Stable isotope analysis of zooplankton carbon nutrition in humic lakes
Stable isotope analysis of zooplankton carbon nutrition in humic lakes
复制标题
腐殖质湖泊浮游动物碳营养的稳定同位素分析
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
L. Arvola
中科院分区：
文献类型：
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作者：
Roger I. Jones;J. Grey;D. Sleep;L. Arvola
碳稳定同位素组成测定浮游动物，POM，DOM，并在两种情况下，浮游植物从12个小森林湖泊在芬兰南部1997年夏季。选择的湖泊，以提供广泛的水色（12-365毫克铂l-1），但在其他湖沼特征的最小变化。POM和DOM显示出相似的稳定同位素比值（δ 13 C约为-28 ‰，与陆地C3植被通常报告的值相当），这些比值与水体颜色无关。浮游动物一致耗尽13 C相对于散装POM上，他们可能的饲料。这种相对的13 C损耗随着水色的增加而显著增加。因此，浮游动物必须有选择性地以同位素轻的食物来源为食，并且在更多的腐殖湖泊中更大程度地这样做。虽然浮游植物13 C-贫相对POM，它们的丰度和湖泊之间的变化似乎没有充分解释所观察到的趋势，浮游动物稳定同位素比值。我们建议，一些浮游动物放牧甲烷营养菌，利用同位素轻甲烷来自异地有机物在厌氧条件下分解。这一过程将更加明显，在有色湖泊具有较高的负荷外来有机质和更大的发展，hypolimnetic缺氧。
Carbon stable isotopic composition was determined for zooplankton, POM, DOM and, in two cases, phytoplankton from 12 small forest lakes in southern Finland during summer 1997. The lakes were selected to provide a wide range of water colour (12-365 mg Pt l-1) but minimum variability in other limnological characteristics. POM and DOM showed similar stable isotope ratios (δ 13 C around - 28‰, comparable with values commonly reported for terrestrial C3 vegetation) and these showed no relationship to water colour. Zooplankton were consistently depleted in 13 C relative to the bulk POM on which they might feed. This relative 13 C depletion increased significantly with water colour. Therefore the zooplankton must have been feeding selectively on isotopically light food sources and doing so to a greater extent in the more humic lakes. Although phytoplankton were 13 C-depleted relative to POM, their abundance and their variability between lakes did not appear to explain adequately the observed trend in zooplankton stable isotope ratios. We propose that some zooplankton were grazing on methanotrophic bacteria which utilise isotopically light methane derived from allochthonous organic matter decomposed under anaerobic conditions. This process would be more pronounced in coloured lakes with a higher loading of allochthonous organic matter and greater development of hypolimnetic anoxia.