Program and Agenda

Abstract

NO EVIDENCE FOR ENHANCED CARBON OR DINITROGEN FIXATION UNDER ELEVATED SEAWATER PCO2 IN THE NORTH PACIFIC SUBTROPICAL GYRE

Long-term observations of oceanic CO2 inventories at Station ALOHA (A Long-term Oligotrophic Habitat Assessment; 22° 45’N, 158° 00’W) in the North Pacific Subtropical Gyre (NPSG) have demonstrated a continuing increase in surface ocean pCO2 (1.92 µatm year-1) and decrease in upper ocean pH (0.0019 year-1), largely due to the combustion of anthropogenic fossil fuels. Uncertainties remain on how these changes might impact ocean ecosystem processes or biogeochemical cycles. In this study, we examined the in situ and experimental response of rates of carbon (C) and dinitrogen (N2) fixation to changes in seawater pCO2. Depth-integrated (0-125m) in situ measurements showed no major differences in C- and N2-fixation between contemporary (~390 ppm) and elevated (~ 800-1000 ppm) seawater pCO2. Similar findings were obtained in CO2 shipboard incubation experiments (48 to 168 hours in duration), suggesting that microorganisms that fix C and N2 in the NPSG are relatively resilient to large, short-term increases in seawater pCO2.

ePoster:

Authors

Böttjer, D., University of Hawaii/C-MORE, USA, dbottjer@hawaii.edu

Viviani, D., University of Hawaii/C-MORE, USA, viviani@hawaii.edu

Karl, D. M., University of Hawaii/C-MORE, USA, dkarl@hawaii.edu

Letelier, R. M., Oregon State University/C-MORE, USA, letelier@coas.oregonstate.edu

Church, M. J., University of Hawaii/C-MORE, USA, mjchurch@hawaii.edu

Details

Poster presentation

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

Presentation is given by student: Yes

PosterID: 2398