Spatiotemporal variation of streambed quality and fine sediment deposition in five freshwater pearl mussel streams,in relation to extreme drought,strong rain and snow melt     

《Limnologica》2020

Oxygenated streambeds are considered a key requirement for the successful recruitment of stream fauna, including highly endangered freshwater pearl mussel Margaritifera margaritifera. Excessive amounts of fines impede exchange between open water and interstitial, leading to colmation and low oxygen levels in the juvenile habitat. Understanding the dynamic relationship between sediment delivery, transport, deposition and remobilization in relation to anthropogenic drivers is still poorly understood, yet is essential for conservation and restoration.This study analysed spatiotemporal sediment dynamics and interstitial habitat quality in five pearl mussel streams at the border region between Bavaria, Saxony and the Czech Republic during 2018 and 2019, comparing extremely dry periods with higher discharge events caused by snow melt and rainfall. Physicochemical habitat conditions within the streambed and sediment deposition were recorded in high spatial resolution along the stream courses, with a particular focus on the effects of tributaries and outflows of man-made fishponds.Habitat conditions were unsuitable for juvenile pearl mussels at the majority of sites, indicated by pronounced differences in physicochemical parameters between open water and the substrate, independent of discharge conditions. Sediment deposition varied markedly between discharge events, in terms of both the quality and quantity of deposits. Snow melt resulted in the highest sedimentation rates, but the smallest proportion of fine particles. During low flow conditions, fine sediment deposition was highly variable, ranging from 0.048 to 4.170 kg/week/m², mostly independent of flow velocity. High spatiotemporal variation was observed within and amongst stream systems, revealing different longitudinal patterns of fine sediment deposition, with catchment land use as the main driver. Temporal variability in sediment deposition was mainly associated with the discharge condition while abiotic parameters varied mainly with season.The high site-specificity of sedimentation rates and substrate conditions in response to different discharge events highlights the importance of an adapted conservation management which considers anthropogenic effects at the local scale.  相似文献   

生物共现网络原理及其在淡水生态系统评估中的应用     

万凌琳  陈芷凡  郭佳  佟立辉  任丽娟  韩博平  吴庆龙 《湖泊科学》2022,34(6):1765-1787

快速有效的生物监测指标对于评估、保护、管理和恢复淡水生态系统至关重要.传统评估方法主要利用指示生物或类群的出现率和多度信息,但是忽略了水体环境中“生物”与“生物”,以及“生物”与“环境”间相互作用的复杂关系,而这些相互作用对淡水生态系统的生物多样性、生态系统服务功能以及生态系统对环境变化的响应有着深刻影响.生物共现网络是群落水平物种互作的结构模型,通过物种在群落出现及丰度数据,描述了物种间潜在的相互作用、群落的基本结构,反映群落在生态系统的功能和结构特性.生物共现网络展示了淡水生态系统中所有生物体之间潜在的相互作用关系,其拓扑结构特性可与特定的生态系统状态相关联,能够揭示生态系统的组织规律及其功能,可作为早期的、灵敏的生物指标,是一种很有应用前景的评估淡水生态系统状态和稳定性的工具.  相似文献   

关于淡水浮游动物和原生动物分开研究的建议   总被引：1，自引：0，他引：1  

陈非洲 《湖泊科学》2016,28(3):691-691

正《湖泊科学》编辑部:国内关于淡水浮游动物的文章中,一般浮游动物包含四大类,即原生动物、轮虫、枝角类和桡足类,其中枝角类和桡足类又合称为浮游甲壳动物.除了这四大类外,浮游动物还包括软甲类甲壳动物(如糠虾、钩虾等)、水生昆虫(如幽蚊等)、水蜘蛛、丰年虫、淡水水母、浮游贝类幼虫等,由于这些类群在淡水水体中分布有限,尤其在敞水区,一般的浮游动物研究并不包括这些类群.从分类阶元来看,淡水原生动物的主要种类属于原生动物亚界的肉鞭门和纤毛门,肉鞭门包括鞭毛亚门(植鞭毛纲-自养鞭毛虫和动鞭毛纲一异养鞭毛虫)、肉足亚门根足总纲(变形虫和有壳肉足虫),一般将淡  相似文献   

贻贝发育早期酯酶和过氧化物酶活性     

王宜艳  孙虎山  梁建光  李华  王楠  唐海田 《海洋科学进展》2007,25(4):446-452

采用组织化学和分光光度技术对贻贝(Mytilus edulis)发育早期酯酶(Esterase,EST)和过氧化物酶(Per-oxidase,POD)活性进行了研究,以探讨贝类早期发育过程中的免疫防御机制。EST和POD均存在于贻贝的卵母细胞、胚胎和幼虫中,但在各个发育时期的分布和含量不同。组织化学定位结果表明,从卵母细胞到D型面盘幼虫各个发育时期的胚胎和幼虫均呈EST强阳性和POD阳性;卵母细胞核区较大且颜色较浅;桑椹期开始出现不同细胞阳性的强弱差异;原肠胚、担轮幼虫和D型面盘幼虫细胞间阳性强弱的差异逐步增大。分光光度测定结果表明,α-醋酸酯酶活力,卵母细胞最低,受精卵略有提高,卵裂期胚胎提高较大且达最高峰,囊胚、原肠胚和担轮幼虫又逐渐下降,D型面盘幼虫下降较大;α-丁酸酯酶活力,卵母细胞较高,受精卵略有提高且达到最高峰,卵裂期胚胎到D型面盘幼虫各个时期逐渐下降,D型面盘幼虫最低。不依赖卤素POD活力,卵母细胞最低,受精卵提高较大,囊胚达到最高峰,原肠胚、担轮幼虫和D型面盘幼虫逐渐降低。依赖卤素POD活力与不依赖卤素POD活力的变化规律相似,但受精卵提高较小,而卵裂期提高较大。EST和POD可能在贻贝的发育早期抵抗病原微生物侵染方面发挥重要作用。  相似文献   

Contribution of Oceanic Circulation to the Poleward Heat Flux     

HUANG Ruixin 《中国海洋大学学报(英文版)》2005,4(4):277-287

Oceanic contribution to the poleward heat flux in the climate system includes two components： the sensible heat flux and the latent heat flux. Although the latent heat flux has been classified as atmospheric heat flux exclusively, it is argued that oceanic control over this component of poleward heat flux should play a critically important role. The so-called swamp ocean model practice is analyzed in detail, and the critical role of oceanic circulation in the establishment of the meridional moisture transport is emphasized.  相似文献   

Two Early Cretaceous fishes discovered from the most northern area of China: implications for the palaeobiogeography of the Jehol Biota     

Li Xiao‐Bo  Zhang Mei‐Sheng  Wang Yi‐Ni 《Geological Journal》2011,46(4):323-332

From a newly discovered Early Cretaceous fossil site at the Sanlianhe Coal Mine in Tahe County, Heilongjiang Province, the most northern area in China, two freshwater fossil fish had been recovered. This paper reports their classifications and implications regarding the palaeobiogeography of the Jehol Biota. The fish assemblage consists of Yanosteus sp. (Acipenseriforms) and Sinamia sp. (Amiiformes). Both are important members of the well known Jehol Biota, and their occurrence supports the correlation of the Yiliekede Formation at Sanlianhe Coal Mine site with the Jiufotang Formation of West Liaoning. The remains of the Yanosteus sp. from this locality is the first known record of the genus other than in the Yan‐Liao area of China, and the specimens of Sinamia sp. is quite similar to what may be a new species of Sinamia from West Liaoning. The new fossil site represents the most northern site that is undoubtedly part of the extent of the Jehol Biota as currently understood. The northern Great Xing'an Range area is an important region that may link correlations between the Early Cretaceous continental biotas of China, Mongolia and Russia. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

沿黄地区浅层淡水水源地傍河取水技术探讨   总被引：1，自引：0，他引：1  

赵志强  安美艳  赵永安  王合秋  李生清 《山东国土资源》2009,25(12):38-41,45

为开辟区域供水新途径，经过对沿黄地区供水勘察资料的分析研究，认为临黄靠渠区，浅层地下水水质较好。从黄河侧渗补给稳化的角度分析，具备了形成中小型供水水源地的条件，技术可行、经济便利，能够满足该区村镇生活及工矿企业用水需求，是缓解该区供水危机的新途径。  相似文献