象山港不同温度区围隔浮游生态系统营养盐迁移—转化的模拟对比

为评估象山港海域电厂温排水对水体富营养化影响,以生态系统中氮、磷营养盐循环为主线,建立了适用于海洋围隔浮游生态系统的多变量的营养盐迁移—转化动力学模型。该模型包括浮游植物、浮游动物、溶解无机态营养盐、溶解有机态营养盐和生物碎屑5 个模块,涉及溶解无机氮、磷酸盐、溶解有机氮、溶解有机磷、浮游植物、浮游动物和生物碎屑7 个状态变量。利用2010年10月象山港其中一个温度区的围隔生态实验数据成功地进行了模型的验证,确定了相关参数的量值,并用该参数同时模拟3个不同温度区围隔氮、磷营养盐生物化学迁移—转化过程,进而得出温度对围隔浮游生态系统氮、磷营养盐迁移—转化影响的结论。结果表明,象山港电厂温排水加剧了受纳水体的富营养化程度。     

水温升高对水体性质及水生生物的影响研究进展

全球变暖导致水温升高,河流、湖泊普遍升温,而这种增温趋势还将加剧。水温升高,直接导致水体稳定度提高,垂向对流减少,分层现象加剧,冰河解冻提前,水体封冻期缩短;间接导致水体溶解氧含量降低,尤其底层水体缺氧现象更加严重,底层水体缺氧导致沉积物中营养盐向上覆水的释放量增加,两者均会诱导水体发生气候变化富营养化。水温升高影响水生有机体的生物过程、物种组成及食物网变化;水体分层及溶解氧含量降低均会增加水体营养物负荷,促进水体浮游藻类种群发生变化;水温变化还会改变水生植物生长条件、生物量及分布,影响水体中鱼类的生存、生长发育,以及栖息地发生变化,使水生无脊椎动物种群数量减少。因此,水温增加势必对水生生态系统产生重要影响。     

电厂取水设施运行对水生生物影响与减缓措施

直流冷却水系统电厂从地表吸入大量的冷却水,该设施取水和运行可能伤害冷却水中的水生生物。对于较大的水生生物,其无法通过滤网,若不被移出取水设施,则受滤网的撞击影响;对于小型的水生生物,有可能穿过滤网进入冷凝器冷却系统而受到热应力、机械应力、压应力及杀生剂的影响,即夹带影响。我国直流冷却水系统电厂(尤其是核电厂)的机组数量多、取水量大,取水设施运行的环境影响未得到重视,没有考虑撞击的影响,无相关的缓解措施。美国对直流冷却水系统电厂水生生物的撞击和夹带影响进行了30多年的监测和研究,本文对此进行了系统调研和分析。研究表明:(1)有些电厂取水设施对鱼类、贝类等水生生物撞击和夹带的负面影响水平为中等,甚至是大的,对生态系统可能造成直接和间接的影响;(2)采用闭式循环冷却水系统替代直流冷却水系统,控制取水通过滤网流速≤0.15 m/s,在取水设施外围设置屏障网,采用改进型滤网和离岸蘑菇头式取水等措施,能够有效地降低对鱼类、贝类等水生生物的撞击损失;而对于夹带影响,当前除了采用闭式循环冷却替代技术外,其他措施效果有限,应继续开展相关研究。     

浅析青苔的影响和控制方法

<正>水体中的"青苔"又称青泥苔、水毛子,是丝状绿藻形成藻华后的俗称。丝状藻类的大量生长、繁殖,并形成藻华,对水体及水生生物会造成一定的危害。近年来,在农业生产水体包括养殖河蟹的水体、养鱼池塘及城市景观水体(包括人工湿地和种植观赏水草的池塘),青苔使水质恶化,进而引起生态失衡,给水产养殖、水生动植物生态恢复及湖泊管理带来了很大困难。一、青苔1.作为浮游动物等的栖息场所和食物来源作为湖泊水生态系统中重要初级生产力之一的丝状绿藻,不仅能产     

秦山核电站温排水附近海域鱼类群落分布空间的差异

根据秦山核电站温排水扩散数学模拟结果以及在秦山核电站附近海域春季(2010年5月)、夏季(2010年9月)和冬季(2009年12月)渔业资源调查资料,通过聚类分析方法对鱼类群落分布进行划分,从不同群落空间分布及种类组成、种类数及多样性的分析等方面,探讨并分析了秦山核电站温排水对附近海域鱼类群落分布的影响。结果显示,春、夏和冬季秦山核电站温排水附近海域均划分为2个群落:温排水影响海域(即群落Ⅰ,以下简称内侧;位于秦山核电站排水口附近,温排水排入水域使水温升高,水温向外侧扩散逐渐降低)和温排水外侧海域(即群落Ⅱ,以下简称外侧)。鱼类群落结构差异表现为春夏季鱼类种类数和多样性指数特征差异一致,外侧高于内侧,数量密度差异较大,夏季和冬季差异明显,呈相异特征。春季鱼类种类数外侧(14种)内侧(6种),尾数和重量多样性指数(Hn′)平均值类似,外侧(2.30和1.93)内侧(1.76和1.56),数量密度差异较大,尾数密度外侧(1.95×103个/km)内侧(0.88×103个/km),而重量密度内侧(6.14 kg/km2)外侧(2.26 kg/km2),主要与春季温排水影响海域鱼类产卵,鱼类在内侧滞留且体质量较大有关;夏季与春季类似,鱼类种类数、尾数和重量多样性指数、尾数和重量密度都是外侧(11种、1.76、1.92、2.57×103个/km和9.06 kg/km2)内侧(9种、1.75、1.65、1.98×103个/km和3.67 kg/km2),主要因为夏季水温较高,温排水进入海域改变内侧鱼类群落特征,表现为内侧低于外侧;而冬季与夏季正相反,各指标都是内侧(15种、1.61、1.86、1.09×103个/km和8.64 kg/km2)外侧(7种、1.24、1.13、0.84×103个/km和4.72 kg/km2),主要与冬季水温较低,温排水影响海域具有暖池效应,形成部分鱼类滞留在此越冬有关。温排水对不同适温性的鱼类影响不同,一些暖温性鱼类能够适应一定的低温,因而在冬季温排水附近海域鱼类暖温种数和种类数(8种和15种)均为三季最高,这与物种在温排水的热羽区域分布密集有关,从而形成温排水附近海域鱼类种类多于其他群落的现象。研究表明,秦山核电站温排水附近海域鱼类群落分布空间差异显著,温排水引起的水温变化是主要原因。     

水文气象过程对千岛湖氮磷变化的影响

水库作为一类人工修建的重要水资源调蓄地,其水体营养盐含量等指标受水文气象过程的影响很大。为探索我国东南山区水库营养盐的时空变化规律,以钱塘江流域千岛湖(新安江水库)为例,利用2016年8月至2017年12月的水质调查数据,结合同期气温、降雨量和入库流量等气象水文数据,分析了水文气象过程对千岛湖水体氮、磷等营养盐浓度的影响特征。结果显示:(1)千岛湖营养盐浓度具有较大的时空差异性,TN浓度0.69～2.06 mg/L,平均值为(1.12±0.26) mg/L,高值出现在冬季和春季;TP浓度0.004～0.096 mg/L,平均值为(0.030±0.021)mg/L,高值出现在春季;空间上呈现为河流区到湖泊区浓度逐渐降低的趋势;(2)千岛湖降雨量、入库流量及气温等水文气象条件存在显著季节差异(P0.01),3-7月的降雨和入库流量超过总量的70%,高温出现在7-8月,月均温度高达30℃;(3)氮磷营养盐浓度与入库流量的相关性强于降雨,且入库流量及降雨对磷的影响更大;不同区域对入库流量的响应时间存在差异,河流区响应最快,其次是过渡区,湖泊区最慢,反映出氮、磷在水库扩散过程中的滞后性;(4)温度通过影响水体浮游植物生长带来的水体颗粒态氮、磷变化影响水体TN、TP浓度,但不同湖区的响应不同;3～7 d的累积温度与过渡区氮、磷的关系好于河流区,可能与过渡区浮游植物生长与营养盐浓度变化更为敏感有关。研究表明,水文气象过程对大型水库水体氮磷的影响作用强烈且复杂,物理扩散与沉降、化学变化及生物生长累积等作用使得水体氮磷浓度对水文气象过程响应具有较大的时空差异性,在水库水质管理和机制分析中应当充分考虑这种非同步性。     

秦山核电温排水对鱼类分布的影响

根据2010年5月(春季)、2010年9月(夏季)和2009年12月(冬季)秦山核电海域渔业资源调查资料以及秦山核电站温排水扩散数学模拟结果,通过秦山核电温排水海域鱼类季节密度的时空分布、优势种、优势种对鱼类总数量的贡献,探讨并分析了秦山核电海域温排水对鱼类分布的影响。结果显示,春季、夏季和冬季的尾数密度分别为5.55×10~3 ind/km~2、22.10×10~3 ind/km~2和10.52×10~3 ind/km~2,重量密度分别为33.80 kg/km~2、59.06 kg/km~2和66.46 kg/km~2。秦山核电海域渔业资源数量季节变化的规律与其他海域相反,冬季最高,春夏季较低,主要与冬季温排水海域具有暖池效应,形成部分鱼类滞留在此越冬有关。温排水平面分布对鱼类分布有重要的影响。主要表现在夏季温排水区域鱼类密度低于其他水域,冬季相反,鱼群滞留在温排水热羽区域,因而显示出温排水海域有较高的鱼群密度。温排水对不同适温习性鱼类影响不同,暖温种能够适应一定的低温,例如,刀鲚(Coilia ectenes)可以在温排水水域越冬,而对高温有耐受性的棘头梅童鱼(Collichthys lucidus)夏季在温排水水域成为优势种。鱼类优势种的适温性决定着鱼群的分布特征,冬季最重要的优势种为刀鲚,在尾数上的贡献率高达45.02,由于该种在温排水的热羽区域分布密集,形成温排水水域鱼群密度大于周边水域的现象。由于温排水改变了渔场环境,导致新的越冬场的形成,有可能形成新的渔汛,引起当地渔场属性的改变。     

热环境内不同类型水体降温效应的时空变化及景观影响

探索不同类型水体降温效应的时空变化特征,可为缓解城市热环境问题提供理论支持。基于Landsat遥感数据,以福州市2002-2020年典型湖泊、河流为例,利用缓冲分析法定量描述不同类型水体降温效应的时空变化;对湖泊采用网格分析法、河流采用等距离分段分析法,探讨了水体周边景观特征对不同类型水体降温效应的影响。结果表明：(1)福州市中心城区热环境问题加剧,水体成为环境内部的主要“冷源”;(2)城市河流比城市湖泊更具备“冷岛”潜力;(3)湖泊的降温效应受周边植被占比、建设用地占比影响较大,在湖泊周边120m内,当绿地面积占比>34%时,建设用地面积占比<48%,湖泊与绿地的综合降温效果最好;(4)河流的降温效应受周边植被占比、建设用地占比及裸地占比影响较大,在河流周边180m内,当绿地面积占比>44%时,建议建设用地面积占比<31%,河流可产生最大的降温效应。在未来城市规划中,水体周边景观的合理布设将有助于水体发挥最佳降温效果。     

总氨对水生生物毒性的研究进展

水环境的好坏和水生生物的生长及存活密切相关,有时甚至可威胁到整个种群的存在。目前,工业废水和养殖废水的排放,导致近岸海域污染严重,总氨毒害作用已成为限制养殖生产、造成水体富营养化、制约水产养殖可持续快速发展的主要环境因素。     

青海湖裸鲤资源枯竭的成因及恢复途径的探讨

青海湖是我国最大的内陆湖泊,青海湖区的气候、环境条件和水体条件孕育了独特的鱼类资源。青海湖及其附属的河流、淡水湖泊水体中生长着6种鱼类:即青海湖裸鲤、甘子河裸鲤和4种高原鳅,其中:青海湖裸鲤是水生生物的主体。青海湖裸鲤体形大,肉质细嫩,     

Effects of river regulation and diversion on marine fish and invertebrates

The effects of freshwater regulation and diversion on the adult and larval stages of fish and invertebrates in coastal marine waters are reviewed. Potential impacts of river modification are highlighted based on our present understanding of the role of fresh water on the physical, chemical and biological processes on the marine environment. These include effects on migration patterns, spawning habitat, species diversity, water quality and distribution and production of lower trophic levels. The effect of dams on anadromous and catadromous fish are also presented. We discuss in detail the marine response to specific river regulation projects on the Nile, Indus and rivers flowing into the Black Sea, San Francisco Bay and James Bay in Canada. A decline in some coastal fisheries with an overall negative impact on the biota is generally associated with reductions in freshwater flow. Extensive ecological considerations are needed during the planning stage of large-scale freshwater modification projects to minimize potential impacts.     

Alien species in aquatic environments: a selective comparison of coastal and inland waters in tropical and temperate latitudes

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Water resources management of the southern rivers of Russia with reference to fisheries requirements

Water consumption from Russia's southern rivers has increased substantially in recent years as a consequence of intensified economic activity. The volume of irreversible river-flow withdrawal from the Azov Sea basin varies between 11 and 13 km³ year^1. The majority of the abstracted water is used for irrigation. By 1990, the decrease in discharge into the Caspian Sea was 41 km³ year^1. Withdrawals of water from the Kura, Terek, Ural and other rivers have so far exceeded the ecologically admissible limits and become critical. The paper discusses methodological approaches for the elaboration of standards for water withdrawal and ecologically safe discharges into the southern seas. New data are presented on the dynamics of fish abundance as a function of the hydrological characteristics of rivers and water salinity. The results of the system analysis and regressive modelling formed the basis of a programme to develop policies for water management for fisheries in the lower Don. The principles and criteria for water withdrawal under variable hydrological regimes for the rivers entering the Azov and the Caspian Seas should be tested for their applicability for other water bodies (e.g. rivers, water reservoirs and lakes).     

A Survey of Water Quality Characteristics of Effluent from Hawaiian Aquaculture Facilities

Ten water quality parameters were measured in influent and effluent water at 11 aquaculture facilities in Hawaii. The data were grouped into four categories based on the types of organisms cultured: freshwater fish, freshwater prawn, marine fish, and marine shrimp. Within each category, concentrations of most parameters were lognormally distributed and spanned one to two orders of magnitude. Geometric mean concentrations of suspended materials, total nitrogen, total phosphorus, and pigments were highest in effluent from freshwater prawn ponds and lowest in marine fish pond effluent. Nitrate/Nitrite and total ammonia concentrations were higher in fish pond effluent than in crustacean pond effluent. Parameter concentrations were generally higher in effluent than in influent water, with freshwater fish and prawn ponds exhibiting the greatest increases in suspended materials and pigments. In contrast, nitrate/nitrite concentrations were lower in effluent than in influent waters. These data provide a basis for analyzing the environmental impacts of warm-water aquaculture effluent discharges.     

Making agricultural landscapes more sustainable for freshwater biodiversity: a case study from southern England

• 1. Agriculture is known to have a range of deleterious impacts on freshwater habitats and biota and many countries have introduced measures to attempt to mitigate these impacts through agri‐environment initiatives. Despite the protection they provide, water bodies (any discrete body of surface fresh water) in farmland landscapes commonly remain impaired by agriculture. In some areas of the UK there have been calls to halt farming completely, indicating that the measures offered for the widespread protection of aquatic systems, particularly the use of buffer strips, may not be extensive enough to provide sufficient protection for freshwater biota.
• 2. This study investigated whether existing agri‐environment measures for the widespread protection of aquatic habitats could be better deployed to provide a higher level of protection for the aquatic macrophytes and macroinvertebrates of a study area in southern England.
• 3. Reserve selection procedures were used to reallocate the area of land that could be remunerated under the Environmental Stewardship scheme as buffer strips bordering water bodies, so that a higher level of protection was provided for both the richness and rarity of aquatic species in the study area.
• 4. Almost 395 ha were available for reallocation in the reserve selection process, which was found to provide a satisfactory level of protection for up to 90% of the surveyed species.
• 5. The results showed that the agri‐environment scheme in England has a great deal of potential to provide more effective protection for the aquatic biodiversity of agricultural landscapes if measures are targeted.

Copyright © 2008 John Wiley & Sons, Ltd.     

Biological filters in aquaculture: Trends and research directions for freshwater and marine applications

Factors such as limitations in water quality and quantity, cost of land, limitations on water discharges, environmental impacts and diseases, are driving the aquaculture industry toward more intensive practices. This will force producers to adopt environmentally friendlier technologies. Recirculating systems, with a biofilter as the most prominent characteristic, treat internally the water contaminated with dissolved organics and ammonia and reduce the amount of water use and discharge from aquaculture operations. This paper reviews the implications of the changing use of recirculating aquaculture systems (RAS) on biofiltration research for freshwater and marine operations. Demand for cost effective biofilters will increase with the expansion of recirculating systems, both as a complement and replacement of traditional ponds. For freshwater aquaculture, emphasis should be placed in cost competitiveness, low head operations, intensification of ponds with RAS biofiltration and the evaluation of suspended growth systems. In the marine systems, an increase in demand of oligotrophic and ultraoligotrophic systems is expected, particularly in the nursery systems. Sizing and cost efficiency of biofilters for nursery operations should be addressed. Problems in marine biofilter acclimation appear to justify the development of new acclimation procedures. Biosecurity concerns, land cost and storm threats will drive nursery systems inland, where saltwater supply and disposal will force an increased water reuse. Denitrification strategies will need to be redefined and optimized for the marine nursery environment.     

江苏省6个典型湖泊水生植物分布及其与环境因子的关系

针对近30年来江苏省湖泊富营养化问题较为严重的现状,2016年4-5月(春季)和7-9月(夏季)进行了6个典型湖泊(白马湖、宝应湖、高邮湖、邵伯湖、长荡湖、滆湖)水生植物的野外分布情况调查,计算其优势度,判定典型湖泊的水生植物优势种。结果表明,江苏省6个典型湖泊常见水生植物19科、29种,呈现明显的季节及地域差异,主要优势种为芦苇(Phragmites australis)、茭草(Zizania latifolia)、菹草(Potamogeton crispus)、穗状狐尾藻(Myriophyllum spicatum)、荇菜(Nymphoides peltata)、空心莲子草(Alternanthera philoxeroides)及野菱(Trapa natans),生活型主要以挺水植物为主。综合营养指数法评价结果显示,6个典型湖泊均属于富营养化湖泊;其中长荡湖和滆湖为中度富营养水平,白马湖、宝应湖、高邮湖、邵泊湖均达到轻度富营养化水平。结合环境因子相关性和冗余分析(RDA),认为总氮(TN)、五日生化需氧量(BOD_5)是影响江苏省湖泊优势水生植物生长分布最主要的环境因子。     

Fish assemblage structure in relation to seasonal environmental variation in sub‐lakes of the Poyang Lake floodplain,China

The Yangtze River and its watershed have undergone vast changes resulting from centuries of human impacts, yet ecological knowledge of the system is limited. The seasonal variation and spatial variation of three sub‐lakes of Poyang Lake, a huge wetland in the middle Yangtze Basin, were investigated to examine how fish assemblages respond to seasonal hydrology and associated environmental conditions. In all three sub‐lakes, fish assemblage structure revealed strong variations associated with seasonal water level fluctuation. Fish species richness in all sub‐lakes was highest during the middle of the monsoon season and lowest during the dry season. Fish numerical abundance and biomass varied significantly, with several of the most common species having inconsistent patterns of seasonal variation among sub‐lakes. Fish assemblage structure was significantly associated with environmental gradients defined by water level, aquatic macrophyte coverage, conductivity and dissolved oxygen concentration. Assemblage composition in all three sub‐lakes underwent strongest shifts between December and April, the period when water levels were lowest and fishing has the greatest impact on fish stocks. Future impacts that change the hydrology of the middle Yangtze would alter the dynamics of habitat connectivity and affect environmental conditions and fish assemblages of the Poyang Lake wetland system.     

Distribution of Atlantic salmon, Salmo salar L., in freshwater bodies of Europe

Data are presented on the current geographic distribution of Atlantic salmon, Salmo salar L., in freshwater bodies of Europe. They dwell in 14 hydrological systems, including basins of U lakes and three rivers. Nine of the lakes (Ladoga, Onega, Kuito and others) arc located in Russia, one in Finland (Saimaa) and one in Sweden (Vänern). All the rivers inhabited by freshwater salmon flow within Norwegian borders. Most of the lakes and rivers have good connection with the Baltic, White or Norwegian Seas. Over the past 20 years the freshwater salmon stock in Lake Imandra (the Kola Peninsula) has completely disappeared as a result of heavy human impact. The situation with such non-migratory salmon, which used to be important to fishing and trade, is also critical in all other water bodies. It is necessary, therefore, to elaborate effective measures for protecting and restoring freshwater salmon in the lakes and rivers of Europe.