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lasting up to six months. For these re- cent missions the glider, diving to less than 100 meters at a 19-degree angle of attack, covered approximately 20 kilometers per day. A pumped CTD sensor is standard to combat the biofouling that is typi- cal in shallow-water environments, especially during long deployments. Optional sensors include turbidity, dissolved oxygen, fluorometer, photo- synthetically active radiation, acoustic Doppler current profiler and altimeter. For the purpose of phytoplankton dis- tribution and water quality measure- ments at these mesophotic reefs, the Spray Glider was outfitted with Turner Designs (Sunnyvale, California) C7 sensors to measure chlorophyll-a fluo- rescence and optical scattering, and a pumped Sea-Bird Electronics Inc. (Bel- levue, Washington) CTD. The FLOSEE II glider missions took place at Pulley Ridge, a shelf-edge mesophotic coral reef on the southern edge of the west Florida shelf, which is more than 60 meters below the surface. Mesophotic reefs, the deep- est coral communities that depend on sunlight for survival, are not particu- larly well studied, as they tend to be beyond the maximum scuba depths of 30 to 40 meters. Pulley Ridge is char- acterized as hard, flat, gently sloping bottom with rock rubble and cobble. Live coral cover had previously been reported at up to 60 percent in some areas. Macroalgae, sponges and sedi- ment also occupy the benthos, which is shared by shallow- and deepwater fish species and is considered an im- portant breeding habitat. The Loop Current brings clear, warm water to Pulley Ridge, which is also within a thermocline that provides nutrients during upwelling. Considered in the context of sudden or persistent environmental change, Pulley Ridge reef communities that survive on 1 to 2 percent of available surface light are therefore very vulner- able to persistent elevations in turbid- ity, which result in reduced available light and benthic productivity. Further- more, persistent temperature maxima have been associated with bleaching events affecting hard and soft corals and sponges. Corals are also suscep- tible to persistent salinity depressions, which can result from proximity to the Loop Current and possibly heavy rains or hurricanes. Surprisingly little data exists on the seasonal dynamics www.sea-technology.com SEPTEMBER 2012 / st 41 of phytoplankton populations and envi- ronmental correlates at shelf-edge reef environments. The capabilities of the Spray Glider en- able data collection that can help answer some of these scientific questions. Under- standing the temporal and spatial patterns of temperature, salinity, chlorophyll-a and turbidity provides insight into ecologically significant fluctuations associated with coral-reef function and health. Similarly, characterizing the large- scale distribution of phytoplankton con- centrations above the reefs and in sur- rounding waters provides a marker of system health. Two missions have been conducted at Pulley Ridge with the Spray Glider. The first deployment was launched dur- ing FLOSEE II in September 2011, with recovery in November after more than 3,200 dives between 50 and 80 meters water depth. The Spray Glider was also deployed off Naples, Florida, bound for Pulley Ridge, approximately 130 nauti- cal miles away, in February 2012, per- forming almost 2,000 dives down to 90 meters off the western edge of the ridge.