Decoupled contributions of mangrove trees and saltmarsh plant to labile and bulk organic carbon in a mangrove system from the Southeast China
Jiachen Li 1,2，Tengteng Wang 1,2，Tiantian Tang 1,2*
1. College of Ocean and Earth Sciences, Xiamen University, China
2. State Key Laboratory of Marine Environmental Science (Xiamen University)
Mangrove systems are known for high productivity from multiple primary producers such as mangrove trees, saltmarsh plants, algae etc., which may have varied contributions to carbon cycling in the coasts and the carbon flux to the ocean. In order to evaluate their contributions, we studied the organic matter in a mangrove system from the Southeast China by using amino acids to represent labile OM—the OM with relatively high turnover rates. The molecular composition and δ13C values of bulk organic matter and individual amino acids of collected samples show that mangrove leaves and salt marsh plants are two major sources of sediment (SOM) and suspended (POM) particles in this system. But the two sources contribute differently to bulk OC and amino acids: for bulk OC, the contribution of salt marsh plants increases in samples from the inside to the outside of the mangrove system; while for amino acids, more contributions were observed from mangrove leaves. This research observed decoupled contributions of mangrove leaves and saltmarsh plants to labile and bulk organic carbon pools in this mangrove system, suggesting the varied potentials of OM from the two sources to be transported from mangrove system to the ocean.
Keywords：Amino acids, stable carbon isotopes, mangrove system
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