Discipline: Biological Sciences
Subcategory: Geosciences and Earth Sciences
Michael Mateo - New York City College of Technology
Co-Author(s): Andrea Gomez and Kyle McDonald, City College of New York, New York, NY Caitlin Tsang, Baccalaureate School for Global Education, Astoria, NY Samantha Verdugo, City College Academy Arts M.293, New York, NY Alexandra Seemungal, Cardinal Spellman High School, Bronx, NY
The purpose of this project is to further study the viability of satellites as an assessment tool in the monitoring and classification of coral reefs and coral bleaching by evaluating the relationship between coral health and coral’s reflectance signature. Recent research by Downs et al. 2015, demonstrated that the chemical oxybenzone, which is commonly found in sunscreens, can actually lead to increased rates of coral bleaching in planulae. Building off their research, a controlled laboratory based experiment was performed using the Caribbean coral species Porites furcata. The experimental group was subjected to stress from a 200 ppm solution containing the chemical oxybenzone. The experiment was conducted for 5 days, and the reflectance measurements of the corals were taken each day around 1:30 p.m. In addition to the experiment, data from the satellite Landsat 8 was downloaded from the USGS Earth Explorer, and processed using the GRASS GIS application. A k-means unsupervised classification was performed on the coral reefs surrounding Heron Island, Australia, with the corals being classified by information pertaining to their reflectance. The hypothesis is that the reflectance signature of the experimental group will increase as it bleaches due to stress from the chemical oxybenzone, due to the fact that the coral’s skeleton will become more exposed. This research can eventually establish whether or not satellite monitoring can be an appropriate monitoring tool to asses coral bleaching. The results from the experiment demonstrated that as the corals bleached, the reflectance signatures decreased. The reason for this is that as the coral’s health deteriorated, algae built up on the coral’s surface, thus causing the reflectance signature to decrease. Therefore, the experiment showed that coral health and reflectance signatures may have an inverse relationship. Because satellites can be used to monitor reflectance signatures, then it is possible that they could be used to monitor coral reefs. However, Landsat 8’s 30 meter pixel size and small number of bands proved to be insufficient in classifying corals around Heron Island, which shows that a relative miniscule pixel size and a greater number of bands would be required to effectively monitor coral reef health and bleaching.
Funder Acknowledgement(s): NSF CREST REU
Faculty Advisor: Andrea Gomez, firstname.lastname@example.org
Role: The experiment and unsupervised classification using grass gis.