Geology

Seamount Dynamics

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Science  06 Aug 2004:
Vol. 305, Issue 5685, pp. 754
DOI: 10.1126/science.305.5685.754c

The circulation of seawater through the ocean crust extracts heat from the volcanically produced crust and, by altering rocks, is a major control on the composition of the oceans; it also conducts nutrients to vents and springs that harbor a variety of microbes. This circulation occurs both along the hot ocean ridges and more gradually—over tens of millions of years—beyond the ridges as ocean plates move toward subduction zones. As they move, however, they accumulate sediments that retard heat and mass exchange.

Harris et al. consider a third avenue through which seawater permeates the ocean crust. This one is associated with seamounts, which are produced volcanically but, due to their prominent topography, are not buried by sediments. Temperature and density gradients within the seamounts drive the flow of seawater. Collectively, the oceans contain about 15,000 seamounts, and thus the amount of seawater circulated through seamounts may exceed that associated with ridges. — BH

Geology 32, 725 (2004).

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