View Abstract

THE INFLUENCE OF ABRUPT INCREASES IN SEAWATER PCO2 ON RATES OF MICROBIAL PRODUCTION IN THE SUBTROPICAL NORTH PACIFIC OCEAN

We examined short-term (24–96 hours) effects of abrupt increases in the partial pressure of carbon dioxide (pCO2) on rates of primary and bacterial production in near-surface waters (5 m) at Station ALOHA in the North Pacific Subtropical Gyre. In the majority of experiments, we observed no response in rates of primary production (PP) as measured by 14C-bicarbonate assimilation under elevated pCO2 (1100 µatm) treatments compared to ambient controls (< 390 µatm). In 2 experiments, PP decreased significantly in treatments relative to controls. Similarly, no significant differences between treatments were observed in 6 of 7 experiments where bacterial production was measured via incorporation of 3H-leucine (3H-Leu) in both light and dark. In 1 experiment, 3H-Leu measured in the dark increased more than 2-fold in treatments relative to controls. We also examined short-term (~12 hours), depth-dependent responses in size-fractionated rates of PP and rates of 3H-Leu to pCO2 increases (to 750 µatm). In 4 of 5 experiments, PP demonstrated no consistent response; on 1 occasion PP in the >2 µm size fraction increased ~33% in the lower euphotic zone (75–125 m) in treatments relative to controls. Depth-integrated (<125 m) rates of 3H-Leu in the dark were lower (10–15%) in treatments in 2 of 5 experiments; rates measured in the light were greater (10–30%) in controls for all experiments. Overall we find abrupt changes in pCO2 had little effect on rates of PP and 3H-Leu incorporation in this oligotrophic ecosystem.

Authors

Viviani, D. A., University of Hawaii at Manoa, USA, viviani@hawaii.edu

Böttjer, D., University of Hawaii at Manoa, USA, dbottjer@hawaii.edu

Letelier, R. M., Oregon State University, USA, letelier@coas.oregonstate.edu

Church, M. J., University of Montana, USA, mjchurch@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: 355