TERRELL'S ISLAND: A CASE STUDY IN BIOLOGICAL AND CHEMICAL EFFECTS OF WATERFOWL ON FRESHWATER ENCLOSURES
File(s)
Date
2013-12Author
Hadi, Asbah Z
Advisor(s)
McDermott, Colleen
Metadata
Show full item recordAbstract
Although American White Pelicans (Pelecanus erythrorhynchos) (AWP) typically reside
in the western plains of North America, within the last 30 years they have migrated to unexpected
locations, perhaps due to climate change. One area of Wisconsin that has encountered unexpectedly
high numbers of AWP (and other waterfowl) is Terrell's Island on Lake Butte des Morts, estimated to
have over 1,500 nesting AWP. The presence of pelicans and other waterfowl is likely to have a
significant, negative impact on recreational water quality in this area.
Water samples were collected twice weekly from two sites around Terrell's Island on Lake Butte des
Morts from inside the breakwall, directly adjacent to nesting islands, and from a "control" area in
Shubert Marsh, away from pelican populations. A total of 24 samples were collected throughout the
summer of 2012. Fecal indicator bacteria (FIB) were measured from both locations using the
Colilert and Enterolert assays (for E. coli and enterococci, respectively). Each sample type was
also filtered through nitrocellulose and polycarbonate filters for further microbial testing.
Nitrocellulose filters were plated in triplicate onto various selective media to qualitatively
identify potential pathogens (Salmonella, Campylobacter). Each set of polycarbonate filters was
frozen at -80C to enumerate C. jejuni using quantitative PCR (qPCR). Equal numbers of samples were
collected for both culture-based enumeration as well as molecular-based enumeration.
Average culturable FIB concentrations were notably greater in waters adjacent to pelican nesting
areas (E. coli: 480 vs. 76 MPN/100 ml, enterococci: 637 vs. 290 MPN/100 ml). Fecal pathogens
(Salmonella, Campylobacter) were undetectable in water samples by traditional culture methods and
by quantitative PCR (qPCR).
On average, chlorophyll a concentrations were also considerably higher in the breakwall area
compared to chlorophyll a concentrations in Shubert Marsh (119.83 vs. 92.74 g/L). In summary, AWP
have a negative impact on water quality in Lake Butte des Morts and may impair
recreational water quality at other locations with high waterfowl densities.
Subject
White pelican
White pelican - Habitat
Permanent Link
http://digital.library.wisc.edu/1793/69522Description
A Thesis Submitted In Partial Fulfillment of the Requirements For the Degree of Master of Science
Microbiology