Program and Agenda

Abstract

BENTHIC NITROGEN CYCLING ACROSS PERUVIAN OXYGEN MINIMUM ZONE SURFACE SEDIMENTS

Oxygen minimum zones (OMZ) are key regions for benthic nitrogen turnover. Benthic fluxes of dissolved inorganic nitrogen (DIN: nitrate, nitrite, ammonium) and di-nitrogen gas in combination with water column profiles of these species were measured at several sites along a depth transect across the Peruvian OMZ at 12°S. Bottom water oxygen levels were <3 µM down to 400 m water depth yet increased below. In water depths from 73 m to 300 m seafloor imaging revealed dense coverage of the sediments with sulfide oxidizing microbial mats. The Peruvian shelf sediments were identified as prominent recycling sites for DIN releasing up to 23.5 mmol m-2d-1 ammonium co-occurring with unusually high seabed sulfide release of 14.6 mmol m-2d-1. In contrast, sediments inside the core of the OMZ and below its lower boundary represented sinks for DIN. Mass balance calculations indicated that benthic nitrogen turnover at the upper boundary was not at steady state, probably caused by a shift in the nitrogen metabolism in the microbial community, particularly the microbial mats, in response to changing environmental conditions.

ePoster:

Authors

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

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

Gier, J., GEOMAR Helmholtz Centre for Ocean Research, Kie, Germany, jgier@geomar.de

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

Dengler, M., GEOMAR Helmholtz Centre for Ocean Research, Kie, Germany, mdengler@geomar.de

Details

Poster presentation

Session #:125
Date: 2/24/2014
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 2399