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Science  15 Nov 2013:
Vol. 342, Issue 6160, pp. 778
DOI: 10.1126/science.342.6160.778-a

Deposits of windblown dust originating from the Sahara may have been responsible for the prehistoric condition of the Everglades, the vast area of wetlands at the southern end of the Florida peninsula. Our understanding of the history of the Everglades ecosystem and of the ecological conditions that produced and sustained it has been hampered by the extensive human transformation of the landscape, particularly in the past century. An analysis of sediments deposited over the past 4600 years provides a record of the vegetation and soil nutrient patterns and shifts in hydrology, revealing some of the processes that have hitherto remained obscure. Glaser et al. show that dust deposition mediated by frequent tropical storms was an important source of nutrients for the Everglades until about 2800 years ago, when a climatic shift in the tropical Atlantic and Gulf of Mexico led to weather patterns that sharply decreased the level of dust inputs and led to a drier climate and a gradual loss of soil phosphorus, carbon, and nitrogen. The vegetation concomitantly changed from a slough assemblage of aquatic and semiaquatic plants to communities of sawgrass and pine, which began to dominate as the water table fell and the nutrient levels decreased.

Proc. Natl. Acad. Sci. U.S.A. 110, 10.1073/pnas.1222239110 (2013).

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