An update of data compilation on the biological response to ocean acidification and overview of the OA-ICC data portal

Abstract. Studies investigating the effects of ocean acidification on marine organisms and communities are increasing every year. Results are not easily comparable since the carbonate chemistry and ancillary data are not always reported in similar units and scales, and calculated using similar sets of constants. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (https://doi.pangaea.de/10.1594/PANGAEA.962556, Ocean Acidification International Coordination Centre, 2023). By November 2023, a total of 1501 data sets (over 25 million data points) from 1554 papers have been archived. To easily filter and access relevant biological response data from this compilation, a user-friendly portal was launched (https://oa-icc.ipsl.fr) in 2018. Here we present the updates of this data compilation since its second description by Yang et al. (2016) and provide an overview of the “OA-ICC portal for ocean acidification biological response data” launched in 2018. Most of the study sites from which data have been archived are in the North Atlantic Ocean, North Pacific Ocean, South Pacific Ocean and Mediterranean Sea, while polar oceans are still relatively poorly represented. Mollusca and Cnidaria are still the best represented taxonomic groups. The biological processes most reported in the datasets were growth and morphology. Other variables that can potentially be affected by ocean acidification and are often reported include calcification/dissolution, primary production/photosynthesis, and biomass/abundance. The majority of the compiled datasets have considered ocean acidification as a single stressor, but their relative contribution decreased from 68 % before 2015 to 57 % today, showing a clear tendency towards more data archived from multifactorial studies.