A nondestructive inventory to determine species diversity and density that have colonized artificial substrates in Kachemak Bay was conducted during the University of Alaska Fairbanks Advanced Scientific Diving class in March 2005. Researchers, diving during daylight hours, employed a point-count sampling method using 25-centimeter quadrats; these measuring tools are constructed of 1-inch diameter PVC (polyvinyl chloride) frame with fishing line strung to create an internal grid. At the points where the lines cross, counts and identifications of all encrusting organisms were recorded. A total of 10 quadrat surveys at a depth of 20 feet were made at each of the three sites studied Ñ Jakolof Bay pilings, Kasistna Bay pilings and a submerged boat near the Kasitsna Bay Laboratory.
Species diversity and density was greatest at the Jakolof Bay dock, a wooden-planked deck with wood pilings. Due to submergance for multiple decades, the colonization of available space by encrusting organisms was nearly complete for all surfaces. Anemones and barnacles dominated the surface of the pilings, with sponges and kelp also found here. This habitat hosted a few mobile organisms such as nudibranchs, sea stars and juvenile sculpins. Data collected at the sunken boat Ñ a small wood-frame watercraft submerged in March 2004 Ñ yielded a limited diversity and density of organisms. Here, barnacles covered the majority of the boat's surface that was void of anti-fouling paint. Nudibranchs and their egg sacs were present on the southern side of the boat, and large sunflower stars (Pycnopodia helianthoides) were common on the north side. The new steel pier at Kasitsna Bay Laboratory, completed in February 2005, had a minimal presence of fouling communities; a small algal patch was found growing on the southwest corner of the floating deck.
These surveys indicate that the longer an artificial environment is submerged, the higher the diversity and abundance of encrusting organisms are that colonizes it. This pattern supports the eventual development of a more complex fouling community, through ecosystem succession, that ultimately attracts bottom-dwelling and swimming organisms to the site as migratory and resident species.
To learn more about the Kachemak Bay Research Reserve, please visit www.kbayrr.org.
Alice Orlich is conducting multi-site inventories of fouling communities in Jakolof and Kasitsna bays as a University of Alaska Fairbanks undergraduate student in field support of scientific research in polar regions.
Artificial submarine environments created by dock pilings and a submerged boat in Jakolof and Kasitsna bays have been colonized Ñ or "fouled" Ñ by an interesting assortment of encrusting organisms. By studying these fouling communities, we can learn how encrusting organisms might be attracted to particular surfaces and the nature of encrusting species invasions. Colonization of fouling species leads to destruction and corrosion of many materials used in the design of marine structures and ship hulls. Researchers are currently attempting to develop nontoxic, anti-fouling surfaces for ships, docks, platforms and marine research instruments to reduce or eliminate this problem. A long-term study of artificial substrates would aid this process by documenting the species composition, distribution, change over time and substrate preferences within a fouling community.
