Harmful freshwater algal blooms, with an emphasis on cyanobacteria.
Harmful freshwater algal blooms, with an emphasis on cyanobacteria.
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DOI：
10.1100/tsw.2001.16
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发表时间：
2001-04-04
影响因子：
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通讯作者：
Dyble J
中科院分区：
文献类型：
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作者：
Paerl HW;Fulton RS 3rd;Moisander PH;Dyble J
悬浮藻类或浮游植物是淡水生态系统中维持食物网的有机物质的主要来源。浮游植物的生产力依赖于充足的营养供应;然而，营养供应的增加，其中大部分是人为的，加速了初级生产或富营养化。富营养化的一个明显和有问题的症状是浮游植物的快速生长和积累，导致受影响的沃茨变色。这些事件被称为开花。水华是水质恶化的主要因素，包括恶臭和味道、底层沃茨水的脱氧（缺氧和缺氧）、毒性、鱼类死亡和食物网改变。水华产生的毒素可对娱乐和饮用沃茨中的动物（包括人类）健康产生不利影响。浮游植物门中的许多淡水属都能够形成水华;然而，蓝绿藻（或蓝藻）是最臭名昭著的水华形成者。这对于有害的有毒的、表面居住的、形成浮渣的属（例如，鱼腥藻属（Anabaena）、束丝藻属（Aphanizomenon）、节球藻属（Nodularia）、微囊藻属（Microcystis））和一些善于利用富营养条件的地下水华形成者（拟球藻属（Aciddrospermopsis）、颤藻属（Oscillatoria））。它们能够在富辐射的表层沃茨和富营养的底层沃茨之间迅速迁移，从而在高生产力的沃茨中茁壮成长。此外，许多有害物种能够忍受极端的环境条件，包括非常高的光照水平、高温、不同程度的干燥和周期性的营养缺乏。一些最有害的蓝藻水华属（例如，鱼腥藻属（Anabaena）、束丝藻属（Aphanizomenon）、拟球藻属（Aciddrospermopsis）、节球藻属（Nodularia））能够固定大气氮（N2），使它们能够在氮有限的条件下周期性地占优势。蓝细菌产生一系列有机化合物，包括那些对高级消费者有毒的化合物，从浮游动物到食物链的上游。固氮和不固氮的属都参与与微生物、高等植物和动物的互利共生关系。这些协会似乎对它们的生存和周期性的优势有很大的好处。在这篇综述中，我们将讨论有害水华的生态影响和环境控制，重点是蓝藻水华类群的生态学，生理学和管理。自然沃茨的物理、化学和生物特征的组合以协同方式起作用，以确定水体的敏感性。在易发生水华的沃茨，水域和空气区的人类活动与水华的范围和规模有关。蓝藻和其他浮游植物水华的控制和管理总是包括养分输入的限制，最常见的集中在氮（N）和/或磷（P）。养分输入限制的类型和数量取决于水文、气候、地理和地质因素，这些因素与人为和自然养分输入机制相互作用。虽然单一的营养素输入限制可能是有效的，在某些水体中，双N和P输入减少通常需要有效的长期控制和管理有害水华。在一些系统中，水文操纵（即，虽然有可能实现水的充分供应，但通过加强冲洗和人工混合（结合营养物输入限制）来减少水的停留时间可能是特别有效的替代办法。各种管理策略的影响，结合生态生理和环境因素，进行了讨论。
Suspended algae, or phytoplankton, are the prime source of organic matter supporting food webs in freshwater ecosystems. Phytoplankton productivity is reliant on adequate nutrient supplies; however, increasing rates of nutrient supply, much of it manmade, fuels accelerating primary production or eutrophication. An obvious and problematic symptom of eutrophication is rapid growth and accumulations of phytoplankton, leading to discoloration of affected waters. These events are termed blooms. Blooms are a prime agent of water quality deterioration, including foul odors and tastes, deoxygenation of bottom waters (hypoxia and anoxia), toxicity, fish kills, and food web alterations. Toxins produced by blooms can adversely affect animal (including human) health in waters used for recreational and drinking purposes. Numerous freshwater genera within the diverse phyla comprising the phytoplankton are capable of forming blooms; however, the blue-green algae (or cyanobacteria) are the most notorious bloom formers. This is especially true for harmful toxic, surface-dwelling, scum-forming genera (e.g., Anabaena, Aphanizomenon, Nodularia, Microcystis) and some subsurface bloom-formers (Cylindrospermopsis, Oscillatoria) that are adept at exploiting nutrient-enriched conditions. They thrive in highly productive waters by being able to rapidly migrate between radiance-rich surface waters and nutrient-rich bottom waters. Furthermore, many harmful species are tolerant of extreme environmental conditions, including very high light levels, high temperatures, various degrees of desiccation, and periodic nutrient deprivation. Some of the most noxious cyanobacterial bloom genera (e.g., Anabaena, Aphanizomenon, Cylindrospermopsis, Nodularia) are capable of fixing atmospheric nitrogen (N2), enabling them to periodically dominate under nitrogen-limited conditions. Cyanobacteria produce a range of organic compounds, including those that are toxic to higher-ranked consumers, from zooplankton to further up the food chain. Both N2- and non-N2-fixing genera participate in mutualistic and symbiotic associations with microorganisms, higher plants, and animals. These associations appear to be of great benefit to their survival and periodic dominance. In this review, we address the ecological impacts and environmental controls of harmful blooms, with an emphasis on the ecology, physiology, and management of cyanobacterial bloom taxa. Combinations of physical, chemical, and biotic features of natural waters function in a synergistic fashion to determine the sensitivity of water bodies. In waters susceptible to blooms, human activities in water- and airsheds have been linked to the extent and magnitudes of blooms. Control and management of cyanobacterial and other phytoplankton blooms invariably includes nutrient input constraints, most often focused on nitrogen (N) and/or phosphorus (P). The types and amount of nutrient input constraints depend on hydrologic, climatic, geographic, and geologic factors, which interact with anthropogenic and natural nutrient input regimes. While single nutrient input constraints may be effective in some water bodies, dual N and P input reductions are usually required for effective long-term control and management of harmful blooms. In some systems where hydrologic manipulations (i.e., plentiful water supplies) are possible, reducing the water residence time by enhanced flushing and artificial mixing (in conjunction with nutrient input constraints) can be particularly effective alternatives. Implications of various management strategies, based on combined ecophysiological and environmental considerations, are discussed.