长江口及邻近渔业水域生态系统重建及管理对策   总被引：7，自引：3，他引：4  

晁敏  沈新强  李纯厚  程炎宏 《海洋渔业》2005,27(1):74-79

本文通过对长江口生物及非生物环境现状及所面临的胁迫压力的分析 ,对长江口及邻近水域的生态系统保护、重建和管理对策进行了讨论。本文认为 ,应建立以生态系统为基础的管理机制 ,贯穿于关键种群的保护及恢复、重要生境的保护及修复和污染物控制等修复行动计划 ;在长江口建立长期、动态的环境监测体系、政府管理部门间的协调机制及相关生物修复技术在重点水域的推广是目前有效、可行的生态系统管理计划。  相似文献   

长江口底泥浸出液和悬浮液对叶绿素a含量的影响   总被引：4，自引：3，他引：1  

徐兆礼  沈新强  马胜伟 《海洋渔业》2005,27(4):309-313

以微绿球藻(Nannochloropsis oculata)和牟氏角毛藻(Chaetoceros muelleri)为受试生物,检验不同浓度的底泥浸出液和悬浮液对其叶绿素a含量的影响试验,探讨长江口底泥污染物析出对浮游植物生长的影响。研究结果表明,浓度低于或等于20%时,底泥浸出液对牟氏角毛藻和微绿球藻生长影响不显著;高于20%时,浓度越高,抑制作用越加明显。悬浮液抑制作用强于浸出液。浸出液对叶绿素a含量增长的抑制作用,在牟氏角毛藻试验的第4天开始显现,在微绿球藻试验和悬浮液试验中,第3天就开始显现。在较低浓度中,微绿球藻对污染物的反应更加灵敏,而牟氏角毛藻是适合较高浓度的受试物种。底泥重金属溶出是影响浮游植物生长的主要原因之一。  相似文献   

大沽河河口滩涂植被群落动态特征研究     

柳新伟  秦志华 《青岛农业大学学报(自然科学版)》2010,27(3):241-243

定点测定大沽河河口滩涂不同植被类型生物多样性、地上部和地下部初级净生产力(NPP,Net Primary Pro-duction),基本可将其分为4个演替阶段,这个演替序列代表了受到人为干扰后滩涂植物群落组成的动态变化。结果表明,在演替前期,群落生物多样性较低,群落组成以碱蓬为主,地上部和地下部干物质分别为1.9922kg/m2和0.3427kg/m2;随着演替进行,生物多样性达到最大,群落组成包括碱蓬、结缕草、罗布麻、白茅,地上部和地下部干物质比演替初期有所降低为1.1378kg/m2和0.2452kg/m2;在演替后期,生物多样性又有所降低,群落中的生物组成以芦苇为主,地上部和地下部干物质达到最大分别为2.7189kg/m2、0.7370kg/m2。深入研究不同植被与干扰的关系以及植被动态,对于科学管理滩涂生态系统具有重要的理论价值和指导意义。  相似文献   

河口区底泥中重金属再悬浮的研究进展     

孙玮玮  胡蓓蓓 《绿色科技》2014,(11)

综述了重金属在全球主要河口区再悬浮过程中的迁移转化过程进展,并概述了用实验室模拟再悬浮的方法来判别重金属污染的来源的进展。  相似文献   

长江口滨岸重金属含量、形态及其分布特征   总被引：2，自引：0，他引：2  

李亭亭  王京刚  王颖  李丽芳  尹世磊 《农业环境科学学报》2014,33(6):1189-1196

采集长江口南支、北支滨岸表层水体及沉积物样品,分析了其中7种重金属Cd、Cr、Cu、Hg、Ni、Pb、Zn和类金属As的含量以及表层沉积物中重金属的形态,并对其分布特征和生态风险进行分析。结果表明:表层水中7种重金属和类金属As含量均小于地表水I类标准;沉积物中As、Cr、Ni平均浓度大于效应临界浓度TEL值,具有潜在的生态风险;与2007年相比,沉积物中所有重金属平均含量均有所升高;由于沿岸排污、支流污染物输入,南支沉积物中多数重金属含量高于北支。重金属形态分析表明,Cd由于具有较高的离子交换态和碳酸盐结合态,生态风险较大。相关分析结果表明,除Hg和As外,沉积物中其他重金属之间均呈现较明显的正相关关系,多数重金属与活性铁铝氧化物、锰、TOC含量有明显的相关性。  相似文献   

基于16S rRNA技术的长江口微生物分子生物学鉴定与分析   总被引：1，自引：2，他引：1       下载免费PDF全文

曹波  杨红  许强华  刘榕磊 《上海海洋大学学报》2011,20(2):191-197

基于2007年12月与2008年6月长江口上海附近海域采集的海水样品,使用27F和1492R两种通用引物对海洋微生物16S rRNA基因片段进行直接扩增,克隆并测序,构建细菌16S rRNA文库,通过NCBI数据库的基因比对,区分微生物种群,并使用Mega 4.0软件利用16S rRNA序列建立微生物的分子发育树。通过直接提取DNA进行扩增的方法,共检测出17个属的53种不同微生物,微生物种群结构随温度变化明显,优势种随温度变化有所不同,在不同季节水温下,微生物优势种优势明显;冬季以不动杆菌属为优势种群,分子发育树体现的遗传差异性较小;夏季微生物种群结构较复杂,其中以希瓦氏菌属及假单胞菌属为优势种群,分子发育树体现的遗传差异性较大;微生物分布存在明显的季节变化。  相似文献   

福建漳江口红树林生长与气象条件的关系     

福建漳江口红树林生长与气象条件的关系 《勤云标准版测试》2007,(8)

漳江口是福建唯一的红树林国家级自然保护区,对生态环境意义重大,为了红树林合理布局的需要;采用农业气候分析方法,探讨漳江口红树林生长与气象条件的关系,分析温度、降水量、大风、日照等对红树林生长的利弊影响。结果表明,漳江口1￣3月上旬的极端低温和6月上旬￣8月中旬的极端高温都对红树林生长不利,5￣8月雨量充沛有利于红树林的生长,2￣3月阴雨寡照,不利于红树林生长发育,从台湾南部正面登陆云霄的台风和从台湾南部登陆粤东的影响云霄的超强台风,风力可达11级以上,对红树林产生较大损害;分析红树林生长与气象条件关系,提供专题气象服务,能为红树林合理布局、趋利避害提供科学的决策依据,为生态建设做出较大的贡献。  相似文献   

中国河口环境问题及其可持续管理对策   总被引：7，自引：0，他引：7  

白军红  邓伟 《水土保持通报》2001,21(6):12-15

河口位于河流—海洋交互区 ,是一具有重大资源潜力和环境效益的湿地生态系统类型。但由于长期以来不合理地开发利用 ,已导致了中国河口生境退化 ,生物多样性急剧下降 ,环境污染加剧 ,海岸侵蚀及河口淤积日益严重等环境问题 ,保护及合理开发利用河口资源势在必行。分析了我国河口面临的威胁 ,河口管理、保护和开发利用中存在的主要问题 ,并由此提出了解决这些问题的可持续管理对策与措施。  相似文献   

Variations of Fatty Acids During the Sulphidization Process in the Authie Bay Sediments (8 pp)     

Gabriel Billon  Guy Thoumelin  Jean-François Barthe  Jean-Claude Fischer 《Journal of Soils and Sediments》2007,7(1):17-24

Background, Aim and Scope   The sulphidization process in relatively clean sediments sampled in a mudflat of the Authie estuary (located in Northern France) has been studied by coupling geochemical expertise and the use of fatty acids (FAs) as biochemical markers. Materials and Methods: Three sediment cores have been sampled in September 2003, November 2003 and May 2004, and cut every 2 cm in the field under nitrogen atmosphere so as to prevent any oxidation of reduced species. In the solid phase, reduced sulphur compounds, e.g. AVS (Acid Volatile Sulphides) and CRS (Chromium Reducible Sulphur) [including also the calculation of the degree of sulphidization (DOS) and the degree of pyritization (DOP)], and fatty acids have been carried out. Eh, pH, metal species (mostly iron and manganese), dissolved S(-II) and sulphate have also been determined in the porewaters. Results: The sediment cores display a lot of differences due to the high sedimentation rate and the seasonal evolution as well. The presence of Mn2+, Fe2+, S(-II) and the decrease of the redox potential and the concentration of sulphates clearly indicate early diagenetic transformations promoted by the bacterial activity. Acid Volatile Sulphides are produced in the first cm and are stabilized with depth. A rapid decrease of FAs concentrations in September and May has also been pointed out owing to a rapid consumption of the labile organic matter. Several categories of FAs have been separated and most of them belong here to the saturated and monounsaturated groups. In the saturated group, branched chain FAs, iso and anteiso C15:0 are predominant and represent the bacterial imprint in the sediments. Maximum proportions are observed between 5 and 10 cm in September, and between 13 and 17 cm in November and May. Discussion: As sulphate concentrations remain high in the porewater, the limitation of the sulphidization process in our sediments must be due to a lack of labile organic matter input. The presence of pyrite in our sediment is bound to its formation at the water-sediment interface, where partial reoxidation may take place. However, at deeper depths, pyritization processes does not continue any more. Presence of maximum, dissolved S(-II) concentrations have been observed, simultaneously with maximum proportion relative to total FAs of iso and anteiso C15:0, and, in September, with an increase in proportions of C18:1ω7. This indicates the presence of sulphate-reducing bacterial activity at the time when the sediments were sampled. However, no close correspondence between bacterial FAs concentrations and S(-II) concentrations has been found. Conclusions: In each core, the sulphidization process is not complete, and this is probably due to the lack of biodegradable organic matter, which appears as the limiting factor from a qualitative point of view. S(-II) production in porewaters is linked with the activity of sulphate-reducing bacteria. Seasonal effects have also been pointed out and, especially, a more important input of diatom organic matter in May when compared to September and November. Recommendations and Perspectives: Fatty acid analyses represent an original and a useful tool for a better understanding of an early diagenetic process in the first cm of the sediments. More studies should be carried out associating inorganic chemical parameters and chemical biomarkers for pointing out stronger and more reproducible relations. Moreover, the use of microcosms in our group is on the way to take into account the kinetics of the organic matter degradation during the early diagenesis.  相似文献   

Effects of freshwater limitation on distribution patterns and habitat use of the West Indian manatee,Trichechus manatus,in the northern Brazilian coast     

Iana Tavares Favero  Gabriel Eduardo Favero  Katherine Fiedler Choi‐Lima  Heleno Francisco dos Santos  Joo Pedro Souza‐Alves  Josenildo de Souza e Silva  Joo Lucas Leo Feitosa 《水产资源保护:海洋与淡水生态系统》2020,30(8):1665-1673

1. The West Indian manatee (Trichechus manatus) is a Vulnerable species threatened by habitat loss in the coast of north‐eastern Brazil. This study investigates how the distribution and habitat use of the West Indian manatee is influenced by resource availability in a scenario of freshwater limitation.
2. Land‐based and boat surveys were conducted to record manatee sightings and habitat use, in a total of 206 hours of observation.
3. Manatee abundance was significantly influenced by freshwater availability, with greater abundances occurring close to freshwater sources. Food availability and the variation in freshwater availability between seasons were also important to determine their distribution. For the 47 manatees sighted, 39 were recorded during the rainy season and eight during the dry season.
4. Habitat use was influenced by freshwater sources and manatees spent more time (average coefficient of area use = 24.96%) in areas with greater availability of fresh water. Under conditions of freshwater limitation, manatees were more abundant and spent more time closer to fresh water than to food sources; as a result, animals' distribution varied between seasons.
5. The results found here can help to determine conservation strategies for the region with the highest population density and genetic variability of West Indian manatees in Brazil.

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