The Potential of Mangrove-Derived Organic Matter in Sediments for Tracing Mangrove Development During the Holocene

The responses of mangroves to future climate change can be reconstructed from past mangrove dynamics using proxies preserved in sediments. The contributions of mangrove-derived organic matter (MOM) can be calculated by using δ13Corg and molar C:N values. In order to verify the effectiveness of MOM for tracing mangrove development, four typical regions are chosen, including the Beibu Gulf of SW China, western coast of peninsular India, Flamenco Lagoon of Puerto Rico, and Amazon estuary of northern Brazil. The results showed that the temporal variation of calculated MOM is similar to the abundance of mangrove pollen (MP) in each core. There are significant positive correlations between them, with correlation coefficients ranging from 0.68 to 0.89 (P < 0.01). However, there is no correlation (R = 0.02, P > 0.05, n = 281) between MOM and MP globally, owing to the complexities of OM provenance and pollen transmission. It is indicated that MOM is a potential proxy for regional mangrove development during the Holocene. The proxy should be useful to reconstruct high-resolution mangrove development, owing to its easily fine-cut sampling and cheaper cost of instrumentation compared with pollen and biomarkers.