Effects of temperature, soil moisture, and labile C on soil respiration in a northern Michigan forest: understanding the consequences of global climate change.

Abstract

The three global change scenarios I examined, increased temperature, decreased soil moisture, and increased labile carbon, affect soil respiration to different degrees in different directions. While this study looked at the effect of these factors individually, the interaction of how the three predicted global change conditions will affect soil respiration is not yet understood. Further, the effect of these three scenarios on soil respiration need to be looked at over a longer period of time for better understanding of the annual response of soils. Soil respiration is an important part of the forest carbon budget. Soil respiration releases nearly as much CO2 as is taken in by the system through photosynthesis. If in response to global changes the soils release more CO2 through respiration than the forest takes in via photosynthesis, the system will become a carbon source. It will thus contribute additional CO2 to the already elevated CO2 conditions. On theother hand, if the soils take in more CO2 by storing the carbon as microbial biomass or as additional organic matter then the forest system will become a carbon sink. In this way, it will help to reduce atmospheric CO2 levels. The response of soils to global changes, therefore, could either aid in slowing or accelerating future changes.