Researchers analyzed dissolved organic carbon from water column samples collected in five regions to establish baseline data about its relative persistence and cycling in the northern Gulf of Mexico. The team found that the Mississippi River exports large amounts of dissolved organic carbon with an anthropogenic 14C signature, which is removed and recycled offshore as the river plume moves offshore. The researchers observed a persistent dissolved organic carbon plume near the Macondo wellhead four years after the Deepwater Horizon incident, likely from bacteria transforming much of the spilled petroleum and methane into natural dissolved organic carbon molecules and dissolving this carbon into deep ocean water. The researchers published their findings in Geophysical Research Letters: Oceans: Stable and radiocarbon isotopic composition of dissolved organic matter in the Gulf of Mexico.
Tuesday, March 20, 2018