Project Team: Coastal Texas Oceans Team
Team Location: Stennis Space Center, Stennis, Mississippi

This Landsat 8 OLI image from Feb. 18, 2014, shows Sargassum and boat wakes located in the Gulf of Mexico. The image to the left shows a calculated NIR/Red band ratio, whereas the image to the right is the LandsatLook ‰ÛÏNatural Color‰Û image that has been preprocessed by USGS.

Authors:
Shelby Barrett, Project Lead (William Carey University)
Emma Strong (University of Southern Mississippi)
Jeffrey Frazier (Texas A&M University at Galveston)
Brandon Hill (Texas A&M University at Galveston)
Kirsten Stokes (Texas A&M University at Galveston)

Mentors/Advisors
Joseph Spruce (Senior Research Scientist, Computer Sciences Corporation; Science Advisor)
Dr. Kenton Ross (NASA DEVELOP National Science Advisor)

Past/Other Contributors:
Brittany Arceneaux (University of New Orleans)
Mekdes Smith (University of Southern Mississippi)

Abstract:

Sargassum is a pelagic brown macroalgae that can be found floating in large, dense mats in the Gulf of Mexico. In open water, these Sargassum mats serve as a viable habitat to unique communities of marine organisms. However, when these large quantities of Sargassum land on Texas beaches, they pose a serious threat to the coastal economy. The decomposition of Sargassum and the organisms therein give rise to unattractive odors. Floating marine debris such as plastics, paper, medical and industrial waste also tend to accumulate within Sargassum mats. Furthermore, several Texas beaches have been anthropomorphically elongated, therefore Sargassum can no longer naturally migrate up and supplement the dune system. Because of this, coastal managers now have to rent and operate expensive machinery to move the Sargassum wracks off of the beach-fronts to the top of the dunes. The transference of these large mats is both costly and time consuming, especially if landings are unexpected. In 2012, scientists at Texas A&M University at Galveston began utilizing NASA Earth observations, specifically LandsatLook ‰ÛÏNatural Color‰Û images, to track Sargassum mats in the Gulf of Mexico as they approach the Texas Gulf Coast. Their Sargassum Early Advisory System (SEAS) notifies coastal managers of these Sargassum episodes so they can better prepare for proper cleanup efforts. In the Fall 2013 DEVELOP term, the Coastal Texas Oceans I team established methodologies for locating Sargassum using environmental monitoring indices in ArcMap10.2. This included calculating various indices on Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI) images such as Normalized Difference Vegetation Index (NDVI), Floating Algae Index (FAI), and a Near Infrared/Red band ratio. This continuing term of the project focuses on converting methodologies previously mentioned for use in the open-source GIS software, QGIS. Tutorials produced from this project were provided to the Sargassum Early Advisory System as a potential method for enhancing Sargassum visibility within a Landsat scene.

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