TY - JOUR
T1 - Influence of land use, nutrients, and geography on microbial communities and fecal indicator abundance at Lake Michigan beaches
AU - Cloutier, Danielle
AU - Alm, Elizabeth Wheeler
PY - 2015/8
Y1 - 2015/8
N2 - Microbial communities within beach sand play a key role in nutrient cycling and are important to the nearshore ecosystem function.
Escherichia coli and enterococci, two common indicators of fecal pollution, have been shown to persist in the beach sand,
but little is known about how microbial community assemblages are related to these fecal indicator bacteria (FIB) reservoirs. We
examined eight beaches across a geographic gradient and range of land use types and characterized the indigenous community
structure in the water and the backshore, berm, and submerged sands. FIB were found at similar levels in sand at beaches adjacent
to urban, forested, and agricultural land and in both the berm and backshore. However, there were striking differences in
the berm and backshore microbial communities, even within the same beach, reflecting the very different environmental conditions
in these beach zones in which FIB can survive. In contrast, the microbial communities in a particular beach zone were similar
among beaches, including at beaches on opposite shores of Lake Michigan. The differences in the microbial communities that
did exist within a beach zone correlated to nutrient levels, which varied among geographic locations. Total organic carbon and
total phosphorus were higher in Wisconsin beach sand than in beach sand from Michigan. Within predominate genera, finescale
sequence differences could be found that distinguished the populations from the two states, suggesting a biogeographic
effect. This work demonstrates that microbial communities are reflective of environmental conditions at freshwater beaches and
are able to provide useful information regarding long-term anthropogenic stress.
AB - Microbial communities within beach sand play a key role in nutrient cycling and are important to the nearshore ecosystem function.
Escherichia coli and enterococci, two common indicators of fecal pollution, have been shown to persist in the beach sand,
but little is known about how microbial community assemblages are related to these fecal indicator bacteria (FIB) reservoirs. We
examined eight beaches across a geographic gradient and range of land use types and characterized the indigenous community
structure in the water and the backshore, berm, and submerged sands. FIB were found at similar levels in sand at beaches adjacent
to urban, forested, and agricultural land and in both the berm and backshore. However, there were striking differences in
the berm and backshore microbial communities, even within the same beach, reflecting the very different environmental conditions
in these beach zones in which FIB can survive. In contrast, the microbial communities in a particular beach zone were similar
among beaches, including at beaches on opposite shores of Lake Michigan. The differences in the microbial communities that
did exist within a beach zone correlated to nutrient levels, which varied among geographic locations. Total organic carbon and
total phosphorus were higher in Wisconsin beach sand than in beach sand from Michigan. Within predominate genera, finescale
sequence differences could be found that distinguished the populations from the two states, suggesting a biogeographic
effect. This work demonstrates that microbial communities are reflective of environmental conditions at freshwater beaches and
are able to provide useful information regarding long-term anthropogenic stress.
M3 - Article
VL - 81
SP - 4904
EP - 4913
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 15
ER -