The constant growth of sea life within a cooling system can cost even small vessels a significant amount.  Mollusks, algae, slime and weed constrict the flow of cooling water to the heat exchanger surface.  They also hasten localized corrosion by restricting oxygen diffusion, and cause destructive turbulence at inlets, which can severely shorten the life of the equipment affected.  This results in over-heated diesel engines and reduced rpm, reduced air conditioning capacity and irate passengers, inadequate refrigeration and spoiled cargo, loss of steam condenser vacuum and increased fuel consumption.