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Stoichiometric effects of pCO_2 on aquatic communities

pCO_2对水生群落的化学计量效应

基本信息

批准号：
15370010
负责人：
URABE Jotaro
金额：
$ 9.73万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15370010/
关键词：
lakes carbon dioxide plankton watershed Dissolved organic carbon ecosystems carbon budget biological community CO_2 溶存炭素有機物 CO2

项目摘要

The present study was performed to clarify (1) how land use/cover in the watershed affects on pCO2 in lake ecosystems, (2) how changes in pCO2 affects zooplankton communities through changes in species composition, abundance and stoichiometry of planktonic algae, and then (3) how local and global environmental changes influence on aquatic communities in lakes through these stoichiometric effects of pCO2. For these, we first examined limnological and biological characteristics of 48 lakes located at east-north area in Japan with GIS analyses on the watershed of these lakes. The analyses revealed that pCO2 in the lakes varied over 5 orders magnitude and highly related with land cover of vegetation in the watershed, water depth and food web structures, suggesting that effects of changes in land use and atmospheric pCO2 on lake carbon metabolisms differ depending on the basin morphometry and biota.To examine changes of pCO2 to aquatic communities, laboratory experiments with manipulation of pCO2 in water were made using several taxonomic group of algal plankton as primary producers and Daphnia as consumers. The experiments showed that algal competitive interactions differed depending on pCO2 and nutrient supplies. In any experiments with single algal species, increase of pCO2 increased algal abundance but decreased growth rate of consumers due to decrease in specific nutrient contents of the algal food. However, in experiments with multiple algal species, increase of pCO2 also increased algal abundance but did not decrease growth rate of consumers, probably due to complementary effects in nutrition of algae. These results suggest that algal species diversity functions to mitigate negative effects of increased pCO2 on community structures and mass transfer efficiency in lake ecosystems.

本研究的目的是阐明 (1) 流域的土地利用/覆盖如何影响湖泊生态系统中的 pCO2，(2) pCO2 的变化如何通过浮游藻类的物种组成、丰度和化学计量的变化影响浮游动物群落，然后 (3) 当地和全球环境变化如何通过 pCO2 的这些化学计量效应影响湖泊中的水生生物群落。为此，我们首先通过对这些湖泊流域的 GIS 分析，研究了位于日本东北部地区的 48 个湖泊的湖泊学和生物特征。分析表明，湖泊中的 pCO2 变化超过 5 个数量级，并且与流域植被的土地覆盖、水深和食物网结构高度相关，这表明土地利用和大气 pCO2 的变化对湖泊碳代谢的影响因流域形态和生物群而异。浮游藻类作为初级生产者和水蚤作为消费者的几个分类群。实验表明，藻类竞争性相互作用根据 pCO2 和养分供应而有所不同。在任何单一藻类的实验中，pCO2 的增加增加了藻类丰度，但由于藻类食物中特定营养成分的减少而降低了消费者的生长速度。然而，在多种藻类的实验中，pCO2 的增加也增加了藻类丰度，但并没有降低消费者的生长速度，这可能是由于藻类营养的互补效应。这些结果表明，藻类物种多样性可以减轻 pCO2 增加对湖泊生态系统群落结构和传质效率的负面影响。