ORGANIC CARBON CONCENTRATION IN CAVE SEDIMENTS AS A TRACER OF INPUT FROM HURRICANE MARIA
Sets of pre/post Maria samples were collected from a small passage at the back of the cave (upstream), a wider passage in the middle of the cave, and near the exit of the cave where a dam and weir system typically create a pond used for water supply. At the most upstream location, the organic carbon (expressed as the fraction of organic carbon - a percent of total sediment mass) decreased after the storm (0.47 to 0.18%). In contrast, the further downstream locations had significant pre/post Maria increases in organic carbon (0.31 to 0.88% in the middle of the cave; 0.16 to 0.97% near the front of the cave). These results show that changes in the organic carbon concentrations within the cave can vary with location after a major storm event. The changes in the carbon may be influenced by proximity to an injection site, how the configuration of the cave passage controls zones of deposition and erosion, and how much influence the storm surge had on the specific sediment deposits. Additional data will be obtained from sediment cores to better understand the range of organic carbon concentration as well as to quantify textural and detailed chemical properties.