Responses of lake phytoplankton to micronutrient enrichment: a study in two New Zealand lakes and an analysis of published data
Responses of lake phytoplankton to micronutrient enrichment: a study in two New Zealand lakes and an analysis of published data
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DOI：
10.1007/s00027-008-8065-6
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发表时间：
2008-12-01
期刊：
影响因子：
2.4
通讯作者：
Burns, Carolyn W.
中科院分区：
文献类型：
--
作者：
Downs, Theresa M.;Schallenberg, Marc;Burns, Carolyn W.
营养物浓度的自然和人为变化可影响海洋和淡水环境中的浮游植物。然而，在淡水沃茨植物生产力的潜在微量营养盐限制往往被忽视。为了研究湖泊浮游植物对微量营养元素富集的响应，我们在新西兰两个对比湖泊中进行了研究，并分析了已发表的国际文献中的数据。我们对从中营养水库和富营养沿海湖泊中取样的浮游植物群落进行了营养盐富集生物测定，以确定微量营养元素的相对存在（铁、硼、钴、铜、钼）和常量营养素（氮、磷）限制。在中营养型水库中，浮游植物生产力受到磷的限制。在夏季的6个生物测定中没有发现微量营养素限制的证据。在富营养化的湖泊，10倍的环境微量营养素浓度的富集增加了初级生产力的11个生物测定。在富营养化的湖泊蓝藻水华期间，实验富集硼，钴，铜或钼，初级生产力提高了40%。这四种微量营养素通常用作湖泊集水区的农业肥料。氮或磷的富集没有影响浮游植物的生产力在这个时候。国际上已有40多个湖泊报告了微量营养素限制，我们对已发表数据的分析表明，微量营养素限制的流行与湖泊大小或营养状态无关。由于微量营养素富集可以显著增加各种湖泊类型中浮游植物的生产力，因此不应忽视微量营养素富集对富营养化的潜在贡献。
Natural and anthropogenic changes in nutrient concentrations can affect phytoplankton in marine and freshwater environments. However, potential micronutrient limitation of phytoplankton productivity in fresh waters is often overlooked. To investigate the responses of lake phytoplankton to micronutrient enrichment, we conducted a study in two contrasting New Zealand lakes, and analysed data from the published international literature.We undertook nutrient enrichment bioassays of phytoplankton communities sampled from a mesotrophic reservoir and an eutrophic coastal lake to determine the relative occurrence of micronutrient (iron, boron, cobalt, copper, molybdenum) and macronutrient (nitrogen, phosphorus) limitation. In the mesotrophic reservoir, phytoplankton productivity was phosphorus limited. No evidence of micronutrient limitation was found in six bioassays in summer. In the eutrophic lake, tenfold enrichment of ambient micronutrient concentrations increased the primary productivity in four of 11 bioassays. During a cyanobacterial bloom in the eutrophic lake, experimental enrichment with boron, cobalt, copper or molybdenum increased primary productivity by 40%. These four micronutrients are commonly applied as agricultural fertiliser in the lake's catchment. Nitrogen or phosphorus enrichment had no effect on phytoplankton productivity at this time. Micronutrient limitation has been reported in more than 40 lakes internationally, and our analysis of published data suggests that the prevalence of micronutrient limitation is unrelated to lake size or trophic state. As micronutrient enrichment can significantly increase phytoplankton productivity in a range of lakes types, the potential contribution of micronutrient enrichment to eutrophication should not be overlooked.