Interstitial Porewater Release

We labelled play sand with Fluorescein in artificial seawater until the sand was uniformly damp. After placing a 2.5-3cm layer of this sand in an 8-liter bucket we capped it with 1-1.5 cm of unlabelled sand (wet with artificial seawater). The bucket was then filled gently with artificial seawater, and a single Cassiopea jellyfish was placed on the sand in the center of the buckets. Samples of interstitial porewater and the water column were taken at the start of the experiment, and water column samples were taken again at 2 and 3 hours after the start of the experiment. These samples were analyzed for absorbance at 494nm to measure fluorescein concentrations and the rate of interstitial porewater release was calculated.