OEST 740 Marine Biofilms: Ecology and Impact Spring 2008 Instructor:

Biocorrosion This chapter considers the issue of biofilm based bacterial assisted corrosion (i.e. biocorrosion) of metals submerged in the marine environment. Through water channels within the biofilm, the thriving bacterial colony is able to absorb nutrients and oxygen from the water. However, as growth continues and the depth of the slime layer increases, there is little penetration of oxygen in the layers against the pipe or vessel surface. Anaerobic bacteria can propagate in the deeper layers of the biofilm where little oxygen reaches. Some of these anaerobes are capable of metabolizing carbon from stainless steel, and some produce nitric, sulfuric, or other organic acids that further accelerate corrosion. The depletion of oxygen in the wetted surfaces under bacterial colonies can result in the formation of "differential aeration cells" that can lead to galvanic corrosion. For information on the course can be found at the following website: http://www2.hawaii.edu/~mcooney/oest740/.