Perturbation to North Atlantic Ocean‐Climate Dynamics Tripled Whitings Mud Production in the Bahamas

Abstract

AbstractProfound changes in Earth's biogeochemical cycles are recorded in the sedimentology and geochemistry of carbonate sediments, with much of the early geological history of our planet recorded in carbonate mud precipitated from seawater. Despite their relevance for understanding early Earth, the trigger for whitings—carbonate spontaneously precipitated from the water column—remains intensely debated. Here, we used a neural network to map whitings imaged by daily MODIS Aqua satellite overpasses between 2003 and 2018 on Great Bahama Bank (GBB). Our results show that the frequency of whitings after 2011 increased by 3.3× compared to those recorded between 2003 and 2010, with the frequency of winter whitings increasing more than those in the summer. We contend that the period of increased whitings frequency was spurred by concurrent perturbations to the North Atlantic Oscillation, Atlantic Multidecadal Oscillation, and the El Niño Southern Oscillation in 2010 that facilitated enhanced hydrodynamic mixing between the waters atop GBB and those that surround it. We conclude that whitings can exhibit a sensitive but non‐linear response to ocean‐atmosphere dynamics which is unlikely to be resolved in the geological record using conventional stratigraphic techniques. This pronounced fluctuation in mud production on short timescales contrasts with expectations of persistent tranquility in the depositional environments that produce lime mud. Our results suggest that long‐established links between ocean‐atmosphere dynamics and the lime mud budget through Earth history may require reevaluation.