IMPACT OF LAND USE CHANGES ON CARBON CYCLING IN SELECT TERRESTRIAL ENVIRONMENTS
TA: Christine Angelini
University of Florida
Land use alterations highly affect the carbon cycling at work in terrestrial ecosystems, which reflects on the constant flux of the pools of carbon in all environments around the biosphere. Changes such as deforestation, or the reverse, modify the levels of carbon in the soil and vegetation of an ecosystem. Occurring mainly in living organisms and decaying organic matter in soils, carbon is transferred across landscapes and through the atmosphere, geosphere, and hydrosphere. The carbon emissions we measured came from four terrestrial ecosystems: a forest lawn, 10 and 40 year old field. The ecosystems tested presented variation in turnover rate of vegetation, allowing for greater observation of effects that land use change could have on terrestrial environments, which in turn permitted quantifications of the effects of habitat modification. Using the portable LICOR machine, respiration rates were measured from the soil/vegetation in our four terrestrial environments via extraction of excess vegetation from 25x25cm quadrats. The concentration in the respiration chamber was used to calculate carbon flux and overall turnover time for the amount of carbon that resides in each ecosystem. The carbon flux (or soil respiration) in the lawn environment was surprisingly greater than the forest environment, indicating more variation in vegetation than was previously suspected for the lawn. The carbon pool, on the other hand, was much greater in the forest than the lawn. Carbon resides in the forest structure 10,224 weeks, compared to the mere 2.08 weeks for the lawn. With the large difference in turnover time between the lawn, 10 and 40 year old field and forest ecosystems, it is clear that allowing vegetation to remain rooted and varied will produce more cycled...