系统地综述了国内外相关研究进展, 对菌根真菌如何影响土壤呼吸和凋落物分解这两个过程及这种影响如何受到环境变化的制约做了全面的分析, 并对以往研究中存在的问题以及未来的研究方向提出了展望。