Seawater carbonate chemistry and calcium carbonate of Padina spp., photosynthesis of Padina pavonica in nature CO2 gradients experiment, supplement to: Johnson, Vivienne R; Russell, Bayden D; Fabricius, Katharina Elisabeth; Brownlee, Colin; Hall-Spencer, Jason M (2012): Temperate and tropical brown macroalgae thrive, despite decalcification, along natural CO2 gradients. Global Change Biology, 18(9), 2792-2803

• Main Authors: Johnson, Vivienne R, Russell, Bayden D, Fabricius, Katharina Elisabeth, Brownlee, Colin, Hall-Spencer, Jason M
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2012
• Subjects: Animalia; Benthic animals; Benthos; Biomass/Abundance/Elemental composition; Calcification/Dissolution; Chromista; CO2 vent; Coast and continental shelf; Echinodermata; Field observation; Growth/Morphology; Macroalgae; Mediterranean Sea; Ochrophyta; Padina pavonica; Padina spp.; Primary production/Photosynthesis; Single species; South Pacific; Temperate; Tropical; Event label; Identification; Species; Replicate; Station label; Coverage; Calcium carbonate; Maximum photochemical quantum yield of photosystem II; Maximal electron transport rate, relative; Electron transport rate, relative; Chlorophyll a; Chlorophyll c per cell; Length; Width; Abundance; pH; Partial pressure of carbon dioxide water at sea surface temperature wet air; Alkalinity, total; Alkalinity, total, standard deviation; Carbon, inorganic, dissolved; Carbonate ion; Bicarbonate ion; Calcite saturation state; Aragonite saturation state; Temperature, water; Salinity; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; In situ sampler; Potentiometric; Calculated using CO2SYS; Potentiometric titration; Calculated using seacarb after Nisumaa et al. 2010; Mediterranean Sea Acidification in a Changing Climate MedSeA; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.823111; https://doi.pangaea.de/10.1594/PANGAEA.823111

Predicting the impacts of ocean acidification on coastal ecosystems requires an understanding of the effects on macroalgae and their grazers, as these underpin the ecology of rocky shores. Whilst calcified coralline algae (Rhodophyta) appear to be especially vulnerable to ocean acidification, there is a lack of information concerning calcified brown algae (Phaeophyta), which are not obligate calcifiers but are still important producers of calcium carbonate and organic matter in shallow coastal waters. Here, we compare ecological shifts in subtidal rocky shore systems along CO2 gradients created by volcanic seeps in the Mediterranean and Papua New Guinea, focussing on abundant macroalgae and grazing sea urchins. In both the temperate and tropical systems the abundances of grazing sea urchins declined dramatically along CO2 gradients. Temperate and tropical species of the calcifying macroalgal genus Padina (Dictyoaceae, Phaeophyta) showed reductions in CaCO3 content with CO2 enrichment. In contrast to other studies of calcified macroalgae, however, we observed an increase in the abundance of Padina spp. in acidified conditions. Reduced sea urchin grazing pressure and significant increases in photosynthetic rates may explain the unexpected success of decalcified Padina spp. at elevated levels of CO2. This is the first study to provide a comparison of ecological changes along CO2 gradients between temperate and tropical rocky shores. The similarities we found in the responses of Padina spp. and sea urchin abundance at several vent systems increases confidence in predictions of the ecological impacts of ocean acidification over a large geographical range. : 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). The date of carbonate chemistry calculation by seacarb is 2013-11-20.