近1800年来云南洱海流域气候变化与人类活动的湖泊沉积记录

对云南洱海湖泊岩芯沉积物进行了多环境指标（年代学、色素、硅藻、有机碳稳定同位素、磁化率、化学元素）的分析,建立了近１８００年来云南洱海流域气候与环境变化的序列,气候演化具有暖干、冷湿交替的组合呈些特征气候阶段如中世纪温暖期、小冰期气候特征在洱海源泊沉积记录中均有反映,洱海湖泊上沉积记录的气候暖干－冷湿交替变化规律,反映了西南委风影响下的气候演化特征,湖泊沉积记录中包含丰富的人类以的信息,磁化率,元     

全新世以来云南洱海流域气候变化与人类活动的湖泊沉积记录

根据云南洱海湖泊沉积岩芯多环境指标的高分辨分析, 在精确定年基础上, 建立了全新世以来洱海流域气候与环境变化的序列. 研究表明, 云南洱海地区约12950~8399 cal. a BP气候由冷湿转为暖湿, 转换时间发生在约10329 cal. a BP. 洱海湖面从约10329 cal. a BP开始扩张主要是由于全新世早期西南季风增强、降雨增多所致. 全新世中期流域气候暖湿, 最温暖期出现在约8399~6371 cal. a BP, 但由于全新世中期湖泊所在盆地内有效湿度降低, 湖面出现下降趋势. 洱海流域人类活动始于约6371 cal. a BP, 初始的人类活动方式主要以砍伐森林为主, 至大约2139 cal. a BP, 由于外来移民大量迁入该地区, 耕作农业得到广泛发展, 随后采矿业(主要为煤矿)也逐步开始.     

中国湖泊生态系统突变时空差异

人类活动的加强导致湖泊生态系统发生"突变",造成生物多样性下降、藻类暴发、水质恶化等等环境和生态问题.中国许多湖泊已经发生"突变"或面临着突变风险.获悉湖泊生态系统发生突变的时空差异对于区域湖泊的保护,预防湖泊突变的发生以及制定合适的修复策略至关重要.本研究收集了中国55个不同区域湖泊的古湖沼学数据,探讨了湖泊突变的区...     

近0.3 ka来龙感湖流域人类活动的湖泊环境响应

通过210Pb测年、历史事件记载和沉积记录, 对钻孔岩芯沉积物年代进行了确定. 利用花粉、硅藻、磁参数、色素及结合态磷等多环境代用指标分析, 讨论了近0.3 ka来龙感湖流域植被、土壤侵蚀变化与湖泊环境演化之间的关系, 特别是龙感湖营养态的变化. 湖泊经历了两次由贫营养向中等营养的转变, 两次富营养化的发生(1770AD后和1906AD后)与人类活动增强导致的湖泊营养外负荷的增加密切相关. 历史时期降水的变化又是决定该区人类活动强度变化的诱因. 近0.04 ka来, 湿地的严重破坏和流域化学肥料的使用, 使得湖泊富营养化程度呈现明显加重趋势.     

云南九大高原湖泊流域人类活动强度对水质的多尺度影响

人类活动强度的空间异质性是理解区域人地关系和生态环境效应的基础。基于云南九大高原湖泊流域2020年土地利用数据,构建不同景观类型的人类影响强度系数,运用GIS空间分析量化流域人类活动强度与空间分异,探讨人类活动强度对水质的影响。结果表明:人类活动强度总体特征由高到低依次是杞麓湖(4.83)、星云湖(4.71)、滇池(4.19)、阳宗海(4.11)、抚仙湖(4.03)、异龙湖(4.01)、程海(3.93)、洱海(3.88)和泸沽湖(2.96)。人类活动强度指数(HAI)在流域尺度、坝区尺度、湖岸尺度的空间分异特征明显,每个流域都受到高强度人类活动影响,最大值出现在坝区,滇池、杞麓湖岸线存在完全开发的区域。人类活动强度随海拔和坡度增高而下降,高强度区集中在地势低平的湖泊周围。湖泊营养状态指数与流域尺度和坝区尺度高强度区呈显著正相关,这些区域应作为景观优化和管理的重点;与岸线尺度低强度区呈显著负相关,有必要减少湖滨带人类活动。综合考虑流域地形地貌-人类活动强度-水质的级联效应,应从不同空间尺度对各景观要素与过程管控。鉴于人类活动强度对水质的影响,可把湖泊管理分为预防型、保护型、治理型。     

人类活动对洱海的影响及对策分析

针对洱海生态环境问题,１９９６－１９９７年间通过系列动态资料分析,环境现状调查和水,土,生物取样测试等方法进行湖泊人为影响和对策感化研究。结果显示１９８０－１９９６年扶持续降低水位给洱海下灾难性后果;近年来资源过量开发和面源污染又使洱海面临富营养化威胁。     

人类活动对乌梁素海湿地环境演变的影响分析

乌梁素海是我国半荒漠地区具有很高生态价值和社会效益的大型多功能湖泊湿地[1],是黄河流域最大的淡水湖泊,也是内蒙古河套灌区唯一的承泄途径.乌梁素海的补给水源主要包括含高N,P的农田退水,工业废水以及生活污水,这些退水及废污水的排入使得湿地环境发生着重大的变化.本文在收集1986-2004年19年间Landsat TM/ETM遥感影像数据的基础上,结合乌梁素海历史资料,分析了80年代以来人类活动对湿地环境的影响,这种影响主要体现在人工芦苇面积不断扩大,富营养化程度逐年增高,水生资源迅速减少等方面,尽管2003年以来"引黄入海"工程的实施某种程度上缓解了湿地环境恶化的进程,但湿地环境仍然面临严重的威胁.     

东北松嫩平原区湖泊对气候变化响应的初步研究

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.     

1960年以来气候变化与人类活动对鄱阳湖流域生态径流改变的影响

基于鄱阳湖流域五河水文站1960-2013年逐日径流量和14个国家级气象站的日气象数据,本文利用长短记忆模型框架构建神经网络模型来开展鄱阳湖流域的径流过程模拟,结合生态赤字与生态盈余等生态径流指标,定量分析了鄱阳湖流域的水文变异特征.同时,利用差异化的情景模拟方式,定量区分了人类活动和气候变化对鄱阳湖流域生态径流变化的...     

古湖沼学研究揭示湖泊生态系统服务变化的过程

当今在气候变化和人类活动等多重压力影响下,作为地表过程重要组成部分的湖泊生态系统正遭受着巨大威胁,其服务功能急剧退化.如何客观地评价湖泊生态系统服务的现状,并科学地预测其发展趋势,是当前亟待解决的问题.开展长期生态系统服务变化过程与机理的分析,有助于未来生态系统服务变化趋势的预测.然而,现有的观测数据往往时间较短(通常小于50年).连续的湖泊沉积记录为研究生态系统服务变化的长期过程提供了可能.本文结合前人研究成果,列举了可反映湖泊生态系统服务变化的一些古湖沼学指标,依据这些指标相对明确的生态和环境指示意义,将其与各项服务关联起来.最后,结合巢湖实例分析来说明这些指标在评估湖泊生态系统服务方面的具体应用,研究表明当今巢湖生态系统服务供应能力的持续增加是以调节服务的丧失为代价的.尽管目前的研究尚处于起步阶段,但古湖沼学手段无疑为今后湖泊生态系统服务历史状况的评估提供了途径,为古湖沼学的应用提供了一种新的思路,并为今后生态系统的保护和可持续利用提供重要的决策依据.     

中国湖泊古生态研究进展

湖泊古生态学是古湖沼学的一个主要分支学科,主要通过沉积记录中的各种生物化石指标分析,重建不同时空尺度的湖泊生态系统演化过程,回答生态学、全球变化和环境管理应用方面的议题.本文回顾了国内外湖泊古生态研究的发展历程,在介绍湖泊古生态系列指标和研究基本原理基础上,着重评述了过去20 a来我国湖泊古生态研究取得的主要进展和成果,包括:(1)建立了基于多种生物和生物标记化合物指标进行古气候环境要素(温度、盐度、水体总磷等)定量重建的系列转换函数模型;(2)重点揭示了不同地质历史时期和近百年来湖泊生态环境演变的规律,及其对自然和人为驱动的响应特征与机理;(3)利用古生态记录诊断了湖泊生态系统突变模式与早期信号特征,定量揭示了湖泊生物群落演替与生态系统弹性损失的关系.上述成果为湖泊环境管理和治理提供了重要依据.本文最后对我国湖泊古生态研究进行了展望,提出了今后研究的重点方向.     

湖泊渔业研究:进展与展望

作为一种传统产业,渔业在我国经济社会发展中具有不可缺失的重要地位.而渔业作为湖泊最重要的功能之一,其资源变动是湖泊生态系统演变的重要影响因子,同时湖泊渔业资源的变动和退化也是对环境变化最直接的响应.自1980s以来,随着湖泊水环境的改变,湖泊渔业资源衰退趋势明显,中上层浮游生物食性鱼类在鱼类群落中占优势,鱼类资源小型化、低龄化现象严重.本文以湖泊渔业发展的历程为切入口,系统阐述人类活动及湖泊环境变化对渔业资源及生态系统的影响,厘清现阶段湖泊水环境管理、湖泊生态系统修复、湖泊渔业可持续发展等关系,展望我国湖泊渔业的发展前景及新型模式.     

Study on the nutrient evolution and its controlling factors of Longgan Lake for the last 200 years

Based on the total phosphorous (TP) concentration in sediment core, the TP concentration in lake water quantitatively reconstructed from fossil diatoms and diatom-TP transfer function in the Longgan Lake during the last 200 years, the temperature and precipitation data from meteorological observation for the last 50 years, the temperatures and precipitation sequences of climate simulation for the last 200 years, as well as the amount of the agricultural phosphate fertilizer in Longgan area for nearly 50 years, the characteristic and the law of the nutrient status evolution were analyzed, and the influence of the climatic factor, the anthropologic factor and the aquatic biology factor on the nutrient status evolution and its mechanism were discussed for the Longgan Lake during the last 200 years. The results showed that, in the nearly 200 years, the TP concentration in the sediment core of the Longgan Lake gradually increased, its range of variation was situated between 330-580 mg/kg, the mean value was 388 mg/kg, a nearly 30-year vibration adjustment period existed at 1950 around. The TP concentration in lake water changed in a different way. Before 1950, it had a slow increasing tendency in fluctuated background, to 1950 around it reached up to the mean value (52.18μg/L), and vibrated and adjusted around the mean value, then it fast declined, its change range was situated between 37.75-62.33μg/L. The analyses indicated that, in the centennial time scale, the climate change was the main controlling factor, while in the decadal time scale in the recent 50 years, human activities were the leading factors for the nutrient status evolution of the Longgan Lake. 60% of the variability of the TP concentration in the sediments and 57% of that in lake water were due to human activities. The differentiation between phosphorus concentration in the sediment and in the lake water reflected the response processes and the adjustment abilities of the lake aquatic ecosystems to the lake nutrient level, implying the maintenance and the destruction of the balances between the algae and the aquatic plants, as well as the corresponding accumulating characteristics of the phosphorus.     

The importance of aquatic macrophytes in a eutrophic tropical shallow lake

Inlay Lake is the second largest natural lake in Myanmar. Located in Shan State, in the eastern part of the country, it is a known biodiversity hotspot. The lake is negatively affected by an increasing local human population and rapid growth in both agriculture and tourism. In recent decades, several studies have listed faunistic and floristic groups in Inlay Lake, but there is still a general lack of knowledge about the aquatic macrophyte and phytoplankton community composition and abundance, and their interactions. To fill this knowledge gap, field surveys of biological and physical and chemical parameters were carried out in the period 2014–2017. They show that Inlay Lake is a shallow, clear water and calcareous lake, with nutrient concentrations indicating mesotrophic-eutrophic conditions. However, close to the shore, nutrient concentrations are generally higher, reflecting pollution from inflowing rivers, shoreline villages and floating gardens. Both the richness and abundance of aquatic macrophytes in Inlay Lake were high, with several species forming extensive stands in most of the lake over the whole survey period. Total phytoplankton and cyanobacterial biomass were low, but cyanobacteria included toxin-producing strains of Microcystis, suggesting that cyanobacterial and total phytoplankton biomass need to be kept low to avoid potentially harmful cyanobacterial blooms. Submerged macrophyte abundance and phytoplankton biomass were inversely correlated in the heavily vegetated northern lake area. Our survey suggests a great importance of the submerged macrophytes to the general water quality and the clear water state in Inlay Lake. Maintaining high macrophyte abundances should therefore be a goal in management strategies, both for Inlay Lake and other lakes in Myanmar. It is highly desirable to include macrophytes and phytoplankton in the lake monitoring in Myanmar.     

The influence of extreme floods from the River Danube in 2006 on phytoplankton communities in a floodplain lake: Shift to a clear state

The influence of extreme floods from the River Danube in 2006 on the species composition and vertical distributions of phytoplankton was studied in a shallow floodplain lake, Lake Sakadaš (Kopa?ki Rit Nature Park, Croatia) which in the last few decades was in a turbid state characterised by high phytoplankton concentrations. As a consequence of extremely high floods, the whole floodplain area (approximately 16 km²) became one lentic habitat with well developed macrophyte vegetation. Seasonal dynamics of chlorophyll a (Chl a) concentration in the lake had a characteristic pattern for the shallow lakes with dense macrophyte vegetation. Extremely low mean phytoplankton abundance and biomass were found in the conditions of very high nutrient concentrations. Dominant phytoplankton species were diatoms and chlorococcal green algae from the functional groups characteristic for a mixed environment. The canonical correspondence analysis (CCA) demonstrated that nutrients and temperature were significant environmental variables for their development. The sequence of phytoplankton seasonality, vertical distribution of phytoplankton, as well as the domination of rapidly acclimating phytoplankton forms (R-strategists) indicated clear, well-mixed conditions and a highly disturbed environment. Our results suggest that the occurrence of extreme flooding can be a stressor high enough for the transition from a turbid to a clear state of the floodplain lake. Possibly, cyclic shifts between alternative stable states in floodplain ecosystems can be expected as a consequence of the impact of extreme hydrological events induced by a climate change.     

湖泊微生物宏基因组学研究进展

湖泊微生物作为湖泊生态系统重要组成部分,在局域和区域的元素循环中发挥着关键作用.由于自然环境中微生物之间的复杂关系和对微生物认知的片面性,可在实验室培养的湖泊微生物比例不足1%.近10年来,宏基因组学技术在微生物生态学研究中得到了广泛应用,不仅扩展了对湖泊微生物群落组成和多样性的认识,更揭示了湖泊微生物的功能多样性和微生物之间的相互作用.特别是基于宏基因组数据的分装(Binning)手段,可以获取大量湖泊中未培养微生物的基因组信息,用于后续的比较基因组、生态进化和培养组学等研究.随着宏基因组学相关学科和技术的不断发展,其将在湖泊微生物生态学基础理论研究和环境生物监测应用中发挥更为重要的作用,成为人类了解湖泊生态系统功能和维持机制的有力工具.