Seawater carbonate chemistry, gross photosynthesis and metabolically induced rate of pH change during experiments with macroalgae, 2012

DOI

Ocean acidification (OA) is a reduction in oceanic pH due to increased absorption of anthropogenically produced CO2. This change alters the seawater concentrations of inorganic carbon species that are utilized by macroalgae for photosynthesis and calcification: CO2 and HCO3 increase; CO32 decreases. Two common methods of experimentally reducing seawater pH differentially alter other aspects of carbonate chemistry: the addition of CO2 gas mimics changes predicted due to OA, while the addition of HCl results in a comparatively lower [HCO3]. We measured the short-term photosynthetic responses of five macroalgal species with various carbon-use strategies in one of three seawater pH treatments: pH 7.5 lowered by bubbling CO2 gas, pH 7.5 lowered by HCl, and ambient pH 7.9. There was no difference in photosynthetic rates between the CO2, HCl, or pH 7.9 treatments for any of the species examined. However, the ability of macroalgae to raise the pH of the surrounding seawater through carbon uptake was greatest in the pH 7.5 treatments. Modeling of pH change due to carbon assimilation indicated that macroalgal species that could utilize HCO3 increased their use of CO2 in the pH 7.5 treatments compared to pH 7.9 treatments. Species only capable of using CO2 did so exclusively in all treatments. Although CO2 is not likely to be limiting for photosynthesis for the macroalgal species examined, the diffusive uptake of CO2 is less energetically expensive than active HCO3 uptake, and so HCO3-using macroalgae may benefit in future seawater with elevated CO2.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI).

Supplement to: Cornwall, Christopher Edward; Hepburn, Christopher D; Pritchard, Daniel; Currie, Kim I; McGraw, Christina M; Hunter, Keith A; Hurd, Catriona L (2012): Carbon-use strategies in macroalgae: Differential responses to lowered pH and implications for ocean acidification. Journal of Phycology, 48(1), 137-144

Identifier
DOI https://doi.org/10.1594/PANGAEA.775819
Related Identifier https://doi.org/10.1111/j.1529-8817.2011.01085.x
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.775819
Provenance
Creator Cornwall, Christopher Edward ORCID logo; Hepburn, Christopher D; Pritchard, Daniel ORCID logo; Currie, Kim I; McGraw, Christina M ORCID logo; Hunter, Keith A; Hurd, Catriona L ORCID logo
Publisher PANGAEA
Contributor Nisumaa, Anne-Marin
Publication Year 2012
Funding Reference Seventh Framework Programme https://doi.org/10.13039/100011102 Crossref Funder ID 211384 https://cordis.europa.eu/project/id/211384 European Project on Ocean Acidification; Sixth Framework Programme https://doi.org/10.13039/100011103 Crossref Funder ID 511106 https://cordis.europa.eu/project/id/511106 European network of excellence for Ocean Ecosystems Analysis
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 480 data points
Discipline Earth System Research