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homogenized waters into contact with warmer, less saline, stratified waters. The steep density gradients that commonly form at the interface of upwelled and stratified waters, called the upwelling front, are thought to concentrate and transport a variety of plankton. Upwelling fronts are postulated to play a role in local retention of larvae from broadcast spawning organisms and have been correlated with recruitment peri- ods for ecologically and economically important fish and invertebrate species. From March to June 2009, the Dorado collected water samples from upwelling-stratified water interfaces while sampling at preprogrammed waypoints in Monterey Bay. Bi- ological results from these upwelling front samples included elevated molecular signals for calanoid copepods and pro- vided impetus for the development of upwelling front detec- tion and sampling software for the AUV. As a result, the Do- rado can now autonomously identify and sample three water types within upwelling environments: newly upwelled water in the core of an upwelling filament, the upwelling front and the stratified water beyond the upwelling front. Precise sam- pling of the anatomy of upwelling frontal environments is enabling examination of the complex relationships between environmental processes and plankton diversity and abun- dance. (Top) A graphical depiction of the AUV Dorado chlorophyll peak capture algorithm. (Bottom) The AUV Dorado ran the chlorophyll peak capture al- gorithm in a thin-phytoplankton-layer survey in October 2010. Seven Gulpers were triggered at chlorophyll fluorescence peaks (i.e., red triangles), and two Gulpers were triggered at lower-than-average fluorescence (i.e., black circles). Upwelling Fronts Wind-driven Ekman transport of coastal surface layers re- sults in upwelling, bringing colder, nutrient-rich, vertically Robotic Cooperation Using multiple intelligent AUVs can enhance the preci- sion of observational targeting. Designed for long-endurance missions, the Tethys AUV has led cooperative multi-AUV operations that include the Dorado. The Tethys' persistence and algorithms permit localization and tracking of targeted phenomena within a complex and rapidly changing envi- ronment. Following the Tethys' lead, the Dorado can direct more extensive sensing and sampling capabilities to the localized target. This robotic teamwork has been applied to track bio- logical patches containing toxic phytoplankton populations, as well physical and biological processes in fronts, e.g., phy- toplankton bloom tracking and sampling conducted in Oc- tober 2010, and upwelling front tracking and sampling in June 2011, both conducted in Monterey Bay. "The New Glider on the Block" • Operates in high coastal currents • Handles large variations in water densities • Operates up to 60 days with a lithium battery • Easily integrates additional sensors Exocetus Development LLC 1444 East 9th Avenue Anchorage, AK 99501 USA tel. 907-227-8073 | sales@exocetus.com | www.exocetus.com www.sea-technology.com SEPTEMBER 2012 / st 53