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Barbeau, K, Moffett JW.  2000.  Laboratory and field studies of colloidal iron oxide dissolution as mediated by phagotrophy and photolysis. Limnology and Oceanography. 45:827-835. AbstractWebsite

In a previous work, we have employed colloidal ferrihydrite impregnated with an inert radiotracer to probe the mechanistics of iron redox cycling in seawater via phagotrophic and photochemical processes. This paper reports further studies using the inert tracer technique, directed towards obtaining a more quantitative sense of the importance of phagotrophy relative to photolysis as a pathway for the production of bioavailable iron in oxygenated seawater. Our results indicate a maximal (i.e., near-surface at noon) rate of 12% per day for the photochemically-mediated dissolution of colloidal ferrihydrite. Protozoan-mediated dissolution of the same iron oxide phase proceeds at a rate ranging from 1-6% per day, depending on grazing turnover rates. Thus, while photolysis should dominate the redox cycling of refractory iron solids in near-surface waters under bright daytime conditions, phagotrophy is likely to be a more important process overall when the entire euphotic zone is considered on a time-averaged basis.

Earley, PJ, Swope BL, Barbeau K, Bundy R, McDonald JA, Rivera-Duarte I.  2014.  Life cycle contributions of copper from vessel painting and maintenance activities. Biofouling. 30:51-68.   10.1080/08927014.2013.841891   AbstractWebsite

Copper-based epoxy and ablative antifouling painted panels were exposed in natural seawater to evaluate environmental loading parameters. In situ loading factors including initial exposure, passive leaching, and surface refreshment were measured utilizing two protocols developed by the US Navy: the dome method and the in-water hull cleaning sampling method. Cleaning techniques investigated included a soft-pile carpet and a medium duty 3M((TM)) pad for fouling removal. Results show that the passive leach rates of copper peaked three days after both initial deployment and cleaning events (CEs), followed by a rapid decrease over about 15days and a slow approach to asymptotic levels on approximately day 30. Additionally, copper was more bioavailable during a CE in comparison to the passive leaching that immediately followed. A paint life cycle model quantifying annual copper loading estimates for each paint and cleaning method based on a three-year cycle of painting, episodic cleaning, and passive leaching is presented.