MEPS 388:13-25 (2009)  -  doi:10.3354/meps08133

Effects of increased pCO2 and temperature on the North Atlantic spring bloom. I. The phytoplankton community and biogeochemical response

Yuanyuan Feng1,8, Clinton E. Hare1, Karine Leblanc1,9,10, Julie M. Rose1,11, Yaohong Zhang1, Giacomo R. DiTullio2, Peter A. Lee2, Steven W. Wilhelm3, Janet M. Rowe3,12, Jun Sun4, Nina Nemcek5, Celine Gueguen5,13, Uta Passow6, Ina Benner6, Christopher Brown7, David A. Hutchins1,8,*

1College of Marine and Earth Studies, University of Delaware, 700 Pilottown Road, Lewes, Delaware 19958, USA
2Hollings Marine Laboratory, College of Charleston, 331 Fort Johnson Road, Charleston, South Carolina 29412, USA
3Department of Microbiology, University of Tennessee, 1414 West Cumberland Ave, Knoxville, Tennessee 37996, USA
4Key Laboratory of Marine Ecology and Environmental Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China
5Department of Earth and Ocean Science, The University of British Columbia, 6339 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada
6Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven 27568, Germany
7Earth System Science Interdisciplinary Center, University of Maryland Research Park (M-Square),
5825 University Research Ct, Ste 4001, College Park, Maryland 20740, USA
8Present address: Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA
9Present address: Aix-Marseille Université, CNRS, LOB-UMR 6535, Laboratoire d’Océanographie et de Biogéochimie, OSU/Centre d’Océanologie de Marseille, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France
10Present address: CNRS (CNRS/INSU), UMR 6535, Campus de Luminy Case 901, 163 Avenue de Luminy,
13288 Marseille Cedex 09, France
11Present address: Biology Department, MS #32, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA
12Present address: Department of Biological Sciences, The University of Nebraska, 204 Morrison Center Lincoln, Nebraska 68583-0900, USA
13Present address: Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada
*Corresponding author. Email:

ABSTRACT: The North Atlantic spring bloom is one of the largest annual biological events in the ocean, and is characterized by dominance transitions from siliceous (diatoms) to calcareous (coccolithophores) algal groups. To study the effects of future global change on these phytoplankton and the biogeochemical cycles they mediate, a shipboard continuous culture experiment (Ecostat) was conducted in June 2005 during this transition period. Four treatments were examined: (1) 12°C and 390 ppm CO2 (ambient control), (2) 12°C and 690 ppm CO2 (high pCO2), (3) 16°C and 390 ppm CO2 (high temperature), and (4) 16°C and 690 ppm CO2 (‘greenhouse’). Nutrient availability in all treatments was designed to reproduce the low silicate conditions typical of this late stage of the bloom. Both elevated pCO2 and temperature resulted in changes in phytoplankton community structure. Increased temperature promoted whole community photosynthesis and particulate organic carbon (POC) production rates per unit chlorophyll a. Despite much higher coccolithophore abundance in the greenhouse treatment, particulate inorganic carbon production (calcification) was significantly decreased by the combination of increased pCO2 and temperature. Our experiments suggest that future trends during the bloom could include greatly reduced export of calcium carbonate relative to POC, thus providing a potential negative feedback to atmospheric CO2 concentration. Other trends with potential climate feedback effects include decreased community biogenic silica to POC ratios at higher temperature. These shipboard experiments suggest the need to examine whether future pCO2 and temperature increases on longer decadal timescales will similarly alter the biological and biogeochemical dynamics of the North Atlantic spring bloom.


KEY WORDS: Ocean acidification · Global change · Carbon dioxide · Temperature · Coccolithophores · Diatoms · Calcification · North Atlantic bloom


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Cite this article as: Feng Y, Hare CE, Leblanc K, Rose JM and others (2009) Effects of increased pCO2 and temperature on the North Atlantic spring bloom. I. The phytoplankton community and biogeochemical response. Mar Ecol Prog Ser 388:13-25

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