Dataset: Carbon cycling in mangrove forests in Sawi Bay, Thailand


Measurements of above and below ground biomass and primary productivity of 4 mangrove forests (aged 3-yrs old (n=2), 5-yrs and 25-yrs) in Sawi Bay, Southern Thailand. Below ground root (live and dead) biomass measurements were made in October 1999. Above ground biomass and primary production estimates were made in April 2000. Measurements made on species identification, basal area, height at breast height were used to calculate stem density, which was in turn used to estimate biomass (t ha-1). Branch biomass was also calculated. Net canopy production was estimated using light interception method, using measurements of light readings to first estimate a leaf area index.

Nutrients, light levels, community pelagic respiration, and phytoplankton primary production rates were estimated for Sawi Bay.

Organic carbon and dissolved and particulate nutrient concentrations and fluxes from three mangrove lined creeks flowing in to Sawi Bay were measured.

An organic carbon mass balance was constructed for the entire Sawi Bay based on the data collected and described above.

On the basis of soil organic carbon deposition, accumulation, mineralisation and burial measurements in mangrove forests of Sawi Bay, these sites accumulated approx. 60% of the organic carbon input and are therefore storage sites of carbon.

Accumulation, transformation and availability of sediment nitrogen in 4 mangrove forests of different age and type in Sawi Bay, Southern Thailand. Samples were taken during the dry (April 1999) and the wet (October 1999) monsoon seasons.

Forest characteristics recorded were: type (Rhizophora apiculata or Ceriops decandra); age (3, 5, 25 years), sediment type; % tidal inundations per month; % soil total carbon

Measurements were made on sediment concentrations of ammonium, nitrite, nitrate, total nitrogen and carbon content. Measurements were also made on the total nitrogen and total carbon content of green leaves. Rainwater was analysed for dissolved nitrogen species.

Soil samples were analysed for fluxes of ammonium and dissolved organic nitrogen (DON) across the sediment-water interface. Net ammonium production was estimated using a core incubation method, and the rate of nitrogen fixation was estimated using the acetylene technique, and denitrification was measured using the direct gas technique.

Partitioning and storage of mineral nutrients and trace elements were examined in tree components and soils of Rhizophora apiculata forests of Sawi Bay.

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