Tyler Harman defends thesis on coral resistance to thermal stress and disease

Tyler Harman defends thesis on coral resistance to thermal stress and disease

On August 28, 2020, graduate student Tyler Harman successfully defended his Master’s thesis, titled “Analysis of seasonal changes in thermal stress resilience and innate immunity in the temperate coral, Astrangia poculata (Ellis & Solander 1786), from future climate impacts.” His thesis committee consisted of Drs. Kevin B. Strychar, Daniel Barshis, Sarah E. Hamsher, and Briana Hauff-Salas.

This thesis research aimed at discovering how the temperate coral, Astrangia poculata, reacted to simulated future climatic stressors. This coral species lives up and down the east coast and is a facultative coral, meaning that these corals can live with and without symbiotic algae. These Astrangia colonies were collected from Narragansett Bay, RI and were subjected to two different experiments.

The first used an elevated temperature to simulate “end of the century” ocean temperatures. This study measured algal density and photosynthetic efficiency to detect bleaching in corals, along with using imaging flow cytometry to detect concentrations in reactive oxygen species (ROS), which are a toxic byproduct of photosynthetic dystopia when subjected to high temperatures. Tyler found there were generally no changes in measurements across treatments, making this coral resilient to these elevated temperatures in the near future.

The second experiment subjected corals to a disease exposure simulation using lipopolysaccharides (LPS) which trigger immunological responses in marine invertebrates. Tyler looked at the melanin-synthesis pathway which is considered an important baseline immunity pathway in coral organisms, and how concentrations of signal proteins changed when exposed to different temperatures. He found that symbiotic state primarily drove changes in these immunity components. However, this is the first instance of immunity research in this coral, and many more immunity pathways need to be researched in order to fully understand this species immunity responses.

Tyler continues his work with Dr. Strychar and other colleagues on publishing multiple research papers regarding coral photo-physiology and disease. In addition, he is applying PhD programs for Fall 2021 to continue studying coral biology.

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Page last modified September 15, 2020