Funded by the ERC
Calcite can isotopically reequilibrate and exchange in calcite-saturated fluids, even at low temperatures (<100 °C) with no visible indicators of textural diagenesis. This exchange process challenges the premise that “unaltered” calcite is sufficiently chemically-robust to be used for palaeothermometry. This project will determine the rates, extents and controls of this exchange process at low temperatures in abiogenic and biogenic calcites.
With the aid of the NanoSIMS, this study aims to visualize the 3D architecture of fluid penetration and subsequent isotopic exchange on different biogenic carbonates to understand their (species-dependent) susceptibility to diagenesis.
This multidisciplinary project combines biomineralization, nanofabrication and NanoSIMS experiments to study paleoclimate-altering isotope exchange in abiotic calcite ultrastructure
Funded by internal funding
My research focuses on host-microbe interactions in complex cnidarian holobionts, such as reef-building corals and anemones. I am specifically interested in the roles of associated endosymbiotic bacteria and algae in holobiont acclimatization and ecological adaptation to rapid global environmental change.
Many of us feel that a dish is incomplete by the absence of that pinch of salt, but plants can easily do without it or are easily stressed by slightly elevated levels of it. Increasing salinity in soils therefore represents a major environmental stress factor for a wide variety of plants, and a growing threat to modern agriculture. In this project, we work with the model plant Arabidopsis thaliana to combine genetics, physiology and high-resolution spatial mapping to understand cellular-level responses to saline environment.
Funded by the SNSF
The Cassiopea sp jellyfish, like scleractinian corals, rely on nutrient input from their symbiotic and photosynthetic dinoflagellates to thrive. This symbiotic relationship in corals is much more sensitive to elevation of sea water temperature than in the upside-down jellyfish. Recently, an unbalance in the nutrient exchanges between the host and the symbiont under elevated temperature has been described in corals as a potential cause of bleaching. What are the metabolic underpinnings of this remarkable thermal resistance in Cassiopea?
A plethora of cnidarians, especially corals and anemones, forms a symbiotic relationship with photosynthesizing dinoflagellates of the family Symbiodiniaceae. At what spatial and temporal scale does translocation of photosynthates from symbiont to host take place in a homeostatic cnidarian holobiont system? A working hypothesis is that such translocation and transport of photosynthates within the host tissue can be highly directional and targeted to tissue regions with high metabolite demands. This project explores this by using a novel combination of microsensors with correlated electron microscopy and NanoSIMS isotopic labeling.
Coral bleaching is causing global reef degradation in times of climate change. However, the underlying causes of this collapse of the cnidarian-algal symbiosis remain unknown. Understanding the metabolic regulation of this symbiosis could hold the key to developing new strategies to predict and mitigate bleaching in the future.
Elevation of seawater temperatures is pushing most corals to their upper thermal limits. Their survival therefore depends on their ability to express the optimal phenotype given the local environment. The mechanisms underpinning phenotypic plasticity and thermal performance of corals remain poorly understood, especially over spatial and temporal scales, and may include genetic and non-genetic processes. Characterizing the phenotype of corals over such scales and identifying potential drivers will help better understand the role that plasticity might play in acclimatization or adaptation of reef organisms to environmental change.
Funded by the TRSC
Jonathan Paul Sauder
Unprecedented abundance of remote sensing data promises to enable monitoring ecosystems at global scale and high resolutions. The goal of this project is to develop novel machine learning methods to get a better understanding of how coral reef ecosystems change over time and assess the effects of climate change & human influences on reef ecosystems.