Seawater carbonate chemistry and gross photosynthesis, respiration, calcification of coralline algae


Rhodolith beds built by free-living coralline algae are important ecosystems for marine biodiversity and carbonate production. Yet, our mechanistic understanding regarding rhodolith physiology and its drivers is still limited. Using three rhodolith species with different branching morphologies, we investigated the role of morphology in species' physiology and the implications for their susceptibility to ocean acidification (OA). For this, we determined the effects of thallus topography on diffusive boundary layer (DBL) thickness, the associated microscale oxygen and pH dynamics and their relationship with species' metabolic and light and dark calcification rates, as well as species' responses to short-term OA exposure. Our results show that rhodolith branching creates low-flow microenvironments that exhibit increasing DBL thickness with increasing branch length. This, together with species' metabolic rates, determined the light-dependent pH dynamics at the algal surface, which in turn dictated species' calcification rates. While these differences did not translate in species-specific responses to short-term OA exposure, the differences in the magnitude of diurnal pH fluctuations ( 0.1–1.2 pH units) between species suggest potential differences in phenotypic plasticity to OA that may result in different susceptibilities to long-term OA exposure, supporting the general view that species' ecomechanical characteristics must be considered for predicting OA responses.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2021) 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 by seacarb is 2021-10-12.

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Metadata Access
Creator Schubert, Nadine; Hofmann, Laurie C; Almeida Saá, Antonella C; Moreira, Anderson Camargo; Arenhart, Rafael Güntzel; Fernandes, Celso Peres; de Beer, Dirk; Horta, Paulo Antunes; Silva, João
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Contributor Yang, Yan
Publication Year 2021
Rights Creative Commons Attribution 4.0 International;
OpenAccess true
Language English
Resource Type Dataset
Format text/tab-separated-values
Size 198 data points
Discipline Earth System Research
Spatial Coverage (-47.633 LON, -26.726 LAT)