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1.
东北松嫩平原区湖泊对气候变化响应的初步研究   总被引:5,自引:3,他引:2  
以气候变暖为主要特点的气候变化已成为当前研究的焦点,气候变化和不同类型的生态系统之间的相互作用更是受到广泛关注.东北地区作为我国气候变化的一个敏感区,观测记录和多种模式预估显示该区气候变暖显著并将进一步增强,降水变化趋势则不明显或略有增加.东北松嫩平原湖泊群是我国湖泊密度最大的湖区之一,但近几十年来,该区湖泊生态环境不断恶化,其中气候因素最为受人关注.本文从以下几个角度综述了松嫩平原湖泊群对气候变化的响应:(1)湖泊面积和湖泊水位;(2)湖泊水质;(3)湖泊生态多样性.在此基础上,探讨了该区未来气候变化对湖泊的可能影响以及湖泊的演变趋势,也阐述了在这种自然背景下的人类活动对湖泊环境演变的影响.  相似文献   

2.
湖、库水体是重要的N2O排放源,在全球氮素循环及全球气候变化中具有重要作用.本文综述了目前有关湖、库水体N2O排放研究进展,重点介绍湖、库水体N2O产生和排放的过程、不同时空尺度的排放特征、N2O排放的影响因子框架及监测方法.湖、库水体N2O不仅源于内部微生物硝化作用、反硝化作用、硝化-反硝化耦合作用、脱氮作用以及极少数底栖无脊椎动物代谢过程,同时流域上游河流汇入、地表径流输入、污水排放以及地下水排泄等构成湖、库水体N2O的重要外源,但目前对内源/外源的相对贡献的定量化研究不足;湖、库水体N2O排放方式包括扩散、植物传输及少量气泡排放,对水库而言,大坝下游水电涡轮机形成的脱气作用可能是N2O排放的潜在途径.对文献综合分析表明,湖、库水体N2O排放通常呈现明显的季节变化(夏季>冬季)和日变化,同时在全球(一般低纬度>高纬度)、区域及水体内部等不同尺度上表现出显著的空间变异性;这种时空变异特征主要受到湖、库自身理化因子(温度、营养盐、溶解氧、C/N、水文)、生物因子(水生植物、藻华)以及陆域人类活动(污水排放、农业活动以及城市化等)的影响;湖、库N2O排放不同监测方法的差异也是潜在的影响因素,传统的漂浮箱法和薄边界层法均可能低估水体N2O排放通量,未来需将传统的监测方法与新型的涡度相关法相结合,减小监测方法的不确定性.结合当前湖、库水体N2O排放的研究不足,建议未来可以从湖、库N2O产生的微生物机制,区域尺度上人类活动与湖、库群N2O排放的耦合关系,水陆交错带的产、排过程,变化环境下的湖、库N2O排放以及监测方法等方面深入研究.  相似文献   

3.
全球变暖对淡水湖泊浮游植物影响研究进展   总被引:9,自引:6,他引:3  
全球变暖对湖泊生态系统的影响已经成为近年来湖沼学领域的研究热点.本文首先列举了目前研究全球变暖对淡水湖泊浮游植物影响的常用方法:监测数据分析、时空转换、遥感信息提取、控制实验、模型预测和古湖沼学技术等.研究结果表明气候变暖导致的气温升高、湖泊热力分层提前破坏以及无冰期提前等因素可导致春季物候提前;在全球变暖大背景下浮游植物群落结构正朝着蓝藻占优的方向发展,但是不同地区以及不同物种对全球变暖的响应不一致.在营养盐充足的湖泊中,由于全球变暖延长了浮游植物生长季节等,从而能提高浮游植物初级生产力;但在贫营养湖泊中,浮游植物初级生产力与变暖趋势甚至可能呈负相关.由于生态系统往往是多因子的共同作用,这也使得全球变暖对浮游植物群落的影响效应复杂化,区分各因子的净影响份额是目前研究的一个难点;全球变暖引起的风场改变会促进浅水湖泊中营养盐从底泥的释放,同时也会增加水体中悬浮物的浓度而影响水下光场,因此开展气候变化对再悬浮及浮游植物群落结构的影响可能是将来研究的一个切入点.  相似文献   

4.
云的形成过程及其类型复杂多样,在气候系统中发挥着重要作用.在当前气候背景下,云在大气顶的净辐射效应为负值,即对地气系统起着强烈的冷却作用.云反馈过程是当前气候变化研究中不确定性最大的因子之一,其强度会随时间、空间、云量、云高、云光学厚度等发生变化.目前,观测研究和气候模拟都表示全球平均云反馈为正值,以热带高云高度反馈和热带海洋低云量反馈两个正反馈为主,但是云反馈仍然存在较大的不确定性.在温室气体驱动的全球变暖下云如何对气候系统进行反馈至关重要,它直接影响气候敏感度的估算并决定着气候模式对未来全球变暖预估的准确性.因此,云反馈强度也会在很大程度上影响温室气体减排政策的制定.为此,本文回顾了云在气候系统中反馈作用的最新研究进展,指出了该研究领域当前面临的关键挑战,最后,对未来需要开展的研究进行了讨论与展望,以期为全球和东亚区域云辐射物理过程模拟、模式不确定性分析以及未来气候变化和全球变暖预估等方面的研究提供系统的科学参考.  相似文献   

5.
作为全球变化的主要表现之一,气候变暖对人类赖以生存的地球环境已经产生了不可磨灭的影响.其中,气候变暖如何影响污染物传播引起了科学家的广泛关注.持久性有机污染物(POPs)是可以进行全球传输的污染物.揭示气候变暖对POPs全球循环的影响机制对于准确理解POPs循环的过程和相关政策的制定具有重要的指导意义.本文综述了此领域近十年来的主要研究工作,总结了气候变暖对POPs排放、迁移、储存、降解和毒性的影响,简述了相关模型的特点和主要应用,并指出目前研究中存在的问题以及未来研究的主要方向.在气候变暖条件下,POPs全球循环的变化主要体现在以下几个方面:(1)全球变暖直接促进了POPs的二次排放,升温将导致POPs从土壤和海洋中挥发出来,而冰川融化、冻土退化则可以将POPs二次释放进入淡水生态系统;(2)全球极端气候(干旱和洪水)通过剧烈的地表侵蚀过程,将土壤所负载的POPs重新释放进入环境,进而改变了POPs的全球分布;(3)气候变暖条件下大气与海洋环流的变化将显著改变全球POPs的迁移路径;(4)气候变暖改变了海洋生物生产力,进而改变了海洋对POPs的储存能力;(5)部分地区水生及陆地食物链结构在气候变暖的情景下发生了明显变化,这种变化可以导致POPs在生态系统中毒性的放大;(6)尽管气候变暖在促使POPs再挥发的同时也加速着其降解的过程,但是总体上气候变暖增加了环境中POPs的总量;(7)各种模型的耦合应用对未来气候变暖情景下POPs环境行为的反馈与响应进行了预测,这些工作有助于政策和法律制定者在POPs控制措施中全面考虑气候变暖对POPs环境载荷的影响.在未来,气候变暖与全球变化的其他表现协同影响POPs的循环将是下一步的研究重点,POPs与碳循环、水循环互相关联耦合,其相互作用机制将是生态系统对气候变化适应性研究的一个新方向.  相似文献   

6.
全球变暖、碳排放及不确定性   总被引:4,自引:0,他引:4  
近年来人们对全球变化尤其是对气候变暖及其机制的争论达到了前所未有的程度.本文对气候变化研究的最新进展和国内外动态进行了梳理,得出如下观点和结论:(1)全球变暖是客观事实,但由于多种原因,全球升温多少存在不确定性;(2)人类活动和自然因素共同影响着气候变化,但其相对贡献量难以量化;(3)政府间气候变化专门委员会(IPCC)认为CO2等温室气体浓度的增加是全球变暖的主要因素,但学术界对此有异议,因为作用于温度变化的自然和人为机制并不十分明确,大气中CO2的来源也存在不确定性.因此,在得出准确结论之前,需要加大力度研究和明确这些不确定性.  相似文献   

7.
甲烷是潜在的高效清洁能源,同时也是重要的温室气体,对全球气候的变化和调节有重要影响.海底沉积物中蕴藏着大量的甲烷,主要包括有机质热裂解与生物成因气两种来源,一般以水合物的形式较为稳定地储存在深部沉积物中.海洋每年向大气中释放的甲烷仅占大气中甲烷总量的1~5%,海底大部分的甲烷被海洋中的甲烷代谢微生物消耗.海洋中甲烷的生物转化(微生物代谢)影响并控制了海洋释放到大气中的甲烷通量.在全球气候逐渐变暖的背景下,解析海洋环境中甲烷的生物转化机制有助于理解和评估海洋-大气甲烷通量对全球气候变化的影响.文章综述了海洋环境,尤其是海底沉积物中甲烷生物转化机制研究的最新研究进展,主要介绍已知甲烷代谢微生物的种类、分布和甲烷产生和氧化的代谢机制;探讨海洋中甲烷的生物转化对全球气候变化的影响,并且提出了甲烷代谢机制的未来研究方向和对其他科学研究的意义.  相似文献   

8.
全球变暖对湖泊生态系统的影响已经成为近年来湖沼学领域的研究热点。本文首先列举了目前研究全球变暖对淡水湖泊浮游植物影响的常用方法:监测数据分析、时空转换、遥感信息提取、控制实验、模型预测和古湖沼学技术等。研究结果表明气候变暖导致的气温升高、湖泊热力分层提前破坏以及无冰期提前等因素可导致春季物候提前;在全球变暖大背景下浮游植物群落结构正朝着蓝藻占优的方向发展,但是不同地区以及不同物种对全球变暖的响应不一致。在营养盐充足的湖泊中,由于全球变暖延长了浮游植物生长季节等,从而能提高浮游植物初级生产力;但在贫营养湖泊中,浮游植物初级生产力与变暖趋势甚至可能呈负相关。由于生态系统往往是多因子的共同作用,这也使得全球变暖对浮游植物群落的影响效应复杂化,区分各因子的净影响份额是目前研究的一个难点;全球变暖引起的风场改变会促进浅水湖泊中营养盐从底泥的释放,同时也会增加水体中悬浮物的浓度而影响水下光场,因此开展气候变化对再悬浮及浮游植物群落结构的影响可能是将来研究的一个切入点。  相似文献   

9.
贵阳市"两湖一库"不同季节硫酸盐还原菌分布变化   总被引:3,自引:0,他引:3  
基于MPN法对贵阳市"两湖一库"——阿哈水库、红枫湖、百花湖不同季节沉积物中硫酸盐还原菌(SRB)分布规律及其影响因素进行了研究.结果表明,"两湖一库"SRB含量及分布季节差异显著,冬季SRB含量明显低于夏、秋季节.冬季,SRB含量峰值主要集中在沉积物中部,而在夏、秋季节,SRB含量峰值主要集中在沉积物上部.在受到酸性矿山废水污染的阿哈水库,硫酸根含量远高于红枫湖和百花湖,但沉积物中的SRB含量整体上和其它2个未受硫酸盐影响的湖泊差异不大,仅在夏、秋季节表层沉积物中明显升高,表明"两湖一库"丰富的有机质及适宜的pH为硫酸盐还原菌提供了良好的生长环境,硫酸根含量没有成为SRB含量的主要限制因素.  相似文献   

10.
脂肪酸在生物的摄食活动中相对稳定,可用于辨别消费者的食物来源.不同营养水平的湖泊与水库中浮游动物的碳源组成有差异,因而可能具有不同的脂肪酸组成特征.本研究对南京市及其周边21个湖库的颗粒有机物(POM)、浮游动物的脂肪酸组成进行了对比分析.结果 表明,南京市及其周边湖库21个湖库由中营养、轻富营养、中富营养、重富营养共...  相似文献   

11.
Reservoirs are man‐made lakes that severely impact on river ecosystems, and in addition, the new lake ecosystem can be damaged by several processes. Thus, the benefits of a reservoir, including energy production and flood control, must be measured against their impact on nature. New investigations point out that shallow and tropical reservoirs have high emission rates of the greenhouse gases CO2 and CH4. The methane emissions contribute strongly to climate change because CH4 has a 25 times higher global warming potential than CO2. The pathways for its production include ebullition, diffuse emission via the water‐air interface, and degassing in turbines and downstream of the reservoir in the spillway and the initial river stretch. Greenhouse gas emissions are promoted by a eutrophic state of the reservoir, and, with higher trophic levels, anaerobic conditions occur with the emission of CH4. This means that a qualitative and quantitative jump in greenhouse gas emissions takes place. Available data from Petit Saut, French Guinea, provides a first quantification of these pathways. A simple evaluation of the global warming potential of a reservoir can be undertaken using the energy density, the ratio of the reservoir surface and the hydropower capacity; this parameter is mainly determined by the reservoir's morphometry but not by the hydropower capacity. Energy densities of some reservoirs are given and it is clearly seen that some reservoirs have a global warming potential higher than that of coal use for energy production.  相似文献   

12.
Climate warming, one of the main features of global change, has exerted indelible impacts on the environment, among which the impact on the transport and fate of pollutants has aroused widespread concern. Persistent organic pollutants (POPs) are a class of pollutants that are transported worldwide. Determining the impact of climate warming on the global cycling of POPs is important for understanding POP cycling processes and formulating relevant environmental policies. In this review, the main research findings in this field over the past ten years are summarized and the effects of climate warming on emissions, transport, storage, degradation and toxicity of POPs are reviewed. This review also summarizes the primary POP fate models and their application. Additionally, research gaps and future research directions are identified and suggested. Under the influence of climate change, global cycling of POPs mainly shows the following responses. (1) Global warming directly promotes the secondary emission of POPs; for example, temperature rise will cause POPs to be re-released from soils and oceans, and melting glaciers and permafrost can re-release POPs into freshwater ecosystems. (2) Global extreme weather events, such as droughts and floods, result in the redistribution of POPs through intense soil erosion. (3) The changes in atmospheric circulation and ocean currents have significantly influenced the global transport of POPs. (4) Climate warming has altered marine biological productivity, which has changed the POP storage capacity of the ocean. (5) Aquatic and terrestrial food-chain structures have undergone significant changes, which could lead to amplification of POP toxicity in ecosystems. (6) Overall, warming accelerates the POP volatilization process and increases the amount of POPs in the environment, although global warming facilitates their degradation at the same time. (7) Various models have predicted the future environmental behaviors of POPs. These models are used to assist governments in comprehensively considering the impact of global warming on the environmental fate of POPs and therefore controlling POPs effectively. Future studies should focus on the synergistic effects of global changes on the cycling of POPs. Additionally, the interactions among global carbon cycling, water cycling and POP cycling will be a new research direction for better understanding the adaptation of ecosystems to climate change.  相似文献   

13.
全球变化下青藏高原湖泊在地表水循环中的作用   总被引:2,自引:2,他引:0  
青藏高原是地球上最重要的高海拔地区之一,对全球变化具有敏感响应.青藏高原作为"亚洲水塔",其地表水资源及其变化对高原本身及周边地区的经济社会发展具有重要的影响.然而,在气候变暖的情况下,构成高原地表水资源的各个组分,如冰川、湖泊、河流、降水等水体的相变及其转化却鲜为人知.湖泊是青藏高原地表水体相变和水循环的关键环节.湖泊面积、水位和水量对西风和印度季风的降水变化非常敏感,但湖泊面积和水量变化在不同区域和时段的响应也不尽相同.湖泊水温对气候变暖具有明显响应,湖泊水温和水下温跃层深度的变化能够对水—气的热量交换具有明显影响,从而影响了区域蒸发和降水等水循环过程.由于湖泊水量增加,高原中部色林错地区湖泊盐度自1970s以来普遍下降.根据60多个湖泊实地监测建立的遥感反演模型研究发现,2000—2019年湖泊透明度普遍升高.对不同补给类型的大湖水量平衡监测发现,影响湖泊变化的气象和水文要素具有较大差异.在目前的暖湿气候条件下,青藏高原的湖泊将会持续扩张.为了深入认识湖泊变化在青藏高原区域水循环和气候变化中的作用,需要全面了解湖泊水量赋存及连续的时间序列变化,需要深入了解湖泊理化参数变化及对湖泊大气之间热量交换的影响,需要更多来自大湖流域的综合连续观测数据.  相似文献   

14.
Freshwaters in different regions show many similarities and differences in their responses to climatic warming. Bases for comparison include reports from regional committees, long-term records for several sites where climate has warmed in the past two decades and other human alterations to freshwaters that simulate some of the expected results of climatic warming, such as reservoir construction. Palaeoecological studies of freshwaters under climatic warming and differences in communities under different climatic regimes are also considered. Major changes in the physical, chemical and biological characteristics of lakes occur. Many of the changes to lakes and streams are the result of strong effects of climatic warming on terrestrial catchments. Inputs from catchments can be either dampened or amplified by in-lake processes, in some cases causing counter-intuitive responses, such as the acidification of streams but alkalinization of lakes in areas where supplies of base cations are limited. Consideration of land–water interactions and interactions between climatic warming and other human stresses are important for the accurate prediction of the effects of climatic change. © 1997 John Wiley & Sons, Ltd.  相似文献   

15.
Climate change characterized by increasing temperature is able to affect precipitation regime and thus surface hydrology.However,the manner in which river sediment loads respond to climate change is not well understood,and related assessment regarding the effect of climate change on sediment loads is lacking.We present a quantitative estimate of changes in sediment loads(from 1.5 Gt yr-1 pre-1990 to 0.6 Gt yr-1 from 1991-2007) in response to climate change in eight large Chinese rivers.Over the past decades,precipitation change coupled with rising temperatures has played a significant role in influencing the sediment delivery dynamics,although human activities, such as reservoir construction,water diversion,sand mining and land cover change,are still the predominant forces. Lower precipitation coupled with rising temperatures has significantly reduced sediment loads delivered into the sea in semi-arid climates(4-61%).In contrast,increasingly warmer and wetter climates in subtropical zones has yielded more sediment(0.4-11%),although the increase was offset by human impact.Our results indicate that,compared with mechanical retention by reservoirs,water reduction caused by climate change or human withdrawals has contributed more sediment reduction for the rivers with abundant sediment supply but limited transport capacity(e.g.,the Huanghe).Furthermore,our results indicate that every 1%change in precipitation has resulted in a 1.3%change in water discharge and a 2%change in sediment loads.In addition,every 1%change in water discharge caused by precipitation has led to a 1.6%change in sediment loads,but the same percentage of water discharge change caused largely by humans would only result in a 0.9%change in sediment loads.These figures can be used as a guideline for evaluating the responses of sediment loads to climate change in similar climate zones because future global warming will cause dramatic changes in water and sediment in river basins worldwide at rates previously unseen.  相似文献   

16.
Region 2 comprises arctic and subarctic North America and is underlain by continuous or discontinuous permafrost. Its freshwater systems are dominated by a low energy environment and cold region processes. Central northern areas are almost totally influenced by arctic air masses while Pacific air becomes more prominent in the west, Atlantic air in the east and southern air masses at the lower latitudes. Air mass changes will play an important role in precipitation changes associated with climate warming. The snow season in the region is prolonged resulting in long-term storage of water so that the spring flood is often the major hydrological event of the year, even though, annual rainfall usually exceeds annual snowfall. The unique character of ponds and lakes is a result of the long frozen period, which affects nutrient status and gas exchange during the cold season and during thaw. GCM models are in close agreement for this region and predict temperature increases as large as 4°C in summer and 9°C in winter for a 2 × CO2 scenario. Palaeoclimate indicators support the probability that substantial temperature increases have occurred previously during the Holocene. The historical record indicates a temperature increase of > 1°C in parts of the region during the last century. GCM predictions of precipitation change indicate an increase, but there is little agreement amongst the various models on regional disposition or magnitude. Precipitation change is as important as temperature change in determining the water balance. The water balance is critical to every aspect of hydrology and limnology in the far north. Permafrost close to the surface plays a major role in freshwater systems because it often maintains lakes and wetlands above an impermeable frost table, which limits the water storage capabilities of the subsurface. Thawing associated with climate change would, particularly in areas of massive ice, stimulate landscape changes, which can affect every aspect of the environment. The normal spring flooding of ice-jammed north-flowing rivers, such as the Mackenzie, is a major event, which renews the water supply of lakes in delta regions and which determines the availability of habitat for aquatic organisms. Climate warming or river damming and diversion would probably lead to the complete drying of many delta lakes. Climate warming would also change the characteristics of ponds that presently freeze to the bottom and result in fundamental changes in their limnological characteristics. At present, the food chain is rather simple usually culminating in lake trout or arctic char. A lengthening of the growing season and warmer water temperature would affect the chemical, mineral and nutrient status of lakes and most likely have deleterious effects on the food chain. Peatlands are extensive in region 2. They would move northwards at their southern boundaries, and, with sustained drying, many would change form or become inactive. Extensive wetlands and peatlands are an important component of the global carbon budget, and warmer and drier conditions would most likely change them from a sink to a source for atmospheric carbon. There is some evidence that this may be occurring already. Region 2 is very vulnerable to global warming. Its freshwater systems are probably the least studied and most poorly understood in North America. There are clear needs to improve our current knowledge of temperature and precipitation patterns; to model the thermal behaviour of wetlands, lakes and rivers; to understand better the interrelationships of cold region rivers with their basins; to begin studies on the very large lakes in the region; to obtain a firm grasp of the role of northern peatlands in the global carbon cycle; and to link the terrestrial water balance to the thermal and hydrological regime of the polar sea. Overall, there is a strong need for basic research and long-term monitoring. © 1997 John Wiley & Sons, Ltd.  相似文献   

17.
Abstract

Changes in water resources availability, as affected by global climate warming, together with changes in water withdrawal, could influence the world water resources stress situation. In this study, we investigate how the world water resources situation will likely change under the Special Report on Emissions Scenarios (SRES) by integrating water withdrawal projections. First, the potential changes in water resources availability are investigated by a multi-model analysis of the ensemble outputs of six general circulation models (GCMs) from organizations worldwide. The analysis suggests that, while climate warming might increase water resources availability to human society, there is a large discrepancy in the size of the water resource depending on the GCM used. Secondly, the changes in water-stressed basins and the number of people living in them are evaluated by two indices at the basin scale. The numbers were projected to increase in the future and possibly to be doubled in the 2050s for the three SRES scenarios A1b, A2 and B1. Finally, the relative impacts of population growth, water use change and climate warming on world water resources are investigated using the global highly water-stressed population as an overall indicator. The results suggest that population and socio-economic development are the major drivers of growing world water resources stress. Even though water availability was projected to increase under different warming scenarios, the reduction of world water stress is very limited. The principal alternative to sustainable governance of world water resources is to improve water-use efficiency globally by effectively reducing net water withdrawal.
Editor Z.W. Kundzewicz; Associate editor D. Gerten  相似文献   

18.
Climate change adaptation has become the current focus of research due to the remarkable potential of climate change to alter the spatial and temporal distribution of global water availability. Although reservoir operation is a potential adaptation option, earlier studies explicitly demonstrated only its historical quantitative effects. Therefore, this article evaluated the possibility of reservoir operation from an adaptation viewpoint for regulating the future flow using the H08 global hydrological model with the Chao Phraya River basin as a case study. This basin is the largest river system in Thailand and has often been affected by extreme weather challenges in the past. Future climate scenarios were constructed from the bias-corrected outputs of three general circulation models from 2080 to 2099 under RCP4.5 and RCP8.5. The important conclusions that can be drawn from this study are as follows: (i) the operation of existing and hypothetical (i.e., construction under planning) reservoirs cannot reduce the future high flows below the channel carrying capacity, although it can increase low flows in the basin. This indicates that changes in the magnitude of future high flow due to climate change are likely to be larger than those achieved by reservoir operation and there is a need for other adaptation options. (ii) A combination of reservoir operation and afforestation was considered as an adaptation strategy, but the magnitude of the discharge reduction in the wet season was still smaller than the increase caused by warming. This further signifies the necessity of combining other structural, as well as non-structural, measures. Overall, this adaptation approach for assessing the effect of reservoir operation in reducing the climate change impacts using H08 model can be applied not only in the study area but also in other places where climate change signals are robust.  相似文献   

19.
李静  陈光杰  黄林培  孔令阳  索旗  王旭  朱云  张涛  王露 《湖泊科学》2023,35(6):2170-2184
区域增温和大气氮沉降作用已成为高山湖泊面临的重要环境胁迫,已有高山湖泊生物群落响应的长期模式研究主要集中于藻类而缺乏更高营养级生物(如浮游动物)的系统调查。本研究选择滇西北地区深水型的高山湖泊沃迪错开展沉积物调查,通过多指标分析(总氮、总磷、叶绿素a、氮稳定同位素等)并结合区域气候重建记录,识别近两百年来该湖泊及流域环境的变化历史,进一步利用枝角类群落指标(物种组成、生物量等)定量评价了湖泊生物群落的响应模式与驱动因子。结果表明,湖泊营养水平(如总氮浓度)和初级生产力(叶绿素a浓度等)在过去近两百年总体呈上升趋势。相关分析显示,大气氮沉降和流域外源输入是影响总氮上升的主要因素,同时区域增温和营养盐富集促进了湖泊初级生产力的不断上升。自1960s以来区域升温明显,湖泊营养水平和叶绿素a浓度呈现加速上升的趋势。钻孔中枝角类群落以浮游属种(Daphnia longispina等)为优势种,在1900AD以前D.longispina相对丰度较为稳定(40.83%±8.02%),之后出现下降趋势且在1948—1965年间明显下降,之后再次明显上升并成为主要优势种。排序分析显示,气温、叶绿素a和总...  相似文献   

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