Phytoplankton production and grazing balances in the Costa Rica Dome.
We investigated phytoplankton production rates and grazing fates in the Costa Rica Dome (CRD) during summer 2010 based on dilution depth profiles analyzed by flow cytometry and pigments and mesozooplankton grazing assessed by gut fluorescence. Three community production estimates, from14C uptake (1025 ± 113 mg C m-2day-1) and from dilution experiments analyzed for total Chla(990 ± 106 mg C m-2day-1) and flow cytometry populations (862 ± 71 mg C m-2day-1), exceeded regional ship-based values by 2-3-fold. Picophytoplankton accounted for 56% of community biomass and 39% of production. Production profiles extended deeper forProchlorococcus(PRO) and picoeukaryotes than forSynechococcus(SYN) and larger eukaryotes, but 93% of total production occurred above 40 m. Microzooplankton consumed all PRO and SYN growth and two-third of total production. Positive net growth of larger eukaryotes in the upper 40 m was balanced by independently measured consumption by mesozooplankton. Among larger eukaryotes, diatoms contributed ∼3% to production. On the basis of this analysis, the CRD region is characterized by high production and grazing turnover, comparable with or higher than estimates for the eastern equatorial Pacific. The region nonetheless displays characteristics atypical of high productivity, such as picophytoplankton dominance and suppressed diatom roles.
Scripps Institution of Oceanography , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA.
Michael R
MR
Landry
Department of Oceanography , University of Hawaii at Manoa , Honolulu, HI 96822 , USA.
Karen E
KE
Selph
Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA; National Institute of Water and Atmospheric Research (NIWA), 301 Evans Bay Parade, Hataitai, Wellington 6021, New Zealand.
Moira
M
Décima
Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA; Centre National de la Recherche Scientifique and Universite Pierre et Marie Curie, Station Biologique, Roscoff 29680, France.
Andrés
A
Gutiérrez-Rodríguez
Earth, Ocean and Atmospheric Science , Florida State University , Tallahassee, FL 32306 , USA.
Michael R
MR
Stukel
Scripps Institution of Oceanography , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA.
Andrew G
AG
Taylor
Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0227, USA; Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Alexis L
AL
Pasulka
grazing; plankton community; productivity