Physical controls on the seasonal migration of the North Pacific transition zone chlorophyll front
Article first published online: 4 MAY 2010
Copyright 2010 by the American Geophysical Union.
Journal of Geophysical Research: Oceans (1978–2012)
Volume 115, Issue C5, May 2010
How to Cite
2010), Physical controls on the seasonal migration of the North Pacific transition zone chlorophyll front, J. Geophys. Res., 115, C05001, doi:10.1029/2009JC005596., and (
- Issue published online: 4 MAY 2010
- Article first published online: 4 MAY 2010
- Manuscript Accepted: 27 OCT 2009
- Manuscript Revised: 10 SEP 2009
- Manuscript Received: 24 JUN 2009
- North Pacific;
- transition zone;
- Ekman transport
 The large seasonal migration of the transition zone chlorophyll front (TZCF) is of interest because a number of marine fauna, both commercial and endangered, appear to track it. Herein we examine the physical dynamics driving this seasonal migration of the TZCF. Vertical processes, traditionally viewed as controlling the dynamical supply of nutrients to surface waters, prove insufficient to explain seasonal variations in nutrient supply to the transition zone. Instead, we find that the horizontal Ekman transport of nutrients from higher latitudes drives the TZCF's southward migration. The estimated horizontal transport of nitrate supports up to 40% of new primary productivity in the region annually and nearly all of new primary productivity in the winter. The significance of horizontal advection to the North Pacific transition zone supports revising the paradigm that nutrients are supplied to surface waters from below.