BUSCADOR RECOLECTA

Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/200303

This dataset is composed of 2 files: a database (in csv format) with 695 records of biogeochemical variables (temperature, salinity, oxygen, nutrients, pH and total alkalinity) analyzed in water samples collected at the GIFT time series and a Readme (txt) file that includes a short description of the variables provided., If the dataset is used, please consider citing Flecha et al., (2019) (doi: 10.1038/s41598-019-52084-x)., This data set includes recently published data used to assess the temporal evolution of pH in Atlantic and Mediterranean water masses exchanging at the Strait of Gibraltar (Long:-5.345, Lat: 36.137, Datum:WSG84) during the decade 2005-2015 and to calculate the magnitude of natural and anthropogenic components on total pH changes (Flecha et al., 2019). The database provides measurements of carbon system parameters in water samples collected at 3 stations that form the marine time series GIFT during 26 oceanographic campaigns conducted over the decade 2005–2015. Geographic coordinates of sampling stations are provided. Some physical data (i.e. pressure, temperature and salinity) are also included. During the cruises, a temperature and salinity profile in each station was obtained with a Seabird 911 Plus CTD probe connected to a rosette sampler. Conductivity measurements were converted into practical values of the salinity scale with the UNESCO equation (1986). Seawater was subsequently collected for biogeochemical analysis using Niskin bottles immersed in the oceanographic rosette at variable depths (from 5 to 8 levels) depending on the instant position of the interface between the Atlantic and Mediterranean flows that was identified by CTD profiles. The biogeochemical variables shown in the database are pH in total scale at 25 °C (pHT25), total alkalinity (AT), Dissolved Oxygen (DO) and inorganic nutrients (nitrate, NO3− and Silicate, SiO44−). pHT25 data were obtained by the spectrophotometric method with m-cresol purple as indicator (Clayton & Byrne 1993) with an addition of 0.0047 (DelValls & Dickson, 1998). Samples were taken directly from the oceanographic bottles in 10 cm path-length optical glass cells and measurements were carried out with a Shimadzu UV-2401PC spectrophotometer containing a 25 °C-thermostated cells holder. Samples for AT analysis were collected in 500-ml borosilicate bottles, and poisoned with 100 μl of HgCl2-saturated aqueous solution and stored until measurement in the laboratory. AT was measured by potential titration according to Mintrop et al. (2000) with a Titroprocessor (model Metrohm 794). DO concentration was obtained through automated potentiometric modification of the original Winkler method using the Titroprocessor. Upon collection, flasks were sealed, stored in darkness and measured within 24 h. Water samples (5 mL, two replicates) for inorganic nutrients determination were taken, filtered immediately (Whatman GF/F, 0.7 μm) and stored frozen for later analyses in the shore-based laboratory. Nutrients concentrations were measured with a continuous flow auto-analyzer using standard colorimetric techniques (Hansen & Koroleff 1999). More details on procedures and data structure are given in a single README file (txt). The data are provided as [space] delimitated plain text files., Plan Estatal de I+D+i, European Commission, CSIC. CARBOOCEAN (FP6-511176), SESAME (FP6-036949), CARBOCHANGE (FP7-264879), PERSEUS (FP7-287600), COMFORT (H2020-820989), CTM2006-28141-E/MAR, CTM2016-75487-R., 1 data csv‘GIFT_carbonparameteres_2005_2015.csv’ file and 1 readme.txt file., Peer reviewed