Simulations of phytoplankton species and carbon production in the equatorial Pacific Ocean 1. Model configuration and ecosystem dynamics

Date

2007-03-01

Author

Salihoğlu, Barış
Hofmann, Eileen E.

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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The primary objective of this research is to investigate phytoplankton community response to variations in physical forcing and biological processes in the Cold Tongue region of the equatorial Pacific Ocean at ON, 140W. This research objective was addressed using a one-dimensional multicomponent lower trophic level ecosystem model that includes detailed algal physiology, such as spectrally-dependent photosynthetic processes and iron limitation on algal growth. The ecosystem model is forced by a one-year (1992) time series of spectrally-dependent light, temperature, and water column mixing obtained from a Tropical Atmosphere-Ocean (TAO) Array mooring. Autotrophic growth is represented by five algal groups, which have light and nutrient utilization characteristics of low-light adapted Prochlorococcus, high-light adapted Prochlorococcus, Synechococcus, autotrophic eukaryotes, and large diatoms. The simulated distributions and rates are validated using observations from the 1992 U.S. Joint Global Ocean Flux Study Equatorial Pacific cruises. The model-data comparisons show that the simulations successfully reproduce the temporal distribution of each algal group and that multiple algal groups are needed to fully resolve the variations observed for phytoplankton communities in the equatorial Pacific. The 1992 simulations show seasonal variations in algal species composition superimposed on shorter time scale variations (e.g., 8-20 days) that arise from changes in the upwelling/downwelling environmental structure. The simulated time evolution of the algal groups shows that eukaryotes are the most abundant group, being responsible for half of the annual biomass and 69% of the annual primary production and organic carbon export.

Subject Keywords

Marine synechococcus wh7803, Particulate Organic-carbon, JGOFS EQPAC, Central North Pacific, 140 degrees w, Tropical pacific, Iron limitation, El-Nino, Photosynthetic prokaryote, Coastal phytoplankton

URI

https://hdl.handle.net/11511/53158

Collections

Graduate School of Marine Sciences, Article