Bahamas Creation Linked to African Dust

Yet another study on the role of African dust in shaping the historic and current environment of the Caribbean (popular press summary here and the scientific article here). Authors’ summary after the jump.

The enigma of the Bahamas is that this highly productive carbonate system has existed for at least 100 m.y., building a vast edifice of carbonates, thousands of meters thick, in an essentially nutrient poor environment. Based on measurements of the insoluble material, the Fe and Mn in the carbonate fraction, and the d15N of the sedimentary organic matter, we suggest a paradigm shift in order to explain the formation of the Bahamas and possibly other similar platforms. We propose that the Great Bahama Bank is currently, and may in the past have been, fertilized by atmospheric dust, promoting the fixation of atmospheric N2 by cyanobacteria. These cyanobacteria provided a source of nitrogen to the rest of the community in this nutrient-poor environment. The fixation of N has imparted a characteristic d15N signal and has been responsible, through the drawdown of CO2, for initiating the precipitation of carbonate in the shallow waters. This phenomenon might be responsible for the formation of vast amounts of sediments in the oceans, not only within recent times, but throughout geological history, particularly in the early history of the Earth prior to the existence of calcium carbonate–secreting organisms.

By | 2014-09-19T15:53:57-05:00 August 5th, 2014|Categories: Beaches, Global change|0 Comments

About the Author:

Craig Layman
My lab’s interdisciplinary pursuits provide for a multi-faceted understanding of environmental change in the coastal realm. We are ecologists, asking questions that span population, community, ecosystem and evolutionary sub-disciplines. We often use a food web based perspective, exploring top-down (e.g., predation) and bottom-up (e.g., nutrient excretion) mechanisms by which animals affect ecosystem processes. All of our efforts are framed within a broader outreach framework, directly integrating science and education, using approaches such as this website.

Leave A Comment