CO2 and inorganic nutrient enrichment affect the performance of a calcifying green alga and its noncalcifying epiphyte, supplement to: Hofmann, Laurie C; Bischof, Kai; Baggini, Cecilia; Johnson, Andrew; Koop-Jakobsen, Ketil; Teichberg, Mirta (2015): CO2 and inorganic nutrient enrichment affect the performance of a calcifying green alga and its noncalcifying epiphyte. Oecologia, 177(4), 1157-1169

• Main Authors: Hofmann, Laurie C, Bischof, Kai, Baggini, Cecilia, Johnson, Andrew, Koop-Jakobsen, Ketil, Teichberg, Mirta
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2015
• Subjects: Benthos; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria <20 L; Calcification/Dissolution; Chlorophyta; Coast and continental shelf; Dictyota sp.; Growth/Morphology; Halimeda opuntia; Laboratory experiment; Macroalgae; Macro-nutrients; North Atlantic; Plantae; Primary production/Photosynthesis; Respiration; Single species; Tropical; Table; Figure; Species; Sample ID; Change; Identification; Treatment; Carbon, organic, particulate; Nitrogen, total, particulate; Calcium carbonate; Carbon, organic, particulate/Nitrogen, particulate ratio; Phosphates; Nitrogen/Phosphorus ratio; Net photosynthesis rate, oxygen; Comment; Respiration rate, oxygen; Incubation duration; Calcification rate; Growth rate; Irradiance; Maximum photochemical quantum yield of photosystem II; Electron transport rate, relative; Percentage; Salinity; Temperature, water; Temperature, water, standard deviation; pH; pH, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Aragonite saturation state; Aragonite saturation state, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Calcite saturation state; Experiment; Potentiometric; Potentiometric titration; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. 2010; Biological Impacts of Ocean Acidification BIOACID; Ocean Acidification International Coordination Centre OA-ICC; Hofmann; Jakobsen; Laurie; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.847446; https://doi.pangaea.de/10.1594/PANGAEA.847446

Ocean acidification studies in the past decade have greatly improved our knowledge of how calcifying organisms respond to increased surface ocean CO2 levels. It has become evident that, for many organisms, nutrient availability is an important factor that influences their physiological responses and competitive interactions with other species. Therefore, we tested how simulated ocean acidification and eutrophication (nitrate and phosphate enrichment) interact to affect the physiology and ecology of a calcifying chlorophyte macroalga (Halimeda opuntia (L.) J.V. Lamouroux) and its common noncalcifying epiphyte (Dictyota sp.) in a 4-week fully crossed multifactorial experiment. Inorganic nutrient enrichment (+NP) had a strong influence on all responses measured with the exception of net calcification. Elevated CO2 alone significantly decreased electron transport rates of the photosynthetic apparatus and resulted in phosphorus limitation in both species, but had no effect on oxygen production or respiration. The combination of CO2 and +NP significantly increased electron transport rates in both species. While +NP alone stimulated H. opuntia growth rates, Dictyota growth was significantly stimulated by nutrient enrichment only at elevated CO2, which led to the highest biomass ratios of Dictyota to Halimeda. Our results suggest that inorganic nutrient enrichment alone stimulates several aspects of H. opuntia physiology, but nutrient enrichment at a CO2 concentration predicted for the end of the century benefits Dictyota sp. and hinders its calcifying basibiont H. opuntia. : 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.