Phytoplankton production and taxon-specific growth rates in the Costa Rica Dome
Abstract
During summer 2010, we investigated phytoplankton production and growth rates at 19 stations in the eastern tropical Pacific, where winds and strong opposing currents generate the Costa Rica Dome (CRD), an open-ocean upwelling feature. Primary production (^(14)C-incorporation) and group-specific growth and net growth rates (two-treatment seawater dilution method) were estimated from samples incubated in situ at eight depths. Our cruise coincided with a mild El Niño event, and only weak upwelling was observed in the CRD. Nevertheless, the highest phytoplankton abundances were found near the dome center. However, mixed-layer growth rates were lowest in the dome center (∼0.5–0.9 day^(−1)), but higher on the edge of the dome (∼0.9–1.0 day^(−1)) and in adjacent coastal waters (0.9–1.3 day^(−1)). We found good agreement between independent methods to estimate growth rates. Mixed-layer growth rates of Prochlorococcus and Synechococcus were largely balanced by mortality, whereas eukaryotic phytoplankton showed positive net growth (∼0.5–0.6 day^(−1)), that is, growth available to support larger (mesozooplankton) consumer biomass. These are the first group-specific phytoplankton rate estimates in this region, and they demonstrate that integrated primary production is high, exceeding 1 g C m^(−2) day^(−1) on average, even during a period of reduced upwelling.
Additional Information
© 2015 Author. Published by Oxford University Press. Received April 11, 2015. Accepted July 13, 2015. First published online: August 3, 2015. The authors thank Captain Christopher Curl, the crew, and resident technicians (Jim Dorrance, John Calderwood and Frank Delahoyde) aboard the RV Melville, for their excellent support of this research. They also thank the rest of the team that helped on board, in particular Darcy Taniguchi, Moira Décima and Alain de Verneil. This is contribution no. 9476 from the School of Ocean and Earth Science and Technology, University of Hawai'i at Manoa, Honolulu, HI 96822. This study was supported by U.S. National Science Foundation grant OCE-0826626 to M.R.L. Additional support was provided by a Ramón Areces Foundation Fellowship to A.G.R., a NASA National Aeronautics and Space Administration, Earth and Space Science Fellowship to M.R.S. and a National Science Foundation Graduate Research Fellowship to A.L.P.Additional details
- PMCID
- PMC4889980
- Eprint ID
- 66419
- Resolver ID
- CaltechAUTHORS:20160422-135912695
- OCE-0826626
- NSF
- Ramón Areces Foundation Fellowship
- NASA Earth and Space Science Fellowship
- NSF Graduate Research Fellowship
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2016-04-22Created from EPrint's datestamp field
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2022-05-24Created from EPrint's last_modified field