珠江口无瓣海桑(Sonneratia apetala)湿地中浮游动物构成及富营养化评价

选择珠江口南沙区两处典型的以大面积人工种植红树植物无瓣海桑(Sonneratia apetala)为主的感潮河涌,进行湿地区域中的浮游动物研究。于2011年5月和11月对开放性河涌湿地14涌(A区)和封闭性河涌湿地19涌(B区)中的浮游动物进行调研,从种类数和丰度、污染指示种和优势种、营养指数E和污染指数A等方面对浮游动物进行群落结构和功能的分析,并以此对湿地水质和无瓣海桑的净化能力进行评价。结果表明,B区林内原生动物总丰度可达106ind/L数量级,7种丰度优势种均为纤毛虫类,优势种哑铃中缢虫(Mesodinium rubrum),1种赤潮原生动物种类,单种丰度在春秋两季可达1.8×105ind/L、5.1×105ind/L。桡足类、枝角类在春季B区林内丰度最高,分别可达576ind/L和46ind/L,显示春季可能为其繁殖季节。轮虫相对不耐污染生境。指数E和指数A均远高于判断阈值。提出了二项浮游动物的富营养判断标准和二条原则。据此判断,B区湿地存在极重的有机污染现象,主要可能与无瓣海桑林内凋落物量较大或根系分泌物的作用且林内水流不畅有关。     

厦门海域鱼类群落分类学多样性的研究

根据厦门海域鱼类种类组成历史资料和调查资料,系统整理了厦门海域的鱼类总名录和现有名录,并应用分类学等级多样性指数和分类差异变异指数分析了厦门海域鱼类群落分类学多样性的时空变化。结果表明:厦门海域有记录鱼类共649种;现有鱼类有331种,隶属2纲22目90科181属,其中软骨鱼纲共5目9科9属15种,辐鳍鱼纲共17目81科172属316种。厦门海域鱼类总名录的等级多样性指数Δ+和分类差异变异指数Λ+分别为79.267和220.96;现有鱼类群落分类多样性指数Δ+和分类差异指数Λ+分别为77.504和245.34。分类多样性指数Δ+在冬、春季较高,秋季次之,而夏季最低;而分类差异指数Λ+夏季较高,秋季次之,冬春季较低。秋季和冬季鱼类组成的相似度最高,其次为夏季,最后为春季。与历史总名录相比,厦门海域的现有鱼类群落分类学范围较小,生态幅变窄,群落稳定性较差。     

黄河口海域2004-2009年春季大型底栖动物群落的时空变化

根据 2004年-2009年春季6个航次共186个站次的黄河口附近海域生态调查资料,对该海域的大型底栖动物进行了群落特征分析。调查共采集到大型底栖动物153种,生物量变化范围为6.31~13.20 g/m2,丰度的变化范围为44~902 ind./m2。优势种类历年变化较大,出现频率较高的优势种类为纵沟纽虫、细长涟虫、寡节甘吻沙蚕和绒毛细足蟹;调查区域内丰富度指数及Shannon-Wiener多样性指数历年来呈下降的趋势。聚类结果显示,调查区域大致可分为近岸和远岸2个底栖动物群落。分析表明,水深、底质的中值粒径和海水盐度是影响底栖生物群落结构变化的主要因素。     

Stomach content analysis of juvenile Cape stumpnose Rhabdosargus holubi in the Swartkops Estuary,South Africa

Stomach content analyses were performed on the Cape stumpnose Rhabdosargus holubi. The contents were identified to species level and the dietary importance of each component assessed by employing unrelated quantifying methods, which were subsequently combined to determine an index of relative importance (IRI). The index was determined on a seasonal basis as well as for individual sampling stations. The aquatic macrophyte Zostera capensis was the single most abundant item and, together with filamentous algae, constituted the major proportion (IRI = 7 314) of the diet. Crustacea were the next most abundant (IRI = 6 534), followed by Mollusca (IRI = 160). Stomach contents from the sampling stations in the lower reaches were dominated by aquatic macrophytes and algae, whereas those from the middle and upper reaches had a higher incidence of Crustacea. Mollusca in the diet were uniformly distributed throughout the estuary. There was considerable flexibility in the feeding pattern of R. holubi.     

Diversity and coverage of seagrass ecosystems in south-west Madagascar

Seagrass meadows provide important nursery and feeding grounds for many commercially valuable fish species. Here, we address the paucity of published information on the status of seagrasses in Madagascar by documenting the results from ecological surveys of 11 seagrass beds in Velondriake, a locally managed marine area (LMMA) in south-west Madagascar. The diversity and coverage of meadows was highest in the north of the LMMA with up to 51% coverage, and lowest in the south (26%). Overall, eight seagrass species were recorded: Cymodocea rotundata, C. serrulata, Halodule uninervis, Halophila ovalis, H. stipulacea, Syringodium isoetifolium, Thalassia hemprichii and Thalassodendron ciliatum. We discuss the natural and anthropogenic factors that may account for the observed low diversity of seagrasses in southern Velondriake, including overfishing, beach-seining, cyclones, siltation and mangrove deforestation. Based on these baseline surveys, as well as discussions with local communities, it is recommended that measures should be taken to reinforce efforts to ban beach-seines and that the role of seagrasses as carbon sinks and potential sustainable financing options through blue carbon initiatives should be investigated through further, more detailed surveys.     

钨的地球化学研究进展

钨矿是我国的优势矿产资源,储量、产量、消费量和出口量均居世界首位,尤其自本世纪以来,我国钨的年产量稳居全球80%以上。钨在现代工业和生活中有广泛的应用,是一种重要的战略资源。对近20年来,钨的地球化学研究进展进行了概括性综述,包括钨在太阳系、行星地球及其各种主要内生、表生产物中的分布,钨在岩浆-热液过程和表生作用中的地球化学行为,以及钨的生物效应和环境影响等。值得指出的是,近十年来,最值得关注的是有关钨的生物效应和环境影响方面的研究进展。我国作为世界产钨大国,对钨在生物地球化学和环境化学及其健康影响方面的研究几乎还是空白,亟需尽快开展这方面的数据积累和研究。     

塔里木河下游绿洲荒漠过渡带群落多样性特征分析

结合塔里木河下游铁干里克绿洲荒漠过渡带29个植被样地的调查资料,对植物的群落结构和数量特征做了分析。结果表明:研究区群落结构较为简单,植物群落物种多样性水平较低,物种组成单一,天然植物20种,隶属12科18属。从多样性指数的数量特征来看,Simpson多样性指数的变化范围为0.517~0.830,Shannon-Wiener指数变化范围0.851~1.974;Menhinick丰富度指数的变化范围为0.977~3.784,Margalef丰富度指数的变化范围为1.517~8.496;JSW均匀度指数的变化范围为0.719~0.908,JSI指数变化范围为0.729~0.949;植被盖度的变化范围在0.035~1.001之间。     

科尔沁沙质草地不同恢复年限草本层群落结构及其与土壤理化性质的关系

草本植物在沙地植被恢复过程中具有重要作用,研究自然恢复沙质草地草本层植物群落组成变化规律及其与土壤因子之间的关系,对植被与土壤恢复具有重要的意义.本研究对科尔沁严重退化沙地封育12、17年和20年的自然恢复沙质草地植物组成和土壤理化性质进行研究,同时分析了植物组成与土壤因子的相关关系.结果表明:随着恢复年限的增加,土壤...     

2012年夏季南海西北部网采浮游植物群落结构

根据2012年8—9月在南海西北部海区的采样调查,对网采浮游植物的群落结构进行了研究。本次调查共检出浮游植物206种(包括变种及变形),隶属于4门55属,其中硅藻门40属114种,占总种数的55.3%;甲藻门10属86种,占总种数的41.7%。浮游植物平均细胞丰度为66.67×10⁴cells·m^-3,硅藻平均细胞丰度为65.79×10⁴cells·m^-3,甲藻平均细胞丰度为0.88×10⁴cells·m^-3。优势种为伏氏海线藻 Thalassionema franenfeldii、翼根管藻 Rhizosolenia alata和菱形海线藻 Halassionema nizschioides。调查海区的Shannon-Weiner多样性指数(H′)平均值为2.67,高值区位于西沙群岛和调查区东部。对比分析浮游植物细胞丰度与环境因子可知,浮游植物细胞丰度高和种类多的区域,其水体营养盐含量也高,说明营养物质与该区浮游植物细胞丰度分布和群落结构密切相关。