Carbon cycle in the soil of theflood planire of rio mapire, Anzoátegui State

Abstract

During the rainy season, the mouth of the Mapire River is transformed into a complex system, a floodplain due to the increase of the water level in this river, due to the damming caused by the Orinoco River. In this region, there are areas with variable flood intensity, and spatial differences in soil texture and moisture content as a consequence of the topographic gradient perpendicular to the riverbed. The samples were collected at three times of the year (drought, onset of rain and flood) following a systematic sampling at 4 gradient points, defined by the intensity of the flood: maximum flood zone (MAX); medium flood zone (MED); minimum flood zone (MIN) and never flooded zone (NF). Physicochemical parameters associated with the carbon cycle (total carbon, soluble carbon and light fraction) were determined and associated with the physiological profile of the microbial community through linear correlations and principal component analysis (PC). The results indicate that the carbon cycle is regulated by factors that affect microbial activity, establishing successional processes in the community in response to the availability of substrates for mineralization. Anaerobic metabolism in soil is relevant in the decomposition of organic matter throughout the hydroperiod and could be influenced by the availability of labile carbon.