From fluvial dynamics to eco-fluvial dynamics     

《国际泥沙研究》2019,34(6):531-536

Sediment plays a very important role in the functioning of river ecosystems. It is the basic substance for the survival of benthic animals and aquatic plants. On the other hand, the growth of biofilms and bio-disturbance of benthos affect the sediment transport characteristics. With the increasing attention to protect aquatic ecosystems, the importance of habitats has become increasingly researched. The need to study the interactions among sediment, flow, riverbed deformation, and aquatic ecosystems naturally leads to the proposed discipline of eco-fluvial dynamics. In this paper, the basic concept and main research content of eco-fluvial dynamics is introduced with the Yarlung Tsangpo River as the research example. This case study is an example of an aquatic ecosystem in an ever-changing environment because of the effects of climate change. The results of analysis of eco-fluvial dynamics will provide a scientific basis for decision support for the government.  相似文献   

山东省海洋水产原、良种产业的发展和对策          下载免费PDF全文

田敬云  张守都  姜勇  赵喜喜  郑冰  刘学庆  胡建廷 《海洋开发与管理》2018,35(12):42-46

为进一步提高山东省海洋水产种业的发展水平，促进海水养殖业和渔业经济的可持续发展，文章总结山东省海洋水产原、良种产业的发展特点，分析存在的问题，并提出对策建议。研究结果表明：山东省海洋水产原、良种产业具有起步较晚但发展速度较快，品种多、覆盖面广，代际连续性较强以及原、良种场建设全国领先的特点；目前仍然存在海洋水产良种的市场化程度较低、水产企业良种研发能力较弱以及国家级原、良种场的作用未有效发挥的问题；今后应重点推动育种技术进步，推进育、繁、推一体化发展模式，树立品牌意识，建立良种独立技术体系，加大对水产企业的支持力度，加强种质资源保护以及建立市场准入制度。  相似文献   

贻贝附着基海带苗种运输技术探究     

吕继发  杜欣欣  曲学伟  刘升平 《海洋科学》2019,43(6):88-94

中介生物辅助大型海藻海底基质附着技术,是采用海面撒播苗种方法,进行大型海藻海底增殖的核心技术。研究发现,该贝、藻复合体苗种的运输比普通水产苗种运输难度显著增加。本文采取传统的干运、水运以及发明的淋水运输3种不同方式,进行了贻贝附着基海带苗种运输技术研究。结果表明:干运3h内苗种的存活率和生长速度与对照组差异不显著(P0.05);水运1h以上苗种的存活率与对照组差异显著(P0.05);淋水运输24 h内苗种的存活率和生长速度与对照组差异不显著(P0.05)。实验说明:水运不适合该苗种运输;在露空时间3 h以内,干运是最经济、最便捷的苗种运输方法;在露空24 h以内,采取淋水运输能够保证苗种的成活率,可以作为该苗种常规的运输方法。  相似文献   

Establishing habitat-specific indicator species in Tierra del Fuego with freshwater macroinvertebrates     

Christopher B. Anderson  Montana Johnson  María Eugenia Lopez 《新西兰海洋与淡水研究杂志》2018,52(1):145-154

As a tool to understand Tierra del Fuego’s basic ecology and detect changes due to human pressures, this study develops habitat bioindicators. We compared the freshwater benthic macroinvertebrates at 61 study sites in six habitat types: grassland streams, urbanised streams, forested streams, beaver ponds, lakes and peat bog ponds. Forty-nine taxa were identified; insects were the most diverse group. Beaver pond, lake and grassland stream assemblages were similar, as were those from lakes, grassland streams and peat bog ponds. Fourteen taxa were habitat-specific. In forests, these included mayfly scrapers (Andesiops, Meridialaris) and blackfly filterers (Gigantodax). In lakes, two copepod filterers were indicators, and in urban streams, one shredder (Aphroteniella) and three collector-gatherers (springtail, earthworm, aquatic worm). Predators (Corixa, Aeshna) were characteristic of peat bog ponds. Beaver ponds had no indicator species. Establishing links between species and ecosystems constitutes the beginning of a broader effort to understand anthropogenic impacts to Fuegian watersheds.  相似文献   

基于R-FCN_ResNet的深海冷泉区生物的识别与分布研究     

李海菊  连超  管利聪  李超伦  栾振东 《海洋科学》2020,44(9):54-62

针对深海冷泉生物数量多、密度大、特征低，人工识别它们的种类和数取它们的数量耗时费力且准确度低这一问题，利用残差学习块，改进了基于区域的全卷积网络算法，用以深海冷泉生物的自动识别与检测。首先，构建了一组包括5类目标生物的深海冷泉生物图像目标检测数据集；然后，在TensorFlow框架下对比了R-FCN_ResNet、Faster R-CNN和SSD_MobileNet三种典型的卷积神经网络算法。从训练耗损时间、平均检测速度、平均置信度三方面权衡，突出了R-FCN_ResNet模型的优势；最后，将测试集图片输入至该模型中检测深海冷泉生物的种类和数量，并且以此复现了生物的分布情况。实验证明，所提方法结合本文数据集进行的深海冷泉生物识别与分布研究，是有效可行的，且具有较高的目标分类和定位准确率。  相似文献   

老碳对水生态系统食物网的贡献     

胡恩  张振文  王文科  孙长顺  苏雅玲  刘正文 《湖泊科学》2018,30(5):1187-1195

传统理论认为,支撑水生态系统食物网的碳主要来自于系统内部的初级生产者,如藻类、大型水生植物等,或者来自陆源输入的新鲜且容易分解的有机质;而部分生物或非生物生产的有机碳,在冰川、冻土等环境中可停留数百年至数千年(定义为老碳),由于储存环境稳定、物理化学性质顽固,难以参与水生生态系统有机碳循环.近年来这一观念不断被挑战.研究表明老碳能够参与水生态系统食物网碳循环:可以被微生物分解利用;被浮游动物、无脊椎动物直接或者间接摄取、或沿着营养级传递至鱼类、水禽等高级消费者.这意味着除了内部初级生产,老碳是支撑水生态系统重要的碳源.本文概述了当前老碳与水生态系统食物网关系研究最新进展和所取得的研究成果,介绍放射性14C同位素技术在水生态学领域的应用,同时提出研究中存在的问题以及未来研究应关注的方向,以期促进我国水生态系统碳循环研究的进一步发展.  相似文献   

Forest-steppe oxbows in limnophase — Abiotic features and biodiversity     

《Limnologica》2019

The aim of our study was to identify the main abiotic factors that influence the biodiversity of forest-steppe oxbows in limnophase. Experiments were performed in 2016–2017 in Penza oblast, Central Russia. In addition to disturbed water exchange, isolated oxbows experienced such human influence as logging and plowing on watersides, and the construction of roads and mounds. Under those conditions, some water bodies became unstable and temporal, while others remained stable and were relatively unaffected. Higher light intensity in unstable oxbows led to higher plant diversity because of the mass occurrence of helophytes. However, the diversity of hydrophytes in stable oxbows remained higher, which contributed to higher vegetation coverage. This resulted in increased zooplankton diversity, which was also influenced by lower fluctuations in water level and oxygen level. Disturbed water regimes impacted organisms with a full aquatic life cycle (phyto- and zooplankton, fish). The diversity of unstable oxbows decreased due to their isolation from the river and from drying. The absence of fish may positively affect the abundance and biomass of benthos; however, we found no influence on zooplankton. Instability and high fluctuations in water level may lead to the high diversity of organisms that spawn in water. The higher diversity of benthos may also be influenced by the abundance of amphibian larvae which are a necessary food resource. In addition to predation, amphibians are at risk of mass larval mortality because of drying. Although the degradation of oxbows in limnophase is an undesirable consequence of anthropogenic impact, the coexistence of all types of oxbows is necessary to conserve the freshwater biodiversity of forest-steppes.  相似文献   

华南伊迪卡拉纪类水母化石新发现     

唐烽  钟玲  金幸生  郭东辉  尹崇玉 《地质通报》2016,35(1):1-9

An abundant and diversified assemblage of benthic fossils from the Ediacaran Doushantuo black shales in the Wenghui section of Guizhou Province contains two discoidal carbonaceous forms, Kullingia rotadiscopsis sp. nov. and Eoaequorea xingi gen. & sp. nov. The fossils have well-preserved concentric rings and radiating lines, and resemble many circular casts and moulds in Ediacaran clastic and carbonate rocks in the world, such as Aspidella, Ediacaria, Cyclomedusa, Eoporpita, Ovatoscutum, Spriggia and Kullingia. The Doushantuo carbonaceous macrofossils help us to inquire into the current functional identifications of circular disks as the holdfasts of unknown organism or scratch circles. Although there is not sufficient correspondence in morphology to warrant reinterpreting all previously described Kullingia and Aspidella form-genus-type structures, these carbonaceous compressions are prone to be the ancestor of pelagic jellyfish-like organisms with medusoid hydrozoan affinity.  相似文献   

基于L系统的水生植物根系动态生长模型构建     

黄晓龙  李松阳  李宽意 《湖泊科学》2022,34(6):2083-2094

植物根系在地球生物圈物质循环中起到关键性作用.陆生植物中目前基于根系具有对称性和自相似性假设建立的L系统已经做了较好研究,但在水生植物中相关的研究较少,更缺乏根系动态生长模型的构建.本文拟通过发展L系统来模拟水生植物从初生结构到次生结构,从简单根系到复合根系的动态生长过程.根系动态生长模型主要包含根系伸长规则和根系分支规则,并包含由主根与侧根的夹角θ和径向角γ确定初始根系生长方向.特别地,系统建立了2种代表性水生植物——世界上入侵严重的水生植物凤眼莲（Eichhornia crassipes）和被研究较多的水生植物穗状狐尾藻（Myriophyllum spicatum）根系动态生长模型.结果表明凤眼莲成熟根系总长度可达到2042.78 m,可能有利于其占据较多的空间和资源,使得凤眼莲在与本地植物的竞争中占有优势.穗状狐尾藻的总根系长度为73.08 m,由于穗状狐尾藻表现出最为典型的叉状分支构型,表明其对沉水生长环境有较好的适应性.  相似文献   

红海湾底质硫化物的分布和变化     

甘居利  贾晓平  林钦  王增焕 《广东海洋大学学报》1998,(4)

根据南海区半封闭型海湾规模化养殖技术研究的需要,对红海湾底质硫化物进行了研究。用碘量法分析的结果表明：红海湾底质中硫化物含量的区域分布极不均匀,呈北部河口区＞虾池＞鱼湾＞中部＞南部自然水域＞礁滩区的特点。虾池、鱼的硫化物含量清淤前分别为清淤后的8.4、3．6倍;湾南部硫化物含量春季明显高于夏季,其余区域的两季差异不明显。46份样品中约13％、28％分别超过国内外评价标准,超标测站位于河口和清淤前的虾池、鱼。礁滩护养增殖区、南部自然水域、湾中部牡蛎养殖区和清淤后的虾池、鱼尚未见硫化物的污染。  相似文献