Distribution, Abundance, and Growth Rates at Phytoplankton in the California Coastal Zone.
Final rept. 1 Oct 94-30 Nov 96
SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE LIFE RESEARCH GROUP
Pagination or Media Count:
Pigments associated with microalgae are one of the most important factors absorbing light in the ocean. Yet, the dynamics of these pigments in the ocean and factors controlling their distribution and rates of change are little known. We studied the abundance and growth rates of micoalgal taxa in the California Coastal Zone to elucidate the factors controlling these and their associated pigments. The methods we used were primarily pigment-based. The composition of the phytoplankton community was dominated by eucaryotes close to shore and by cyanobacteria, particularly Prochlorococcus, offshore. Growth rates of these different groups were highly variable, ranging from low values of O.25d-1 in nutrient depleted offshore areas to 1.8d-1 in upwelling areas dominated by diatoms. Growth rates of most other taxa under nutrient replete conditions only reached values of 0.6 to 0.9 d-1, suggesting that maximum growth rates of these different taxa differ significantly. Results of nutrient enrichment experiments suggest that phytoplankton growth is often limited by the availability of inorganic nitrogen in the offshore areas of the California Coastal Zone.
- Physical and Dynamic Oceanography