Kelsey is originally from the US, and received her Bachelor's from Cornell University in 2015. She earned a MPhil at the University of Adelaide in 2019, studying the effects of tropicalization on the trophic niches of fishes. Kelsey has worked as a field researcher at Scripps Institution of Oceanography where she tracked coastal cliff erosion. She has held various positions in the field including researching humpback whale songs, seagrass wasting disease, sea star wasting disease, and fish biology, and is working towards a PhD on the role of heterotrophy in post-bleaching coral resilience. She now lives in Townsville with her little yellow sailboat.

The role of heterotrophy in post-bleaching coral resilience

2024 to 2028

Project Description

Kelsey is investigating how heterotrophy (cf. autotrophy) may contribute to the energetics and resilience of reef-building corals, especially during severe marine heatwaves that cause mass coral bleaching. More specifically, she will investigate the role that heterotrophy plays in explaining spatial and taxonomic variation in bleaching susceptibility, testing whether heterotrophic feeding provides necessary energetic subsidies to allow some corals to withstand major bleaching. This thesis aims to answer the following questions:
• Does spatial variation affect post-bleaching susceptibility?
• How does heterotrophic food availability influence trophic flexibility?
• How does trophic flexibility vary inter- and intra-specifically?
• What factors influence a more highly heterotrophic diet?
• What are the limits of heterotrophy in prolonging coral survivorship?

Project Importance

This research will improve our understanding of differential bleaching susceptibility and resilience, as well as the limits of heterotrophy, which are necessary to understanding how ongoing environmental change will shape future coral assemblages.

Project Methods

Methods include a combination of field work, laboratory work, remote sensing, and statistical data analysis and modelling. More specifically, corals will be tagged via SCUBA on the outer GBR, and monitored throughout a coral bleaching event. Monitoring includes the collection of coral tissue for stable isotope analysis, Symbiodiniaceae density, and chlorophyll-a density, the collection of water samples for chlorophyll-a and Symbiodiniaceae densities, and in-water assessment of coral colour (using CoralWatch colour indices score cards), and water temperature. Laboratory work will be much the same, but will also include zooplankton counts to see how many zooplankton the corals fed upon. Temperatures will be increased to simulate a heating event, and heterotrophic food will be systematically withheld and provided, depending on the treatment. Remote sensing has been used to look at water temperature and chlorophyll-a of the GBR, and these values are being compared to in-water coral bleaching and mortality surveys that have already been conducted. Statistical data analysis and modelling has already begun, and will be used throughout the thesis.

Project Results

Results to date include having found a statistical correlation between regions of higher chlorophyll-a concentrations and lower coral mortality, throughout the GBR. These findings are included in a manuscript that is currently being written.

Keywords

Climate change,
Coral reefs,
Corals,
Ecology,
Field based,
Ocean warming,
Quantitative marine science,
Remote Sensing,
Temporal change