Monitoring Carbonate Production and Degradation (Azores, Portugal)

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Studies on the various facies of the widespread cool-water carbonate factory in the N-Atlantic are far advanced, however, quantitative data on growth and degradation rates are almost lacking. This project focuses on the warm-temperate Azores Archipelago because of its remote location far from land, its poorly studied carbonate environment and because of the easy accessibility to a manned submersible at the island Faial. By covering a wide environmental gradient with respect to light regime and different water-mass properties along bathymetric transect (0-500m), we intend to carry out budgeting of carbonate-accretion and bioerosion rates with an experimental approach. Complementing, we aim for a detailed stable isotope analysis (¿ 18O and ¿ 13C) of selected long- living epibenthos (stylasterids, scleractinian corals and giant oysters) for growth-rate analyses and for the detection of subtle climate variability (e.g., NAO) in this area. The experiment comprises quantitative and qualitative monitoring of carbonate production and degradation as well as the recording of in situ environmental data (temperature, salinity and photosynthetically active radiation along with depth). The anticipated results are expected to yield (1) warm-temperate carbonateproduction and bioerosion rates, (2) enhanced insight in the suitability of stable isotopes for growth rate studies and high-resolution climate variability analyses, (3) knowledge on the bathymetric as well as biogeographic distribution of bioeroding and carbonate-accreting agents and (4) new insights in the relative contribution of boring organisms versus grazers on different substrate orientations to the process of bioerosion.