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METHANE PRODUCTION FROM SINKING PARTICULATE MATTER AT STATION ALOHA

Methane (CH4) is a potent greenhouse gas with 20 times more warming potential than carbon dioxide. Typically, the oxygenated surface waters of the world’s oceans are supersaturated with CH4 relative to the atmospheric equilibrium concentration and are considered a source to the atmosphere. This has been referred to as the marine methane paradox since CH4 production has traditionally been thought to occur only in anaerobic environments. One hypothesis to explain this phenomenon suggests that marine microorganisms use methylphosphonic acid (MPn) aerobically as a resource for phosphorus (P), and release CH4 as a by-product (Karl et al., 2008). Here we hypothesized that sinking particles could potentially be a significant source for CH4 production through degradation of phosphonates in the aerobic surface waters. To test this hypothesis, we collected particles at 140 m and 250 m depth in sediment traps near station ALOHA and incubated the particles in different media to assess CH4 production. Whole surface seawater and ultra-filtered seawater were amended with glucose and nitrate to promote P-limiting conditions and with P for P-repleted conditions. Overall, we show that there is greater production of CH4 when sinking particles are present in the treatments. Also, high CH4 concentrations were observed for treatments without P addition, which is in agreement with the biological transformation of MPn acting as a source of CH4 in the aerobic upper water column under P-stressed conditions.

Authors

Royer, S. J., University of Hawaii, USA, sjroyer@hawaii.edu

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 Southern Mississippi, USA, daniela.delvalle@usm.edu

Sosa, O., University of Hawaii, USA, ososa@hawaii.edu

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

Details

Poster presentation

Session #:040
Date: 03/01/2017
Time: 15:30 - 16:30
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 356