Nuclei-Induced Inorganic Carbonate Precipitation

A fundamental pathway in the marine carbon cycle is the formation of calcium carbonate (CaCO₃), which is typically attributed to biological calcification of shells and skeletons. While most surface seawater in both open and coastal oceans is supersaturated with CaCO₃, inorganic CaCO₃ precipitation is inhibited by several factors including the presence of dissolved organic carbon or Mg²⁺. Because of this, abiotic CaCO₃ precipitation is typically assumed to be an insignificant pathway in carbon cycling. However, laboratory experiments have shown that seeding solid particles, or nuclei, into seawater supersaturated with CaCO₃ triggers nuclei-induced inorganic carbonate precipitation (NICP). This has been observed in some unique settings, such as Little Bahama Banks and the deep Red Sea, but conditions of carbonate supersaturation and high suspended sediment loads may be common enough in coastal oceans that NICP may be an important factor in coastal carbon cycling.

The goal of this project is to evaluate the significance of NICP caused by flood sediment and dust resuspension in coastal waters through a series of laboratory-based kinetic experiments as well as a series of instrumented coastal mesocosm experiments. These in-situ mesocosm experiments take place in the coastal Red Sea at Eilat, Israel, to take advantage of the warm water temperatures, high CaCO₃ supersaturation, and large particle inputs from the surrounding desert.