Influence of volcanic ash on growth and morphology of coccolithophore algae
Changes in coccolithophore productivity and coccolith numbers or sizes as a reaction to increased metal concentrations, could influence sinking rates and CO2 uptake and could therefore alter the efficiency of organic carbon export to deep waters. For example, if volcanic material acts as a fertilizer in open ocean waters, it might stimulate phytoplankton growth, increasing the flux of CO2 between the atmosphere and the surface ocean organic pool, and result in significant carbon sequestration.
To clarify the potential impacts of volcanic ash on coccolithophores, we performed culturing experiments with two coccolithophore strains and different volcanic ashes at a range of concentrations. Here we present results from these experiments, showing the release of an array of metals from the volcanic ashes in Antarctic seawater and the physiological (growth, Fv/Fm) and morphological responses of both coccolithophore strains (SEM).
Finally, from a broader perspective, we compare our results with paleo-data to increase the applicability of calcareous nannofossils (coccolithophore remains) as proxies for trace metal concentrations. In particular, the modeling of nannoplankton species-specific reactions/adaptations to excess volcanic trace metal released during different geological episodes is expected to open new scenarios on the characterization of critical past events.
 Hoffmann, L. J., et al. (2012).
 Schulz, K. G., et al. (2004).