Volcanic vent activity and skeletal chemistry – Chemical imprint of environmental conditions on the calcified skeletons of corals and coralline red algae (Sebastian Flöter)

My research interests include the study of calcifying organisms as recorders of environmental signals. Currently, I am primarily focussing on corals and CCA and their potential to record hydrothermal activity. Volcanic and hydrothermal activity can significantly impact climatic and biogeochemical cycles over a range of temporal and spatial scales. One example of this activity includes shallow submarine volcanic CO2 vent sites, which are frequently used to investigate the effects of ocean acidification on calcifying marine organisms, such as crustose coralline red algae (CCA) and corals. To investigate the influence of CO2 vent site activity on CCA biomineralisation, I investigate samples collected off Ischia (Italy), Vulcano (Italy), Gran Canaria (Spain), and Shikine Island (Japan). The methods I am applying for this investigation include e.g. laser ablation ICPMS, electron microprobe analysis, and confocal Raman microscopy. Collaborators in that project are Nuria Texido (Stazione Zoologica Anton Dohrn, Ischia Marine Centre, Italy) and Steeve Comeau (Sorbonne Université, CNRS, Laboratoire d’Océanographie de Villefranche, France), José Carlos Hernández (Universidad de La Laguna, Spain), Juan Pablo D’Olivo Cordero (FU Berlin, Germany), Chris Cornwall (Victoria University of Wellington, New Zealand), Ben Harvey and Sylvain Agostini (University of Tsukuba, Japan).

Experimental assessment of the impact of volcanic ash on coral reef physiology, growth and skeletal composition (Frank Förster)

The interaction between volcanic ash and the ecosystem coral reef has not been thoroughly investigated yet. My PhD project investigates the complex relationship between ash leaching and elemental incorporation on the holobiont coral in an laboratory environment.For this, biogenic experiments on living corals are carried out at the Centre Scientifique de Monaco, while simultaneously assessing physiological parameters and growth rate. Furthermore, my project aims to understand how and if volcanic geochemistry can be incorporated in the skeleton of the coral, utilizing mass spectrometry. Results of my research should help to understand geochemical signals in field-based experiments and if volcanic activity can be archived in corals.

Investigating the effects of volcanic ash from the April 2021 eruption of La Sourfrière St. Vincent (James Vincent)

PhD Student : James Vincent

Explosive volcanic eruptions are capable of depositing large quantities of nutrient-rich ash over sizable areas of the ocean. Ash particles are known to rapidly leach high concentrations of major, minor and trace elements in water, although the influence of this process on corals is poorly studied. Chemical proxies in the skeleton of tropical reef-building corals have been widely used to reconstruct oceanic parameters, such as sea surface temperature, salinity, light intensity, pH, sedimentation and seawater composition. Seeing as though many of these parameters are affected by ash deposition, we hypothesise that the effects of volcanic ash leaching can leave a geochemical imprint on the chemical composition of the coral skeleton. To test this hypothesis, we are measuring LA-ICP-MS profiles on coral core samples taken from the northwest fringing reefs of Barbados, Lesser Antilles. Massive colonies of Diploria strigosa and Siderastrea siderea were cored 15 months following the April 2021 eruption of La Soufrière, St. Vincent (192 km east of Barbados), which deosited volcanic ash on Barbados. Each core sample is approximately 6cm in depth, and thus represents skeletal aragonite precipitated before, during and after the eruption. Our results may provide crucial information regarding distinguishing volcanic eruptions in coral archives.

The leaching potential of proximal and distal ash deposits upon interaction with sea-water (Isabelle Beney)

This masters project focusses on the leaching potential of proximal and distal ash deposits upon interaction with sea-water. The project is driven by the clear window for further research in this field - principally volcanic ash leaching in a sea-water solute over a mid-term time period (e.g.: one month), and with high initial experimental resolution. The main goal of this project is two-fold: 1. to investigate the chemical evolution of a sea-water solute over time, following different durations of agitation in combination with volcanic ash, and, 2. to investigate changes in the morphology of the volcanic ash following leaching - e.g.: changes to particle size and shape. This is to allow comparison of the ash morphology pre-leaching, with that post-leaching.