Program and Agenda

Abstract

METHANE SOURCES IN THE UPPER OCEAN AT STATION ALOHA

Methane (CH4) supersaturation in the mixed layer is a widespread feature of the global oceans, but the specific mechanisms responsible for this saturation are still unknown and, until 5 years ago, it was exclusively attributed to anaerobic methanogenesis by Archaea in reduced microenvironments, such as sinking particles and zooplankton guts. The discovery that methylated compounds, such as methylphosphonates, are metabolized to CH4 under aerobic conditions has transformed our understanding of the upper ocean CH4 cycle. We have conducted a series of in situ and deck-board incubation experiments, and deployed free-drifting sediment trap arrays between 100 and 500 m depth at Station ALOHA in the North Pacific Subtropical Gyre, to analyze CH4 production in an oligotrophic open ocean habitat. We have revisited the association of CH4 production in sinking particles (Karl and Tilbrook, 1994) by comparing CH4 measurements in preserved versus non-preserved sediment traps. In addition, we have investigated the effects of light intensity on CH4 production rates. The results highlight the relative contribution of biological and photo-chemical CH4 production to the supersaturation of dissolved CH4 in the upper ocean. REFERENCES Karl, D.M. and Tilbrook, B.D., 1994. Production and transport of methane in oceanic particulate matter. Nature 368: 732-734.

ePoster:

Authors

Ferrón, S., University of Hawaii, USA, sferron@hawaii.edu

Wilson, S. T., University of Hawaii, USA, stwilson@hawaii.edu

del Valle, D. A., University of Hawaii, USA, dadv@hawaii.edu

Karl, D. M., University of Hawaii, USA, dkarl@hawaii.edu

Details

Poster presentation

Session #:043
Date: 2/24/2014
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 31