Around 2011, residents, tourists, and researchers began noticing unprecedented amounts of sargassum seaweed on and offshore of the southern U.S. coasts and Caribbean islands. Sargassum quickly began to disrupt fishing, tourism, nearshore ecosystems, and even caused health problems for populations exposed to rotting sargassum seaweed. Sargassum arrives on shore mixed with plastic trash and can be difficult and costly to clean up. An estimated 5-13 million tons of plastic enters the ocean each year, and sargassum blooms are estimated at over 20 million tons each year. While there have been increased efforts to track, collect, and create valuable products out of sargassum, research and development has vastly ignored the connection between sargassum and ocean plastics. This IRES project investigates plastic-sargassum interactions in the ocean and develops valuable products from sargassum-plastic pollution, such as concrete and composite lumber, for the building and construction industry. Simultaneously, this project trains U.S. students in innovation and international collaborations through mentored research experiences in the Dominican Republic. This research progresses through three of the most prominent challenges in creating valuable products from sargassum-plastic pollution: tracking, collection, and product development. One of the main challenges facing management of sargassum is tracking seasonal flows: when will the seaweed blooms reach shore, where will they arrive,