AME 77:37-50 (2016)  -  DOI: https://doi.org/10.3354/ame01785

Response of a coastal tropical pelagic microbial community to changing salinity and temperature

Gurpreet Kaur-Kahlon1, Sanjeev Kumar2, Ann-Sofi Rehnstam-Holm3, Ashwin Rai4, P. S. Bhavya2, Lars Edler5, Arvind Singh1,2, Björn Andersson1, Indrani Karunasagar4,6, Rengaswamy Ramesh2, Anna Godhe1,*

1Department of Marine Sciences, University of Gothenburg, 405 30 Göteborg, Sweden
2Geosciences Division, Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India
3Department of Science, Kristianstad University, 291 88 Kristianstad, Sweden
4Department of Fishery Microbiology, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore 575002, India
5WEAQ Lab, 262 52 Ängelholm, Sweden
6Present address: Nitte University, Mangalore 575018, India
*Corresponding author:

ABSTRACT: Studies on the responses of tropical microbial communities to changing hydrographic conditions are poorly represented. We present here the results from a mesocosm experiment conducted in coastal southwestern India to investigate how changes in temperature and salinity may affect a coastal tropical microbial community. The onset of algal and bacterial blooms, maximum production and biomass, and the interrelationship between phytoplankton and bacteria were studied in replicated mesocosms. The treatments were set up to feature ambient conditions (28°C, 35 PSU), hyposalinity (31 PSU), warming (31°C), and a double manipulation treatment with warming and hyposalinity (31°C, 31 PSU). The hyposaline treatment had the most considerable influence, manifested as significantly lower primary production, and the most dissimilar microphytoplankton species community. The increased temperature acted as a catalyst in the double manipulation treatment, and higher primary production was maintained. We investigated the dynamics of the microbial community with a structural equation model and found a significant interrelationship between phytoplankton biomass and bacterial abundance. Using this methodology, it became evident that temperature and salinity changes, individually and together, mediate direct and indirect effects that influence different compartments of the microbial loop. In the face of climate change, we suggest that in relatively nutrient-replete tropical coastal zones, salinity and temperature changes will affect nutrient assimilation, with subsequent significant effects on the quantity of microbial biomass and production.


KEY WORDS: Phytoplankton · Bacteria · Climate change · Temperature · Salinity · Structural equation modeling · Tropical microbial community


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Cite this article as: Kaur-Kahlon G, Kumar S, Rehnstam-Holm AS, Rai A and others (2016) Response of a coastal tropical pelagic microbial community to changing salinity and temperature. Aquat Microb Ecol 77:37-50. https://doi.org/10.3354/ame01785

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