Using Field Experimentation to Assess Recovery of the Benthic
Macroinvertebrate Community in Onondaga Lake, NY
Brandeis L. Brown
M.S. Candidate Ecology
SUNY College of Environmental Science and Forestry
Final Report
Edna Bailey Sussman Foundation
December 2009
Rationale
Onondaga Lake is a highly disturbed urban system (Syracuse, NY) that has
experienced more than a century of industrial and municipal pollution. A large scale
multimillion dollar remediation is currently underway and has recently resulted in
significant improvements in surface water quality. These initial water quality
improvements have led to positive changes in aquatic communities, including plants and
fish, but have had limited influence on the recovery of the benthic macroinvertebrate
community. Recovery of the benthic macroinvertebrate community is limited by the
contaminated sediments that still exist in the lake and may be limited by dispersal from
the similarly impaired tributaries. Future sediment remediation is planned for this lake,
but it is unclear whether this will allow for the natural recovery of the benthic
macroinvertebrate community or if further management actions are needed.
Summary of Proposed Work
The overall purpose of this research was to investigate the ability of the benthic
macroinveretebrate community to recolonize the lake after remediation is complete. We
conducted a field experiment in 2008 using artificial substrates to eliminate the poor
sediment quality as a factor in recovery and assess natural dispersal to the lake. We
collected these clean substrates at five sites in Onondaga Lake and a reference lake
(Otisco Lake) over a 14 month period. Macroinvertebrates were sorted and identified to
family level. The objective of this internship was to work with the New York State
Department of Environmental Conservation (NYDEC) Stream Biomonitoring Unit
(SBU) to further analyze the colonists on these artificial substrates. Specifically we
aimed to analyze (1) specimens to a higher taxonomic resolution, (2) use this information
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to compare macroinvertebrate dispersal to Onondaga Lake vs. Otisco Lake and (3)
determine which macroinvertebrate bioassessment metrics differed between Onondaga
Lake and the reference lake in order to suggest useful parameters in future monitoring
protocols. In addition, the NYDEC is working to implement a new lake bioassessment
protocol that will be used to assess and monitor the level of impairment of freshwater
lakes in New York State. I planned to use preliminary data collected by the NYDEC
SBU in the development of this new metric to incorporate into my analyses as another
goal of this internship.
Narrative of Research
The first goal of this internship was to further identify certain aquatic insect
groups that were of special interest to a higher taxonomic resolution (genus and species)
with the verification of specially trained taxonomists. This was made possible by
working with Alexander J. Smith and other taxonomists at the NYDEC SBU. This new
taxonomic information enhanced many aspects of this project. Not only did it allow
accurate assessment of dispersal to these lakes but also allowed incorporation of speciesspecific pollution sensitivity values into the interpretation of the results of this study. In
addition, with the help of further identification, I was able to monitor the colonization of
a new exotic species to Onondaga Lake, the quagga mussel (Dreissena bugensis). This
study revealed that quagga mussels were not found in the less disturbed Otisco Lake,
supporting the classic ecological hypothesis that disturbed ecosystems are more prone to
invasion by exotic species.
Next, I analyzed macroinvertebrate dispersal to Onondaga Lake to determine the
potential for natural recovery of the community. I did not find any new taxa dispersing to
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the lake that were not found recently in macroinvertebrate surveys. Next, I determined
that there were 24 taxa found dispersing to substrates in Otisco Lake and that the major
difference between dispersers to the lakes include two families of mayflies found
exclusively in Otisco Lake. These results may be evidence to suggest that Onondaga
Lake is limited by dispersal. The ability of more sensitive lentic mayfly species found
regionally to colonize Onondaga Lake in the future might be one good measure of
success of the ongoing remediation effort for this lake.
Next, I compared various bioassessment metrics from substrates collected in
Onondaga Lake with Otisco Lake. I selected these candidate metrics with the help of
preliminary data collected and analyzed from 13 lakes around NY State by the NYDEC
SBU. We compared 11 metrics between Onondaga Lake and Otisco Lake to determine
which were able to distinguish between the lakes, and thus which were most effective in
evaluating disturbed versus undisturbed lake conditions. It was determined that 3 of the
11 bioassessment metrics showed significant differences between the lakes most often.
We also assessed these same 11 metrics between sites within Onondaga Lake. This was
important because only some sites within Onondaga Lake are slated for future sediment
remediation. We found that a different set of metrics were better at distinguishing
between sites within the lake itself. This information has important implications that
should be considered in future monitoring protocols during and after the remediation of
Onondaga Lake.
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In closing, I would like to express my immense gratitude to the Edna Bailey
Sussman Foundation for giving me this unique and rewarding opportunity. This
internship provided me with the chance to work closely with the NYDEC and gain
valuable insight and expertise from professionals currently working in the field of
freshwater management. This research project is connected to a large-scale remediation
project with high public exposure. The Edna Bailey Sussman Foundation will certainly
be acknowledged in my thesis and all publications that result from this work.
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