AME 54:101-112 (2009)  -  DOI: https://doi.org/10.3354/ame01259

Differential response of grazing and bacterial heterotrophic production to experimental warming in Antarctic waters

Dolors Vaqué1,*, Òscar Guadayol1,2, Francesc Peters1, Jordi Felipe1, Andrea Malits1,3, Carlos Pedrós-Alió1

1Institut de Ciències del Mar, CSIC, Departament de Biologia Marina i Oceanografia, Passeig Maritim de la Barceloneta,
37-49, 08003 Barcelona, Catalonia, Spain
2College of Oceanic and Atmospheric Sciences, Oregon State University, 104 COAS Administration Building, Corvallis, Oregon 97331-5503, USA
347, Chemin des Collettes, 06800 Cagnes sur Mer, France

ABSTRACT: Narrow annual ranges of temperature characterize polar waters. Consequently, small increases in temperature could significantly affect the metabolic processes of marine microorganisms. We investigated the response of bacterial heterotrophic production (BHP) and grazing rates to small temperature changes in 3 zones near the western Antarctic Peninsula—Bransfield and Gerlache Straits, and Bellingshausen Sea—during December 2002. We performed 8 grazing experiments with water samples collected from depths where chlorophyll a (chl a) concentration was maximum, and incubated the samples at ambient temperature and at –1, 1, 2 and 5°C. We expected that grazing would increase in parallel with BHP at increasing temperatures; however, temperature differentially affected these 2 microbial activities. Thus, grazing rates increased maximally at temperatures ≤2°C, except in 1 station in the Gerlache Strait, while BHP increased maximally at temperatures ≥2°C, except in 1 station in the Bellingshausen Sea. The percentage of grazed bacteria to BHP at the highest experimental temperatures was low (56 ± 19%) in the Gerlache Strait, high (395 ± 137%) in the Bransfield Strait and approximately balanced (97 ± 24%) in the Bellingshausen Sea. This suggests that differential microbial processes in each zone at increasing temperatures will also depend on the autochthonous community. The present study contributes to the understanding of the variability of polar biogeochemical fluxes, and may aid in predicting the response of microorganisms in future scenarios with local and seasonal changes in temperature.


KEY WORDS: Bacterial heterotrophic production · Grazing rates · Temperature · Antarctic waters


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Cite this article as: Vaqué D, Guadayol Ò, Peters F, Felipe J, Malits A, Pedrós-Alió C (2009) Differential response of grazing and bacterial heterotrophic production to experimental warming in Antarctic waters. Aquat Microb Ecol 54:101-112. https://doi.org/10.3354/ame01259

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