Seawater carbonate chemistry and diatom silica production in the Southern Ocean

• Main Authors: Petrou, Katherina, Baker, Kirralee G, Nielsen, Daniel A, Hancock, Alyce M, Schulz, Kai Georg, Davidson, Andrew T
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2019
• Subjects: Antarctic; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Entire community; Fragilariopsis curta; Fragilariopsis cylindrus; Laboratory experiment; Other metabolic rates; Pelagos; Polar; Primary production/Photosynthesis; Proboscia truncata; Pseudonitzschia turgiduloides; Stellarima microtrias; Thalassiosira antarctica; Type; Species; Abbreviation; Registration number of species; Uniform resource locator/link to reference; Identification; Replicate; Biogenic silica; Maximum photochemical quantum yield of photosystem II; Experiment day; Number of cells; Silicification; Chlorophyll a; Cell biovolume; Fugacity of carbon dioxide water at sea surface temperature wet air; pH; Proton concentration; Temperature, water; Salinity; Nitrate and Nitrite; Phosphorus, reactive soluble; Silicate; Carbon, inorganic, dissolved; Alkalinity, total; Carbonate system computation flag; Carbon dioxide; Partial pressure of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Calcite saturation state; Experiment; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Southern Ocean; Antarc*; Antarctica; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.914329; https://doi.pangaea.de/10.1594/PANGAEA.914329

Diatoms, large bloom-forming marine microorganisms, build frustules out of silicate, which ballasts the cells and aids their export to the deep ocean. This unique physiology forges an important link between the marine silicon and carbon cycles. However, the effect of ocean acidification on the silicification of diatoms is unclear. Here we show that diatom silicification strongly diminishes with increased acidity in a natural Antarctic community. Analyses of single cells from within the community reveal that the effect of reduced pH on silicification differs among taxa, with several species having significantly reduced silica incorporation at CO2 levels equivalent to those projected for 2100. These findings suggest that, before the end of this century, ocean acidification may influence the carbon and silicon cycle by both altering the composition of the diatom assemblages and reducing cell ballasting, which will probably alter vertical flux of these elements to the deep ocean. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2019) 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 2020-03-18.