Mass and nutrient fluxes around Sedlo Seamount

Abstract

We use data from a hydrographic cruise in November 2003 over Sedlo Seamount, in conjunction with historical hydrographic and altimeter data, to describe the circulation patterns near the seamount and within the region. A mixing model that incorporates two water types and two water masses assesses the water composition within the region, and an inverse model provides estimates of mass transports within different water strata. Eastern North Atlantic Central Water dominates for the upper neutral-density (γn) levels, γn<27.2, and Western North Atlantic Central Water does so in the 27.2⩽γn⩽27.7 band. In the 27.5⩽γn⩽27.8 band Mediterranean Water constitutes slightly more than 10%, except in the northwestern portion where this water type is less abundant. For 27.7⩽γn⩽27.9 Labrador Sea Water becomes the predominant water mass. The results from the inverse model and direct velocity measurements draw a gross picture of central waters flowing northwest along the northeastern margin of the seamount, while the net fluxes of Labrador Sea Water are relatively small. The central water flow appears to be topographically guided, with a region of high eddy kinetic energy over a spur that stretches southeast from the Mid-Atlantic Ridge. A gross calculation suggests the existence of significant net nutrient transport into the seamount that would support an enhanced level of primary production.