Aquatic Sciences Meeting, Albuquerque 2001

CS15 Harmful Algal Blooms

Date: Tuesday, February 13, 2001, Time: 2:00:00 PM

Location: Cochiti/Taos

Moisan, T, A, NASA/GSFC, Wallops Island, VA, USA, tmoisan@osb.wff.nasa.gov

Mitchell, B, G, Scripps Institution of Oceanography, UCSD, La Jolla, CA, USA, bgmitchell@ucsd.edu

MODELING NET GROWTH OF PHAEOCYSTIS ANTARCTICA BASED ON PHYSIOLOGICAL AND OPTICAL RESPONSES TO LIGHT AND TEMPERATURE

Temperature and light play a critical role in controlling net primary productivity in polar regions during spring blooms. Using colonial Phaeocystis antarctica cultures, we assessed the combined effect of these two environmental conditions on growth rate, spectral absorption, and quantum yields for growth. Specific net growth rates varied from 0.04 to 0.34 day-1 within a matrix of light and temperature ranging from 14 to 542 umol quanta m-2 s-1 and 1.5 to 4C. Chlorophyll-specific absorption varied significantly with light but only slightly with temperature. Values of quantum yield for growth ranged from 0.003 to 0.09 mol C (mol quanta absorbed)-1. Models for absorption (300-700 nm) and quantum yields for growth were developed and take into account systematic changes in pigment packaging effects and pigmentation. The newly developed models and parameterizations are combined into an overall model of growth that can be applied easily to environmental research using input parameters of temperature, light, and chlorophyll a. Applications of this model to natural populations of Phaeocystis are feasible due to its ecological importance and widespread distribution in polar seas.

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Aquatic Sciences Meeting, Albuquerque 2001

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