The dynamics of Chaoborus americanus in an Adirondack lake following the reintroduction of fish     

《Limnologica》2017

Acid deposition during the 20th century led to the gradual elimination of fish in Brooktrout Lake (Adirondack Mountains, New York State). Thereafter, the lake was colonized by Chaoborus americanus, a dipteran with an aquatic larval stage that typically resides in the pelagic zone in fishless lakes. During subsequent chemical recovery from acidification, the lake was stocked with Brook Trout (Salvelinus fontinalis). For seven years following this reintroduction we examined the re-adaptation of the food chain. The C. americanus abundance and distribution was quantified utilizing a combination of hydroacoustics, traditional vertical net tows and Schindler-Patalas trap collections. Hydroacoustic backscattering signals were repeatable and correlated (r = 0.86, p = 0.003) with C. americanus abundance. Backscattering, depth, month and year were used to develop a random forest model that predicted the C. americanus density (r² = 0.67,  p< 0.05). The hydroacoustic signal revealed a clear but limited diurnal vertical migration of C. americanus. The signal continued in the presence of the fish population beginning with reintroduction in 2005 and extending through 2011. In 2012, the hydroacoustic signal no longer was present in the lake, suggesting that the fish had eliminated the C. americanus population, which was verified with net tows. Using novel and traditional survey methods, we demonstrate that the reintroduction of fish can alter the lake community structure significantly through the extirpation of the major component of the pelagic zone.  相似文献   

Suspended solids induce increasing microbial ammonium recycling along the river-estuary continuum of the Yangtze River     

Jingya Xue  Zhonghua Zhao  Xiaolong Yao  Weiting Liu  Lu Zhang 《水文研究》2021,35(8):e14345

Many large rivers worldwide are enriched with high levels of suspended solids (SS), which are known to be hotspots of many nitrogen (N) transformation processes (e.g., denitrification, nitrification). However, the influence of SS on microbial ammonium (NH₄⁺) recycling remains unclear. Water column NH₄⁺ regeneration rates (REGs) and potential uptake rates (U_pots) as well as community biological NH₄⁺ demand (CBAD) was measured in the river-estuary continuum of the third longest river in the world—Yangtze River, which has dramatic SS gradients. We found that REGs, U_pots, and CBAD all increased downriver, with higher REGs, U_pots, and CBAD in the estuary than in the river sections. The regeneration and uptake of NH₄⁺ were nearly balanced in the river sections, while the positive CBAD in the estuary indicated obvious NH₄⁺ demand of microbes. Concentrations of SS, which also control the content of chemical oxygen demand and particulate N, were the main factor influencing NH₄⁺ recycling rates and CBAD. SS-induced regenerated NH₄⁺ in the river-estuary continuum of Yangtze River was estimated to be 11.02 × 10⁸ kg N yr⁻¹ and accounted for about 14% of total N inputs, suggesting that regenerated NH₄⁺ is an important N source for microbes and may influence nutrient dynamics in lower coasts. To our knowledge, this is the first study to report NH₄⁺ recycling in Yangtze River with an emphasis on its influencing factors and contribution to N budgets.  相似文献   

Reed litter Si content affects microbial community structure and the lipid composition of an invertebrate shredder during aquatic decomposition     

《Limnologica》2016

The decomposition of plant litter is an important mechanism in regard to energy and nutrient dynamics of ecosystems. Silicon concentration of plant tissue can affect these processes by changing litter quality, i.e. nutrient stoichiometry and cellulose and phenols content. To determine which group of microbial decomposers benefits from high Si content in plants and how this impacts on animal decomposers, a batch experiment was conducted with reed leaf litter (Phragmites australis) differing in Si content in the presence/absence of invertebrate shredders (Gammarus pulex). Lipid concentration of G. pulex, in reed litter and fine particulate matter (FPOM) were examined. High Si concentration in reed resulted in a decline of gram positive bacteria in the heterotrophic biofilm and of gram negative bacteria in FPOM. The lipid composition in the next trophic level, the decomposer G. pulex, changed too, indicating a diet shift in favor of bacteria and algae with increasing litter Si concentration. Thus, basal decomposers were affected by the Si availability in plant resources, and these effects likely persist along the food chain, as FPOM is a dominant food supply for other groups, e.g. collectors. This impact of Si content on plant substrate quality for decomposer food webs may have global relevance, due to related modifications in carbon and nutrient cycling during litter decomposition.  相似文献   

The role of experimental work in hydrological sciences – insights from a community survey     

Theresa Blume  Ilja van Meerveld  Markus Weiler 《水文科学杂志》2017,62(3):334-337

This opinion paper summarizes the results of an online survey on the role of experimental work in the hydrological sciences. The 20 survey questions covered various topics, such as advancements, needs, potentials and challenges in the hydrological sciences, and also touched on the issue of data sharing and data publication. A total of 336 hydrologists with both modelling and experimental backgrounds participated.  相似文献   

Implications of Nontraditional Housing Arrangements for Urban Water Management in the United States Intermountain West     

Matthew J. Barnett  Douglas Jackson-Smith  Joanna Endter-Wada 《社会与自然资源》2019,32(5):508-529

Homeowners living in single-family detached housing have dominated the literature exploring drivers of residential water use. Meanwhile, rentals, multiunit buildings, and residences governed by private associations are an increasingly important component of the American residential landscape. We used data from a large sample of households in northern Utah cities to explore the effects of these nontraditional housing arrangements on water use decision-making, attitudes and behaviors, and their implications for urban water management. After accounting for the sociodemographic characteristics of respondent households, we found that residents of nontraditional housing arrangements are much less likely to have authority over key water use decisions, and differ significantly from residents of traditional housing in regards to water use perceptions and concerns, self-reported water behaviors, and support for various local water policy options. Traditional approaches to urban residential water management should be adapted to renters, residents in multiunit buildings, and members of community associations.  相似文献   

2018年烟台四十里湾及其邻近海域网采浮游植物群落结构的时空变化     

张文静  董志军  孙西艳  张晨  刘永亮  侯朝伟  赵建民 《海洋与湖沼》2020,51(5):1151-1161

本文基于2018年5月（春季）、8月（夏季）、11月（秋季）和2019年1月（冬季）季度航次调查，采用冗余分析（RDA）和Bray-Curtis相似性聚类分析方法，讨论了烟台四十里湾及其邻近海域网采浮游植物丰度、优势种组成、多样性指数、均匀度指数的分布特征以及浮游植物与环境因子的关系。本年度调查共发现浮游植物4门69属116种，其中硅藻门50属85种，甲藻门15属27种，着色鞭毛藻门3属3种，未定类1种（三深碎裂藻，Ebria tripartita）。浮游植物丰度在8月份达到年度最高值，为2.89×10⁸cells/m³，秋季次之，春季最低，春、秋、冬季浮游植物丰度均为~10⁵cells/m³。硅藻门在4个季节中均占绝对优势，除春季出现甲藻门（夜光藻）优势种外，其余季节浮游植物优势种均为硅藻门。相邻季节浮游植物优势种更替明显，未出现4个季节共有的优势种。浮游植物多样性和均匀度指数均在夏季达到最低值，分别为1.58和0.31。RDA排序分析显示，不同季节影响浮游植物群落分布的环境因子不同，总体来讲，温度、溶解氧浓度、SiO₃^2-浓度和NO₃^-浓度对浮游植物的丰度和平面分布有显著影响。Bray-Curtis相似性聚类结果显示，2018年每个季节浮游植物群落分布均可分为两个类群，其分布受营养盐分布的影响较为明显。  相似文献   

深海生态学研究进展和几点建议     

李永祺  王蔚 《海洋与湖沼》2020,51(6):1267-1274

深海及其底部生物圈的探测和研究，是当前海洋大科学研究的焦点，是未来的海洋科学，具有重要的战略意义。深海及其底深部生态学的研究，是其中的一项重要内容。本文简要回顾了深海生态学发展的三个里程碑以及中国在该学科的研究进展，提出了大力发展深海探测和钻探设备、技术，建设深海生态站和大洋钻探船；以生态系统为中心开展深海生态研究；将深海生态研究纳入国家和有关部门的研究计划、支持多学科交叉和融合的建议。  相似文献   

南黄海近岸海域初夏浮游动物的群落特征   总被引：2，自引：2，他引：0  

李奕璇  葛汝平  叶振江  陈洪举  庄昀筠  刘光兴 《海洋科学》2020,44(4):33-43

采用2016年7月和2017年6-7月在南黄海近岸海域获取的浮游动物样品,研究了种类组成、丰度、生物量、优势种和生物多样性的变化,并分析其与环境因子的相关性关系。结果显示,两个航次的温盐及浮游动物群落特征差异较大。2016年7月表层平均温度为(22.8±1.8)℃,表层平均盐度为30.0±1.6;2017年6-7月表层平均温度为(25.7±3.6)℃,表层平均盐度为(27.8±4.3)℃。2016年浮游动物的种类数为70种(含浮游幼虫24类),2017年种类数为56种(含浮游幼虫18类)。2016年浮游动物平均丰度(4838.2±5186.7 ind·m–3)和平均湿重生物量(324.9±481.5mg·m–3)均高于2017年(2652.4±3507.5 ind·m–3,216.6±245.2 mg·m–3)。两个航次共同的优势种为小拟哲水蚤(Paracalanus parvus)、近缘大眼剑水蚤(Corycaeus affinis)和双毛纺锤水蚤(Acartia bifilosa)。2016年7月的生物多样性略高于2017年6-7月。温、盐等水文特征的差异是造成2016年和2017年夏季浮游动物群落结构变化的主要原因。  相似文献   

水生动物行为生态学研究进展     

张立斌  冯其明  范鑫昊  张双艳 《海洋科学》2020,44(8):85-97

水生动物行为生态学是动物行为生态学的重要分支，对理解水生动物的生存行为机制、指导渔业生产和保护濒危水生动物具有重要意义。近年来，随着新型研究技术和手段的出现，水生动物行为生态学在短时间内得到了迅速发展。水生动物行为多种多样，本文主要综述了水生动物行为生态学的研究方法与手段，探讨了水生动物运动行为、摄食行为、繁殖行为和集群行为等方面的研究进展，并展望了水生动物行为生态学的研究与应用前景，以期为水生动物行为生态学研究与应用提供借鉴和参考。  相似文献   

韭山列岛海洋生态自然保护区及其附近海域底拖网生物资源的分布及群落结构分析   总被引：1，自引：0，他引：1  

李进京  刘颖  李祥付  刘好真  徐鹏  孙元  焦海峰  王一农  尤仲杰 《海洋与湖沼》2020,51(1):176-185

为了解韭山列岛海洋生态自然保护区(下简称保护区)生物资源分布、群落结构特征及受干扰情况,于2012年4月(春)、7月(夏)对保护区及其附近海域进行了底拖网生物资源调查。运用物种多样性指数、丰度生物量比较曲线(abundance-biomass comparison curves,ABC)、相似性聚类(Bray-Curtis)及非度量多维尺度分析(non-metric multi-dimensional scaling,NMDS)等方法,比较分析了春、夏季保护区及其附近海域底拖网生物资源的物种多样性、群落结构及稳定性。结果显示:(1)调查海域共出现海洋生物45属47种,隶属7门11纲22目36科,其中保护区42种,保护区附近海域37种,节肢动物丰度和生物量最高;(2)日本鼓虾(Alpheus japonicas)为保护区及其附近海域特征种,保护区季节间物种更替率(64.29%)低于其附近海域(72.97%);(3)保护区平均丰度为37.459ind/Agt,平均生物量为59.160g/Agt,其附近海域平均丰度为37.048ind/Agt,平均生物量为37.230g/Agt,保护区丰度和生物量高于其附近海域;(4)春季保护区与其附近海域Shannon-Weiner多样性指数、Margalef物种丰富度指数、Pielou均匀度指数相近且均较低,夏季保护区多样性指数高于其附近海域;(5)ABC曲线表明,春季保护区及其附近海域处于轻微干扰及未受到干扰状态,夏季保护区处于轻微干扰状态,其附近海域处于重度干扰状态。综上所述,韭山列岛海洋生态自然保护区的设立,在提高物种多样性、物种丰度、生物量及维持群落结构的稳定性方面优于其附近海域。  相似文献