Seasonal Variation in C:N:P Stoichiometry in Freshwater Ecosystem: Indicating for Optimal C:N:P Ratio.

Seasonal variation in C:N:P stoichiometry in freshwater ecosystem: indicating for optimal C:N:P ratio

 

Yang Gao, Wendy Francesconi, Chi-hua Huang*

USDA-ARS, National Soil Erosion Research Laboratory, Purdue University, IN 47907, United States

Abstract: C, N and P are three of the most important elements used to indicators for its nutrient status and algal growth. Therefore, the C:N:P ecological stoichiometry can be used as a basis to guide water quality management and understand how aquatic ecosystems function. This study provide the first information on the seasonal change of DOM pool (DOC, DON and DOP) and insight to the optimal variation of C, N and P stoichiometry for freshwater ecosystem. The results show that the value of DOC is significantly higher than DON and DOP, and DOC is mainly responsible for trapping DOM; in contrast to DOC and DON, the change of DOP in the freshwater watershed is smallest. The DOC:DON:DOP molar ratios in three watersheds are shown significantly exponential distribution. The DOC:DON:DOP ratio that is 190～320:19～30:1 would be optimal DOM stoichiometry for freshwater ecosystem. In addition, the results suggest that the DTN:DTP ratio equal to 24～47:1 would be optimal for freshwater ecosystem, which indicate the phytoplankton nutrient limitation in freshwater ecosystems and play an important role in determining the trophic structures and community.

Keywords: Ecological stoichiometry; Freshwater; Nutrients; DOC; DON; DOP