太湖蓝藻水华的扩张与驱动因素
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摘要
蓝藻水华表征指标及驱动因子的多样性增加了研究人员、湖泊管理部门对于蓝藻水华扩张驱动因素的困惑,本研究通过整合太湖蓝藻水华长尺度研究的成果,将蓝藻水华扩张区分为时间扩张、空间扩张和生物量扩张3个方面,分析各自的驱动因子,系统阐述了当下太湖蓝藻水华的扩张和驱动因素.太湖蓝藻水华的时间扩张呈现由夏季集中发生向春季和秋冬季节扩张的趋势,导致春季蓝藻水华发生的提前,以及年度峰值的推迟;空间扩张呈现由西北太湖向湖心和东部湖区、乃至全湖扩张的趋势;太湖蓝藻生物量自2003年以后一直呈现缓慢增加的趋势.蓝藻水华时间扩张的驱动因素相对独立,主要受气象因子的影响,风速和日照时间是主要驱动因子,风速降低和日照时间延长均有助于蓝藻水华时间的扩张;空间扩张和生物量扩张则受气象因子和富营养化的双重影响,其中影响水华空间扩张的因子较多,富营养化和气象因素的主次难以确定,一般偶发性大面积蓝藻水华受气象因子驱动,而频发性大面积蓝藻水华主要受营养盐空间分布影响;影响蓝藻生物量扩张的主要驱动因素为总磷,另外氮磷比、水下可利用光和风速的变化也在一定程度上驱动了太湖蓝藻生物量的扩张.目前表征蓝藻水华强度通常利用空间扩张或生物量扩张指标,但是均具有一定局限性,相互间也缺乏可比性,各指标用于长尺度趋势研究更为可靠,短尺度比较受方法缺陷影响较大,应进一步开发表征水华蓝藻总存量的指标以统一空间扩张和生物量扩张.
The diversity in proxies and drivers of cyanobacterial blooms expansion increased the confusion of understanding for cyanobacterial blooms expansion to scientists and lake managers. This study integrated the previous studies about long-term variation of cyanobacterial blooms in Lake Taihu,and divided the expansion into three aspects: temporal expansion,spatial expansion and biomass expansion,and discussed their trend and drivers. In time,the occurrence of cyanobacterial blooms shows the trend towards spring and autumn/winter from summer. The onset time of cyanobacterial blooms advances,and the annual peak delays. In space,cyanobacterial blooms expands towards center and east of the lake from the north and west. The cyanobacterial biomass increases gradually since 2003. Wind speed and sunshine hours are the primary factors influencing the temporal expansion. Decreasing wind speed and increasing sunshine hours favor the temporal expansion. The drivers for the spatial expansion are relative complicated,and difficult to disentangle the primary factors from nutrient and climate variables. Generally,the occasional large-area cyanobacterial blooms are driven by wind speed and wind direction,and the frequent large-area blooms are driven by nutrient. Total phosphorus is the primary factor driving the variation of cyanobacterial biomass,following by the ratio of total nitrogen to total phosphorus,underwater available light and wind speed. At present,the cyanobacterial blooms area and biomass usually are used to indicate the blooms intensity,both of which are inaccurate due to the defect of methods. Their proxies are reliable for long-term study,but seriously affected by defect of methods when they are used in short-term study. Therefore,it is necessary to build a new proxy as a substitution for bloom area and biomass to show the total cyanobacterial biomass in the whole lake. In addition,reducing phosphorus loading and decreasing phosphorus concentration are the main task of controlling cyanobacterial blooms in Lake Taihu.
The diversity in proxies and drivers of cyanobacterial blooms expansion increased the confusion of understanding for cyanobacterial blooms expansion to scientists and lake managers. This study integrated the previous studies about long-term variation of cyanobacterial blooms in Lake Taihu,and divided the expansion into three aspects: temporal expansion,spatial expansion and biomass expansion,and discussed their trend and drivers. In time,the occurrence of cyanobacterial blooms shows the trend towards spring and autumn/winter from summer. The onset time of cyanobacterial blooms advances,and the annual peak delays. In space,cyanobacterial blooms expands towards center and east of the lake from the north and west. The cyanobacterial biomass increases gradually since 2003. Wind speed and sunshine hours are the primary factors influencing the temporal expansion. Decreasing wind speed and increasing sunshine hours favor the temporal expansion. The drivers for the spatial expansion are relative complicated,and difficult to disentangle the primary factors from nutrient and climate variables. Generally,the occasional large-area cyanobacterial blooms are driven by wind speed and wind direction,and the frequent large-area blooms are driven by nutrient. Total phosphorus is the primary factor driving the variation of cyanobacterial biomass,following by the ratio of total nitrogen to total phosphorus,underwater available light and wind speed. At present,the cyanobacterial blooms area and biomass usually are used to indicate the blooms intensity,both of which are inaccurate due to the defect of methods. Their proxies are reliable for long-term study,but seriously affected by defect of methods when they are used in short-term study. Therefore,it is necessary to build a new proxy as a substitution for bloom area and biomass to show the total cyanobacterial biomass in the whole lake. In addition,reducing phosphorus loading and decreasing phosphorus concentration are the main task of controlling cyanobacterial blooms in Lake Taihu.
引文
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[5]Nanjing Institute of Geography and Limnology,Water Resources Protection Bureau of the Taihu Catchment eds.Water environment,ecology and eutrophication in Lake Taihu(1994-1995).Nanjing:Nanjing Institute of Geography and Limnology,1997.[中国科学院南京地理与湖泊研究所,太湖流域水资源保护局.太湖水环境生态及富营养化研究(1994-1995).南京:中国科学院南京地理与湖泊研究所,1997.]
[6]Ma RH,Kong FX,Duan HT et al.Spatio-temporal distribution of cyanobacteria blooms based on satellite imageries in Lake Taihu,China.J Lake Sci,2008,20(6):687-694.DOI:10.18307/2008.0605.[马荣华,孔繁翔,段洪涛等.基于卫星遥感的太湖蓝藻水华时空分布规律认识.湖泊科学,2008,20(6):687-694.]
[7]Reynolds CS ed.The ecology of freshwater phytoplankton.Cambridge,UK:Cambridge University Press,1984.
[8]Reynolds CS ed.Ecology of phytoplankton(Ecology,biodiversity and conservation).Cambridge,UK:Cambridge University Press,2006.
[9]Paerl HW,Huisman J.Climate:Blooms like it hot.Science,2008,320:57-58.
[10]Rigosi A,Carey CC,Ibelings BW et al.The interaction between climate warming and eutrophication to promote cyanobacteria is dependent on trophic state and varies among taxa.Limnology and Oceanography,2014,59:99-114.
[11]Wagner C,Adrian R.Cyanobacteria dominance:Quantifying the effects of climate change.Limnology and Oceanography,2009,54:2460-2468.
[12]Zhang M,Duan H,Shi X et al.Contributions of meteorology to the phenology of cyanobacterial blooms:implications for future climate change.Water Research,2012,46:442-452.
[13]Deng J,Qin B,Paerl HW et al.Earlier and warmer springs increase cyanobacterial(Microcystis spp.)blooms in subtropical Lake Taihu,China.Freshwater Biology,2014,59(5):1076-1085.
[14]Liu X,Lu X,Chen Y.The effects of temperature and nutrient ratios on Microcystis blooms in Lake Taihu,China:An 11-year investigation.Harmful Algae,2011,10(3):337-343.
[15]Duan H,Ma R,Xu X et al.Two-decade reconstruction of algal blooms in China's Lake Taihu.Environmental Science&Technology,2009,43(10):3522-3528.
[16]Cao H,Tao Y,Kong F et al.Relationship between temperature and cyanobacterial recruitment from sediments in laboratory and field studies.Journal of Freshwater Ecology,2008,23(3):405-412.
[17]Hu CM,Lee Z,Ma RH et al.Moderate resolution imaging spectroradiometer(MODIS)observations of cyanobacteria blooms in Taihu Lake,China.Journal of Geophysical Research,2010,115(C4):C04002.
[18]Zhang Y,Ma R,Duan H et al.A novel algorithm to estimate algal bloom coverage to subpixel resolution in Lake Taihu.IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,2014,7(7):3060-3068.
[19]Shi K,Zhang Y,Zhou Y et al.Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu:Responses to nutrient enrichment and meteorological factors.Scientific Reports,2017,7:40326.
[20]Chen Y,Fan C,Teubner K et al.Changes of nutrients and phytoplankton chlorophyll-a in a large shallow lake,Taihu,China:An 8-year investigation.Hydrobiologia,2003,506(1):273-279.
[21]Zhu GW,Qin BQ,Zhang YL et al.Variation and driving factors of nutrients and chlorophyll-a concentrations in northern region of Lake Taihu,China,2005-2017.J Lake Sci,2018,30(2):279-295.DOI:10.18307/2018.0201.[朱广伟,秦伯强,张运林等.2005-2017年北部太湖水体叶绿素a和营养盐变化及影响因素.湖泊科学,2018,30(2):279-295.]
[22]Vallina SM,Follows M,Dutkiewicz S et al.Global relationship between phytoplankton diversity and productivity in the ocean.Nature Communications,2014,5:4229.DOI:10.1038/ncomms5299(2014).
[23]Zhang M,Straile D,Chen F et al.Dynamics and drivers of phytoplankton richness and composition along productivity gradient.Science of the Total Environment,2018,625:275-284.
[24]Ma J,Qin B,Paerl HW et al.The persistence of cyanobacterial(Microcystis spp.)blooms throughout winter in Lake Taihu,China.Limnology and Oceanography,2016,61(2):711-722.
[25]Sun SC,Huang YP eds.Lake Taihu.Beijing:Ocean Press,1993.[孙顺才,黄漪平.太湖.北京:海洋出版社,1993.]
[26]Chen Y,Qin B,Teubner K et al.Long-term dynamics of phytoplankton assemblages:Microcystis-domination in Lake Taihu,a large shallow lake in China.Journal of Plankton Research,2003,25(4):445-453.
[27]Zhu W,Tan YQ,Wang RC et al.The trend of water quality variation and analysis in typical area of Lake Taihu,2010-2017.J Lake Sci,2018,30(2):296-305.DOI:10.18307/2018.0202.[朱伟,谈永琴,王若辰等.太湖典型区2010-2017年间水质变化趋势及异常分析.湖泊科学,2018,30(2):296-305.]
[28]Qin BQ,Wang XD,Tang XM et al.Drinking water crisis caused by eutrophication and cyanobacterial bloom in Lake Taihu,cause and measurement.Advance in Earth Science,2007,22(9):896-906.[秦伯强,王小冬,汤祥明等.太湖富营养化与蓝藻水华引起的饮用水危机---原因与对策.地球科学进展,2007,22(9):896-906.]
[29]Cao HS,Kong FX,Luo LC et al.Effects of wind and wind-induced waves on vertical phytoplankton distribution and surface blooms of Microcystis aeruginosa in Lake Taihu.Journal of Freshwater Ecology,2006,21(2):231-238.
[30]Xu H,Paerl HW,Qin B et al.Nitrogen and phosphorus inputs control phytoplankton growth in eutrophic Lake Taihu,China.Limnology and Oceanography,2010,55(1):420-432.
[31]Zhang M,Qin B,Yu Y et al.Effects of temperature fluctuation on the development of cyanobacterial dominance in spring:implication of future climate change.Hydrobiologia,2016,763:135-146.
[32]Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences.On the cause of cyanophyta bloom and pollution in water intake area and emergency measures in Meiliang Bay,Lake Taihu in 2007.J Lake Sci,2007,19(4):357-358.DOI:10.18307/2007.0401.[中国科学院南京地理与湖泊研究所.太湖梅梁湾2007年蓝藻水华形成及取水口污水团成因分析与应急措施建议.湖泊科学,2007,19(4):357-358.]
[33]Zhang M,Shi X,Yang Z et al.Long-term dynamics and drivers of phytoplankton biomass in eutrophic Lake Taihu.Science of the Total Environment,2018,645:876-886.
[34]Jochimsen MC,Kümmerlin R,Straile D.Compensatory dynamics and the stability of phytoplankton biomass during four decades of eutrophication and oligotrophication.Ecology Letters,2012,16:81-89.
[2]Qin BQ,Hu WP,Chen WM et al.Process and echanism of water environment evolument in Lake Taihu.Beijing:Science Press,2004.[秦伯强,胡维平,陈伟民等.太湖水环境演化过程与机理.北京:科学出版社,2004.]
[3]Bulletin on environmental conditions in China.2016.[中国环境状况公报.2016.]
[4]Xie P ed.Historical development of cyanobacteria with bloom disaster in Lake Taihu.Beijing:Science Press,2008.[谢平.太湖蓝藻的历史发展与水华灾害.北京:科学出版社,2008.]
[5]Nanjing Institute of Geography and Limnology,Water Resources Protection Bureau of the Taihu Catchment eds.Water environment,ecology and eutrophication in Lake Taihu(1994-1995).Nanjing:Nanjing Institute of Geography and Limnology,1997.[中国科学院南京地理与湖泊研究所,太湖流域水资源保护局.太湖水环境生态及富营养化研究(1994-1995).南京:中国科学院南京地理与湖泊研究所,1997.]
[6]Ma RH,Kong FX,Duan HT et al.Spatio-temporal distribution of cyanobacteria blooms based on satellite imageries in Lake Taihu,China.J Lake Sci,2008,20(6):687-694.DOI:10.18307/2008.0605.[马荣华,孔繁翔,段洪涛等.基于卫星遥感的太湖蓝藻水华时空分布规律认识.湖泊科学,2008,20(6):687-694.]
[7]Reynolds CS ed.The ecology of freshwater phytoplankton.Cambridge,UK:Cambridge University Press,1984.
[8]Reynolds CS ed.Ecology of phytoplankton(Ecology,biodiversity and conservation).Cambridge,UK:Cambridge University Press,2006.
[9]Paerl HW,Huisman J.Climate:Blooms like it hot.Science,2008,320:57-58.
[10]Rigosi A,Carey CC,Ibelings BW et al.The interaction between climate warming and eutrophication to promote cyanobacteria is dependent on trophic state and varies among taxa.Limnology and Oceanography,2014,59:99-114.
[11]Wagner C,Adrian R.Cyanobacteria dominance:Quantifying the effects of climate change.Limnology and Oceanography,2009,54:2460-2468.
[12]Zhang M,Duan H,Shi X et al.Contributions of meteorology to the phenology of cyanobacterial blooms:implications for future climate change.Water Research,2012,46:442-452.
[13]Deng J,Qin B,Paerl HW et al.Earlier and warmer springs increase cyanobacterial(Microcystis spp.)blooms in subtropical Lake Taihu,China.Freshwater Biology,2014,59(5):1076-1085.
[14]Liu X,Lu X,Chen Y.The effects of temperature and nutrient ratios on Microcystis blooms in Lake Taihu,China:An 11-year investigation.Harmful Algae,2011,10(3):337-343.
[15]Duan H,Ma R,Xu X et al.Two-decade reconstruction of algal blooms in China's Lake Taihu.Environmental Science&Technology,2009,43(10):3522-3528.
[16]Cao H,Tao Y,Kong F et al.Relationship between temperature and cyanobacterial recruitment from sediments in laboratory and field studies.Journal of Freshwater Ecology,2008,23(3):405-412.
[17]Hu CM,Lee Z,Ma RH et al.Moderate resolution imaging spectroradiometer(MODIS)observations of cyanobacteria blooms in Taihu Lake,China.Journal of Geophysical Research,2010,115(C4):C04002.
[18]Zhang Y,Ma R,Duan H et al.A novel algorithm to estimate algal bloom coverage to subpixel resolution in Lake Taihu.IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,2014,7(7):3060-3068.
[19]Shi K,Zhang Y,Zhou Y et al.Long-term MODIS observations of cyanobacterial dynamics in Lake Taihu:Responses to nutrient enrichment and meteorological factors.Scientific Reports,2017,7:40326.
[20]Chen Y,Fan C,Teubner K et al.Changes of nutrients and phytoplankton chlorophyll-a in a large shallow lake,Taihu,China:An 8-year investigation.Hydrobiologia,2003,506(1):273-279.
[21]Zhu GW,Qin BQ,Zhang YL et al.Variation and driving factors of nutrients and chlorophyll-a concentrations in northern region of Lake Taihu,China,2005-2017.J Lake Sci,2018,30(2):279-295.DOI:10.18307/2018.0201.[朱广伟,秦伯强,张运林等.2005-2017年北部太湖水体叶绿素a和营养盐变化及影响因素.湖泊科学,2018,30(2):279-295.]
[22]Vallina SM,Follows M,Dutkiewicz S et al.Global relationship between phytoplankton diversity and productivity in the ocean.Nature Communications,2014,5:4229.DOI:10.1038/ncomms5299(2014).
[23]Zhang M,Straile D,Chen F et al.Dynamics and drivers of phytoplankton richness and composition along productivity gradient.Science of the Total Environment,2018,625:275-284.
[24]Ma J,Qin B,Paerl HW et al.The persistence of cyanobacterial(Microcystis spp.)blooms throughout winter in Lake Taihu,China.Limnology and Oceanography,2016,61(2):711-722.
[25]Sun SC,Huang YP eds.Lake Taihu.Beijing:Ocean Press,1993.[孙顺才,黄漪平.太湖.北京:海洋出版社,1993.]
[26]Chen Y,Qin B,Teubner K et al.Long-term dynamics of phytoplankton assemblages:Microcystis-domination in Lake Taihu,a large shallow lake in China.Journal of Plankton Research,2003,25(4):445-453.
[27]Zhu W,Tan YQ,Wang RC et al.The trend of water quality variation and analysis in typical area of Lake Taihu,2010-2017.J Lake Sci,2018,30(2):296-305.DOI:10.18307/2018.0202.[朱伟,谈永琴,王若辰等.太湖典型区2010-2017年间水质变化趋势及异常分析.湖泊科学,2018,30(2):296-305.]
[28]Qin BQ,Wang XD,Tang XM et al.Drinking water crisis caused by eutrophication and cyanobacterial bloom in Lake Taihu,cause and measurement.Advance in Earth Science,2007,22(9):896-906.[秦伯强,王小冬,汤祥明等.太湖富营养化与蓝藻水华引起的饮用水危机---原因与对策.地球科学进展,2007,22(9):896-906.]
[29]Cao HS,Kong FX,Luo LC et al.Effects of wind and wind-induced waves on vertical phytoplankton distribution and surface blooms of Microcystis aeruginosa in Lake Taihu.Journal of Freshwater Ecology,2006,21(2):231-238.
[30]Xu H,Paerl HW,Qin B et al.Nitrogen and phosphorus inputs control phytoplankton growth in eutrophic Lake Taihu,China.Limnology and Oceanography,2010,55(1):420-432.
[31]Zhang M,Qin B,Yu Y et al.Effects of temperature fluctuation on the development of cyanobacterial dominance in spring:implication of future climate change.Hydrobiologia,2016,763:135-146.
[32]Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences.On the cause of cyanophyta bloom and pollution in water intake area and emergency measures in Meiliang Bay,Lake Taihu in 2007.J Lake Sci,2007,19(4):357-358.DOI:10.18307/2007.0401.[中国科学院南京地理与湖泊研究所.太湖梅梁湾2007年蓝藻水华形成及取水口污水团成因分析与应急措施建议.湖泊科学,2007,19(4):357-358.]
[33]Zhang M,Shi X,Yang Z et al.Long-term dynamics and drivers of phytoplankton biomass in eutrophic Lake Taihu.Science of the Total Environment,2018,645:876-886.
[34]Jochimsen MC,Kümmerlin R,Straile D.Compensatory dynamics and the stability of phytoplankton biomass during four decades of eutrophication and oligotrophication.Ecology Letters,2012,16:81-89.