Synergistic negative effects of small-sized benthivorous fish and nitrogen loading on the growth of submerged macrophytes - Relevance for shallow lake restoration
Synergistic negative effects of small-sized benthivorous fish and nitrogen loading on the growth of submerged macrophytes - Relevance for shallow lake restoration
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小型底栖鱼类和氮负荷对沉水植物生长的协同负面影响-浅湖恢复的相关性
DOI：
10.1016/j.scitotenv.2017.06.119
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发表时间：
2018-01-01
影响因子：
9.8
通讯作者：
Li, Kuanyi
中科院分区：
文献类型：
--
作者：
Gu, Jiao;He, Hu;Li, Kuanyi
在温暖的湖泊中，生物操纵后小鱼的快速补充可能会延迟沉水植物的重建，尤其是在高营养盐浓度下。最近在控制许多湖泊的磷（P）负荷方面取得了成功，但氮（N）的输入往往仍然很高。采用析因设计，在太湖北岸进行了一个室外围隔试验，研究了氮负荷和小型鱼类丰度对苦草生长的交互作用。实验涉及两种密度的小鲫鱼-低（10 g m（-2））和更高（40 g m（-2））与两个水平的氮负荷--目前的外部营养负荷杂交（P：5 μ g L-1天（-1），N：130 μ g L-1天（-1））和P：5 μ g L-1天（-1），具有三倍高的N负荷（N：390 μ g L-1天（-1））。结果表明，氮-鱼交互作用显著抑制了浮游植物的生长，尤其是在高氮负荷下。在低氮负荷下，高密度的鱼类使苦草的相对生长速率、平均叶长、叶质量和根质量分别比低密度时降低了16%、5%、8%和23%。鱼的影响甚至更强，当氮负荷高，分别为232%，32%，57%和47%的植物生长措施的下降。在高氮负荷的较强的效果是由于较高的浊度，由于增强浮游植物的生物量和增加消费或损害的植物鱼在响应morenutrient-enriched植物组织。我们的研究结果表明，高丰度的小鲫鱼在温暖的湖泊可能会降低沉水植物的弹性外部N负荷，从而降低成功恢复的机会，通过生物操纵。(C)2017 Elsevier B. V.版权所有。
Rapid recruitment of small fish after biomanipulation in warm lakes may delay the reestablishment of submerged macrophytes, not least at high nutrient concentrations. Success has recently been obtained in controlling phosphorus (P) loading to many lakes, but nitrogen (N) inputs often remain high. To determine the interactive effects of Nloading and the abundance of small-sized fish on the growth of the submerged macrophyte Vallisneria natans, we conducted an outdoor mesocosm experiment with a factorial design on the north shore of Lake Taihu, China. The experiment involved two densities of small crucian carp - low (10 g m(-2)) and high (40 g m(-2)) crossed with two levels of N loading-present-day external nutrient loading (P: 5 mu g L-1 day(-1), N: 130 mu g L-1 day(-1)) and P: 5 mu g L-1 day(-1)with a three times higher N loading (N: 390 mu g L-1 day(-1)). The results showed that nitrogen-fish interactions significantly hindered the growth of V. natans, particularly at the high N loading. At low N loading, high densities of fish decreased the relative growth rate, mean leaf length, leaf mass and root mass of V. natans by 16%, 5%, 8%, and 23%, respectively, compared with these measures at low fish densities. The effect of fish was even stronger when N loading was high, with decreases of 232%, 32%, 57%, and 47% for the respective plant growth measures. The stronger effect at high N loading was attributed to higher turbidity due to enhanced phytoplankton biomass and to increased consumption or damage of plants by the fish in response to the morenutrient-enriched plant tissue. Our results indicate that high abundance of small crucian carp inwarm lakes may reduce the resilience of submerged macrophytes to external N loading, thereby lowering the chances of successful restoration by biomanipulation. (C) 2017 Elsevier B.V. All rights reserved.