Data management in mobile ad-hoc ocean sensor networks

Establishing a fine-grained model of local ocean currents is important since currents carry nutrients and other substances, which affect ecosystems in coastal regions. For example, researchers are interested in establishing current models for the Gulf of Maine (US) since they distribute a specific type of algae to shellfish off the coast of Maine during the warm summer months; the shellfish consuming the algae turn toxic for humans (’red tide’ phenomenon)[1]. Today, major ocean currents are established using coastal radar; however, the information is spatially and temporally too coarse. We are investigating the alternative deployment of a fleet of inexpensive ocean drifters which are passively propelled by the current and report their GPS-based location and trajectories to the end user. Today, large-scale sensing platforms such as stationary moorings, research vessels, costal radar (CODAR) or large gliders are state of the art in ocean monitoring. In the future, they will be combined with new technology developments such as small-scale, inexpensive drifters and/or autonomous underwater vehicles (AUVs) such as gliders [2]. A drifter is a small computing platform the size of a basketball which floats on the ocean surface, usually equipped with a long underwater peddle which moves the sensor as the ocean current moves (instead of the wind). Sensor boards can be attached to detect phenomena such as oil spills or marine microorganisms [3]. In contrast to drifters, AUVs are self-propelled and determine their movement direction and travel speed in a