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www.sea-technology.com October 2015 / st 11 hazardous coastal conditions. Options of interest include measuring the complete set of aids to navigation (AtoN) pa- rameters, such as tide, current, real-time waves, swell, sea state, visibility, wind gust and other meteorological condi- tions, and the capability to broadcast data on the AIS AtoN network, which is ftted on all passenger vessels and cargo ships. Coastal monitoring buoys can also be tailored specif- cally for oil-slick monitoring by integrating an early-warning system for oil-slick hazards or illegal ship water ballast dis- charges. Applications include monitoring and protecting intakes for desalination or other water supply system func- tions, or as an early-warning system to assist port security and response activities. These platforms can also detect a wide range of hydrocarbons using independent detection techniques. A third confguration is suitable for inland lakes and wa- terways extending into estuarine environments, involving smaller, more compact buoys. As with the larger buoys, they are designed for long-term environmental monitoring and resource management, as well as short-term event monitor- ing, such as river, port or harbor extensions or upgrades, ship-loading activities, water sporting events and seasonal climatic impacts. Sampling Methods Among these standard platform confgurations, there is a primary distinction that is defned by the method by which they sample. Historically, the prevailing system was an open-water technique in which the sensors were installed below the buoy, in situ. But rapid fouling from algae, coral and barnacles tend to be prob- lematic for this type of sensor deployment, and in their current state there is no effective way to prevent against this biofouling due to constant exposure to natu- ral elements. In contrast, a fow-through sampling method uses a pump- ing system that draws water up into the buoy and through vari- ous sensors housed inside the buoy, completely dry and out of the elements. Measurements are taken and instruments are drained between measurements which prevents biofouling from taking place by eliminating mois- ture and light as detrimental fac- tors. This technique also makes multidepth sampling simpler and less expensive; whereas an open- water system would require three (Top) Clean pump intakes in the fow-through sampling system for Project Neptune. (Bottom) Comparison of data collected using open-water (in-situ) vs. fow-through systems.