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

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Abstract0128504WetzelCollaborative 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.