An advective mechanism for deep chlorophyll maxima formation in southern Drake Passage


Journal Article

�2016. American Geophysical Union. All Rights Reserved. We observe surface and subsurface fluorescence-derived chlorophyll maxima in southern Drake Passage during austral summer. Backscatter measurements indicate that the deep chlorophyll maxima (DCMs) are also deep biomass maxima, and euphotic depth estimates show that they lie below the euphotic layer. Subsurface, offshore and near-surface, onshore features lie along the same isopycnal, suggesting advective generation of DCMs. Temperature measurements indicate a warming of surface waters throughout austral summer, capping the winter water (WW) layer and increasing off-shelf stratification in this isopycnal layer. The outcrop position of the WW isopycnal layer shifts onshore, into a surface phytoplankton bloom. A lateral potential vorticity (PV) gradient develops, such that a down-gradient PV flux is consistent with offshore, along-isopycnal tracer transport. Model results are consistent with this mechanism. Subduction of chlorophyll and biomass along isopycnals represents a biological term not observed by surface satellite measurements which may contribute significantly to the strength of the biological pump in this region.

Full Text

Duke Authors

Cited Authors

  • Erickson, ZK; Thompson, AF; Cassar, N; Sprintall, J; Mazloff, MR

Published Date

  • October 28, 2016

Published In

Volume / Issue

  • 43 / 20

Start / End Page

  • 10 - 855

Electronic International Standard Serial Number (EISSN)

  • 1944-8007

International Standard Serial Number (ISSN)

  • 0094-8276

Digital Object Identifier (DOI)

  • 10.1002/2016GL070565

Citation Source

  • Scopus