title: Effects of ocean acidification on the brown alga Padina pavonica: decalcification due to acute and chronic events.
abstract: Since the industrial revolution, anthropogenic CO₂ emissions have caused ocean acidification, which particularly affects calcified organisms. Given the fan-like calcified fronds of the brown alga Padina pavonica, we evaluated the acute (short-term) effects of a sudden pH drop due to a submarine volcanic eruption (October 2011-early March 2012) affecting offshore waters around El Hierro Island (Canary Islands, Spain). We further studied the chronic (long-term) effects of the continuous decrease in pH in the last decades around the Canarian waters. In both the observational and retrospective studies (using herbarium collections of P. pavonica thalli from the overall Canarian Archipelago), the percent of surface calcium carbonate coverage of P. pavonica thalli were contrasted with oceanographic data collected either in situ (volcanic eruption event) or from the ESTOC marine observatory data series (herbarium study). Results showed that this calcified alga is sensitive to acute and chronic environmental pH changes. In both cases, pH changes predicted surface thallus calcification, including a progressive decalcification over the last three decades. This result concurs with previous studies where calcareous organisms decalcify under more acidic conditions. Hence, Padina pavonica can be implemented as a bio-indicator of ocean acidification (at short and long time scales) for monitoring purposes over wide geographic ranges, as this macroalga is affected and thrives (unlike strict calcifiers) under more acidic conditions.
authors.affiliation: Centro de Biodiversidad y Gestión Ambiental, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: Teba
authors.initials: T
authors.lastname: Gil-Díaz
authors.affiliation: Centro de Biodiversidad y Gestión Ambiental, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Haroun
authors.affiliation: Centro de Biodiversidad y Gestión Ambiental, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Tuya
authors.affiliation: Centro de Biodiversidad y Gestión Ambiental, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: Séfora
authors.initials: S
authors.lastname: Betancor
authors.affiliation: Centro de Biodiversidad y Gestión Ambiental, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: María A
authors.initials: MA
authors.lastname: Viera-Rodríguez
mesh_terms: D002113:Calcification, Physiologic; D002119:Calcium Carbonate / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D017753:Ecosystem; D006863:Hydrogen-Ion Concentration; D062312:Islands; D015233:Models, Statistical; D000459:Phaeophyceae / Q000187:drug effects / Q000502:physiology*; D012623:Seawater / Q000032:analysis*; D013030:Spain; D018707:Volcanic Eruptions
chemical_list: D002245:Carbon Dioxide; D002119:Calcium Carbonate