SUBTIDAL AND INTERTIDAL MARINE FOULING ON 



ARTIFICIAL SUBSTRATA IN 



NORTHERN PUGET SOUND, WASHINGTON^ 



Charles H. Hanson^ and Jonathan Bell=* 



ABSTRACT 



The design and siting of power plant cooling systems requires detailed information concerning the 

 fouling tendencies of specific organisms on specific construction materials. This study, conducted in the 

 vicinity of Kiket Island, northern Paget Soimd, Wash., attempts to provide some of this information. 

 The sessile community characteristics of five materials exposed at three depths and two locations in 

 the subtidal zone, and of one material in the intertidal zone are described. The degree of biofouling was 

 least for copper-nickel alloy and progressively greater for Plexiglas, wood, steel, and concrete. Media 

 decay and biological accumulation was greatest at the near-surface level, decreasing in intensity with 

 increasing depth. The maximum rate of colonization occurred during the late spring (April-June) and 

 early fall (mid- August-October). The present study, an analysis of biofouling, indicates that if the 

 proposed power plant were to be built at Kiket Island, its cooling system intake should be sited in water 

 deeper than 6 m and should have a safe and adequate fouling control scheme. 



The settlement of entrained fouling organisms 

 seriously affects the proper functioning of indus- 

 trial cooling systems (Dobson 1946; Beauchamp 

 1966; Holmes 1970). Thus, the design of a cooling 

 system requires detailed information concerning 

 the fouling tendencies of specific organisms on 

 specific construction materials. The present study 

 — conducted in the vicinity of Kiket Island, north- 

 ern Puget Sound, Wash. — attempts to provide 

 some of this information. At the time, the study 

 area was the proposed site for a 1,000 MW nuclear 

 power plant with a once-through cooling system. 



The study analyzed the fouling resistances of 

 several common construction materials both in 

 the subtidal and in the intertidal zones. Coloniza- 

 tion in the subtidal zone was examined from April 

 to November 1972, while colonization in the inter- 

 tidal zone was examined from December 1971 to 

 September 1972. Short-term (series I) and long- 

 term (series II) exposures of test materials pro- 

 vided information about the rate of fouling ac- 

 cumulations and progressive community change. 

 The study also determined the seasonal and verti- 

 cal distribution of the dominant fouling organisms 

 endemic to the Kiket Island area. These exposures 



'Contribution No. 433 from the College of Fisheries, Univer- 

 sity of Washington, Seattle, WA 98195. 



^Fisheries Research Institute, University of Washington, 

 Seattle, WA 98195; present address; Department of Animal 

 Physiology, University of California-Davis, Davis, CA 95616. 



^Johns Hopkins University, Baltimore, MD 21218. 



also allowed a determination of the periods of 

 maximum colonization by fouling organisms. 



MATERIALS AND METHODS 

 Subtidal Fouling 



Two test sites for the study of subtidal fouling 

 were established offshore from Kiket and Skagit 

 islands (Figure 1), in water of a mean depth of 18 

 m. At each test site five construction materials 

 were tested for their resistances to fouling. The 

 materials that were tested included a 90% 

 copper-10% nickel alloy, steel, Plexiglas'' (an ac- 

 rylic plastic), white pine wood, and concrete. The 

 materials were cut into 10 cm x 10 cm squares — 

 54 squares each of steel, Plexiglas, and wood; 18 

 squares each of copper-nickel alloy and concrete. 

 The squares or "plates" had two 12.7-mm holes 

 drilled into opposite corners of the plate. Rope was 

 threaded through the holes and the plates were 

 then separated into 18 "test panels"— each panel 

 having three plates of steel, Plexiglas, and wood, 

 and one plate of copper-nickel alloy and concrete. 

 Within each panel there was a random distribu- 

 tion of plates. 



The test panels were suspended in the water at 

 mean depths of 1, 6.1, and 15.3 m below the sur- 



Manuscripf accepted December 1975. 

 FISHERY BULLETIN; VOL. 74, NO. 2, 1976. 



"Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



377 



*^ 



