Variations in CO2 efflux from a riverine mangrove forest as related to tidal, salinity, and temperature dynamics

Soil respiration in mangrove forests represents a significant component of the system's carbon (C) budget. We are investigating soil respiration and carbon cycling in the riverine mangrove forest at Shark River Slough (SRS) 6. The mangrove forest at SRS6 experiences semi-diurnal tidal flooding that imports surface water, recharges groundwater and regulates the site's biogeochemical properties. Soil respiration has been found to vary with temperature, root growth, benthic microalgae, invertebrates, duration and frequency of hydrologic inundation, salinity, pneumatophore (PNPH) presence, and nutrient availability. We are particularly interested in investigating the effects of inundation, temperature, and salinity on soil CO2 efflux.

Previous research has suggested that fluctuations in inundation, temperature and salinity can influence soil microbial activity and thus the process of soil respiration causing release of CO2 from the C rich peat soils of the mangrove forest. In this study, we conducted CO2 efflux measurements with a LICOR-8100 Infrared Gas Analyzer (IRGA) to capture fluxes at the soil/surface water interface. Surface water (SW) and groundwater (GW) data were obtained from a well located at the site. Here we present these CO2 data and patterns of surface water and groundwater salinity, temperature and inundation to better define variation in soil CO2 flux with hydrogeological parameters in this mangrove peat forest.