Dial organic carbon fluctuations in a mangrove tidal creek in Sepetiba bay, Southeast Brazil

CE. Rezende,LFF. Silva,LD. Lacerda,ARC. Ovalle

doi:10.1590/s1519-69842007000400012

CE. Rezende, LFF. Silva + Show 2 more

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https://doi.org/10.1590/s1519-69842007000400012

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Abstract

The carbon (C) concentration and flux, as dissolved organic carbon (DOC), particulate organic carbon (POC) and macrodetritus (MD), were quantified through 4 tidal cycles in a mangrove tidal creek in Southeastern Brazil. DOC was the major fraction of the total C concentration, accounting for 68 and 61% of the total C concentration during ebb and flood periods respectively. Concentrations of DOC (Ebb = 3.41 +/- 0.57 mgC.L-1 and Flood = 3.55 +/- 0.76 mgC.L-1) and POC (Ebb = 1.73 +/- 0.99 mgC.L-1 and Flood = 1.28 +/- 0.45 mgC.L-1) were relatively similar during the four tidal cycles. Macrodetritus presented a wide variation with concentration peaks probably related to external forces, such as winds, which enrich the ebb flow with leaf litter. DOC and POC fluxes depended primarily on tidal and net water fluxes, whereas MD fluxes were not. The magnitude of the DOC and POC fluxes varied with the area flooded at high tide, but not the MD fluxes. DOC was the major form of carbon export to Sepetiba Bay. During the four tidal cycles, the forest exported a total of 1.2 kg of organic carbon per ha, mostly as DOC (60%), followed by POC (22%) and MD (18%).

Highlights

Many studies have focused on the fate of particulate organic carbon (POC) and dissolved organic carbon (DOC) in temperate estuaries and salt marshes (Taylor and Allanson, 1995)
We compare the POC, DOC and MD fluxes through a small mangrove tidal creek in Sepetiba Bay, Rio de Janeiro, Brazil (Lat. 22° 54’ 06” S and 23° 04’ 18” S, and Long. 43° 33’ 44” W and 44° 02’ 30” W; Figure 1) in order to determine the relative importance of each carbon fraction to the total carbon flow to and from adjacent coastal waters
The maximum flooded area (9.0 ha) included a low L. racemosa mangrove forest and salt pans located behind the R. mangle forest

Summary

Introduction

Many studies have focused on the fate of particulate organic carbon (POC) and dissolved organic carbon (DOC) in temperate estuaries and salt marshes (Taylor and Allanson, 1995). Particulate (POC) and dissolved organic carbon (DOC) and macrodetritus (MD) distributions frequently show large temporal and spatial variability. Few simultaneous determinations of these fractions have been attempted These gaps in the literature hamper generalisations regarding the role of mangroves as exporters or importers of organic carbon (Lee, 1995). 43° 33’ 44” W and 44° 02’ 30” W; Figure 1) in order to determine the relative importance of each carbon fraction to the total carbon flow to and from adjacent coastal waters We compare the POC, DOC and MD fluxes through a small mangrove tidal creek in Sepetiba Bay, Rio de Janeiro, Brazil (Lat. 22° 54’ 06” S and 23° 04’ 18” S, and Long. 43° 33’ 44” W and 44° 02’ 30” W; Figure 1) in order to determine the relative importance of each carbon fraction to the total carbon flow to and from adjacent coastal waters

Study Area

Material and Methods

Results and Discussion