三峡库区汉丰湖鱼类群落结构的季节变化

为了解汉丰湖鱼类群落结构的季节变化特征,以便为汉丰湖鱼类资源的合理利用及保护提供理论依据,于2014年12月、2015年4、7和10月按季度共4次对汉丰湖鱼类群落结构进行调查与分析.结果表明:共采集到鱼类8538尾,38种,隶属于5目9科32属;其中,鲤形目鱼类有28种,占总物种数的73.68%.鱼类组成以湖泊定居性种类为主,瓦氏黄颡鱼(Pelteobagrus vachelli)、蛇鮈(Saurogobio dabryi)、银鮈(Squalidus argentatus)、鲫(Carassius auratus)、光泽黄颡鱼(Pelteobagrus nitidus)、鲤(Cyprinus carpio)和贝氏(Hemiculter bleekeri)为汉丰湖的重要优势种,占总尾数的67.45%.汉丰湖鱼类群落Shannon-Wiener多样性指数、Pielous均匀度指数和Margalef丰富度指数在冬季最高,而Pielous均匀度指数在不同季节相对稳定.Jaccard群落相似性指数较高,季节间种类相似度较高.鱼类群落稳定性分析表明,冬季稳定性最高,其次为春季,夏季稳定性最低.湖泊生境尤其是水位的变化对汉丰湖鱼类群落结构影响明显.     

库赛湖—玛曲断裂带东,西大滩段全新世活动特征及古地震的研究

通过对野外调查资料的分析认为:库赛湖—玛曲断裂带东、西大滩段全新世以来具有多次强烈活动,表现为断错晚第四纪地层,断错山脊、水系、河流阶地以及冰水扇等一系列地貌现象。根据对断裂带上古地震破裂带的研究,全新世以来在该段曾发生过三次7.5级左右的古地震事件。     

江西柘林湖水华蓝藻——长孢藻(Dolichospermum)的形态多样性及其分子特征

长孢藻是具有产多种蓝藻毒素及异味物质潜在能力的丝状异形胞蓝藻.为了探究长孢藻的生物学特性,我们从江西柘林湖分离24株长孢藻,经形态鉴定分成4个种类,分别为浮游长孢藻(Dolichospermum planctonicum)、近亲长孢藻(D. affine)、卷曲长孢藻(D. circinale)、螺旋长孢藻(D. spiroides). 16S rRNA基因序列表明柘林湖长孢藻与日本等地区的长孢藻高度相似,但只有近亲长孢藻与日本近亲长孢藻在分子系统进化树上聚为一支.基于16S-23S rRNA之间高变异性的ITS序列分析,4种长孢藻的D1-D1'螺旋结构相同,藻丝为直型的浮游长孢藻、近亲长孢藻与藻丝为弯型的卷曲长孢藻、螺旋长孢藻的Box-B、V3螺旋结构差异较大.通过对毒素和异味的分子生物学检测显示24株长孢藻均不产毒,但是4株浮游长孢藻及1株卷曲长孢藻含有土腥素合成基因.本研究不仅对柘林湖水华蓝藻的多样性以及潜在生态风险提供科学的基础资料,也在流域层面上为鄱阳湖的水生态系统研究和保护提供了一定的科学基础.     

基于环境DNA宏条形码技术的水体无脊椎动物多样性研究：以广州海珠湖为例

于2021年1月,利用环境DNA宏条形码（eDNA）技术,对广州海珠国家湿地公园海珠湖的水体和沉积物进行无脊椎动物多样性和群落结构调查,并比较了eDNA和传统形态学鉴定对浮游动物的检出能力。结果表明：eDNA检出海珠湖无脊椎动物9门16纲34目71科93属137个可操作分类单元（OTUs）;其中,水采样品中共检出9门50属68个OTUs,网采样品中共检出6门27属35个OTUs,沉积物休眠卵样品中共检出9门70属103个OTUs。水采和网采样品中,主要的无脊椎动物均为轮虫动物门和节肢动物门;沉积物中主要的无脊椎动物为环节动物门和节肢动物门。沉积物休眠卵OTU丰富度最高,水采样品的OTU丰富度高于网采样品。比较浮游动物的形态鉴定和eDNA鉴定,发现后者在属水平上能鉴定出更多的种类;形态学鉴定的桡足类（100%）和多数轮虫（58.82%）可被eDNA注释出,而eDNA注释出的多数桡足类（71.43%）和轮虫（58.82%）在形态学鉴定中未发现;eDNA未注释出枝角类。结果表明,eDNA在无脊椎动物调查中具有较高的应用潜力,与传统形态学鉴定组合应用能更全面地了解无脊椎动物的种类和水生生物多样...     

县(市)绝对地震应急能力评估方法的初步研究

县(市)地震应急能力的高低直接关系到中国整个地震应急工作的成效.从县(市)绝对地震应急能力的内涵分析出发,结合汶川地震灾区县(市)地震应急能力实地调研工作取得的认识,首先初步构建了县(市)绝对地震应急能力指标体系框架;然后以四川省县(市)为例,在遵循科学性、系统优化和可操作性原则的基础上,构建了围绕着1个目标层,设定5...     

Local variability of sedimentation rate in Lake Arendsee, Germany

We measured the thickness and the dry weight of recently deposited sediment along several transects across Lake Arendsee in order to quantify the sedimentation rate and its local variability. As a time marker, we used an artificial marl layer that was deposited by a remediation program in the year 1995. A portion of the sediment deposited during the year was transported from the littoral and the top of the submerged hills to the foot of the slope, where we found the greatest deposition. Within the same lake, the deposited sediment layer varied by a factor of 4 between minimal and maximal values over the same time periods. Lake Arendsee is a holomictic and eutrophic lake with depletion of oxygen in summer time.     

Carbon input, production and turnover in the interstices of a Lake Tegel bank filtration site, Berlin, Germany

The sandy littoral zone of Lake Tegel (Berlin, Germany) was investigated during 2004–2006 down to sediment depths ≥26 cm to derive a scheme of seasonal carbon turnover under induced bank filtration conditions. Carbon turnover processes were quantified regarding external and internal sources of dissolved and particulate organic matter (DOM and POM), primary production, community respiration, redox potential as well as specific loads of soluble chemical compounds such as nitrogen, iron, manganese and DOC.Over the course of the year, infiltrating DOC decreased by about 13–20% within the upper 26 cm sediment of the infiltration stretch. Gradients of all observed soluble compounds that are highly cross-linked to biological activities were highest in the topmost centimetre. In this depth mass balances (output–input) were negative concerning NO₃-N (−1 mg dm⁻² d⁻¹, summer mean) and DOC (−2 mg dm⁻² d⁻¹, winter mean), respectively, while specific loads of cations such as manganese reached up to 0.2 mg dm⁻² d⁻¹ during summer. Carbon mineralization ranged between 3 and 7 mg C dm⁻² d⁻¹ and was nearly twice as high in summer as in winter. The turnover of the infiltrating DOC contributed maximally 25% in summer to 50% in winter to the entire organic carbon mineralization. Gross and net primary production differed up to a factor of >10, indicating very fast turnover reactions and the predominance of community respiration and mineralization, respectively. The POC in the upper sediment layer (10 cm) temporally varied around 1% sediment d.w.; benthic algae, organic seston input and autumnal leaf fall contributed similar percentages to the POC pool.     

High accuracy measurements of water storage change in Mining Lake 111, Germany

Several pressure sensors were deployed in a small lake to determine its storage change. It could be shown that a deep enough deployment and an averaging over a time interval of 1 hour and 5 measuring points allowed for a measurement of 1 or 2 kg/m² (i.e. 2 mm of water column) of changes in the storage on the scale of the lake size. This accuracy for the lake storage could not be achieved by other methods, especially if conditions were difficult, e.g. snowfall, or in cases when precipitation was small. Finally, the pressure measurement - originally intended to roughly determine the water level - turned out to be a direct measurement of water mass in the lake, which was the proper magnitude for exchanges between atmosphere and lake. Hence the measurement of lake storage could become an interesting approach even for meteorological measurements, such as precipitation and evaporation on a water surface.     

山东南四湖成湖时代浅析

对南四湖两个沉积岩心进行了多环境代用指标分析,利用１４Ｃ方法测定了沉积剖面下部年代,采用２１０Ｐｂ和１３７Ｃｓ方法测定了剖面上部沉积速率,进而确定了整个沉积剖面的时代根据沉积岩心色素指标特征、有机碳氮比值和有机碳同位素特征分析,初步确定南四湖的成湖时代为２４５０ａＢＰ     

巢湖沉积物柱样中正构烷烃初探

对巢湖湖心沉积物柱样样品的正构烷烃和有机碳进行了分析,利用正构烷烃碳数分布类型、L／H、OEP指标和有机碳数据,对该区近110年来正构烷烃的来源进行初步探讨。研究结果表明：21-25cm和16-20cm处正构烷烃以高等植物和低等生物输入并重;11．15cm即1952-1967年处具有外源性石油污染;从10cm开始,正构烷烃以细菌、藻类为代表的低等生物输人为主;尤其是1-5cm样品正构烷烃和TOC含量明显高值,表明该时期湖泊富营养化加剧。     

抚仙湖富营养化初探

近二十年的水质监测资料研究分析表明,抚仙湖生态系统相当脆弱,出现了加速富营养化趋势,浮游藻类数量增加了2．6倍,Chl．a含量增加了3倍,透明度减小了将近一半,综合营养状态指数呈急剧上升,揭示了发生富营养化的危险性。促进因素主要有外来污染增加,氮、磷等营养盐在湖内迅速积累,湖泊生态系统过于简单、脆弱等因素,呼吁加大对抚仙湖污染防治的力度,防患于未然。     

Pelagic trophic transfer efficiency in an oligotrophic, dimictic deep lake (Lake Stechlin, Germany) and its relation to fisheries yield

We investigated trophic transfer efficiency in the pelagic food chain of deep, oligotrophic Lake Stechlin (Germany) by analyses of the primary, secondary, and fish production. Primary production between April and November 2000 was estimated at 78 g C m⁻², pelagic secondary production at 14 g C m⁻², and production of the main planktivorous fish species [European cisco, Coregonus albula (L.)] at 0.77 g C m⁻². Thus, trophic transfer efficiency between primary and pelagic secondary production was around 18%, whereas between pelagic and fish production around 6%. The high efficiency at the first step of the chain is discussed to be due to the high food quality in oligotrophic lakes due to the dominance of Bacillariophyceae and Chlorophyceae rich in essential fatty acids. In turn, the relatively low trophic transfer efficiency between the secondary and the fish production is mainly explained by the avoidance of calanoid copepods as food source by the ciscoes. Concerning the trophic transfer efficiency, results from this study support the general assumption of a 10% transfer between neighbouring trophic levels within ecosystems.     

巢湖、太湖蓝藻湖靛及其提取物的动物毒性初步研究

对国内淡水湖泊巢湖、太湖中的蓝藻湖靛及其提取物（藻胆蛋白）,进行了动物毒性实验。实验动物为昆明种小白鼠,采用灌胃法给药。给药后小白鼠均无中毒症状,一周内无死亡。说明巢湖、太湖中蓝藻湖靛及其提取物,对以小白鼠为代表的哺乳类动物消化系统,基本不产生毒性。这对于开发两湖中的蓝藻作为鱼、家禽等饲料和提取其中的植物蛋白（藻胆蛋白）作为营养食品添加剂等有一定意义。     

岱海生物群落结构的演变及其对渔业发展的影响

岱海水生生物种类贫乏,生物量低,渔产力不高,优化岱海水体生物群落组成,引种耐低温、耐盐碱的水生植和藻类,改善水体环境调整鱼类种群结构是渔业发展的重要措施。     

内蒙古锡林郭勒盟盐湖浮游生物的群落特征

通过2003年9月-2004年1月的渔获物调查,并结合1984-2002年的鱼类产量统计资料,分析了近二十年来太湖鱼类产量和组成的变化规律以及环境间的相互作用关系.结果表明,太湖鱼类的种类在不断减少,如本次调查和2002年3月-2003年12月的调查只采集到48种鱼类,和历史资源料比较有55种鱼类难以采到;鱼类产量组成表现为仅鲚鱼的产量和组成比例总体呈较快的上升趋势,从1984年的5153.7t、占总产量的36.2%上升到2002年的19571t、64.1%,鲤、鲫鱼基本维持不变,但近四年略有上升,其余鱼类均呈下降趋势.用Wilhm改进式计算的鱼类产量组成的均匀度指数H总体呈逐年下降趋势,近二十年来平均以每年-0.0465的速率下降;分析认为,人类活动以及由此引起的太湖生态环境变化,包括江湖阻隔、过渡捕捞、富营养化及太湖特有的鱼类生态学特点决定了鱼类组成的这一变化趋势:江湖阻隔、过度捕捞是引起太湖鱼类种类减少和鱼类组成发生巨大变化的主要原因;太湖近二十年来富营养化程度不断加重,由此使初级生产力水平持续增长,浮游生物饵料丰富,使鲚鱼等浮游生物食性鱼类产量逐年提高;舶鱼数量的减少又使鲚鱼失去抑制.随着鲚鱼等浮游动物食性鱼类产量的升高,太湖浮游动物的生物量呈下降趋势,这可能是太湖浮游植物数量倍增的生物学因素之一.目前太湖鱼类产量组成的变化正向着抑制浮游动物和有利浮游植物生长的方向发展.