Researchers Track Currents with Drifters and Dye

September 1, 2015

Researchers release red dye into the Altamaha River to study currents. Photo courtesy of Gray’s Reef National Marine Sanctuary.

Researchers from the James H. Oliver, Jr., Institute for Coastal Plain Science (ICPS) at Georgia Southern teamed up with Gray’s Reef National Marine Sanctuary on Tuesday, Sept. 1, to release 50 gallons of a non-toxic red dye into the Altamaha River near Darien, Georgia, to study how the River’s outflow affects hard bottom reefs offshore.

The resulting plume of dye will be monitored visually and with instrumentation as the dye flows from the release point along the Georgia coast and offshore. Tracking the path of the dye (rhodamine WT) will provide estimates of how the Altamaha River outflow delivers dissolved contaminants, nutrients and fresh water along the Georgia coast to hard bottom reefs, such as Gray’s Reef, found approximately 20 miles offshore.

In addition to the dye release, the investigators will deploy two GPS satellite-enabled current drifters that will provide information on how larger materials, such as dead stalks of marsh grass, may disperse after being transported from the Altamaha River estuary.

These drifters are constructed from basic materials found in local hardware stores, and the GPS satellite transmitter tracking and mapping is coordinated through NOAA’s Fisheries Science Center.

Georgia Southern University researchers and Gray’s Reef staff have, in past years, conducted drifter-building workshops with educators to develop ocean current and watershed studies into classroom lesson plans.