Program and Agenda

Abstract

VARIABILITY IN PARTICLE EXPORT AT STATION ALOHA

The biological carbon pump links the atmospheric and deep-sea reservoirs of carbon via primary production, particle export and organic matter remineralization. Since Dec 1988 we have measured particle export from the euphotic zone (150 m) at Station ALOHA using sediment traps deployed for ~3 days on approximately monthly intervals. For selected periods, we have also measured particle fluxes at multiple reference depths throughout the upper mesopelagic zone (150-750 m). Particulate carbon and nitrogen (PC and PN, respectively) fluxes were coupled and exhibited both seasonal and subdecadal scale variability. PC export at 150 m averaged 2.2 mmol C m-2 d-1 and ranged from 2-15% of euphotic zone depth-integrated primary production (14C-based). The temporal pattern of particulate phosphorus (PP) flux was decoupled from PC and PN fluxes, and exhibited a systematic decrease over the 25-yr observation period; molar PN:PP export ratios have more than doubled since 1988 to current values in excess of 40:1. This change in the stoichiometry of the exported particles is hypothesized to be a consequence of enhanced nitrogen fixation, which currently supports more than 50% of the new production at Station ALOHA.

http://hahana.soest.hawaii.edu

Authors

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

Clemente, T., University of Hawaii / C-MORE, USA, tclement@hawaii.edu

Grabowski, E., University of Hawaii / C-MORE, USA, grabowsk@hawaii.edu

Wilson, S. T., University of Hawaii / C-MORE, USA, stwilson@hawaii.edu

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

Details

Oral presentation

Session #:049
Date: 2/27/2014
Time: 15:45
Location: 313 B

Presentation is given by student: No