Document Type

Paper- Restricted to Campus Access

Publication Date


Faculty Mentor

Kate Goddard


Coral reefs are the most diverse marine ecosystem, they are home to thousands of species. The climate change effects of increasing sea surface temperatures (SST) and decreased salinity from increased storm frequency and strength threaten about 70% of all coral reefs. With this in mind, we investigated the effects of increased temperature and decreased salinity on Astrangia poctulata, a temperate coral as a model organism. A. poctulata possesses algae inside its cells that provide energy (“zooxanthellae); loss of the algae is “bleaching” – a strong indicator of coral stress. Coral samples were obtained from Florida (FL) and Massachusetts (MA) the extremes of the range of this species. Corals were acclimated to 35 ppt and 19˚C, then three experiments were performed: increasing temperature, decreasing salinity, and combined increased temperature and salinity drop, all over 8 days. Pictures of each colony were taken every 48h to observe changes in color due to bleaching. Photoshop was used in a blind test by observers to identify the average color of the polyps in each colony. Results showed an increase in zooxanthellae released into the water column and coral bleaching after temperature increase and temperature increase combined with decrease in salinity. Salinity alone had little effect.


Presented as part of the Ursinus College Celebration of Student Achievement (CoSA) held April 22, 2021.

The downloadable file is a poster presentation with audio commentary.


Available to Ursinus community only.