Boscarino B.T.,Cornell University |
Rudstam L.G.,Cornell University |
Tirabassi J.,Cornell University |
Janssen J.,Great Lakes WATER Institute |
Loew E.R.,Cornell University
Limnology and Oceanography | Year: 2010
An understanding of the effect of light on predator-prey interactions in aquatic systems requires the integration of sensory physiology, behavioral ecology, and spatial distributions of predator and prey in the field. Here, we present such an integrative approach to a study on the interactions between the alewife, Alosa pseudoharengus, and the mysid shrimp, Mysis diluviana, (formerly M. relicta) in Lake Ontario at night, when it is unknown whether visual feeding is possible. Visual pigment analyses of alewife rod photoreceptors were used to derive an alewife-specific unit of brightness-the 'alelux' (wavelength of maximum absorbance, λ max 5 505 nm)-which formed the basic unit of light intensity in alewife feeding-rate experiments and field applications. At light levels of 1027 alelux (∼ 10 24.1 lux) and greater in the laboratory, alewives engaged in visual search and strike behaviors and fed at rates that were significantly higher than those under completely dark conditions. Field observations from Lake Ontario showed that light levels at the upper edge of the mysid distribution were within the range of those required for visual feeding in the laboratory on a full moon night, but not on a new moon night. These increased light levels translated into feeding rates that were > 30 times higher on the full moon night, despite a larger degree of spatial separation of the two trophic levels. We hypothesize that observed increased water clarity in Lake Ontario in recent years has led to increased consumption of mysids by alewife at night and associated food-web changes. © 2010, by the American Society of Limnology and Oceanography, Inc.
Sauer E.P.,Great Lakes Water Institute |
VandeWalle J.L.,Great Lakes Water Institute |
Bootsma M.J.,Great Lakes Water Institute |
McLellan S.L.,Great Lakes Water Institute
Water Research | Year: 2011
Human sewage contamination of surface waters is a major human health concern. We found urban stormwater systems that collect and convey runoff from impervious surfaces act as a conduit for sewage originating from breeches in sanitary sewer infrastructure. A total of 828 samples at 45 stormwater outfalls were collected over a four-year period and assessed by culture based methods, PCR, and quantitative PCR (qPCR) to test for traditional and alternative indicators of fecal pollution. All outfalls had the HF183 (human) Bacteroides genetic marker detected in at least one sample, suggesting sewage contamination is nearly ubiquitous in the urban environment. However, most outfalls were intermittently positive, ranging from detection in 11%-100% of the samples. Positive results did not correlate with seasonality, rainfall amounts, or days since previous rainfall. Approximately two-thirds of the outfalls had high (>5000 copy number, i.e. CN, per 100 ml) or moderate levels (1000-5000 CN per 100 ml) of the human Bacteroides genetic marker. Escherichia coli (E. coli) and enterococci levels did not correlate to human Bacteroides. A total of 66% of all outfall samples had standard fecal indicator levels above 10,000 CFU per 100 ml. A tiered assessment using this benchmark to identify high priority sites would have failed to flag 35% of the samples that had evidence of sewage contamination. In addition, high fecal indicators would have flagged 33% of samples as priority that had low or no evidence of sewage. Enteric virus levels in one outfall with high levels of the human Bacteroides genetic marker were similar to untreated wastewater, which illustrates stormwater can serve as a pathway for pathogen contamination. The major source of fecal pollution at four of five river sites that receive stormwater discharge appeared to be from sewage sources rather than non-human sources based on the ratios of human Bacteroides to total Bacteroides spp. This study shows the feasibility and benefits of employing molecular methods to test for alternative indicators of fecal pollution to identify sewage sources and potential health risks and for prioritization of remediation efforts. © 2011 Elsevier Ltd.
Wu X.,University of Wisconsin - Milwaukee |
Li Y.,University of Wisconsin - Milwaukee |
Consi T.R.,Great Lakes WATER Institute
ASME 2010 Dynamic Systems and Control Conference, DSCC2010 | Year: 2010
This paper presents a life extending minimum-time path planning algorithm for legged robots, with application for a six-legged walking robot (hexapod). The leg joint fatigue life can be extended by reducing the constraint on the dynamic radial force. The dynamic model of the hexapod is built with the Newton Euler Formula. In the normal condition, the minimum-time path planning algorithm is developed through the bisecting-plane (BP) algorithm with the constraints of maximum joint angular velocity and acceleration. According to the fatigue life model for ball bearing, its fatigue life increases while the dynamic radial force on the bearing decreases. The minimum-time path planning algorithm is thus revised by reinforcing the constraint of maximum radial force based on the expectation of life extension. A symmetric hexapod with 18 degree-of-freedom is used for simulation study. As a simplified treatment, the magnitudes of dynamic radial force on proximal joints at the pair of supporting legs are set identical to achieve similar degradation rates on each joint bearing and obtain the dynamic radial force on each joint. The simulation results validate the effectiveness of the proposed idea. This scheme can extend the operating life of robot (joint bearing fatigue life) by modifying the joint path only without affecting the primary task specifications. Copyright © 2010 by ASME.
Drayna P.,Medical College of Wisconsin |
McLellan S.L.,Great Lakes WATER Institute |
Simpson P.,Medical College of Wisconsin |
Simpson P.,Childrens Research Institute |
And 4 more authors.
Environmental Health Perspectives | Year: 2010
Background: Microbial water contamination after periods of heavy rainfall is well described, but its link to acute gastrointestinal illness (AGI) in children is not well known. Objectives: We hypothesize an association between rainfall and pediatric emergency department (ED) visits for AGI that may represent an unrecognized, endemic burden of pediatric disease in a major U.S. metropolitan area served by municipal drinking water systems. Methods: We conducted a retrospective time series analysis of visits to the Children's Hospital of Wisconsin ED in Wauwatosa, Wisconsin. Daily visit totals of discharge International Classification of Diseases, 9th Revision codes of gastroenteritis or diarrhea were collected along with daily rainfall totals during the study period from 2002 to 2007. We used an autoregressive moving average model, adjusting for confounding variables such as sewage release events and season, to look for an association between daily visits and rainfall after a lag of 1-7 days. Results: A total of 17,357 AGI visits were identified (mean daily total, 7.9; range, 0-56). Any rainfall 4 days prior was significantly associated with an 11% increase in AGI visits. Expected seasonal effects were also seen, with increased AGI visits in winter months. Conclusions: We observed a significant association between rainfall and pediatric ED visits for AGI, suggesting a waterborne component of disease transmission in this population. The observed increase in ED visits for AGI occurred in the absence of any disease outbreaks reported to public health officials in our region, suggesting that rainfall-associated illness may be underestimated. Further study is warranted to better address this association.
Mueller-Spitz S.R.,Great Lakes WATER Institute |
Stewart L.B.,Great Lakes WATER Institute |
McLellan S.L.,Great Lakes WATER Institute
Journal of Applied Microbiology | Year: 2010
Aims: The purpose of the work was to evaluate the mCP method to correctly identify and enumerate Clostridium perfringens that are present in surface waters impacted by a mixture of faecal pollution sources. Methods: Clostridium perfringens were enumerated and isolated from sewage influent, surface water and suspended sediments using the mCP method. Molecular characterization of isolates was performed using species-specific PCR, along with full-length sequencing of the 16S rRNA gene for a subset of isolates. Results: The environmental isolates were presumptively identified as C. perfringens based on utilization of sucrose, inability to ferment cellobiose and a positive action for acid phosphatase activity. All isolates (n = 126) were classified as C. perfringens based on positive results with species-specific PCR with a subset confirmed as C. perfringens based on the 16S rRNA gene identity. Conclusions: The molecular results indicated all of the presumptive positive isolates were C. perfringens regardless of the source, e.g. sewage influent or environmental water samples. Sequencing revealed that C. perfringens obtained from sewage and the aquatic environment were nearly identical (c. 99·5% similarity). Significance and Impact of the Study: From this study we conclude that the mCP method is a robust approach to enumerate and isolate C. perfringens from aquatic environments that receive diverse sources of faecal pollution. © 2009 The Society for Applied Microbiology.
Tomlinson L.M.,Michigan Technological University |
Auer M.T.,Michigan Technological University |
Bootsma H.A.,Great Lakes WATER Institute |
Owens E.M.,Upstate Freshwater Institute
Journal of Great Lakes Research | Year: 2010
A recent review of the Great Lakes Water Quality Agreement has concluded that while controls on phosphorus inputs to Lake Michigan achieved the desired effect in offshore waters, the nearshore region continues to suffer from elevated phosphorus levels. Failure to achieve trophic state goals in the nearshore is manifested in nuisance growth of Cladophora and attendant impacts on property owners, utilities, and the public health and welfare. This study focuses on a site in Lake Michigan near Milwaukee, Wisconsin, where nuisance growth of Cladophora and associated beach fouling occur regularly. A mechanistic model simulating Cladophora growth, suitable for guiding nutrient management in the Great Lakes nearshore, is presented. The model represents an update of the Canale and Auer framework, reflecting current understandings of Cladophora ecology and offering a user-friendly interface making the software more widely available to decision makers. This Great Lakes Cladophora Model (GLCM) is first validated for the Auer/Canale data set collected in 1979 at a site on Lake Huron and then for a data set developed in 2006 for a site on Lake Michigan. Model performance under the strikingly different forcing conditions (depth, light, phosphorus levels) characteristic of these two sites affirms the widespread applicability of the tool. The GLCM is then extended to examine the impacts of ecosystem perturbation (dreissenid colonization) on Cladophora growth and to future approaches to monitoring and management. © 2010 Elsevier B.V. All rights reserved.
Auer M.T.,Michigan Technological University |
Tomlinson L.M.,Michigan Technological University |
Higgins S.N.,University of Waterloo |
Higgins S.N.,University of Wisconsin - Madison |
And 3 more authors.
Journal of Great Lakes Research | Year: 2010
Nuisance growth of the attached, green alga Cladophora was considered to have been abated by phosphorus management programs mandated under the Great Lakes Water Quality Agreement. The apparent resurgence of nuisance growth in Lakes Erie, Michigan and Ontario has been linked conceptually to ecosystem alterations engineered by invasive dreissenid mussels (Dreissena polymorpha and Dreissena bugensis). Here, we apply contemporary modeling tools and historical water quality data sets in quantifying the impact of long-term changes in phosphorus loading and dreissenid-mediated changes in water clarity on the distribution and production of Cladophora. It is concluded that reductions in phosphorus loading in the predreissenid period achieved the desired effect, as model simulations were consistent with the biomass declines reported from the early 1970s to the early 1980s. These declines were, however, largely offset by dreisseniddriven changes in water clarity that extended the depth of colonization by Cladophora, increasing total production. We were not able to isolate and quantify the significance of dreissenid mediation of phosphorus cycling using the historical database. Phosphorus management remains the appropriate mechanism for reducing nuisance levels of Cladophora growth. The development of action plans will require an improved understanding of nearshore phosphorus dynamics such as might be obtained through regular monitoring of soluble reactive phosphorus levels, internal phosphorus content and Cladophora biomass in impacted nearshore regions of the Great Lakes. © 2010 Elsevier B.V. All rights reserved.
Newton R.J.,Great Lakes WATER Institute |
VandeWalle J.L.,Great Lakes WATER Institute |
Borchardt M.A.,U.S. Department of Agriculture |
Gorelick M.H.,Medical College of Wisconsin |
And 2 more authors.
Applied and Environmental Microbiology | Year: 2011
The complexity of fecal microbial communities and overlap among human and other animal sources have made it difficult to identify source-specific fecal indicator bacteria. However, the advent of next-generation sequencing technologies now provides increased sequencing power to resolve microbial community composition within and among environments. These data can be mined for information on source-specific phylotypes and/or assemblages of phylotypes (i.e., microbial signatures). We report the development of a new genetic marker for human fecal contamination identified through microbial pyrotag sequence analysis of the V6 region of the 16S rRNA gene. Sequence analysis of 37 sewage samples and comparison with database sequences revealed a human-associated phylotype within the Lachnospiraceae family, which was closely related to the genus Blautia. This phylotype, termed Lachno2, was on average the second most abundant fecal bacterial phylotype in sewage influent samples from Milwaukee, WI. We developed a quantitative PCR (qPCR) assay for Lachno2 and used it along with the qPCR-based assays for human Bacteroidales (based on the HF183 genetic marker), total Bacteroidales spp., and enterococci and the conventional Escherichia coli and enterococci plate count assays to examine the prevalence of fecal and human fecal pollution in Milwaukee's harbor. Both the conventional fecal indicators and the human-associated indicators revealed chronic fecal pollution in the harbor, with significant increases following heavy rain events and combined sewer overflows. The two humanassociated genetic marker abundances were tightly correlated in the harbor, a strong indication they target the same source (i.e., human sewage). Human adenoviruses were routinely detected under all conditions in the harbor, and the probability of their occurrence increased by 154% for every 10-fold increase in the human indicator concentration. Both Lachno2 and human Bacteroidales increased specificity to detect sewage compared to general indicators, and the relationship to a human pathogen group suggests that the use of these alternative indicators will improve assessments for human health risks in urban waters. © 2011, American Society for Microbiology.
Boltana S.,Autonomous University of Barcelona |
Reyes-Lopez F.,University of Santiago de Chile |
Morera D.,Autonomous University of Barcelona |
Goetz F.,Great Lakes WATER Institute |
MacKenzie S.A.,Autonomous University of Barcelona
BMC Genomics | Year: 2011
Background: Pathogen-associated molecular patterns (PAMPs) are structural components of pathogens such as lipopolysaccharide (LPS) and peptidoglycan (PGN) from bacterial cell walls. PAMP-recognition by the host results in an induction of defence-related genes and often the generation of an inflammatory response. We evaluated both the transcriptomic and inflammatory response in trout (O. mykiss) macrophages in primary cell culture stimulated with DAP-PGN (DAP; meso-diaminopimelic acid, PGN; peptidoglycan) from two strains of Escherichia coli (PGN-K12 and PGN-O111:B4) over time.Results: Transcript profiling was assessed using function-targeted cDNA microarray hybridisation (n = 36) and results show differential responses to both PGNs that are both time and treatment dependent. Wild type E. coli (K12) generated an increase in transcript number/diversity over time whereas PGN-O111:B4 stimulation resulted in a more specific and intense response. In line with this, Gene Ontology analysis (GO) highlights a specific transcriptomic remodelling for PGN-O111:B4 whereas results obtained for PGN-K12 show a high similarity to a generalised inflammatory priming response where multiple functional classes are related to ribosome biogenesis or cellular metabolism. Prostaglandin release was induced by both PGNs and macrophages were significantly more sensitive to PGN-O111:B4 as suggested from microarray data.Conclusion: Responses at the level of the transcriptome and the inflammatory outcome (prostaglandin synthesis) highlight the different sensitivity of the macrophage to slight differences (serotype) in peptidoglycan structure. Such divergent responses are likely to involve differential receptor sensitivity to ligands or indeed different receptor types. Such changes in biological response will likely reflect upon pathogenicity of certain serotypes and the development of disease. © 2011 Boltaña et al; licensee BioMed Central Ltd.
Schaeffer J.S.,U.S. Geological Survey |
Bland J.K.,EPS Inc |
Janssen J.,Great Lakes WATER Institute
Fisheries | Year: 2012
Maintaining aquatic biodiversity in urban or suburban areas can be problematic because urban landscapes can be nearly devoid of aquatic habitats other than engineered basins for storm water management. These areas are usually of questionable value for fish, but we examined a case study in which five regionally imperiled fish species were reintroduced into an artificial storm water detention pond and subsequently thrived. Although not a formal experiment, post introduction survey data suggested that three of the five species maintained high population densities for 10 years after initial stocking, and two persisted in lower numbers. Success was likely due to a combination of unique design features and prior habitat preparation that resulted in clear water conditions that supported dense vegetation. Stocked fish persisted despite occasional bouts of low dissolved oxygen and increased chloride levels resulting from road salt application within the watershed. Transplanted fish served as a source population for both research and further reintroduction experiments. We suggest that, for some fish species, habitat preservation has a middle ground between natural habitats and completely artificial environments that require constant husbandry and that storm water systems could be used to create engineered sanctuaries within the human landscape that have many potential benefits for both humans and fish.