Light limitation of nutrient-poor lake ecosystems
Light limitation of nutrient-poor lake ecosystems
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DOI：
10.1038/nature08179
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发表时间：
2009-07-23
期刊：
影响因子：
64.8
通讯作者：
Jansson, Mats
中科院分区：
文献类型：
--
作者：
Karlsson, Jan;Bystrom, Par;Jansson, Mats
生产力是指生态系统中生物量合成的速率，是确定生态系统功能和管理的基本特征。养分有效性对生产力的限制是湖泊生态系统的一个既定范例（1-3）。在这里，我们评估了这种模式的相关性，为世界上大多数的小，营养贫乏的湖泊，与不同浓度的有色有机物（4，5）。通过比较小的非生产性湖泊沿着水的颜色梯度，我们表明，彩色陆地有机物控制新的生物质合成（底栖生物初级生产）的关键过程，通过其对光衰减的影响。我们还表明，这转化为生产和生物量的影响，更高的营养水平（底栖无脊椎动物和鱼类）。这些结果是不一致的想法，营养供应主要控制湖泊的生产力，我们建议，世界上的非生产性湖泊，有机碳和营养物质输入的自然变化范围内，很大一部分是有限的光，而不是营养物质。我们预计，我们的研究结果将有影响，了解湖泊生态系统功能和对环境变化的反应。有色有机物的集水区输出对短期自然变化和长期大规模变化敏感，这些变化由气候和不同的人为影响驱动（6，7）。因此，陆地碳循环的变化将通过调节湖泊光气候和生产力的变化对大多数湖泊生态系统产生显著影响。
Productivity denotes the rate of biomass synthesis in ecosystems and is a fundamental characteristic that frames ecosystem function and management. Limitation of productivity by nutrient availability is an established paradigm for lake ecosystems(1-3). Here, we assess the relevance of this paradigm for a majority of the world's small, nutrient-poor lakes, with different concentrations of coloured organic matter(4,5). By comparing small unproductive lakes along a water colour gradient, we show that coloured terrestrial organic matter controls the key process for new biomass synthesis (the benthic primary production) through its effects on light attenuation. We also show that this translates into effects on production and biomass of higher trophic levels (benthic invertebrates and fish). These results are inconsistent with the idea that nutrient supply primarily controls lake productivity, and we propose that a large share of the world's unproductive lakes, within natural variations of organic carbon and nutrient input, are limited by light and not by nutrients. We anticipate that our result will have implications for understanding lake ecosystem function and responses to environmental change. Catchment export of coloured organic matter is sensitive to short-term natural variability and long-term, large-scale changes, driven by climate and different anthropogenic influences(6,7). Consequently, changes in terrestrial carbon cycling will have pronounced effects on most lake ecosystems by mediating changes in light climate and productivity of lakes.