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Presenters Notified: November 2012

Program Schedule Posted:November 2012

Abstracts Available: January 2013

Meeting:
17-22 February 2013

Heal, K. R., University of Washington, USA, kheal@uw.edu
Smith, S. R., Scripps Institute of Oceanography, USA, sarahsmith@ucsd.edu
Church, M. J., University of Hawaii, USA, mjchurch@hawaii.edu

PHOTOSYNTHETIC PARAMETERS OVER HOURLY AND DAILY TIMESCALES SHED LIGHT ON POPULATION STABILITY AT STATION ALOHA

Light availability is a key factor in structuring phytoplankton communities, yet little is known about the time-scales on which surface and depth-adapted communities respond to daily fluctuations in light in the open ocean. At Station ALOHA, in the oligotrophic North Pacific, hourly to daily-scale variations in photosynthetic carbon fixation from phytoplankton assemblages dwelling in the surface (25m) and the deep chlorophyll maximum (DCM, approx. 125m) were quantified over a 10 day period in June 2012 during the CMORE summer course. High-light adapted phytoplankton assemblages were found to be highly responsive to diel fluctuations in light while no clear diel pattern was observed for the DCM assemblage. However, a correlation between the light saturation index and daily integrated irradiance was observed for the depth-adapted community indicating that longer timescale processes, such as those driven by mescoscale forcing, could contribute to changes in productivity among the low light-adapted assemblages. These results suggest that the time-scales on which phytoplankton respond to light variability is a key adaptation that determines the relative success of surface and depth-adapted communities.

Poster presentation

Session #:SS73
Date: 2/19/2013
Time: 18:00 - 19:30