Mangroves: coastal vegetation and marine influence in LaCaimanera wetland (Sucre) during the last 6000 years

We recovered a 7.25 m sediment core from the center of La Caimanera wetland (department of Sucre, 9°24'11.88"N 75°37'52.39"W) using a Russian probe. We sent samples from different depths for radiocarbon dating (C14 by AMS at the University of Colorado, USA). We characterized the main sediment components (minerals, organic matter), micro-stratigraphy (organic matter classes), moisture variations (%), organic and inorganic carbon, and palynological associations. We linked these to the current types of vegetation in the wetland and its surroundings. In the paleoenvironmental reconstruction, two well-defined and contrasting periods were observed, as follows: between the beginning or base of the sediment column analyzed (at 725 cm, 6185 years BP, and at the upper middle part, 175 cm, 2142 years BP), the environment was that of a continental freshwater wetland, including all the phases of the hydric ecological series (aquatic vegetation, marsh vegetation, floodplain vegetation with Symmeria paniculata forests, and mainland forests of Mabea montana, Spondias mombin, and Anacardium excelsum). The mineral fraction dominated the sediment, while peat and plant remains predominated inside the organic fraction of continental origin. Towards the upper part of the core, a transition towards a brackish environment was evident, related to the greatest expression of marine components (shells). In the last 1000 years BP, the mangrove (Rhizophora mangle) grew vigorously, and the high representation of molluskshells and crustacean remains consolidated at a sedimentation rate (accretion) of 1.14 cm/year;this marked marine influence could not be correlated with changes in sea level documented for theColombian Caribbean.