CARBO-ACID Investigating the Potential Effects of Ocean Acidification on Marine Carbonate Organisms along the Iberian Margin Coastal Upwelling System: Coccolithophores, pteropods, planktonic and benthic foraminifera, and corals.

Citation from PI: In this cruise we will collect multi-samples from the water column, plankton, corals and sediments to evaluate, for the first time along the Iberian margin, the acidification effects into the entire water column for the pre / post-industrial transition.

Abstract & Main objectives: This cruise establishes the bases for the investigation of the potential effects of ocean acidification on carbonate marine organisms (coccolithophores, pteropods, planktonic and benthic foraminifera, and corals) along the Iberian margin. For that, we will collect oceanographic data and water, plankton, cold-water corals, and sediment samples during an upwelling season, along two transects coinciding with the two prominent upwelling filaments of the Iberia Margin: the Cape Finisterra and Estremadura Spur filaments. This study will focus on seawater pH trends in this seasonal coastal upwelling region during the pre- and post-industrial transition (centennial-to-decadal time resolution) and interglacial/ glacial climatic cycles. The expected results of this cruise will allow to compare variations at different time-scales and under different forcings (natural vs. anthropogenic), and to estimate the amplitude of future changes in the ocean in terms of CO2 biogeochemistry and biota response.

Preliminary Results: Specimens of Globigerina bulloides collected from surface sediments closer to the coast off NW Iberia, where upwelling influence is stronger, record lower Mg/Ca ratios than those collected further offshore, which could indicate dissolution in the sediment (Salgueiro et al. 2020).