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Saturating light and not increased carbon dioxide under ocean acidification drives photosynthesis and growth in Ulva rigida (Chlorophyta)
Citation
Rautenbuerger, R and Fernandez, PA and Strittmatter, M and Heesch, S and Cornwall, CE and Hurd, CL and Roleda, MY, Saturating light and not increased carbon dioxide under ocean acidification drives photosynthesis and growth in Ulva rigida (Chlorophyta), Ecology and Evolution, 5, (4) pp. 874-888. ISSN 2045-7758 (2015) [Refereed Article]
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Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/
Abstract
Carbon physiology of a genetically identified Ulva rigida was investigated under different CO2(aq) and light levels. The study was designed to answer whether (1) light or exogenous inorganic carbon (Ci) pool is driving growth; and (2) elevated CO2(aq) concentration under ocean acidification (OA) will downregulate CAext-mediated 
dehydration and alter the stable carbon isotope (δ13C) signatures toward more CO2 use to support higher growth rate. At pHT 9.0 where CO2(aq) is <1 μmol L−1, inhibition of the known 
use mechanisms, that is, direct 
uptake through the AE port and CAext-mediated 
dehydration decreased net photosynthesis (NPS) by only 56–83%, leaving the carbon uptake mechanism for the remaining 17–44% of the NPS unaccounted. An in silico search for carbon-concentrating mechanism elements in expressed sequence tag libraries of Ulva found putative light-dependent 
transporters to which the remaining NPS can be attributed. The shift in δ13C signatures from –22‰ toward –10‰ under saturating light but not under elevated CO2(aq) suggest preference and substantial 
use to support photosynthesis and growth. U. rigida is Ci saturated, and growth was primarily controlled by light. Therefore, increased levels of CO2(aq) predicted for the future will not, in isolation, stimulate Ulva blooms.
dehydration and alter the stable carbon isotope (δ13C) signatures toward more CO2 use to support higher growth rate. At pHT 9.0 where CO2(aq) is <1 μmol L−1, inhibition of the known use mechanisms, that is, direct uptake through the AE port and CAext-mediated dehydration decreased net photosynthesis (NPS) by only 56–83%, leaving the carbon uptake mechanism for the remaining 17–44% of the NPS unaccounted. An in silico search for carbon-concentrating mechanism elements in expressed sequence tag libraries of Ulva found putative light-dependent transporters to which the remaining NPS can be attributed. The shift in δ13C signatures from –22‰ toward –10‰ under saturating light but not under elevated CO2(aq) suggest preference and substantial use to support photosynthesis and growth. U. rigida is Ci saturated, and growth was primarily controlled by light. Therefore, increased levels of CO2(aq) predicted for the future will not, in isolation, stimulate Ulva blooms.Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | Ulva, ocean acidification, seaweed, carbon dioxide, photosynthesis, physiological ecology |
| Research Division: | Environmental Sciences |
| Research Group: | Climate change impacts and adaptation |
| Research Field: | Ecological impacts of climate change and ecological adaptation |
| Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
| Objective Group: | Adaptation to climate change |
| Objective Field: | Ecosystem adaptation to climate change |
| UTAS Author: | Cornwall, CE (Dr Chris Cornwall) |
| UTAS Author: | Hurd, CL (Professor Catriona Hurd) |
| ID Code: | 100168 |
| Year Published: | 2015 |
| Web of Science® Times Cited: | 65 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2015-05-06 |
| Last Modified: | 2017-10-31 |
| Downloads: | 398 View Download Statistics |
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