| Autor: |
Helbling, E., Banaszak, Anastazia, Villafañe, Virginia |
| Předmět: |
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| Zdroj: |
Estuaries & Coasts; Jul2015, Vol. 38 Issue 4, p1134-1146, 13p |
| Abstrakt: |
The combined impact of solar ultraviolet radiation (UVR) and elevated temperature on the photosynthesis of phytoplankton communities from the two end members of the Chubut River estuary was studied using short- and long-term incubations. Samples from the river and seawater sections of the estuary were collected during the austral Spring (November 2011) and exposed to solar radiation (with and without UVR) under two temperatures: in situ and increased by 5 °C. The long-term incubations were designed to assess the potential acclimation of each phytoplankton community to the experimental conditions. Short-term incubations, at day 1 and day 5 of the acclimation period, included the determination of Photosynthesis vs. irradiance curves, Biological Weighting Functions and daily cycles of Chl-a fluorescence measurements, and were used as an estimation of the ability to cope with either increased temperature or UVR. There was a synergistic effect between UVR and temperature in the seawater community, with samples demonstrating a better photosynthetic response in the absence of UVR and at the in situ temperature. In contrast, temperature had an antagonistic effect when combined with UVR in the river community, with increased temperature counteracting the negative impact of UVR. Despite this, both communities showed an acclimation capacity toward UVR and increasing temperature. Our results point to a differential impact of global change variables on phytoplankton communities within the estuary, which affect photosynthesis and might influence the species composition with potential repercussions on the food web. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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