| 1. |
- Kaur-Kahlon, G., et al.
(författare)
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Response of a coastal tropical pelagic microbial community to changed salinity and temperature
- 2016
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Ingår i: Aquatic Microbial Ecology. - 0948-3055 .- 1616-1564. ; 77:1, s. 37-50
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Tidskriftsartikel (refereegranskat)abstract
- Studies on the responses of tropical microbial communities to changing hydrographic conditions are presently poorly represented. We present here the results from a mesocosm experiment conducted in southwest (SW) coastal India to investigate how changes in temperature and salinity may affect a coastal tropic microbial community. The onset of algal and bacterial blooms, the maximum production and biomass, and the interrelation between phytoplankton and bacteria were studied in replicated mesocosms. The treatments were set up featuring ambient conditions (28 °C, 35 PSU), hyposalinity (31 PSU), warming (31 °C) and a double manipulated 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 manipulated treatment and higher primary production was maintained. We investigated the dynamics of the microbial community with a structural equation model approach, and found a significant interrelation 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.
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| 2. |
- Kaur-Kahlon, Gurpreet, et al.
(författare)
-
Response of a coastal tropical pelagic microbial community to changed salinity and temperature
- 2016
-
Ingår i: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 77:1, s. 37-50
-
Tidskriftsartikel (refereegranskat)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.
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| 3. |
- Kumar, S., et al.
(författare)
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Nitrogen uptake potential under different temperature-salinity conditions: Implications for nitrogen cycling under climate change scenarios
- 2018
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Ingår i: Marine Environmental Research. - : Elsevier BV. - 0141-1136 .- 1879-0291. ; 141:October, s. 196-204
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Tidskriftsartikel (refereegranskat)abstract
- As projected by climate change models, increase in sea surface temperature and precipitation in the future may alter nutrient cycling in the coastal regions due to potential changes in phytoplankton community structure and their ability to assimilate nitrogen (N) and carbon (C). An experiment simulating different temperature and salinity conditions (28 degrees C-35 ambient conditions, 28 degrees C-31, 31 degrees C-35 and 31 degrees C-31) in mesocosms containing 1000 L of coastal water from the Arabian Sea was performed and N uptake rates were measured using N-15 tracer technique on 2nd, 5th, 7th and 10th day of the experiment. The results show that, under all conditions, the total N (NO3- + NH4+) uptake rates were lower in the beginning and on the final day of the tracer experiment, while it peaked during middle, consistent with chlorophyll a concentrations. Total N uptake rate was significantly lower (p = 0.003) under ambient temperature -lower salinity condition (28 degrees C-31) than the others. This indicates that lowering of salinity in coastal regions due to excessive rainfall in the future may affect the N uptake potential of the phytoplankton, which may change the regional C and N budget.
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