Influence of volcanic activity, namely carbon dioxide and ashes emissions, in phytoplankton (coccolithophores) communities from the macaronesia

Objectivo

The first purpose of this project is to demonstrate the possible effect of ash emissions from explosive Cape Verde volcanism on coccolithophore development. This will be performed in close cooperation with the German project “Quaternary explosive volcanism of the Cape Verde Archipelago: on- and offshore tephrostratigraphy”. This task will involve selecting and studying two gravity cores from a set of 28 cores already obtained by IFM-GEOMAR (Leibniz Institute für Meereswissenschaften, Kiel) during the RV METEOR M80/3 cruise, collected from the two most representative areas of Cape Verde volcanic history. This work will perform ultra high-resolution micropaleontological analysis of the coccolithophore assemblages immediately before, during and soon after the deposition of the ash layers. This task will allow recognizing which species were favored (if any) by these catastrophic phenomena, for which the deposition of the volcanic dusts may have acted as a fertilizer and/or a facilitator for the emergence of opportunistic behavior. On the contrary, species disclosing a negative response to these same catastrophic phenomena will indicate that volcanic dust may have directly inhibited their photosynthetic development or, indirectly, induced poisoning in the surrounding waters through specific chemical elements. This goal will be further subdivided in:
a) To determine if some of the volcanic explosive episodes may had induced inhibition of coccolithophore development by sunlight blocking due to airborne ash and which taxa did it influenced the most;
b) To find if metals (e.g. Fe, Mg, Mn) and increasing CO2 released by volcanic activity may have acted as ocean fertilizers/inhibitors and which taxa did they influenced the most;
c) To determine possible variations in size in coccoliths of possible affected species such as Coccolithus pelagicus and Calcidiscus leptoporus.

The second main goal of the present project involves the characterization of living coccolithophore community, and related environmental conditions, associated to Don João de Castro Bank, a large submarine volcano with an impressive fumarole field, located in the Azores halfway between Terceira and San Miguel islands.

The third main goal of the present project is to conduct a series of experimental tests in laboratorial conditions (single species batch cultures) to test the existence of coccolithophore preferential development in reaction to the introduction of different metal element concentrations and increasing carbon dioxide (environmental conditions driven from specific volcanic activity episodes that occurred in Azores and Cape Verde archipelagos). To investigate the existence of distinct tolerance limits to these variables, series of batch culture experiments will be conducted on specific coccolithphore species already isolated and available for experiments at the Center of Climate, Meteorology and Global Changes collection.