Two new coastal time-series of seawater carbonate system variables in the NW Mediterranean Sea : rates and mechanisms controlling pH changes
García-Ibáñez, Maribel I. (Institut de Ciències del Mar)
Guallart, Elisa F. (Institut de Ciències del Mar)
Lucas, Arturo (Institut de Ciències del Mar)
Pascual, Josep (Estació Meteorològica de L'Estartit)
Gasol, Josep M. (Institut de Ciències del Mar)
Marrasé, Cèlia (Institut de Ciències del Mar)
Calvo Costa, Eva (Institut de Ciències del Mar)
Pelejero, Carles (Institució Catalana de Recerca i Estudis Avançats)

Data:	2024
Descripció:	12 pàg.
Resum:	In this work, we present, for the first time, the seawater carbonate system measurements of two coastal time-series in the NW Mediterranean Sea, L'Estartit Oceanographic Station (EOS; 42. 05°N 3. 2542°E) and the Blanes Bay Microbial Observatory (BBMO; 41. 665°N 2. 805°E). At these two time-series, measurements of total alkalinity (TA), pH, and associated variables, such as dissolved inorganic nutrients, temperature, and salinity, have been performed monthly since 2010 in surface seawater. Seasonality and seasonal amplitude are analogous in both time-series, with seasonality in pHTin situ (pH at in situ seawater conditions on the total hydrogen ion scale) primarily determined by seasonality in sea surface temperature. The evaluated pHTin situ trends at BBMO (-0. 0021 ± 0. 0003 yr-1) and EOS (-0. 0028 ± 0. 0005 yr-1) agree with those reported for coastal and open ocean surface waters in the Mediterranean Sea and open ocean surface waters of the global ocean, therefore indicating that these time-series are representative of global ocean acidification signals despite being coastal. The decreases in pHTin situ can be attributed to increases in total dissolved inorganic carbon (DIC; 1. 5 ± 0. 4 µmol kg-1 yr-1 at BBMO and 1. 6 ± 0. 6 µmolESkg-1 yr-1 at EOS) and sea surface temperature (0. 08 ± 0. 02 °C yr-1 at BBMO and 0. 08 ± 0. 04 °C yr-1 at EOS). The increases in carbon dioxide fugacity (fCO2; 2. 4 ± 0. 3 µmol kg-1 yr-1 at BBMO and 2. 9 ± 0. 6 µmol kg-1 yr-1 at EOS) follow the atmospheric CO2 forcing, thus indicating the observed DIC increase is related to anthropogenic CO2 uptake. The increasing trends in TA (1. 2 ± 0. 3 µmol kg-1 yr-1 at BBMO and 1. 0 ± 0. 5 µmol kg-1 yr-1 at EOS) buffered the acidification rates, counteracting 60% and 72% of the pHTin situ decrease caused by increasing DIC at EOS and BBMO, respectively. Once accounted for the neutralizing effect of TA increase, the rapid sea surface warming plays a larger role in the observed pH decreases (43% at EOS and 62% at BBMO) than the DIC increase (36% at EOS and 33% at BBMO).
Ajuts:	Agencia Estatal de Investigación PID2021-122451OB-I00 Agencia Estatal de Investigación CEX2019-000928-S Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-00430
Nota:	Arturo Lucas present address: Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Mediterranean Sea ; Ocean acidification ; Ocean warming ; Seawater pH ; Time series ; Mediterranean Sea; ocean acidification; ocean warming; seawater pH; time series ; SDG 14 - Life Below Water
Publicat a:	Frontiers in marine science, Vol. 11 (Feb. 2024) , art. 1348133, ISSN 2296-7745

DOI: 10.3389/fmars.2024.1348133

12 p, 1.8 MB

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