Program and Agenda

Abstract

DRIVERS AND MECHANISMS FOR HIGH PHOSPHATE (TPO4) RELEASE RATES IN THE OXYGEN MINIMUM ZONE OFF PERU

Sediments overlain by oxygen deficient waters are known to potentially release remarkable amounts of phosphate into the water column, likely having a positive feedback on primary production. Despite this significance, only spare datasets of benthic TPO4 fluxes are available. We measured in situ benthic TPO4 fluxes in combination with DIC fluxes derived from pCO2 and total alkalinity using benthic landers on a depth transect at 12°S in the Peruvian oxygen minimum zone during R/V Meteor cruise M92 in January 2013. At the time of sampling the entire continental shelf and upper slope, down to 400 m water depth, sediments were overlain by anoxic bottom waters with [O2] <3 µM. The TPO4 fluxes are up to ~1 mmol m-2 d-1, while distinct maxima occur at 80 and 250 m water depth in accordance with dense microbial mats at the sediment surface. The magnitude of TPO4 fluxes indicates non-Redfield remobilization mechanisms. Consequently, the drivers of benthic TPO4 release and potential sources of phosphorus will be discussed in this contribution.

ePoster:

Authors

Lomnitz, U., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, ulomnitz@geomar.de

Sommer, S., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, ssommer@geomar.de

Hensen, C., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, chensen@geomar.de

Dale, A. W., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, adale@geomar.de

Wallmann, K., GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, kwallmann@geomar.de

Details

Poster presentation

Session #:099
Date: 2/26/2014
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: 2992