cAMP and sodium transport in the freshwater crayfish, Cherax destructor

Crayfish in which sodium absorption was maximally stimulated had elevated levels of both cAMP and Na⁺-K⁺-ATPase activity in gill tissue. The concentration of cAMP and activity of Na⁺-K⁺-ATPase in gill tissue were monitored following transfer of crayfish from water containing 125 mmol.l⁻¹ Na to Na-free media. Both parameters were significantly elevated within 10 min of transfer to Na-free media and [cAMP] peaked between 1 and 2 h before falling transiently to the control level at 3 h. A second peak of [cAMP] and a further rise in Na⁺-K⁺-ATPase activity were evident 6 h after transfer and elevated levels were then maintained. The pattern observed was consistent with the existence of two separate mechanisms for the control of sodium absorption both of which stimulated the activity of Na⁺-K⁺-ATPase via elevation of the intracellular concentration of cAMP. The initial response was very rapid (<10 min) but of brief duration (1–2 h) and this mechanism appeared to be sensitive to changes in external ion levels. The second mechanism exhibited a much longer response time (3–6 h) and duration and was likely to be sensitive to changes in internal ion concentrations.     

径流雨水中溶解性有机质特征演化及其对典型污染物迁移和生物有效性的影响

地表径流污染已经逐渐成为城市面源污染的重要组成部分。其中溶解性有机质DOM (Dissolved organic matter)是有机污染物的主要组成部分。DOM中因为含有大量不饱和结构、官能团,其中包括羟基、羧基、羰基、胺基等,这些结构容易与径流中重金属结合发生络合反应,改变重金属的赋存形态,从而对其迁移转化及其生物有效性产生很大的影响。本文以北京市地表径流为研究对象,研究城市地表径流在冬、夏季不同功能区不同下垫面中溶解性有机质特征及其与典型重金属的作用机制,通过荧光淬灭滴定实验,研究夏季径流雨水中DOM的不同组分与重金属Cu~(2+)、Pb~(2+)、Zn~(2+)之间的结合机制。研究结果显示PARAFAC将获得的样品都分解成2类6个不同的组分,1种腐殖酸,1种类蛋白;类蛋白物质的荧光强度与Cu~(2+)、Pb~(2+)的淬灭率要强于腐殖酸,而Zn~(2+)则呈现相反趋势;通过使用二维相关同步光谱发现DOM对重金属Cu~(2+)、Pb~(2+)、Zn~(2+)的敏感性呈现递减趋势,二维相关异步光谱发现Cu~(2+)、Pb~(2+)会先与位于270—300nm附近类蛋白光谱带反应,Zn~(2+)则会先与330nm附近的腐殖酸光谱带反应。     

SWAT模型在天山林区林冠截留过程中的改进应用

林冠截留是森林生态水文的重要环节,SWAT （Soil and Water Assessment Tool）模型对其模拟过程还较为粗糙,为了在流域水文模拟中更精细的刻画林冠截留过程从而得到更佳的模拟结果,以SWAT模型为基础,使用半理论林冠截留模型（Gash模型）与SWAT模型进行耦合,以天山林区为研究区对SWAT模型林冠截留模块进行优化改进。通过对改进前后的模拟结果进行对比分析,结果表明：1） SWAT模型和SWAT-Gash模型的R²分别为0.59-0.83和0.65-0.86,NSE值分别为0.58-0.82和0.63-0.85,两种模型PBIAS为7.2%-17.1%,证明SWAT-Gash模型具有更好的适用性;2）相较于出山口径流数据,SWAT模型和SWAT-Gash模型的RMSD值分别为3.49-7.80 m³/s和3.22-4.68 m³/s,SWAT-Gash模型在校准期和验证期的皮尔逊相关系数分别为0.93和0.81,高于SWAT模型的0.91和0.77;3）基于分位数回归（QR）的不确定性分析表明,SWAT模型和SWAT-Gash模型验证期的P因子分别为0.93和0.96,R因子为1.26和1.19,95%不确定性置信区间平均宽度分别为13.50 m³/s和12.86 m³/s;4） SWAT模型与SWAT-Gash模型在验证期的月平均地表径流量分别为6.55 m³/s和8.50 m³/s,表明在该流域内原始SWAT模型会高估林冠截留量。以天山北坡中段林区为例对云杉森林的林冠截留进行精细化模拟,虽然对模型输入数据要求提高,林冠截留数据的收集增加了模型模拟的不确定性,但对本研究区基于物理过程的水文模拟精度提升明显,改进后模型与出山口实测径流数据一致性更强,可以为天山林区小流域水资源管理提供更可靠的依据。     

Cofán Indians’ Monitoring of Freshwater Turtles in Zábalo,Ecuador

The Cofán Indians of Aguarico and Zábalo Rivers in Ecuador in 1990 began a turtle recuperation effort by raising turtle hatchlings (Podocnemis expansa and P. unifilis) in small pools. To evaluate the effectiveness of this program, the Cofán developed and tested three methods to document changes in the populations of turtles. The first method consisted of interviews with people from neighbouring communities about their perceptions of changes in turtle abundance. The second method was a direct count of turtles observed along the rivers from canoe. The third method was an indirect count, involving turtle nest censusing along community beaches. Two of the methods yielded numerical, statistically positive turtle population trends. The turtle program has influenced the community's perception of turtle conservation issues so that, instead of hunting the adults and eggs, they now protect them. The training in record-keeping permits them to make a transparent history of the equitability of access to the turtle egg resource. The Cofán monitoring experience strengthened their successful petition to the Ecuadorian government for the rights to manage their territorial lands within the Cuyabeno Wildlife Reserve, and to receive protected area status and management rights to other ancestral lands. The experience gained by the Zábalo monitors is now serving as a model for the design and implementation of the park monitoring system of the newly-established Cofán Park Ranger Corps, which will be patrolling three Ecuadorian Ecological Reserves which overlap Cofán inhabited areas.     

Variation in the timing of river entry of Atlantic salmon （Salmo salar L. ） in the Baltic

The timing of river entry in the Atlantic salmon is known to depend on genetic, demographic and environmental factors, but little is known about the relative magnitude of among population and among year variation and covariation in this respect in natural state Atlantic salmon rives. To investigate this, variability in the timing of river entry in three historical Finnish Atlantic salmon populations were analyzed using salmon trap data collected during 1870- 1902. The analyses reveled that 1 ） the timing of river entry differed substantially and consistently among the rivers, and that 2） variation among the rivers was much larger than variation among years. Annual variations were not explained by regional environmental conditions, whereas in one river the timing of the local flood peak was a significant predictor of the timing of river entry. Differences in the timing of salmon entry to geographically closely situated rivers suggests that a regionally fixed opening date for coastal fisheries might not be the best management strategy as it may lead to uneven exploitation of salmon populations from different rivers [ Current Zoology 55 （5） ： 342 - 349, 2009] .     

福寿螺的生物防治现状、问题与对策

福寿螺(Pomacea canaliculata)作为一种世界性入侵生物,引入中国已有30余年,现已在中国南方十多个省市大面积分布,造成不可估量的经济损失和生态灾害。本文系统总结了福寿螺生物防治中的天敌资源种类,涵盖了腹足纲、环带纲、昆虫纲、软甲纲、辐鳍鱼纲、爬行纲、鸟纲、哺乳纲等8个类别。并从天敌的引入、研发、利用等方面以及福寿螺应对天敌的防御策略上指出了目前福寿螺生物防治中面临的主要问题。最后对其未来的研究提出了展望,即重点从原产地天敌、寄生性天敌、微生物、生物防治植物和本地经济动物等方面进行筛选,以期为利用中国丰富的生物资源进行福寿螺的生物防治提供参考。     

Inventory and classification of wetlands in India

The Indian subcontinent has a large variety of freshwater, saline and marine wetlands. Whereas the mangroves are relatively well documented, very little is known about the other wetlands, with few exceptions. Only recently an inventory of these welands has been prepared but no effort has been made to classify them. A vast majority of the inland wetlands are temporary and/or man-made, and they have been traditionally used and managed by the local human populations. In this paper, first, we evaluate the classification schemes of the IUCN, US Fish and Wildlife Services and those of the Australian wetlands, for their applicability to Indian wetlands. Then, we propose a simple hierarchical classification of wetlands based on their location (coastal or inland), salinity (saline or freshwater), physiognomy (herbaceous or woody), duration of flooding (permanent or seasonal) and the growth forms of the dominant vegetation. We stress upon the hydrological factors which determine all the structural and functional characteristics of the wetlands. We consider that the various growth forms of wetland vegetation integrate the totality of hydrological variables and therefore, can be used as the indicators of different hydrological regimes.     

Contemporary carbon accumulation in a boreal oligotrophic minerogenic mire – a significant sink after accounting for all C-fluxes

Based on theories of mire development and responses to a changing climate, the current role of mires as a net carbon sink has been questioned. A rigorous evaluation of the current net C-exchange in mires requires measurements of all relevant fluxes. Estimates of annual total carbon budgets in mires are still very limited. Here, we present a full carbon budget over 2 years for a boreal minerogenic oligotrophic mire in northern Sweden (64°11′N, 19°33′E). Data on the following fluxes were collected: land–atmosphere CO₂ exchange (continuous Eddy covariance measurements) and CH₄ exchange (static chambers during the snow free period); TOC (total organic carbon) in precipitation; loss of TOC, dissolved inorganic carbon (DIC) and CH₄ through stream water runoff (continuous discharge measurements and regular C-concentration measurements). The mire constituted a net sink of 27±3.4 (±SD) g C m⁻² yr⁻¹ during 2004 and 20±3.4 g C m⁻² yr⁻¹ during 2005. This could be partitioned into an annual surface–atmosphere CO₂ net uptake of 55±1.9 g C m⁻² yr⁻¹ during 2004 and 48±1.6 g C m⁻² yr⁻¹ during 2005. The annual NEE was further separated into a net uptake season, with an uptake of 92 g C m⁻² yr⁻¹ during 2004 and 86 g C m⁻² yr⁻¹ during 2005, and a net loss season with a loss of 37 g C m⁻² yr⁻¹ during 2004 and 38 g C m⁻² yr⁻¹ during 2005. Of the annual net CO₂-C uptake, 37% and 31% was lost through runoff (with runoff TOC>DIC≫CH₄) and 16% and 29% through methane emission during 2004 and 2005, respectively. This mire is still a significant C-sink, with carbon accumulation rates comparable to the long-term Holocene C-accumulation, and higher than the C-accumulation during the late Holocene in the region.     

Conservation of Freshwater Biodiversity: a Comparison of Different Area Selection Methods

The biodiversity of freshwater systems is endangered, especially in Mediterranean semiarid areas such as the south east of the Iberian Peninsula, whose rich and endemic biota is threatened by the development of surrounding land-crop irrigation. For this reason, the prioritization of areas for biodiversity conservation is an urgent target. In this study we used data records of water beetles from a province of the southeast of Spain for assessing priority areas for freshwater biodiversity conservation. We compare the performance of various area-selection methods, ranging from scoring procedures to complementarity-based algorithms, which are based on different criteria such as richness, rarity and vulnerability. The complementarity approaches were more efficient than methods using scoring or richness and rarity hotspots for representing conservation targets in a given number of areas and for identifying the minimum set of areas containing all species at least once. Within these, the richness-based algorithm was more efficient than rarity-based algorithm. Crucial target habitats for aquatic biodiversity conservation in the area studied are streams at medium altitude, hypersaline streams, and endorreic and karstic complexes.     

Substrate-inhibitory analysis of the cholinesterase in the freshwater oligochaete Lumbriculus variegatus (O.F. Műller, 1773; Lumbriculidae,Oligochaeta)

The substrate-inhibitory analysis has shown that single “atypical” cholinesterase (ChE) presents in tissues of freshwater oligochaete Lumbriculus variegatus (O.F. M?ller). This enzyme differs both from “typical” acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Specific activity of oligochaete ChE ranges 55–100 μmol ATCh g⁻¹ tissue min⁻¹ or 0.7–1 μmol ATCh mg⁻¹ protein min⁻¹, ratio of maximal rates (V) of substrate hydrolysises is 100:72:71:83 for acetyl-, propionyl-, butyryl- and acetyl-β-metylthiocholine respectively. Values of Michaelis constant (K_m) for these substrates are (1.9–2.5) × 10⁻⁴ M. The bimolecular enzyme inhibition rate constants (k_II) for organophosphorus inhibitors paraoxon, DDVP, and iso-OMPA are 10⁷, 10⁶ и 10³ mol⁻¹ | min⁻¹. ATCh and BuTCh exhibit the effect of substrate inhibition of ChE activity, while PrTCh and MeTCh do not.