Sampling Red Tide (image) Georgia Institute of Technology Caption Kelsey Poulson-Ellestad, a former graduate student at the Georgia Institute of Technology, now at Woods Hole Oceanographic Institution, works with a Conductivity, temperature and depth (CTD) sampling rosette, which is lowered over the side of a vessel and is used to collect water samples from various depths. Credit Kelsey Poulson-Ellestad. Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.