Marine Biology - Responses Of Marine Benthic Microalgae To Elevated CO2

[hatrack]

ABSTRACT: Increasing anthropogenic CO2 emissions to the atmosphere are causing a rise in pCO2 concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO2 levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO2 gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO2 concentrations increased. CO2 enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO2 levels increased. The responses of benthic microalgae to rising anthropogenic CO2 emissions are likely to have significant ecological ramifications for coastal systems. <…>

Our findings indicate that periphytic diatoms exhibit a non-uniform response to CO2 enrichment; this is most likely due to taxon-specific differences in their sensitivity to CO2 concentrations and presumably due to their kinetics of carbon use. CO2-induced community shifts have also been observed in many other photoautotrophic assemblages (Tortell, et al., 2002, 2008; Fu, et al., 2007; Russell, et al., 2009; Trimborn, et al., 2009; Connell and Russell 2010; Porzio, et al., 2011) adding to evidence that increasing CO2 emissions are likely to lead to structural and functional changes in a wide variety of marine and coastal systems. <…>

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http://www.springerlink.com/content/x80t124q2x314137/fulltext.pdf

[postulater]

1. Good to know.

I'm thankful that we have smart people studying these important changes. Without this type of data we are less able to make rational decisions about our future.