Role of nutrient supply in grazer-periphyton interactions: reciprocal influences of periphyton and grazer nutrient stoichiometry
Role of nutrient supply in grazer-periphyton interactions: reciprocal influences of periphyton and grazer nutrient stoichiometry
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DOI：
10.1899/0887-3593(2006)25
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发表时间：
2006-09-01
影响因子：
--
通讯作者：
Hillebrand, Helmut
中科院分区：
文献类型：
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作者：
Liess, Antonia;Hillebrand, Helmut
牧草-附生植物的相互作用部分是由营养再生的间接影响形成的。它们是检验生态化学计量学和生长速度假说预测的重要模型系统。我们进行了一项实验室实验，以测试营养丰富和食草动物身份如何相互作用，以调节周生植物和消费者的营养含量和化学计量比。我们考虑了一种情况，在这种情况下，水柱中的P浓度很高，而不是以前的实验中P是限制养分的情况。我们在实验水族箱的水中单独和联合添加N和P，水族箱中有粘土瓷砖和放牧动物(3种蜗牛中的1种)或没有放牧动物(未放牧对照)上的附生植物群落。底栖藻类吸收养分的比例与其在每种养分处理中的有效性密切相关。藻类生物量随着+N+P浓度的增加而显著增加，但不能单独增加+N或+P浓度。放牧对附生生物的C/N比没有影响，对附生生物的C：P和N/P比有正影响。随着水体中N的增加，牧草的P含量(干重百分比)增加，C/P和N/P摩尔比降低。施氮量增加可能是由于放牧者生长速度加快，使放牧者P含量增加。我们假设，在氮素限制条件下添加氮素会增加放牧动物对磷的吸收或滞留，因为它们的生长速度和RNA产量都很高，这与生长速度假说是一致的。
Grazer-periphyton interactions are shaped, in part, by indirect effects of nutrient regeneration. They are an important model system with which to test predictions of ecological stoichiometry and the Growth Rate Hypothesis. We conducted a laboratory experiment to test how nutrient enrichment and grazer identity interact to regulate the nutrient content and stoichiometry of both periphyton and consumers. We considered a situation in which P concentration in the water column was high, in contrast to previous experiments in which P was the limiting nutrient. We added N and P, alone and in combination, to the water in experimental aquaria that contained periphyton communities on clay tiles and grazers (1 of 3 snail species) or no grazers (ungrazed control). Benthic algae incorporated nutrients in close proportion to their availability in each nutrient treatment. Algal biomass increased significantly with +N+P enrichment, but not with +N or +P enrichment alone. Grazers had no effect on periphyton C:N ratios and positive effects on periphyton C:P and N:P ratios. P content of grazers (% dry mass) increased and C:P and N:P molar ratios of grazers decreased in response to N enrichment of the water. Grazer P content increased in response to N enrichment, probably because of increased grazer growth rates. We hypothesize that the addition of N under N-limiting conditions led to increased P uptake or retention by grazers because of high growth rates and RNA production, consistent with the Growth Rate Hypothesis.