Temperature sensitivity of stream gross primary production and respiration from the tropics to the arctic

Friday, 18 December 2015
Poster Hall (Moscone South)
Chao Song1, Alba Argerich2, Christina Baker3, William B Bowden4, Walter K Dodds5, Michael Douglas6, Kaitlin Farrell1, Michael B Flinn7, Erica Garcia8, Keith B Gido5, Tamara Harms9, Jeremy Jones9, Lauren Koenig10, John Stephen Kominoski11, Karlie Sara McDonald12, William H McDowell10, Damien McMaster8, Samuel Parker4, Amy Rosemond1, Janine Rüegg5, Ken Sheehan10, Matt T Trentman5, Wilfred M Wollheim10 and Ford Ballantyne1, (1)University of Georgia, Athens, GA, United States, (2)Oregon State University, Corvallis, OR, United States, (3)University of Alaska, Biology and Wildlife, Fairbanks, AK, United States, (4)University of Vermont, Burlington, VT, United States, (5)Kansas State University, Manhattan, KS, United States, (6)University of Western Australia, Earth and Environment, Perth, Australia, (7)Murray State University, Murray, KY, United States, (8)Charles Darwin University, Research Institute for the Environment and Livelihoods, Darwin, Australia, (9)University of Alaska Fairbanks, Fairbanks, AK, United States, (10)University of New Hampshire Main Campus, Durham, NH, United States, (11)Florida International University, Miami, FL, United States, (12)University of Birmingham, Birmingham, United Kingdom
Understanding the temperature dependence of gross primary production (GPP) and ecosystem respiration (ER) in streams is critical to predict the carbon balance in stream ecosystems under global warming. We collected dissolved oxygen (DO) concentration, photosynthetically active radiation (PAR), channel hydrology and geomorphology, and temperature from multiple locations throughout stream networks in seven sites across six biomes, specifically tropical forest, temperate deciduous forest, temperate coniferous forest, tallgrass prairie, boreal forest, and arctic tundra. We estimated the activation energy (Ea) of GPP and ER from diel changes in DO, temperature and PAR for each stream reach. We showed the relationship between Ea and environmental variables, such as temperature, light availability and discharge. In addition, we found that Ea of GPP and ER were highly variable from reach to reach within each biome. The estimated Ea of GPP and ER was generally higher than predicted by metabolic theory. Ea of GPP ranges from 20 to 140 KJ/mol and Ea of ER ranges from 50 to 150 KJ/mol. There was no consistent trend of larger Ea for GPP or ER. This suggests that the changes in carbon balance in streams caused directly by warming is likely to be site specific.