Prairie River Research Articles

Quantifying Spatial Changes in the Structure of Water Quality Constituents in a Large Prairie River within Two Frameworks of a Water Quality Model

A global sensitivity analysis was carried out on a water quality model to quantify the spatial changes in parameter sensitivity of a model of a large prairie river, the South Saskatchewan River (SSR). The method is used to assess the relative impacts of major nutrient loading sources and a reservoir on the river’s water quality. The river completely freezes over during winter; hence, the sensitivity analysis was carried out seasonally, for winter and summer, to account for the influence of ice-covered conditions on nutrient transformations. Furthermore, the integrity of the river’s aquatic ecosystem was examined through the inter-relationship between variables and comparing hierarchy index values and water quality indices at four locations along the river. Sensitivities of model parameters varied slightly at different locations along the river, with the phytoplankton growth rate being the most influential parameter. Nitrogen and phosphorus transformation processes were more sensitive in winter, while chlorophyll-a and dissolved oxygen parameters showed higher sensitivity in summer. A more complicated correlation between variables was observed downstream of the junction of the Red Deer River. Our results reveal that the lower correlation between variables may suggest a more balanced and healthier system, although further analysis is needed to support this statement.

Metapopulation viability of an endangered shorebird depends on dispersal and human-created habitats: piping plovers (Charadrius melodus) and prairie rivers.

BackgroundMany species are distributed as metapopulations in dynamic landscapes, where habitats change through space and time. Individuals locate habitat through dispersal, and the relationship between a species and landscape characteristics can have profound effects on population persistence. Despite the importance of connectivity in dynamic environments, few empirical studies have examined temporal variability in dispersal or its effect on metapopulation dynamics. In response to this knowledge gap, we studied the dispersal, demography, and viability of a metapopulation of an endangered, disturbance-dependent shorebird. We examined three subpopulations of piping plovers (Charadrius melodus) on the lower Platte and Missouri rivers from 2008–2013. High flow events from an upstream dam on the Missouri River in 2010 and 2011 allowed us to assess the effect of total habitat loss and the subsequent creation of new habitat associated with a large disturbance at one ‘natural’ study location. The other two sites within the metapopulation, which were maintained by anthropogenic activities (e.g., mining, development, habitat restoration), were largely unaffected by this disturbance, resulting in a controlled natural experiment.ResultsHigh flow events were associated with increased emigration, decreased immigration, and decreased survival in the subpopulation that experienced high flows. Following the high flow event, immigration into that subpopulation increased. Dispersal rates among subpopulations were negatively correlated with distance. The metapopulation had a low probability of extinction over 100 years (0 %) under the current disturbance interval and associated dispersal and survival rates. However, persistence depended on relatively stable, human-created habitats, not the dynamic, natural habitat (47.7 % extinction probability for this subpopulation).ConclusionsWe found that functional connectivity, as measured by the rate of dispersal among subpopulations, increased as a result of the high flow event in our study metapopulation. Plovers also increased reproductive output following this event. Although the study metapopulation had a low overall probability of extinction, metapopulation persistence depended on anthropogenically created habitats that provided a small but stable source of nesting habitat and dispersers through time. However, all subpopulations remained small, even if persistent, making them individually vulnerable to extinction through stochastic events. Given the highly dynamic nature of habitat availability in this system, maintaining several subpopulations within the metapopulation and stable sources of habitat will be critical, and this species will likely remain conservation-reliant.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-016-0072-y) contains supplementary material, which is available to authorized users.

Using a Geospatial Model to Relate Fluvial Geomorphology to Macroinvertebrate Habitat in a Prairie River—Part 1: Genus-Level Relationships with Geomorphic Typologies

Modern river ecosystems undergo constant stress from disturbances such as bank stabilization, channelization, dams, and municipal, agricultural, and industrial water use. As these anthropogenic water requirements persist, more efficient methods of characterizing river reaches are essential. Benthic macroinvertebrates are helpful when evaluating fluvial health, because they are often the first group to react to contaminants that can then be transferred through them to other trophic levels. Hence, the purpose of this research is to use a geospatial model to differentiate instream macroinvertebrate habitats, and determine if the model is a viable method for stream evaluation. Through the use of ArcGIS and digital elevation models, the fluvial geomorphology of the Qu’Appelle River in Saskatchewan (SK) was assessed. Four geomorphological characteristics of the river were isolated (sinuosity, slope, fractal dimension, and stream width) and clustered through Principle Component Analysis (PCA), yielding sets of river reaches with similar geomorphological characteristics, called typologies. These typologies were mapped to form a geospatial model of the river. Macroinvertebrate data were aligned to the locations of the typologies, revealing several relationships with the fluvial geomorphology. A Kruskal-Wallis analysis and post hoc pairwise multiple comparisons were completed with the macroinvertebrate data to pinpoint significant genera, as related to the geospatial model.

Identifying links between Fluvial Geomorphic Response Units (FGRUs) and fish species in the Assiniboine River, Manitoba

AbstractThe Assiniboine River, located in east central Saskatchewan and southwestern Manitoba, provides recreational opportunities, irrigation, and industrial and municipal water resources to Manitoba residents while supporting a diverse fish fauna. Improving our understanding of patterns in the spatial distribution of different fish species in relation to physical habitat features can aid management of this important water resource. The Fluvial Geomorphic Response Unit (FGRU) method is a geospatial modelling technique that allows the classification of large‐scale river reaches that exhibit similar geomorphic structure and provide a link between the hydrological regime and physical riverine habitats. Historical electrofishing data provide catch per unit effort data for various fish species and allow an investigation of fish distribution among different FGRUs. This study has identified significant differences (Kruskal–Wallis test, p < 0·05) in the catch per unit effort between three FGRUs for ten fish species in the Assiniboine River. These findings have the potential to increase our understanding of habitat complexity, availability, and connectivity in prairie rivers, a valuable tool for resource managers. This model can contribute to the development of sampling programmes by allowing efficient a priori site selection, ensuring sampling of diverse unit types and thus a greater representation of the range of physical habitats present within a river system. Copyright © 2015 John Wiley & Sons, Ltd.

Historical data reveal fish assemblage shifts in an unregulated prairie river

Wyoming's Powder River is considered an example of a pristine prairie river system. While the river hosts a largely native fish assemblage and remains unimpounded over its 1,146‐km course to the Yellowstone River confluence, the hydrologic regime has been altered through water diversion for agriculture and natural gas extraction and there has been limited study of fish assemblage structure. We analyzed fish data collected from the mainstem Powder River in Wyoming between 1896 and 2008. Shifts in presence/absence and relative abundance of fish species, as well as fish assemblage composition, were assessed among historical and recent samples. The recent Powder River fish assemblage was characterized by increased relative abundances of sand shiner Notropis stramineus and plains killifish Fundulus zebrinus, and decreases in sturgeon chub Macrhybopsis gelida. Shifts in fish species relative abundance are linked to their reproductive ecology with species with adhesive eggs generally increasing in relative abundance while those with buoyant drifting eggs are decreasing. Assemblage shifts could be the result of landscape level changes, such as the loss of extreme high and low flow events and changing land use practices.

Assessing the transport of total phosphorus from a prairie river basin using SPARROW

AbstractRecent changes in land use and new industrial developments in river basins around the world have raised serious concerns regarding future water quality. Assessment of regional nutrient export from river basins are needed in order to identify main nutrient sources and hydrological variables involved. The Red Deer River catchment in Alberta, Canada has been chosen as a test case to assess total phosphorus export regionally. Agricultural and livestock activities in the catchment have increased manure production and the supply of fertilizer to crops. Oil and gas exploitation has also increased the risk of surface water and groundwater contamination. The rapid population growth has not only lead to increases in water consumption and wastewater discharges but also to further construction of transportation infrastructure and the expansion of new urban developments. This has imposed hydraulic controls on waterways, affecting the catchment hydrology and changing the dynamics of sediment and nutrient transport. River ecosystems are not exempt from the negative effects of water quality deterioration. Downstream from the city of Red Deer, the physiology and reproduction habits of native fish species have changed because of high riverine productivity. Although improvements have been made to surface water quality standards by Alberta Environment, further research is needed in order to identify major nutrient sources and quantify nutrient export. The SPAtially Referenced Regression On Watershed model has therefore been used in this study of the Red Deer River catchment to assess regional water quality, in order to describe the spatial and temporal patterns of the processes that affect water quality. The model is suitable for interpreting monitoring data sets that suffer from network sparseness, bias and basin heterogeneity. Ultimately, the model could provide improved information to environmental agencies to guide future water quality management practices and policies. Copyright © 2015 John Wiley & Sons, Ltd.

Lake Sturgeon Geographic Range, Distribution, and Migration Patterns in the Saskatchewan River

AbstractWe examined geographic range, distribution, and migration patterns of Lake Sturgeon Acipenser fulvescens within the largest contiguous section of the Saskatchewan River system in Saskatchewan, Canada. Lake Sturgeon use portions of the North, South, and main‐stem Saskatchewan River during the summer months. The Forks area was observed to be an overwintering area. Lake Sturgeon were observed to migrate each year, and all Lake Sturgeon migrated at least once in the 3‐year study. Lake Sturgeon were observed to undertake significant migrations (>100 km/year) using all three rivers. Migration initiation date was consistent over the 3‐year period, whereas migration return date was more variable and may be linked to river flow rate. No significant differences in distance covered between years were identified, but Lake Sturgeon tended to migrate longer distances in years when flow rates were higher. Finally, the spatial extent of Lake Sturgeon in the Saskatchewan River System appears to be larger than that of many previously studied river and lake populations. This study provides important insights into Lake Sturgeon distribution and migration patterns within large prairie rivers, increasing our basic knowledge of this unique fish species in understudied river systems, and provides important information for conservation within their historic range.Received January 16, 2014; accepted August 5, 2014

The effect of multi-year vs single-year stocking on lake sturgeon (Acipenser fulvescens Rafinesque, 1817) genetic diversity

Summary Many lake sturgeon (Acipenser fulvescens Rafinesque, 1817) populations in the Great Lakes have not recovered from previous threats, whereby stocking can increase population abundances. Stocking in Oneida Lake, New York used two approaches: single-year stocking using sturgeon from the Des Prairies River and multi-year stocking using sturgeon from the St. Lawrence River. Stocked A. fulvescens were sampled and assigned to their corresponding stocking strategy based on age. Samples were analyzed at 12 microsatellite loci to evaluate how a single year of stocking (N = 273) and multiple years of stocking (N = 100) affected genetic diversity and effective population size (Ne). Single-year stocking resulted in lower genetic diversity, likely due to a small number of parents. Multi-year stocking retained most of the genetic diversity of the source population, compensating for the few parents available in a single year. Although multi-year stocking resulted in a higher Ne, the Ne:N ratio was lower (0.34) compared to single-year stocking (0.65), likely due to unequal sex ratios and family size variance across years. It is recommended that stocking of Lake Sturgeon take place over several years. However, consistent numbers need to be stocked each year and family size should be equalized across cohorts in order to maximize Ne.

Resolving Water-Use Conflicts: Insights from the Prairie Experience for the Mackenzie River Basin

The southern regions of Alberta, Manitoba and Saskatchewan suffer from periodic drought more than any other part of Canada. They depend heavily on rivers that rise in the Rocky Mountains and traverse all three provinces to their outlet on Hudson Bay. In 1969, after a prolonged period of disagreement between Alberta and Saskatchewan over conflicting priorities for the use of prairie rivers, the two provinces joined with the governments of Manitoba and Canada to enter into an arrangement known as the Apportionment Agreement. The Agreement was based on the broad principle that each upstream province would allow one-half of the natural flow of the rivers to pass to its downstream neighbors. But much has changed since 1969: A warming climate, a growing population and an expanding economy, particularly in Alberta, has focused increased attention on the water resources of the prairies and demands an examination of how the Agreement works today.

Effects of the development of a newly created spawning ground in the Des Prairies River (Quebec, Canada) on the reproductive success of lake sturgeon (Acipenser fulvescens)

Summary In the fall of 1996, the surface area of an existing spawning ground located downstream of a power dam on the Des Prairies River was expanded. More than 8000 m2 of appropriate substrate were then added to the largest lake sturgeon spawning ground in the lower St. Lawrence River system. The impact of this enhancement project was monitored 3 years before (1994–1996) and 7 years after (1997–2003) habitat modification. Four hypothesis were tested: (i) the newly created spawning ground was utilized by lake sturgeon for egg laying, (ii) the utilization of the newly spawning bed improved the reproductive success of lake sturgeon, (iii) the improvement of the reproductive success increased the lake sturgeon larvae production, and (iv) the increase of larvae production increased the recruitment of lake sturgeon. After the new spawning area was developed, the sampling station located in this new section was one of those most used for egg deposition, under both high (1997) and low (1998–1999) flows conditions. Absolute annual numbers of drifting larvae varied between 1.2 million (1996) and 12.8 million (2003). The mean survival rate of the estimated number of laid eggs compared with drifting larvae was 0.88 and 0.93% in 1995 and 1996, respectively, relative to 5.6% in 1997, 3.82% in 1998 and 2.41% in 1999. These results indicate that the new area had a positive impact on the reproductive success of lake sturgeon in the Des Prairies River. From 1994 to 2003, strong cohorts in the lower St. Lawrence system were related to high larval drift in this river. However, high larval production did not necessarily lead to a strong cohort, and year-class strength determination also appeared affected by environmental factors, with the strongest year classes all associated with high June flow rates (over 1150 m3 s−1) in the Des Prairies River. The information gathered during this study enabled us to refine previous observations on the management of sturgeon spawning grounds and the planning of their design, surface area, substrate and location, as well as other physical parameters.

Spatial and temporal variation in suspended sediment, organic matter, and turbidity in a Minnesota prairie river: implications for TMDLs

The Minnesota River Basin (MRB), situated in the prairie pothole region of the Upper Midwest, contributes excessive sediment and nutrient loads to the Upper Mississippi River. Over 330 stream channels in the MRB are listed as impaired by the Minnesota Pollution Control Agency, with turbidity levels exceeding water quality standards in much of the basin. Addressing turbidity impairment requires an understanding of pollutant sources that drive turbidity, which was the focus of this study. Suspended volatile solids (SVS), total suspended solids (TSS), and turbidity were measured over two sampling seasons at ten monitoring stations in Elm Creek, a turbidity impaired tributary in the MRB. Turbidity levels exceeded the Minnesota standard of 25 nephelometric units in 73% of Elm Creek samples. Turbidity and TSS were correlated (r (2) = 0.76), yet they varied with discharge and season. High levels of turbidity occurred during periods of high stream flow (May-June) because of excessive suspended inorganic sediment from watershed runoff, stream bank, and channel contributions. Both turbidity and TSS increased exponentially downstream with increasing stream power, bank height, and bluff erosion. However, organic matter discharged from wetlands and eutrophic lakes elevated SVS levels and stream turbidity in late summer when flows were low. SVS concentrations reached maxima at lake outlets (50 mg/l) in August. Relying on turbidity measurements alone fails to identify the cause of water quality impairment whether from suspended inorganic sediment or organic matter. Therefore, developing mitigation measures requires monitoring of both TSS and SVS from upstream to downstream reaches.

Nitrogen cycling and metabolism in the thalweg of a prairie river

Nutrient dynamics in rivers are central to global biogeochemistry. We measured ammonium (NH4+) uptake, metabolism, nitrification, and denitrification in the thalweg, the river region of greatest flow, of the Kansas River (discharge = 14,360 L/s). We estimated gross and net uptake with a depleted 15N‐NH4+ release, metabolism with diel O2 measurements, and denitrification with dissolved N2 measurements. Net ecosystem production was negative. Net NH4+ uptake length was 2.1 km when concentrations were elevated, and gross uptake length was 1.9 km at ambient concentrations. Gross uptake rate measurements were comparable to estimates made using extrapolations from data obtained from streams (systems with 1/10th or less the discharge). Calculated lengths were maximal because the isotope pulse was primarily confined to the thalweg and not the shallow side channels or backwaters. Denitrification and nitrification rates were below detection. In the Kansas River, rates of N cycling are driven by heterotrophic processes, and considerable processing of N, particularly NH4+ uptake, occurred over a few kilometers of river length, with net uptake rates of NH4+ increasing with greater NH4+ concentrations.

Basin‐wide impacts of compounds with estrogen‐like activity on longnose dace (Rhinichthys cataractae) in two prairie rivers of Alberta, Canada

Environmental compounds with estrogen- or antiestrogen-like activity can enter rivers from multiple sources, including municipal wastewater and agricultural runoff. We used longnose dace (Rhinichthys cataractae) to investigate exposure to compounds with estrogen-like activity, which we measured in water at multiple sites in the Oldman and Bow rivers (AB, Canada). We evaluated changes in vitellogenin mRNA with quantitative reverse transcription-polymerase chain reaction, then compared vitellogenin levels to sex ratios and fish performance indices to assess how exposure to compounds with estrogen-like activity affects longnose dace populations. Vitellogenin levels were elevated at least 59 to 110 km downstream of municipalities. In the Oldman River, increased vitellogenin expression and female-biased sex ratios suggest severe endocrine disruption, likely resulting from the combined impacts of municipal wastewater, agriculture, and large cattle operations within the basin. In the Bow River, municipal wastewater may be the major source of compounds with estrogen-like activity that affect longnose dace. The sex ratios were not heavily skewed, as in the more agriculturally influenced Oldman River. We detected organic contaminants in river samples at every site, but the highest concentrations were found downstream of municipalities and in areas with intense agriculture. Vitellogenin levels and sex ratios of longnose dace suggest basin-wide exposure to compounds with estrogen-like activity. Our results demonstrate that it is important to assess rivers at large spatial scales to detect fully the impacts of municipal wastewater and agriculture on fish populations.

Changes in Population, Growth, and Physiological Indices of Longnose Dace (Rhinichthys cataractae) in the Red Deer River, Alberta, Canada

The Red Deer River, Alberta, Canada is a prairie river that is impacted by the point-source input of Red Deer's municipal wastewater effluent and non-point- source agricultural runoff. We used population, growth, and physiological performance end points in longnose dace (Rhinichthys cataractae), an endemic and abundant minnow, to evaluate changes in fish health over a 220 km section of the Red Deer River. Longnose dace immediately downstream of Red Deer had elevated catch per unit effort with larger body and liver sizes compared to upstream of Red Deer sites, likely due to elevated riverine productivity from Red Deer's wastewater effluent. Longnose dace immediately downstream of Red Deer showed depressed testosterone production capacity and elevated ethoxyresorufin-O-deethylase (EROD) activity, which is consistent with exposure to endocrine-disrupting compounds and aromatic hydrocarbons, respectively. Longnose dace 150-180 km downstream of Red Deer had reduced liver and gonad sizes, elevated EROD, and increased 11-ketotestosterone production capacity compared to upstream of Red Deer sites, possibly related to a non-point-source agricultural influence on water quality. Longnose dace populations at the most downstream sites were missing the oldest age classes and might reach sexual maturity faster than at upstream sites, which is consistent with a younger age structure. Our results highlight the importance of assessing multiple performance end points to reveal physiological or reproductive effects in natural fish populations. We have demonstrated how longnose dace populations change over a river impacted by municipal wastewater and agricultural runoff; further studies are required to determine if these changes will influence the long-term viability of longnose dace in the Red Deer River.

Effects and Utility of Minimum Length Limits and Mortality Caps for Flathead Catfish in Discrete Reaches of a Large Prairie River

AbstractPopulations of flathead catfish Pylodictis olivaris in four reaches of the Kansas River, Kansas, were examined to evaluate the effects of three minimum length limits (305 (the minimum size that anglers are willing to harvest), 610, and 762 mm total length (TL)) on population size structure and number harvested over a 30‐year simulation. We used electrofishing and hoopnetting to capture and tag flathead catfish throughout the Kansas River from 2005–2006. Current exploitation (u) based on tag returns was probably less than 10%, and total annual mortality A ranged from 14% to 28% across all reaches. Increased river access and promotion of this fishery may increase u in the future, so model simulations were conducted with conditional natural mortality (cm) and u ranging from 10% to 40%. Proportional stock density (PSD) and the relative stock density of preferred‐length fish (RSD‐P) substantially declined (by >25% and >15%, respectively) as u increased with the 305‐mm TL limit over the 30‐year simulation. The PSD showed similar trends across all reaches, indicating that use of different regulations among reaches was not necessary and that differences in growth among reaches were less influential than u and cm. No substantial differences were observed in size structure under the 610‐ and 762‐mm TL limits among reaches, but under a 762‐mm TL limit anglers would have to sacrifice about 42% of the number harvested under the current cm level. Mortality caps revealed that each reach could sustain an A of about 60% and 55% to maintain current PSD and RSD‐P levels, respectively; this result suggests that quality flathead catfish size structure can be preserved. Our results show that the effects (or lack thereof) on flathead catfish and other sport fishes should be evaluated before harvest restrictions are implemented.

Seasonal and Diel Habitat Shifts by Juvenile Ictalurids in a Flow-regulated Prairie River

Currently, no flow regulations exist for the protection of riverine fishes in Missouri. Prerequisites for establishing flow guidelines are understanding what habitats are used by fishes at different times of the year and how much of that habitat will be available to each species under different discharge scenarios. We quantified microhabitat associations and selection for juvenile channel catfish Ictalurus punctatus, flathead catfish Pylodictis olivaris and stonecat Noturus flavus in a flow-regulated prairie river during summer (diurnal and nocturnal periods) and autumn (diurnal period) and then presented two-dimensional hydraulic modeling results from a previous study to determine how diel and seasonal microhabitat shifts might impact the availability of selected habitats at different flows. All ictalurid species exhibited seasonal and diel shifts in microhabitat selection. Selected habitat available would generally be maximized for each species between 10 m3/s and 30 m3/s which is greater than the current median discharge. Stonecats are most susceptible to dewatering during the diurnal summer period; however, the availability of selected habitat becomes flow limited (<10 m3/s) for all species during summer nocturnal and autumn periods because of changes in microhabitat selection during these periods. Channel catfish could be substantially impacted by extremely low flows during the summer nocturnal and autumn periods with no selected habitat available below 1 m3/s. Quantifying the amount of selected habitat that may be available under different discharge scenarios will aid managers in determining appropriate minimum flows for maintaining habitats for these species under a flow regime that continues to be partitioned to different stakeholder groups.

Coping with hydrogeomorphic variations in a prairie river: resiliency in young‐of‐the‐year fishes

AbstractYoung‐of‐the‐year (YOY) fish in sand‐bed rivers of grassland ecoregions frequently encounter dynamic habitat conditions produced by highly variable flow and resulting changes in geomorphic complexity of the river. How these vulnerable life history stages cope with changes in habitat condition and location is largely unknown. Therefore, we examined biodiversity and abundance of YOY fish (larvae and juveniles) at two spatiotemporal scales in response to dynamic flow conditions in the Kansas River. During the summer of 2004, we collected and identified 13 745 YOY fish from various moderate to zero‐flow habitats. Patterns of community structure through time were compared with the river's hydrogeomorphic characteristics, as determined by aerial photographs and measurements of instream flow rate and other water quality characteristics.Our initial hypothesis was that species richness and total YOY abundance would be maximized in larger and longer‐lived slackwater habitats. In contrast, our data suggest that dominant fishes in these highly dynamic ecosystems have adapted to hydrological variations with a more generalist lifestyle by either: (i) temporarily using higher flow habitats (except possibly the thalweg) to cope with intermittent loss of prime habitat; or (ii) extending spawning through favourable and demanding conditions. In contrast to current theories, our results suggest that conditions for YOY success are optimized in dynamic prairie rivers during the intermediate flows that maximize habitat heterogeneity and availability. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Use of Diluted Tomato Petiole Sap for Potassium Measurement with the Cardy Electrode Meter

Tomato petiole sap from potassium (K) rate experiments conducted on prairie loam and river coarse sand soils from 1998 to 2002 was used to measure K concentration via the battery‐operated portable Cardy flat membrane electrode meter and inductive coupled plasma (ICP) laboratory instrumentation. In 1998, for undiluted sap levels less than 3000 mg kg−1 the linear Cardy–ICP correlation was r=0.94, but when K was more than 3000 mg kg−1, r was only 0.53. Diluting the sap with water (1∶1) improved the linear range to 6000 mg K L−1 (r=0.87, n=190). Petiole sap K, measured by either Cardy or ICP, was highly correlated to whole‐leaf K concentration all years, r=0.8 to 0.91. Even through the slope of the regression lines were similar for the years, the intercepts were significantly different (P<0.01). The Cardy electrode can be reliably used for tomato petiole K determination provided the sap is diluted and the usual handling precautions are taken to prevent petiole moisture loss and maintain stability in electrode readings.

Behaviour and fate of tetracycline in river and wetland waters on the Canadian Northern Great Plains

Very little is known about the factors affecting the behaviour, degradation and persistence of tetracycline in sensitive Prairie freshwater aquatic systems in Canada. Reported are results of studies conducted for the first time of tetracycline behaviour in Prairie river and wetland waters. For comparison, studies were also conducted using distilled water as a control. Different amounts of spiked tetracycline (0, 50 and 80 percent) was adsorbed by distilled, river and wetland water, respectively. These different amounts are likely due to the differences in the matrixes of the three waters. In wetland water, the addition of EDTA generally promoted the release of tetracycline indicating that a portion of the tetracycline was bound to metal ions. Decreasing the pH of the wetland water led to increased adsorption of tetracycline suggesting either that tetracycline epimerizes or binds, by hydrogen bonding, to acidic portions of organic material in the water. However, in wetland water, a significant portion of the spiked tetracycline (≅ 50%) was irreversibly bound to the water matrix and was not released by adding EDTA and/or by varying the pH. In laboratory experiments, the t1/2 of “free-form” tetracycline exposed to light (L+) in non-sterile waters was 32, 2 and 3 days in distilled, river and wetland water respectively, while in waters with no light exposure (L−), they were 83, 18 and 13 days. Similarly, t1/2 of tetracycline in L+ sterile waters treatments was 9, 1 and 1 day for distilled, river and wetland water, respectively, and 18, 11 and 7 days in the L−. In the experiment conducted in natural sunlight, tetracycline t1/2 in the presence of ultraviolet radiation (UV) treatments was 26, 17 and 18 min in distilled, river and wetland water and 39, 28 and 32 min in the absence of UV treatment. The combination of the effects of matrixes of the water, light and UV radiation therefore play a significant role in catalyzing the removal of tetracycline from different Prairie waters. In deep waters and in systems where sunlight is highly attenuated, the effects of light on tetracycline may be considerably reduced.

Application and Tests of the Canadian Water Quality Index for Assessing Changes in Water Quality in Lakes and Rivers of Central North America

The Canadian Water Quality Index (CWQI) is a tool for communicating information to the general public and governments about water quality and assessing changes in water quality over time. It has been adopted for national and provincial reporting on water quality within Canada. It is used in this study to describe changes in water quality along a prairie river system and to assess changes in river water quality prior to and after the installation of tertiary clarifiers for the removal of phosphorus from wastewater effluent. CWQI values reflected the composite assessment of changes in individual parameter concentrations along the river. There was a slight increase in the CWQI after the installation of tertiary clarifiers, which reflected the improvement of only a few components of the wastewater. Several weaknesses of the CWQI were explored, including susceptibility to sample number per index period. A sound sampling design should form the basis of any monitoring program and, to a large extent, CWQI values are a reflection of the sampling program.