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Diversity of carbon use strategies in a kelp forest community: implications for a high CO2 ocean
Citation
Hepburn, CD and Pritchard, DW and Cornwall, CE and McLeod, RJ and Beardall, J and Raven, JA and Hurd, CL, Diversity of carbon use strategies in a kelp forest community: implications for a high CO2 ocean, Global Change Biology, 17, (7) pp. 2488-2497. ISSN 1354-1013 (2011) [Refereed Article]
Copyright Statement
Copyright 2011 Blackwell Publishing Ltd
DOI: doi:10.1111/j.1365-2486.2011.02411.x
Abstract
Mechanisms for inorganic carbon acquisition in macroalgal assemblages today could indicate how coastal ecosystems
will respond to predicted changes in ocean chemistry due to elevated carbon dioxide (CO2). We identified the
proportion of noncalcifying macroalgae with particular carbon use strategies using the natural abundance of carbon
isotopes and pH drift experiments in a kelp forest. We also identified all calcifying macroalgae in this system; these
were the dominant component of the benthos (by % cover) at all depths and seasons while cover of noncalcareous
macroalgae increased at shallower depths and during summer. All large canopy-forming macroalgae had attributes
suggestive of active uptake of inorganic carbon and the presence of a CO2 concentration mechanism (CCM). CCM
species covered, on average, 1545% of the benthos and were most common at shallow depths and during summer.
There was a high level of variability in carbon isotope discrimination within CCM species, probably a result of
energetic constraints on active carbon uptake in a low light environment. Over 50% of red noncalcifying species
exhibited values below-30 suggesting a reliance on diffusive CO2 uptake and no functional CCM. Non-CCM
macroalgae covered on average 08.9% of rock surfaces and were most common in deep, low light habitats. Elevated
CO2 has the potential to influence competition between dominant coralline species (that will be negatively affected by
increased CO2) and noncalcareous CCM macroalgae (neutral or positive effects) and relatively rare (on a % cover
basis) non-CCM species (positive effects). Responses of macroalgae to elevated CO2 will be strongly modified by light
and any responses are likely to be different at times or locations where energy constrains photosynthesis. Increased
growth and competitive ability of noncalcareous macroalgae alongside negative impacts of acidification on calcifying
species could have major implications for the functioning of coastal reef systems at elevated CO2 concentrations.
Item Details
Item Type: | Refereed Article |
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Keywords: | ocean acidification, carbon uptake strategies, seaweed, kelp forest, light |
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: | 91475 |
Year Published: | 2011 |
Web of Science® Times Cited: | 170 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2014-05-20 |
Last Modified: | 2014-11-24 |
Downloads: | 0 |
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