Collaborative Research: Elevated Atmospheric CO2 Alters Plant Detritus Nutritional Quality: Effects on Microbial and Detritivore Food Webs in Aquatic Ecosystems

塔赫曼合作研究：大气二氧化碳升高改变植物碎屑的营养质量：对水生生态系统中微生物和分解物食物网的影响。化石燃料燃烧产生的大气二氧化碳(CO2)升高，直接影响树叶的光合作用速率、生长和化学组成。研究人员已经证明，当杨树生长在较高的二氧化碳水平下时，它们的叶子含有较少的氮和较高浓度的植物防御化合物(酚类化合物、木质素和单宁)，这使得它们对动物和微生物消费者的营养较差。由于森林景观中的小型源头溪流严重依赖树叶凋落物作为其食物网的燃料，平行的田野和实验室研究将衡量二氧化碳诱导的杨树叶子凋落物食物质量的变化对溪流细菌、真菌和无脊椎动物消费者的生长和繁殖的影响。微生物和无脊椎动物生长速度的差异反过来会影响水生生态系统中食物网的结构和功能以及碳动态。

TuchmanCollaborative Research: Elevated Atmospheric CO2 Alters Plant Detritus Nutritional Quality: Effects on Microbial and Detritivore Food Webs in Aquatic Ecosystems.Elevated atmospheric carbon dioxide (CO2) resulting from the combustion of fossil fuels, directly affects the photosynthesis rate, growth, and chemical make-up of tree foliage. The investigators have demonstrated that when aspen trees are grown under elevated CO2 levels, their leaves contain less nitrogen and higher concentrations of plant defense compounds (phenolic compounds, lignins and tannins), which renders them less nutritious to their animal and microorganism consumers. Since small headwater streams in forested landscapes rely heavily on tree leaf litter to fuel their food webs, parallel field and laboratory studies will measure the effect that the CO2-induced change in food quality of aspen leaf litter will have on the growth and reproduction of stream bacteria, fungi, and invertebrate consumers. The difference in microbial and invertebrate growth rates in turn could affect food web structure and functions and carbon dynamics in aquatic ecosystems.