Baltimore Ecosystem Study Institute of Ecosystem Studies

2010 BES Annual Meeting Presentation and Poster Abstracts



 
Effects of temperature and source on organic matter leaching and decomposition in Baltimore urban area
 
Duan, Shuiwang
Co-Authors: Sujay Kaushal

 
Abstract: Urbanization has significantly altered temperature and vegetation in urban watersheds. In order to understand the control of temperature and sources on organic carbon/nutrients release or decomposition, dried leaves of pine, elm, willow, grape vine, silver maple and red maple and algae were leached at 4 and 20 degree C for 90 hours, and the leachates were then decomposed at the two temperatures for 252 hours. The results show that, dissolved organic carbon (DOC) of all samples increased during leaching process and then decreased during decomposition; the rates of leaching and decomposition decreased with increasing time of incubation, and temperature significantly enhanced the leaching and decomposition rates. The changes in total dissolved nitrogen (TDN) and phosphorus (TDP) were similar to that of DOC. But, the leaching rates of TDN and TDP were faster than that of DOC. The ratio of TDN to TDP was less than 1 for leaf samples, likely due to relative enrichment of phosphorus relative to nitrogen during the processes. Maple leaves were highest in the yields of DOC, followed by grape vine and willow, elm and algae, and the pine had the lowest value; highest yield of TDN was observed in algal samples. During the decomposition period, higher percents of algae-derived DOC from were mineralized than that from leaves, and flocculation of dissolved organic matter was likely one of the important mechanisms for the DOC loss. Changes in temperature and vegetation due to urbanization likely affect organic matter and nutrient export from urban watershed.