AME 79:49-62 (2017)  -  DOI:

Variable response to warming and ocean acidification by bacterial processes in different plankton communities

Timothy J. Burrell1,2,4,*, Elizabeth W. Maas1,5, Debbie A. Hulston1, Cliff S. Law1,3

1National Institute of Water and Atmospheric Research, Private Bag 14–901, Wellington 6021, New Zealand
2Victoria University of Wellington, School of Biological Sciences, Kelburn, Wellington 6012, New Zealand
3Department of Chemistry, University of Otago, Union Pl, Dunedin 9016, New Zealand
4Present address: C-MORE, University of Hawai’i Manoa, 1950 East West Road, Honolulu, Hawai’i 96822, USA
5Present address: Ministry for Primary Industry, PO Box 12034, Ahuriri, Napier 4144, New Zealand
*Corresponding author:

ABSTRACT: Extracellular bacterial enzymes play an important role in the degradation of organic matter in the surface ocean but are sensitive to changes in pH and temperature. This study tested the individual and combined effects of lower pH (-0.3) and warming (+3°C) projected for the year 2100 on bacterial abundance, process rates and diversity in plankton communities of differing composition from 4 locations east of New Zealand. Variation was observed in magnitude and temporal response between the different communities during 5 to 6 day incubations. Leucine aminopeptidase activity showed the strongest response, with an increase in potential activity under low pH alone and in combination with elevated temperature in 3 of 4 incubations. Temperature had a greater effect on bacterial cell numbers and protein synthesis, with stronger responses in the elevated temperature and combined treatments. However, the most common interactive effect between temperature and pH was antagonistic, with lower bacterial secondary production in the combined treatment relative to elevated temperature, and lower leucine aminopeptidase activity in the combined treatment relative to low pH. These results highlight the variability of responses to and interactions of environmental drivers, and the importance of considering these in experimental studies and prognostic models of microbial responses to climate change.

KEY WORDS: Ocean acidification · Ocean warming · Interactive effects · Extracellular enzyme activity · Bacterial production · Bacterial diversity · Southwest Pacific

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Cite this article as: Burrell TJ, Maas EW, Hulston DA, Law CS (2017) Variable response to warming and ocean acidification by bacterial processes in different plankton communities. Aquat Microb Ecol 79:49-62.

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