Sources of Particulate Organic Matter across Mangrove Forests and Adjacent Ecosystems in Different Geomorphic Settings

Daniel A Saavedra-Hortua,Martin Zimmer,Daniel A Friess,Lucy Gwen Gillis

doi:10.1007/s13157-019-01261-9

Daniel A Saavedra-Hortua, Martin Zimmer + Show 2 more

Open Access

https://doi.org/10.1007/s13157-019-01261-9

Copy DOI

Abstract

Mangrove forests are among the world’s most productive ecosystems and provide essential ecosystem services such as global climate regulation through the sequestration of carbon. A detailed understanding of the influence of drivers of ecosystem connectivity (in terms of exchange of suspended particulate organic matter), such as geomorphic setting and carbon stocks, among coastal ecosystems is important for being able to depict carbon dynamics. Here, we compared carbon stocks, CO2 fluxes at the sediment-air interface, concentrations of dissolved organic carbon and suspended particulate organic carbon across a mangrove-seagrass-tidal flat seascape. Using stable isotope signatures of carbon and nitrogen in combination with MixSIAR models, we evaluated the contribution of organic matter from different sources among the different seascape components. Generally, carbon concentration was higher as dissolved organic carbon than as suspended particulate matter. Geomorphic settings of the different locations reflected the contributions to particulate organic matter of the primary producers. For example, the biggest contributors in the riverine location were mangrove trees and terrestrial plants, while in fringing locations oceanic and macroalgal sources dominated. Anthropogenic induced changes at the coastal level (i.e. reduction of mangrove forests area) may affect carbon accumulation dynamics in adjacent coastal ecosystems.

Highlights

IntroductionMangrove forests play an important role of the tropical seascape, as well as for blue carbon accumulation, as they
Mangrove forests play an important role of the tropical seascape, as well as for blue carbon accumulation, as theyMultiple studies have quantified mangrove carbon stocks (Bhomia et al 2016; Kauffman et al 2011; Murdiyarso et al 2015), suggesting an important role in climate regulation
Overall no significant difference was observed between dark and light incubation chambers at each transect point (T–test; p = 0.4, df = 12, t = 1) with the exception of transect point mangrove forest 1 (MF1) at Seletar Island (Fig. 5), where CO2 fluxes out of the sediment were significantly higher in dark chamber than in light chamber incubations (T–test; p = 0.01, df = 1, t = 63.7)

Summary

Introduction

Mangrove forests play an important role of the tropical seascape, as well as for blue carbon accumulation, as they. Multiple studies have quantified mangrove carbon stocks (Bhomia et al 2016; Kauffman et al 2011; Murdiyarso et al 2015), suggesting an important role in climate regulation. Physical and bio-geographic factors (i.e. climate regime, tidal regime, geomorphology, hydrodynamics, and nutrient dynamics) influence the carbon dynamics in mangrove forests (Alongi 2014). The fluxes and exchange of organic carbon among ecosystems are important in networks of coastal ecosystems that release and trap carbon and nutrient subsidies from adjacent ecosystems (Gillis et al 2014a, 2017). Only few studies have directly measured carbon stocks (Phang et al 2015) or nutrient fluxes (Huxham et al 2018) across adjacent ecosystems such as tidal flats and seagrass beds

Objectives

Methods

Results

Discussion

Conclusion