Dust Fertilization of the Western Atlantic Biota: a Biochemical Model
Abstract
Every year an estimated 50 million tons of African dust reaches the Western Atlantic. This dust is composed of quartz sand, clay, and a mixture of quartz and clay particles agglutinated with micronutrient enriched ferruginous cement. However, whether it is friend or foe to biochemical systems is a matter of conjecture. Corals are ideal recorders of changing conditions as the layers can be dated so that the record of chemical changes is easily assessed. There is extensive shallow-and deep water coral development bordering the Florida Straits. The changes in trace element chemistry within these corals show a positive relationship with the African dust record. Recently, it has been demonstrated that many of the metals contained within the dust are necessary micronutrients in the fertilization of plankton. Using the results of these studies, a biochemical model has been constructed. This model suggests a path from inorganic dust through microbial transformation to micronutrient enzymes (i.e. Cd-enriched carbonic anahydrase) and carbonate precipitation on the Bahamian Banks. It is estimated that more than ten million metric tons of this fine, metal-rich sediment is formed each year. However, for much of this sediment, its deposition is temporary, as it is transported into the Florida Straits yearly by tropical cyclones. This metal-enriched fine carbonate becomes nutrients for phytoplankton, providing food for the corals, both shallow and deep.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.B23A2050H
- Keywords:
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- 3307 Boundary layer processes;
- ATMOSPHERIC PROCESSES;
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 1625 Geomorphology and weathering;
- GLOBAL CHANGE;
- 1809 Desertification;
- HYDROLOGY