b'CHARACTERIZINGBefore he shifts his research to the stage of sampling and analyzing microbiota from the reef, Kapono is characterizing the flow of water and sediment throughout the water column. His tool is a SonTek CastAway-CTD, which measures conductivity, temperature, and depth at a rate of 5 Hz, then calculates salinity, sound speed, and other parameters. To take measurements of the water column, Kapono lets the CastAway sink to the reef and reels it back up on a polypropylene line. About the size of a soda can, the CastAway-CTD tags each cast with its GPS location at both the beginning and end of the measurement. So even while drifting rapidly in strong wave- and tide-induced currents, Kapono has been amassing a detailed, three-dimensional database of the movement of the freshwater lens that drifts over the denser saltwater of Hilo Bay during storms."The CTD provides me with the opportunity to visualize where the water is flowing," he says. DEEPER UNDERSTANDINGKapono\'s original hypothesis was that freshwater runoff reduced the salinity of the water that washed over the reef during storms. However, data from the CastAway revealed that the freshwater river discharge remained closer to the surface instead of sinking to the level of the reef. He noted that sediment was more likely to sink and contact the coral, so Kapono has pivoted his research focus to assessing sediment, not salinity, as the disturbance at the heart of his study.He credits data from the CastAway with helping him adjust his hypothesis and honehis research focus.Whos Minding the Planet? 13'