Calcareous green alga Halimeda tolerates ocean acidification conditions at tropical carbon dioxide seeps, supplement to: Vogel, Nikolas; Fabricius, Katharina Elisabeth; Strahl, Julia; Noonan, Sam; Wild, Christian; Uthicke, Sven (2015): Calcareous green alga Halimeda tolerates ocean acidification conditions at tropical carbon dioxide seeps. Limnology and Oceanography, 60(1), 263-275

DOI

We investigated ecological, physiological, and skeletal characteristics of the calcifying green alga Halimeda grown at CO2 seeps (pHtotal ~ 7.8) and compared them to those at control reefs with ambient CO2 conditions (pHtotal ~ 8.1). Six species of Halimeda were recorded at both the high CO2 and control sites. For the two most abundant species Halimeda digitata and Halimeda opuntia we determined in situ light and dark oxygen fluxes and calcification rates, carbon contents and stable isotope signatures. In both species, rates of calcification in the light increased at the high CO2 site compared to controls (131% and 41%, respectively). In the dark, calcification was not affected by elevated CO2 in H. digitata, whereas it was reduced by 167% in H. opuntia, suggesting nocturnal decalcification. Calculated net calcification of both species was similar between seep and control sites, i.e., the observed increased calcification in light compensated for reduced dark calcification. However, inorganic carbon content increased (22%) in H. digitata and decreased (-8%) in H. opuntia at the seep site compared to controls. Significantly, lighter carbon isotope signatures of H. digitata and H. opuntia phylloids at high CO2 (1.01 per mil [parts per thousand] and 1.94 per mil, respectively) indicate increased photosynthetic uptake of CO2 over HCO3- potentially reducing dissolved inorganic carbon limitation at the seep site. Moreover, H. digitata and H. opuntia specimens transplanted for 14 d from the control to the seep site exhibited similar delta13C signatures as specimens grown there. These results suggest that the Halimeda spp. investigated can acclimatize and will likely still be capable to grow and calcify in inline image conditions exceeding most pessimistic future CO2 projections.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2015) 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 2015-06-01.

Identifier
DOI https://doi.org/10.1594/PANGAEA.846875
Related Identifier https://doi.org/10.1002/lno.10021
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.846875
Provenance
Creator Vogel, Nikolas; Fabricius, Katharina Elisabeth; Strahl, Julia; Noonan, Sam; Wild, Christian; Uthicke, Sven
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Contributor Yang, Yan
Publication Year 2015
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 4151 data points
Discipline Earth System Research
Spatial Coverage (150.840 LON, -9.780 LAT)
Temporal Coverage Begin 2012-04-01T00:00:00Z
Temporal Coverage End 2013-06-01T00:00:00Z