Diurnal fluctuations in seawater pH influence the response of a calcifying macroalga to ocean acidification

DOI

Coastal ecosystems that are characterized by kelp forests encounter daily pH fluctuations, driven by photosynthesis and respiration, which are larger than pH changes owing to ocean acidification (OA) projected for surface ocean waters by 2100. We investigated whether mimicry of biologically mediated diurnal shifts in pH-based for the first time on pH time-series measurements within a kelp forest-would offset or amplify the negative effects of OA on calcifiers. In a 40-day laboratory experiment, the calcifying coralline macroalga, Arthrocardia corymbosa, was exposed to two mean pH treatments (8.05 or 7.65). For each mean, two experimental pH manipulations were applied. In one treatment, pH was held constant. In the second treatment, pH was manipulated around the mean (as a step-function), 0.4 pH units higher during daylight and 0.4 units lower during darkness to approximate diurnal fluctuations in a kelp forest. In all cases, growth rates were lower at a reduced mean pH, and fluctuations in pH acted additively to further reduce growth. Photosynthesis, recruitment and elemental composition did not change with pH, but ?(13)C increased at lower mean pH. Including environmental heterogeneity in experimental design will assist with a more accurate assessment of the responses of calcifiers to OA.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne et al, 2014) 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). The date of carbonate chemistry calculation is 2014-06-10.

Supplement to: Cornwall, Christopher Edward; Hepburn, Christopher D; McGraw, Christina M; Currie, Kim I; Pilditch, Conrad A; Hunter, Keith A; Boyd, Philip W; Hurd, Catriona L (2013): Diurnal fluctuations in seawater pH influence the response of a calcifying macroalga to ocean acidification. Proceedings of the Royal Society B-Biological Sciences, 280(1772), 20132201-20132201

Identifier
DOI https://doi.org/10.1594/PANGAEA.833265
Related Identifier https://doi.org/10.1098/rspb.2013.2201
Related Identifier https://cran.r-project.org/package=seacarb
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.833265
Provenance
Creator Cornwall, Christopher Edward ORCID logo; Hepburn, Christopher D; McGraw, Christina M ORCID logo; Currie, Kim I; Pilditch, Conrad A; Hunter, Keith A; Boyd, Philip W ORCID logo; Hurd, Catriona L ORCID logo
Publisher PANGAEA
Contributor Yang, Yan
Publication Year 2013
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 1763 data points
Discipline Earth System Research
Spatial Coverage (170.671 LON, -45.639 LAT)
Temporal Coverage Begin 2011-03-13T00:00:00Z
Temporal Coverage End 2011-04-30T00:00:00Z