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RATES OF MICROBIAL ACTIVITIES ASSOCIATED WITH SINKING PARTICLES AT STATION ALOHA IN THE NORTH PACIFIC SUBTROPICAL GYRE

Mesopelagic microbial metabolism is supported in large part by the supply of reduced substrates associated with sinking particles. We characterized the composition and reactivity of sinking particles at Station ALOHA in the North Pacific Subtropical Gyre. Particle interceptor traps containing acrylamide gels were used to examine how the size of sinking particles varied with depth (from 150 m to 750 m) during two cruises to Station ALOHA. Sinking particles were imaged and sized by microscopy. Results from these analyses revealed particles <100 μm were dominant contributors to particle flux, with the contribution of particles 200-1000 μm becoming increasingly important in the mesopelagic waters. We also examined the reactivity of sinking particles during these two cruises through a series of remineralization experiments. Sinking particles were inoculated into whole seawater and the subsequent treatments were incubated in the dark over 3 days. The addition of particles stimulated rates of remineralization 2-3-fold relative to whole seawater controls. Rates of bacterial production were 4-6 fold greater than in whole seawater controls, while rates of chemoautotrophic production were 1-2 times greater in the particle-enriched treatments than the seawater controls. These results confirm that sinking particles are “hot-spots” of microbial activity, with the presence of sinking particles fueling elevated chemotrophic production.

Authors

Nelson, A. J., University of Hawaii at Manoa, USA, anelson7@hawaii.edu

Church, M. J., University of Hawaii at Manoa, USA, mjchurch@hawaii.edu

Dornan, N., University of Hawaii at Manoa, USA, ndornan@hawaii.edu

Kyi, E., University of Hawaii at Manoa, USA, ekyi@hawaii.edu

Van Mooy, B., Woods Hole Oceanographic Institute, USA, bvanmooy@whoi.edu

Ossolinski, J., Woods Hole Oceanographic Institute, USA, jossolinski@whoi.edu

Viviani, D., University of Hawaii at Manoa, USA, viviani@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: 350