长江下游潮汛影响下生态浮岛建设技术研究

正生态浮岛是一种针对富营养化的水质、利用生态学原理降低水体中化学需氧量(COD)、氮、磷含量的人工浮岛。其结构由众多浮床(单元)相互联结"锚固"而成,浮于水面。生态浮岛对水质净化最主要的功效是利用植物的根系吸收水中的富营养化物质,如磷、氨氮、有机质等,使得水体的营养得到转移,减轻水体由于封闭或自循环不足带来的水体腥臭、富营养化现象。同时人工营造一个对动物、微生物良好的生长环境,提高水体的自净能力,修复水生生态系统,从而达到自然生态的平衡。     

不同覆盖率的生态浮床对池塘氮、磷的去除率

通过在养鱼池塘设置生态浮床培育空心菜,对比分析生态浮床不同覆盖率对水体氮、磷去除效果的影响。试验结果显示,设置生态浮床系统池塘与对照池塘之间氮磷含量存在显著差异(P0.05);生态浮床系统覆盖率在10%、20%、30%的设置下,对水体总氮的去除率分别为53.6%、62.4%、68.9%,对总磷的去除率分别为62.8%、74.1%、78.7%,三种浮床处理对水体氮、磷去除差异显著(P0.05)。生态浮床系统是一种新型的养殖模式,是池塘养殖生物与无土栽培植物在生态位上实现互利共生,该系统可作为池塘水体富营养化生态防控的措施进行推广应用。     

鱼类氮、磷营养与水体环境

氮、磷为鱼类重要的营养物质 ,随着水产养殖规模化和集约化进程的推进以及水产饲料的广泛使用 ,由此而产生的水体环境氮磷的污染问题也日趋严重 ,有研究证实 ,饲料中 70 %左右甚至更多的氮、磷将通过不同的途径进入养殖水体 ,当氮、磷在养殖水体中逐渐富积并达到一定值时 ,将形成水体富营养化 ,并严重威胁到鱼类生存     

生态基对大口黑鲈养殖池塘氮、磷累积的影响

为了研究生态基对大口黑鲈(Micropterus salmoides)养殖池塘氮,磷累积的影响,对大口黑鲈进行了6个月的室外池塘养殖试验。养殖期间不同时间段内分别对养殖水体亚硝态氮(NO_2-N)、硝态氮(NO_3-N)、铵态氮(NH~+_4-N)、磷酸盐(PO_4~(3-)-P)、总氮(TN)、总磷(TP)、总有机碳(TOC)含量以及养殖池塘底泥的TN、 TP、TOC含量进行了测定。结果显示:养殖水体氮相关指标中,生态基处理组TN、NO~-_3-N、NH~+_4-N含量极显著低于对照组,N累积显著低于对照组;生态基处理组TP含量极显著低于对照组,水体P累积显著低于对照组。池塘底泥中碳、氮、磷相关指标中,生态基处理组池塘底泥TOC、TN、TP含量与对照组无显著差异。实验结果表明,挂设生态基对降低大口黑鲈养殖池塘水体氮、磷含量有显著效果。     

水源水库富营养化问题及生态治理途径

水源水库富营养化严重威胁饮用水安全和人民身体健康,影响我国经济可持续发展,近年来越来越受到人们重视。水源水库富营养化生态治理主要包括前置库、库区生态缓冲带建设和水生植被恢复、人工植物浮岛、生物操纵、水库深层曝气和上下层水体混合交换等技术措施。富营养水库生态治理成本低,操作简便,能有效地将水库水质净化、生态恢复和景观建设有机结合,控制水库水华,减少水厂生产成本。     

盐生植物碱蓬在富营养化海水养殖尾水修复中的应用研究

海水养殖废水的排放导致了严重的近岸海域生态环境问题。植物修复海水养殖废水颇具优势。为了考察盐地碱蓬(Suaeda sala)由内陆生境转移到海水生境后的生长情况及对海水养殖池塘水体修复的效果，配制了4种不同富营养化程度的水体，采用水培的方法，测定了碱蓬对水体中COD、BOD5、TN、TP的处理效果及植株体内实验前后TP、TN含量的变化。结果显示，随净化时间的延长，TN、TP均呈下降趋势，一周后TN浓度维持在1.5~3.0 mg/L；随着水体中TP、TN浓度的增大，碱蓬的处理效果增加，且实验前后碱蓬植株体内TP、TN的含量也随水体中TP、TN浓度的增大而增加。随着净化时间的延长，不同程度富营养化水体中的COD、BOD5呈明显下降趋势。pH值在不同程度富营养化水体中呈先降后升的趋势，修复1周后，各水体均呈弱碱性。由于盐生植物吸收一定的盐离子维持自身的营养需要，水体盐度表现出下降。实验表明，盐地碱蓬从内陆生境转移到海水生境后不但适应了水生环境，也通过根系吸收、根际微生物等作用方式对水中的氮、磷、COD等产生了良好的去除效果，盐地碱蓬修复海水养殖池塘水体具有良好潜力。     

组合生态浮床的水体净化效果与作用机理探讨

通过在美人蕉(Canna glauca)底部悬挂生物陶粒基质构建组合生态浮床,与仅有生物陶粒的基质组和空白组比较了对室内配制富营养化污水的净化效果,分析了各组水体中的微生物数量和活性,研究组合浮床中植物、基质和微生物对水体净化的贡献率及其相互间协同作用.结果表明,经过48 d的运行,组合浮床对总氮、总磷和氨氮的去除率依次为64.03％、95.82％和96.43％,美人蕉对氮、磷的去除贡献率分别为36.03％、37.96％.组合浮床组水中的细菌总量、基质上附着的生物膜脱氢酶活性和耗氧速率均高于基质组,说明植物吸收不是组合浮床去除氮磷的主要机制,但植物对微生物的数量和活性有积极作用;组合浮床对水中污染物的去除存在着植物、基质及微生物之间的协同作用.与基质组和空白组相比,组合浮床可以有效提高对富营养化水体的净化效果.     

太湖流域城市湖泊大型底栖动物群落结构及影响因素研究

太湖流域城市湖泊富营养化问题严重,研究不同营养水平城市湖泊底栖动物群落的差异及成因,可为丰富底栖动物生态学研究和城市湖泊生态系统恢复提供参考。本研究于2018年12月、2019年3月、6月、9月在太湖流域15个城市湖泊开展了四个季度的调查,结果显示,重度、中度、轻度富营养和中营养水体分别占10.03%、36.89%、42.07%和11.00%。随水体营养下降,透明度显著上升,浊度、总磷和叶绿素a浓度显著下降,大型底栖动物总生物量、蚌类密度和生物量上升,寡毛类密度和生物量下降。在重度富营养水体中,底栖动物总生物量显著小于其他类型水体（P<0.01）;在轻度富营养和中营养水体中,蚌类密度和生物量显著大于重度和中度富营养水体（P<0.01）,寡毛类密度则显著小于重度和中度富营养水体（P<0.01）。Shannon-Wiener、Simpson和Pielou指数随水体营养水平下降,先上升再下降,在轻度富营养水体中最高。结构方程模型分析发现,在轻度富营养和中营养湖泊中,水温、总磷和叶绿素a浓度是影响底栖动物群落的关键环境因子。总磷浓度升高会显著促进软体动物增长（P<0.01）,对螺、蚌的路径系数分别高达0.414和0.440。总磷浓度与水温上升都能显著促进多毛类种群增长（P<0.01）,抑制水生昆虫种群（P<0.01）,路径系数分别为0.376和-0.423。本研究认为,城市湖泊水体中总磷和叶绿素a浓度对大型底栖动物群落结构有重要影响,对磷和藻类的控制,对城市湖泊底栖动物群落恢复和水生态系统修复有重要参考价值。     

三种植物对富营养化水体净化效果的比较研究

在富营养化水体中分别栽植美人蕉、鸢尾、再力花等3种植物,50 d后取水样测定各项水质指标,比较这3种植物对富营养化水体的净化效果。结果表明,3种植物对供试水体中总氮的去除率分别为69.96 %、69.19 %和64.20 %,对氨氮的去除率分别为80.44 %、79.51 %和87.73 %,对总磷的去除率分别为75.59 %、66.57 %和58.06 %；对CODCr的去除率分别为68.64 %、83.38 %和62.38 %。3种植物对富营养化水体均有一定的净化能力,对氨氮、总氮、总磷、化学耗氧量的去除效果明显好于对照组；各植物组间对富营养化水体的净化效果无明显差异。     

草鱼与鲢、鲤不同混养模式系统的氮磷收支

采取陆基围隔实验法,选用草鱼(Ctenopharyngodon idellus)、鲢(Hypophythalmichthys molitrix)、鲤(Cyprinus carpio)研究不同养殖模式系统氮磷的收支。实验于2011年5月开始,10月结束,实验周期为6个月,每月定期采样,围隔面积为7 m×7 m。分别测定了草鱼单养(G组)、草鱼–鲢混养(GS组)、草鱼–鲤混养(GC组)、草鱼–鲢–鲤混养(GSC1,GSC2)系统氮磷的输入和输出,并分析了不同养殖模式水体和底泥氮磷的积累情况。主要实验结果为:(1)不同养殖模式下,饵料氮磷的输入是系统氮磷输入的主要途径,分别占总输入的85.54%~93.38%和82.60%~84.26%,其余为放养生物、降水和初始水层。(2)不同养殖模式下,系统氮的输出依次为养殖生物收获、底泥积累、水层积累、围隔布吸附和氨挥发,所占比例分别为62.80%~77.15%、15.19%~27.60%、5.04%~7.71%、1.54%~2.14%和0.22%~0.30%;系统磷的输出依次为底泥积累、水层积累、养殖生物收获、围隔布吸附,所占比例分别为76.46%~80.04%、13.04%~15.14%、4.09%~9.79%、0.71%~1.16%。(3)不同养殖模式下,底泥氮积累量GSC1组和GSC2组显著低于G组、GS组和GC组(P0.05),而磷积累量GSC1组和GSC2组显著低于G组和GS组(P0.05);水体氮磷积累量GSC2组显著低于G组(P0.05)。(4)系统氮磷利用率GSC2组显著高于G组、GC组和GSC1组(P0.05)。实验结果表明,GSC2组(草鱼0.38 ind/m2、鲢0.69 ind/m2和鲤0.55 ind/m2)能有效降低系统氮磷的积累,提高氮磷的利用率,是一种高效清洁的草鱼混养模式。     

Enclosure culture ban and its effects on water quality and phytoplankton community in a subtropical shallow lake

Enclosure culture, ubiquitous anthropogenic activity in shallow lakes, was prohibited in East Taihu Lake with all breeding infrastructure demolished at the end of 2018. However, the ecological responses of water quality change and phytoplankton community succession to the enclosure culture ban remain largely unknown. In this study, we conducted field investigations monthly in East Taihu Lake to present a comprehensive study of water quality and phytoplankton community variation before (2018) and after (2019) the enclosure culture ban. With the cessation of aquaculture activities, water quality significantly improved, TN and TP decreased by 54% and 34%, respectively, and eutrophic state shifted from light eutrophic (mean TSI = 59) to mesotrophic status (mean TSI = 48) in autumn. Chl-a decreased from 33.34 ± 16.87 to 24.84 ± 15.43 μg/L, and SDD increased from 0.76 ± 0.19 to 0.95 ± 0.36 m. Meanwhile, phytoplankton abundance significantly decreased from 3.6 × 10⁷ to 1.6 × 10⁷ cell/L, with the contribution of Cyanophyta markedly decreasing from 82% to 63%. In addition, the heterogeneity of phytoplankton community markedly increased. The changes in water quality and phytoplankton following the enclosure culture ban were largely due to the suspension of external nutrient input from breeding activity and improved water clarity. Redundancy analysis (RDA) analysis further elucidated that water temperature and nutrients were the main factors affecting phytoplankton dynamics. Our findings showed that the ban on enclosure culture had an extremely positive ecological impact.     

Aquaculture wastewater quality improvement by water spinach (Ipomoea aquatica Forsskal) floating bed and ecological benefit assessment in ecological agriculture district

The current ecological situation of aquaculture water quality in Wushe (Songjiang district, Shanghai city) district is not up to mark. In the present study, characteristic of ecological agriculture park was first investigated and then water spinach floating bed was used to improve the aquaculture wastewater quality. The results showed significant improvement in the aquaculture water quality at the experimental site with removal rates of TN, NH₄⁺-N, NO₂⁻-N and TP were 11.2%, 60.0%, 60.2% and 27.3%, respectively. Moreover, we found that the removal mechanism of ammonia nitrogen and nitrate nitrogen by water spinach was mostly by microorganism, whereas the removal mechanism of phosphorus was mainly by plant absorption. In addition, water spinach could be harvested at regular time intervals, which could achieve good economic benefits. This research could provide a good case study for sustainable development in ecological agricultural park for other cities around the world.     

菱角对农村富营养化水体营养盐吸收的初步研究

为探究浮叶植物对农村富营养化废水中营养盐的去除效果,选定华龙村4个典型水塘,以人工种植菱角(Trapa bispinosa)为试验对象,研究菱角对富营养化水体中总氮(TN)、硝态氮(NO_3~--N)、氨态氮(NH_4~+-N)、总磷(TP)及化学需氧量(CODCr)的净化能力。结果表明,经过75 d的试验研究,试验区水塘的TN、NH_4~+-N和NO_3~--N的浓度分别从55 mg/L、25 mg/L和3 mg/L降至13 mg/L、4.3 mg/L和2.1 mg/L,去除效率分别为62.3%、74.5%和23.5%;TP及CODCr的浓度从3.3 mg/L和120 mg/L分别降至1.45 mg/L和52.5 mg/L,去除效率为56.9%和56.3%;对照区水塘各营养元素去除率较低。菱角对农村废水中的N、P有一定的吸收作用,对重度富营养化水体,水生植物优先吸收NH_4~+-N,对TN的去除影响较大;NO_3~--N的去除主要依靠微生物的反硝化作用;TP的吸收需要更长的时间。菱角对重度富营养化农村废水营养盐的去除具有重要意义,且可以取得一定的经济效益。本研究为应用水生植物处理农村生活污水中的营养盐提供科学依据。     

Use of planted biofilters in integrated recirculating aquaculture‐hydroponics systems in the Mekong Delta,Vietnam

The feasibility of using planted biofilters for purification of recirculated aquaculture water in the Mekong Delta of Vietnam was assessed. The plant trenches were able to clean tilapia aquaculture water and to maintain good water quality in the fish tanks without renewal of the water. NH₄‐N was removed efficiently in the plant trenches, particularly in the trenches with Canna glauca L., probably because of plant uptake and nitrification–denitrification. Plant uptake constituted 6% of N and 7% of P in the input feed. Approximately 1.0 m³ of water was needed per kg of fish produced, and 370, 97 and 2842 g fresh aboveground biomass of Ipomoea aquatica Forssk., Lactuca sativa L. and C. glauca, respectively, were produced. The leafy vegetables provide some extra income besides fish products, whereas C. glauca provides nice flowers and contributes to a significant nutrient removal with annual uptake rates of 725 kg N and 234 kg P ha^?1 year^?1. This research demonstrates that integrated recirculating aquaculture‐hydroponics (aquaponics) systems provide significant water savings and nutrient recycling as compared with traditional fish ponds.     

Comparison of bacterial communities in channel catfish Ictalurus punctatus culture ponds of an industrial ecological purification recirculating aquaculture system

The industrial aquaculture pond system has gradually replaced the use of traditional earthen pond, as it causes less pollution and is more economical. In this study, an industrial ecological purification recirculating aquaculture system consisting of the water source pond, high‐density culture ponds, a deposit pond, and ecological purification ponds for channel catfish cultivation was established. Twelve water samples from different ponds were sequenced, and the bacterial communities were analysed. The abundances of Cyanobacteria and Merismopedia varied in different functional ponds of the system. The water quality was stable after two months of cultivation at 1.89 ± 0.22 mg/L total nitrogen, 1.1 ± 0.08 mg/L NH₄‐N and 0.43 ± 0.1 mg/L total phosphorus. The fish weight increased in a nearly linear manner, reaching 237.63 ± 23.8 per fish at day 120. An analysis of the environmental parameters, water quality and fish weight suggested that the system had an effective water purification process. Canonical correspondence analysis showed that the community was affected at the genus and phylum levels by different environmental parameters. We identified several dominant beneficial bacteria with nutrient removal abilities. Overall, our results demonstrated that the ecological purification recirculating aquaculture system had notable effects on water quality improvement and promoted changes in bacterial populations. These results provide important information on the microbial ecology of pond industrial eco‐aquaculture systems.     

The control of floating macrophytes by grass carp in net cages: experiments in two tropical hydroelectric reservoirs

The efficiency of grass carp (Ctenopharyngodon idella Val.) for biological control of floating aquatic macrophytes in net cages was assessed in two eutrophic tropical hydroelectric reservoirs through experiments using three macrophyte species (Eichhornia crassipes, Pistia stratiotes and Salvinia auriculata). A total of twenty experiments were performed in these reservoirs with a duration period between 21 and 30 days, during distinct seasons of the year. Sets of experiments were conducted using the three macrophyte species simultaneously in both reservoirs, and additional experiments were performed in one reservoir involving the separate use of each species. All macrophytes demonstrated significant growth in the absence of fish with total per day biomass increase rate ranging from 0.06 to 17.00%. The presence of grass carp significantly reduced macrophyte biomass in both reservoirs independent of fish size, stocking rate and available cage space. In all seasons, grass carp grazing pressure was higher for S. auriculata and lower for P. stratiotes. The results show that grass carp in net cages was able to use aquatic macrophytes as the only food source, controlling massive plant growth (especially S. auriculata and E. crassipes). Fish cages, already implemented in several reservoirs in Brazil, are easily manageable units at relatively low cost. Thus, biocontrol of macrophytes using caged grass carp is proposed as an effective low‐budget ecotechnological tool to control consumable plants while avoiding the removal of desirable aquatic vegetation and the resultant impact on local fauna.     

蕹菜和水鳖对泥质与沙质底养殖水体的净化效果研究

为解决淡水池塘集约化投饲养殖水体的营养物质富集问题,采用围隔试验方法,研究了蕹菜(Ipomoea aquatica)和水鳖(Hydrocharis dubia)两种植物对泥质和沙质两种底质养殖水体的净化效果。研究发现:泥质底水体的氨氮、亚硝酸盐氮和总磷(TP)自净去除率显著低于沙质底,而泥质底水体的高锰酸盐指数(CODMn)自净去除率显著高于沙质底(P<0.05);不同底质水体中,两种植物对水体氨氮、亚硝酸盐氮、总氮(TN)和CODMn的去除率显著高于相应对照组(P<0.05);12.5%与25.0%的水鳖处理对营养物质的去除率基本无显著差异(P>0.05),12.5%的蕹菜与水鳖处理组仅在泥质底水体中水鳖(MSBI)对氨氮的去除率显著小于蕹菜(MKC)以及MSBI对亚硝酸盐氮的去除率显著高于MKC(P<0.05);泥质底水体中植物处理对氨氮、亚硝酸盐氮、TN、TP和CODMn的最大去除率分别为60.07%、54.78%、52.68%、23.96%和47.32%,沙质底分别为72.43%、83.54%、57.20%、37.07%和40.75%;此外,试验末植物处理组水体的所测营养物质均存在一定程度的上升。沙质底水体中氨氮、亚硝酸盐氮和TP等营养物质波动较大且自净去除率高于泥质底;在泥质和沙质底水体中蕹菜和水鳖浮床均具有显著净化作用,本地种水鳖可作为生态浮床的潜力净水植物;浮床应用过程中应加强收割与收获等管理,以避免水体二次污染。     

Effect of support medium,hydraulic loading rate and plant density on water quality and growth of halophytes in marine aquaponic systems

The development of marine intensive land‐based aquaculture systems has been limited due to the absence of methods to manage saline wastewater. Aquaponic systems, although commonly applied to freshwater aquaculture, can potentially manage nutrient wastes while providing a secondary product. The aim of this study was to evaluate both the capacity for water treatment and the production requirements of two saltwater‐tolerant plant species (Sesuvium portulacastrum and Batis maritima) when grown hydroponically in a marine aquaponic system. The presence of plants was found to significantly contribute to nitrate removal, such that mean nitrate concentrations were 10.1 ± 5.4 and 12.1 ± 6.1 mg/L NO₃^?‐N in planted and unplanted treatments respectively. The use of coconut fibre as a planting medium also significantly contributed to nitrate removal, such that mean nitrate concentrations were 9.78 ± 5.4 and 12.4 ± 6.0 mg/L NO₃^?‐N in coconut fibre and expanded clay treatments respectively. Daily nitrogen removal was greatest in the coconut fibre/plants treatment, ranging from ?18% to 67%. Hydraulic loading rate, plant species and plant density did not significantly affect water quality or plant growth. The low flow/saltwort/low density treatment had the greatest mean daily nitrogen removal, ranging from 25% to 172%. The results indicate that the main nitrogen removal mechanisms were simultaneous nitrification–denitrification in the hydroponic plant beds and nitrogen removal through plant growth. This study demonstrates that marine aquaponics could be an effective way to manage nutrient removal in marine land‐based aquaculture systems.     

池塘循环水生态养殖效果分析

用多种生物修复技术结合池塘工程改造手段,构建封闭型池塘循环水生态养殖系统。养殖水体的水质指标监测结果表明,该循环系统对TN、TP、NH4+-N及CODMn的平均去除率分别达62.89%、60.24%、56.52%、47.81%,具有很好的净化效果,能够满足养殖用水的要求,在整个养殖过程中实现了养殖尾水零排放。该循环水养殖模式符合当前太湖保护的规划要求。