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A DEPTH PROFILE OF DIEL PERIODICITY IN MARINE PICOPLANKTON YIELDS INSIGHT INTO ECOSYSTEM STRUCTURE AND FUNCTION

Nutrient and energy supply change with depth and have a profound effect on the dynamics of planktonic communities. Previous work has revealed ubiquitous diel periodicity in gene expression of key metabolic pathways in both autotrophic and heterotrophic microbes in the mixed layer of the euphotic zone. Community gene regulation in ocean surface waters is intricately choreographed to the light/dark cycle. In this study we investigated how diel periodicity of gene expression in planktonic microbial communities changes with depth. On two different cruises, diel time-series samples were collected at four depths (25, 75, 125 and 250 meters) from oligotrophic subtropical gyre station ALOHA (22° 45’ N 158° W) over two days. Both the number of gene transcripts having diel periodicity, as well as the amplitude of diel oscillations in those that did, were found to decrease with depth. As anticipated, diel signals in gene expression decreased more rapidly with depth in a more stratified water column, compared to storm driven well mixed waters. In addition, gene transcript maxima at greater depths were less pronounced, and many were offset to peaking earlier in the day. Since diel cycling has been postulated to coordinate interspecies interactions and metabolic activities, the observed shifts in the magnitude and timing of transcriptome diel cycling with depth may have significant influence on the daily tempo and mode of biogeochemical cycling throughout the water column.

Authors

Vislova, A., University of Hawaii, USA, avislova@hawaii.edu

Aylward, F. O., University of Hawaii, USA, frank.o.aylward@gmail.com

Romano, A., University of Hawaii, USA, ritchiea@hawaii.edu

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

Den Uyl II, P. A., University of Hawaii, USA, pdenuyl@hawaii.edu

DeLong, E. F., University of Hawaii, USA, edelong@hawaii.edu

Details

Oral presentation

Session #:028
Date: 02/28/2017
Time: 14:45
Location: 323 B

Presentation is given by student: Yes