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At least 1,513 records · Page 84Linked to original sources
USGS2009

Dynamics in phosphorus retention in wetlands upstream of Delavan Lake, Wisconsin

A phosphorus budget was constructed for Delavan Lake Inlet, a perennial riverine wetland with submersed and floating aquatic vegetation in southeastern Wisconsin, to better understand the phosphorus dynamics in natural wetlands and the role of wetlands in lake-rehabilitation efforts. During the growing season, the inlet served as a net source of phosphorus , primarily due to the release of phosphorus from the sediments. More phosphorus was released from the sediments of the inlet (600 kg) than was input from the upstream watershed (460 kg). This release was caused by high pH associated with high photosynthetic activity. During the remainder of the year, the inlet served as a net sink for phosphorus , retaining 6% of die phosphorus input from the watershed. Over the entire year, this wetland was a net source of over 500 kg of phosphorus to downstream Delavan Lake. A constructed riverine wetland upstream of Delavan Lake Inlet demonstrated a similar periodic release of phosphorus . However, in this case, the summer release of phosphorus was less than that trapped during the remainder of the year. The constructed wetland served as a net sink for approximately 20% of the input phosphorus on an annual time scale. The role of existing and constructed wetlands as phosphorus traps is complex. Wetlands can act as a source or a sink for phosphorus depending on the ambient conditions in die wetland . Howa wetland fits into a rehabilitation plan depends upon its net retention efficiency and the importance of the periodic releases of phosphorus to downstream waters.

Wisconsin↗
USGS2009

Estimating phosphorus concentrations following alum treatment using apparent settling velocity

he apparent settling velocity (Vs) is a term used in empirical, steady-state, mass-balance lake models to represent the net phosphorus flux from the water column. The Vollenweider (1969) mixed-reactor lake model was rearranged and used to calculate Vs values for total phosphorus (TP) for three lakes treated with alum to reduce the internal flux of P to the water column (Delavan Lake, Wisconsin; Lake Morey, Vermont; and West Twin Lake, Ohio). An analysis of Vs values was conducted using data from these three lakes for both the pre- and post-alum treated conditions. Analysis of Vs values for both the pre- and post-alum conditions in Lake Morey and West Twin Lake resulted in a post-treatment mean Vs value of 7 ± 2.0 m·yr −1 . The effect of the alum treatment, although short-lived in Delavan Lake, resulted in a mean post-treatment Vs value of 3.4 ± 0.3 m·yr −1 . The consistency in the post-treatment Vs values in Lake Morey and West Twin Lake is used to demonstrate a predictive analysis method for water column TP concentrations in lakes following a successful treatment of the anoxic sediment area with alum. Additional pre- and post-alum in-lake and watershed loading data are needed to advance this concept into a management model.

Ohio, Vermont, Wisconsin↗
USGS1999

Temporal variations of water quality and the taxonomic structures of phytoplankton and zooplankton assemblages in mountain lakes, Mount Rainier National Park, Washington USA

A synoptic inventory of physical and chemical properties and plankton assemblages of 27 mountain lakes was conducted at Mount Rainier National Park in 1988. From 1990–1993, die opportunity was presented to resurvey six of these lakes to determine inter-annual change within die set of characteristics surveyed in 1988. If changes were evident, a second objective was to provide guidance to park management about the value of a long-term lake monitoring program. Secchi-disk clarity, water temperature, and pH of the lakes in 1988 were within the range of values obtained between 1990 and 1993. Conductivities and concentration of nutrients in some lakes were not consistent in 1990–1993 with the values recorded in 1988. Although the dominant phytoplankton taxa in die lakes varied among years, die taxa in individual lakes were in consistent among years, with die exception of two lakes. Rotifer assemblages were consistent among years, but most of die lakes exhibited dramatic changes in some years, as did crustacean zooplankton assemblages. Suggestions were made about die need for a long-term monitoring program to evaluate die status and trends of park lakes.

Washington↗
USGS2013

Lakes without Landsat? Implications of scale and an alternative approach to regional remote lake monitoring using MODIS 250 m imagery

We evaluated use of MODIS 250 m imagery for remote lake monitoring in Maine. Despite limited spectral resolution (visible red and near infrared bands), the twice daily image capture has a potential advantage over conventionally used, often cloudy Landsat imagery (16 day interval) when short time windows are of interest. We analyzed 364 eligible (≥100 ha) Maine lakes during late summer (Aug–early Sep) 2000–2011. The red band was strongly correlated with natural log-transformed Secchi depth (SD), and the addition of ancillary lake and watershed variables explained some variability in ln(SD) (R 2 = 0.68–0.85; 9 models). Weak spectral resolution and variable lake conditions limited accurate lake monitoring to relatively productive periods in late summer, as indicated by inconsistent, sometimes weak regressions during June and July when lakes were clearer and less stable (R 2 = 0.19–0.74; 8 models). Additionally, SD estimates derived from 2 sets of concurrent MODIS and Landsat imagery generally did not agree unless Landsat imagery (30 m) was resampled to 250 m, likely owing to various factors related to scale. Average MODIS estimates exceeded those of Landsat by 0.35 and 0.49 m on the 2 dates. Overall, MODIS 250 m imagery are potentially useful for remote lake monitoring during productive periods when Landsat data are unavailable; however, analyses must occur when algal communities are stable and well-developed, are biased toward large lakes, may overestimate SD, and accuracy may be unreliable without non-spectral lake predictors.

Maine↗
USGS2013

Comparing rapid and culture indicator bacteria methods at inland lake beaches

A rapid method, quantitative polymerase chain reaction (qPCR), for quantifying indicator bacteria in recreational waters is desirable for public health protection. We report that replacing current Escherichia coli standards with new US Environmental Protection Agency beach action values (BAVs) for enterococci by culture or qPCR may result in more advisories being posted at inland recreational lakes. In this study, concentrations of E. coli and enterococci by culture methods were compared to concentrations of Enterococcus spp. by qPCR at 3 inland lake beaches in Ohio. The E. coli and enterococci culture results were significantly related at all beaches; however, the relations between culture results and Enterococcus spp. qPCR results were not always significant and differed among beaches. All the qPCR results exceeded the new BAV for Enterococcus spp. by qPCR, whereas only 23.7% of culture results for E. coli and 79% of culture results for enterococci exceeded the current standard for E. coli or BAV for enterococci.

Lake and Reservoir Management↗
USGS2013

Between- and within-lake responses of macrophyte richness metrics to shoreline developmen

A quatic habitat in littoral environments can be affected by residential development of shoreline areas. We evaluated the relationship between macrophyte richness metrics and shoreline development to quantify indicator response at 2 spatial scales for Minnesota lakes. First, the response of total, submersed, and sensitive species to shoreline development was evaluated within lakes to quantify macrophyte response as a function of distance to the nearest dock. Within-lake analyses using generalized linear mixed models focused on 3 lakes of comparable size with a minimal influence of watershed land use. Survey points farther from docks had higher total species richness and presence of species sensitive to disturbance. Second, between-lake effects of shoreline development on total, submersed, emergent-floating, and sensitive species were evaluated for 1444 lakes. Generalized linear models were developed for all lakes and stratified subsets to control for lake depth and watershed land use. Between-lake analyses indicated a clear response of macrophyte richness metrics to increasing shoreline development, such that fewer emergent-floating and sensitive species were correlated with increasing density of docks. These trends were particularly evident for deeper lakes with lower watershed development. Our results provide further evidence that shoreline development is associated with degraded aquatic habitat, particularly by illustrating the response of macrophyte richness metrics across multiple lake types and different spatial scales.

Minnesota↗
USGS2014

Influence of variable rainbow smelt and gizzard shad abundance on walleye diets and growth

Prey availability influences growth and condition of walleye ( Sander vitreus ) in large systems. In Lake Oahe, South Dakota, rainbow smelt ( Osmerus mordax ) and gizzard shad ( Dorosoma cepedianum ) are primary prey of walleye, but their abundance varies substantially year to year. To evaluate the influence of gizzard shad and rainbow smelt on walleye diets and growth in Lake Oahe, we compared recent estimates of walleye diets and growth in 2008 through 2010 with those from the late 1990s and early 2000s. Walleye diets differed seasonally with increased piscivory in July and October. In 2008, gizzard shad were the dominant prey item of walleye, representing about 60% of the diets by weight; however, by 2009, gizzard shad declined appreciably in the diet (22%) and were completely absent from walleye diets by 2010. Conversely, rainbow smelt abundance represented 12%, 27%, and 90% of walleye diets by weight in 2008, 2009 and 2010, respectively. Changes in growth corresponded to changes in diets, with the slowest growth occurring when gizzard shad were dominant in the diets and increasing growth every year thereafter. Because gizzard shad are only available during short periods (<3 months) in late summer, walleye can only achieve about 50% of their annual maintenance energy requirements from this prey source. Conversely, rainbow smelt, which are available and consumed year round, provide a continuous energy source that contributes to high growth rates. Nonetheless, when abundant, gizzard shad may provide an important subsidy to Lake Oahe walleye during periods of low rainbow smelt abundance.

Lake and Reservoir Management↗
USGS2015

Preliminary evaluation of an in vivo fluorometer to quantify algal periphyton biomass and community composition

The bbe-Moldaenke BenthoTorch (BT) is an in vivo fluorometer designed to quantify algal biomass and community composition in benthic environments. The BT quantifies total algal biomass via chlorophyll a (Chl- a ) concentration and may differentiate among cyanobacteria, green algae, and diatoms based on pigment fluorescence. To evaluate how BT measurements of periphytic algal biomass (as Chl- a ) compared with an ethanol extraction laboratory analysis, we collected BT- and laboratory-measured Chl- a data from 6 stream sites in the Indian Creek basin, Johnson County, Kansas, during August and September 2012. BT-measured Chl- a concentrations were positively related to laboratory-measured concentrations ( R 2 = 0.47); sites with abundant filamentous algae had weaker relations ( R 2 = 0.27). Additionally, on a single sample date, we used the BT to determine periphyton biomass and community composition upstream and downstream from 2 wastewater treatment facilities (WWTF) that discharge into Indian Creek. We found that algal biomass increased immediately downstream from the WWTF discharge then slowly decreased as distance from the WWTF increased. Changes in periphyton community structure also occurred; however, there were discrepancies between BT- and laboratory-measured community composition data. Most notably, cyanobacteria were present at all sites based on BT measurements but were present at only one site based on laboratory-analyzed samples. Overall, we found that the BT compared reasonably well with laboratory methods for relative patterns in Chl- a but not as well with absolute Chl- a concentrations. Future studies need to test the BT over a wider range of Chl- a concentrations, in colored waters, and across various periphyton assemblages.

Kansas↗
USGS2018

Effects of water level and climate on the hydrodynamics and water quality of Anvil Lake, Wisconsin, a shallow seepage lake

Interannual differences in the water quality of Anvil Lake, Wisconsin, were examined to determine how water level and climate affect the hydrodynamics and trophic state of shallow lakes, and their importance compared to anthropogenic changes in the watershed. Anvil Lake is a relatively pristine seepage lake with hydrology dominated by precipitation, evaporation, and groundwater exchange enabling the typically subtle effects of water level and climate to be evaluated. Groundwater and hydrodynamic models were used to describe lake water and phosphorus budgets and how its hydrodynamics are affected by water level and air temperature. Decreases in water level are expected to cause Anvil Lake and other shallow lakes to stratify fewer days, and have warmer bottom temperatures and more deep-mixing events. Increasing air temperatures should cause these lakes to have shorter ice cover, longer summer stratification periods, and warmer bottom temperatures. How water level affects water quality depends on how nutrient loading and lake volume vary: during drier, low-water years, lakes with large interannual changes in loading should have better water quality, whereas lakes with small changes in loading should degrade slightly. Anthropogenic changes in Anvil Lake's watershed over the past ∼100 yr were about 1.5 times the effects of changes in water level when levels were low, but the effects were similar when levels were high. Climate warming is expected to increase productivity in shallow lakes because warmer air temperatures will likely increase bottom temperatures increasing sediment phosphorus release and deep-mixing events enabling this phosphorus to reach the epilimnion.

Wisconsin↗
USGS2018

Segmentation of Mississippi’s natural and artificial lakes

Segmentations divide a diverse resource into groups, or segments, based on distinctive attributes that may respond similarly to management actions. A 4-way segmentation based on lake origin (natural or artificial) and size (small or large) was constructed for Mississippi lakes using a 30 yr data set. We aimed to document elements distinguishing these segments to understand relationships among them and to seek insight into lake management that may be apparent at the segment scale but not at the lake scale. Analyses pinpointed differences among the 4 segments relative to nutrient levels, fish assemblage composition, fishery characteristics, angler catch, and fishery management objectives. In general, most artificial lakes were eutrophic, varied widely relative to species composition depending on whether they impounded small or large rivers, their fish assemblages could be heavily influenced by stocking, provided principally centrarchid fisheries, and the management focus was on angler harvest. Most natural lakes were hypereutrophic, included higher species richness, provided a greater diversity of fisheries, and the management focus was on fish populations and habitat. Fishing success was similar across segments. The group-wise differences substantiate the segmentation and bring into focus a new level of concepts not typically relevant when considering lakes in isolation, such as issues about lake quantities, similarities, and geographical distributions. The segmentation represents the framework needed for considering lakes as parts of a larger and interactive management system.

Mississippi↗
USGS2019

Annual variations in microcystin occurrence in Upper Klamath Lake, Oregon, based on high-throughput DNA sequencing, qPCR, and environmental parameters

Cyanobacteria-dominated blooms in Upper Klamath Lake, Oregon, create poor water quality and produce microcystins that may be detrimental to local wildlife and human health. Genetic tools, including high-throughput DNA sequencing and quantitative polymerase chain reaction (qPCR), have been shown to improve the identification and quantification of key groups associated with these blooms over more traditional techniques. We examined the seasonal and interannual variations in nutrient (nitrogen and phosphorus) concentrations between 2013 and 2014 to describe the relations between these factors and the growth dynamics of Aphanizomenon and toxigenic Microcystis as described by DNA sequencing and qPCR. Although total nutrients and chlorophyll a concentrations were similar between years, qPCR results showed the cyanobacterial populations to be 40 times larger in 2014 and indicated a large shift from an Aphanizomenon -dominant, low microcystin-level regime in 2013 to one dominated later in the season by microcystin-producing Microcystis in 2014. In both years, the transition from Aphanizomenon to Microcystis was coincident with a late-season increase in nitrite-plus-nitrate concentrations and in dissolved inorganic nitrogen to dissolved inorganic phosphorus (DIN:DIP) ratios. However, these increases did not explain the large interannual differences in total cyanobacteria abundance. Rather, we hypothesized that year-to-year differences in bioavailable phosphorus, which also manifested as lower total nitrogen to total phosphorus (TN:TP) ratios, were responsible.

Oregon↗
USGS2019

Adapting to climate change: Guidance for the management of inland glacial lake fisheries

Climate change is altering glacial lake fisheries in the United States, presenting a complex challenge for fisheries managers. Here we provide a regional perspective to guide management of heterogeneous and yet interdependent fishery resources in glacial lakes of the upper Midwest. Our main objective was to promote the adaptation of inland glacial lakes fisheries management to climate change by outlining processes that support regional plans. Using examples from the glacial lakes region, we outline an approach for regional prioritization, specify strategies for moving from regional prioritization to on-the-ground action, and provide guidance on the implementation of management plans given resource limitations and potential stakeholder conflict. We find that integrating ecological, social, and economic data with climate change vulnerability assessments can be useful in generating “lake-priority levels” to help identify where to focus actions to support system resilience. Managers can use lake-priority levels and ecosystem-specific strategies to make decisions about where and when to apply fisheries management action ranging from traditional (i.e., stocking, harvest regulations) to nontraditional approaches (i.e., catchment land management). Although the implementation of several approaches may be beyond an agency’s financial and logistical capacity, funds can be secured through other sources ranging from grant programs to nontraditional partnerships identified by “thinking outside the lake.” Regional plans may be an important step toward successful climate adaptation for inland glacial lakes fisheries management, and the proactive efforts of managers may help facilitate their development and implementation.

Michigan, Minnesota, Wisconsin↗
USGS2020

Importance of accurately quantifying internal loading in developing phosphorus reduction strategies for a chain of shallow lakes

The Winnebago Pool is a chain of 4 shallow lakes in Wisconsin. Because of high external phosphorus (P) inputs to the lakes, the lakes became highly eutrophic, with much P contained in their sediments. In developing a total maximum daily load (TMDL) for these lakes, it is important to determine how their phosphorus concentrations should respond to changes in external P loading. In many TMDLs, internal P loading is assumed to be negligible or it is estimated based on sediment release rates and dissolved oxygen conditions in the lake, and each lake is considered independently. To evaluate these assumptions, internal P loading and external P loading were quantified by developing detailed P budgets for the Winnebago Pool chain of lakes. This information was then inputted into 2 eutrophication models (BATHTUB and Jensen models), which were used to simulate the steady-state and transient effects of various P reduction strategies. The importance of internal P loading varied among lakes, from being a minor source to representing almost 60% of the summer P input. Model results indicate that each lake responds to external P reductions, but internal loading can delay the lake responses, especially in the most downstream lake, Lake Winnebago, where internal P loading was most important to its summer P budget. Accurately quantifying net internal P loading and using this information in lake models are important in evaluating how large shallow lakes should respond to P reduction strategies, setting realistic expectations from watershed P reductions, and guiding TMDL efforts.

Wisconsin↗
USGS2020

Rapid-assessment test strips: Effectiveness forcyanotoxin monitoring in a northern temperate lake

Precise and rapid methods of determining toxin levels are needed in lakes used for recreation and drinking water to facilitate a quick risk assessment during cyanobacteria blooms. Therefore, we evaluated rapid-assessment test strips, a newer technology for estimating the toxicity of cyanobacterial blooms, in Kabetogama Lake, a popular recreational area of Voyageurs National Park in northern Minnesota (USA). Sixty-seven percent of the test strip results matched results of enzyme-linked immunosorbent assays, with individual toxin results of 75% (anatoxin-a), 80% (cylindrospermopsin), and 64% (microcystin). These results provide some evidence that the test strips may be effective for rapid detection of toxins in northern temperate lakes, although improvements to the test strips may be beneficial. Despite the intensive processing required and uncertainty of some results, the availability of a rapid and inexpensive field method allowed us to sample opportunistically in the fall, when we documented dangerously high toxin concentrations at places where waterfowl-retrieving dogs may be at particular risk of exposure.

Minnesota↗
USGS2021

Artificial lights with different spectra do not alter detrimental attraction of young Chinook salmon and sockeye salmon along lake shorelines

Artificial light at night (ALAN) is common in lakes with developed shorelines, especially prevalent in the nearshore areas where juvenile fishes, including salmonids, are present. One concern is that fishes may be attracted to ALAN and become more vulnerable to predators. The use of longer wavelength lights has been suggested to reduce the effects of ALAN; however, the response in juvenile salmonids is not well known. We tested the hypothesis that longer wavelength lights would attract fewer subyearling Chinook salmon ( Oncorhynchus tshawytscha ) and sockeye salmon ( O. nerka ) than shorter wavelength lights. Test lights included 4 LED lights, an incandescent light, and a high-pressure sodium light (HPS). In total, 13 experimental trials were conducted in 2017 and 2018, and in total 1769 Chinook salmon and 870 sockeye salmon were collected with beach seines. The mean catch rate (number per beach seine set) of subyearling salmonids was 51.0 for lighted treatments but only 6.6 for control treatments (no light). In both years, we did not find any significant difference in catch rates for either species between either of the longer wavelength lights (red-filter and yellow-filter LED lights) and other lights, and thus we rejected the hypothesis that longer wavelength light would attract fewer subyearling salmonids. For these early life stages of salmon in shallow shoreline habitats, reducing the intensity of light present is likely more important than altering the spectral composition when trying to minimize maladaptive attraction to ALAN.

Washington↗
USGS2021

Hydrology of annual winter water level drawdown regimes in recreational lakes of Massachusetts, United States

Annual winter water level drawdown (WD) is a common lake management strategy to maintain recreational value by controlling nuisance macrophytes and preventing ice damage to shoreline infrastructure in lakes of the northeastern United States. The state of Massachusetts provides general guidelines for lake managers to implement and practice WDs. However, WD management reporting is not required and as such empirical water level records are scarce, making it difficult to assess guideline adherence and link these management actions to littoral habitat conditions. We monitored water levels bihourly in 18 lakes with ongoing WD regimes and 3 non-drawdown lakes over 3–4 yr. Our results show an interlake drawdown magnitude gradient of 0.07–2.66 m with intralake consistency across years. Corresponding WD magnitudes generated exposure of 1.3–37.6% for entire lakebeds and 9.2–71.1% for littoral zones. WD durations averaged 171 d and ranged widely from 5 to 246 d. Longer recession and refill phase durations and faster recession rates were moderately to strongly correlated with drawdown magnitudes. WDs were predominantly initiated prior to the state of Massachusetts 1 November starting guideline (83.1%) and refilled to summer reference levels after the recommended date of 1 April (70.6%). To minimize ecological impacts while still meeting recreational goals, WD performance guidelines may require a more fine-scale approach that integrates local hydrogeomorphic features and the presence of WD-sensitive littoral biotic assemblages. However, climate change model projections of warmer and wetter winters in the Northeast indicate increasing uncertainty for WD as an effective and worthwhile macrophyte control tool.

Massachusetts↗
USGS2021

An experimental evaluation of the efficacy of imaging flow cytometry (FlowCam) for detecting invasive Dreissened and Corbiculid bivalve veligers

Zebra ( Dreissena polymorpha ) and quagga ( D. bugensis ) mussels, first introduced from central Asia into the Great Lakes of North America in the late 1980s, have crossed the continental divide and more recently spread across western North America. At the same time, several new technologies have been developed for the early detection of dreissenids, including the FlowCam, a digital imaging-in-flow instrument, intended to detect dreissenid planktonic larvae (veligers). However, the efficacy of this technology has rarely been tested. We experimentally evaluated the FlowCam’s ability to capture identifiable images of quagga mussel veligers under 2 different types of conditions: (i) deionized water, and (ii) Columbia River Basin water (CRBW), including natural sediment and native plankton. We further evaluated the FlowCam’s ability to distinguish between dreissenid veligers and corbiculid veligers (Asian clam, Corbicula fluminea ). We interpret our results to indicate that the FlowCam can consistently detect dreissenid veligers across a range of veliger densities. Moreover, the presence of other plankton and detritus only slightly affected dreissenid detection by the FlowCam. However, the orientation of individual bivalve veligers as they were imaged by the FlowCam precluded specific identification of a substantial proportion (24.8%) of veligers as either dreissenid or corbiculid. We suggest that the FlowCam is an important detection tool best utilized as part of a multifaceted approach, including traditional microscopy and possibly environmental DNA.

Lake and Reservoir Management↗
USGS2024

Comparison of imaging flow cytometry and microscopy for freshwater algal bloom detection

Imaging flow cytometry (IFC) is an emerging tool that allows for rapid identification and enumeration of phytoplankton in freshwater systems. However, few studies have assessed the effects of preservation on IFC results or compared live IFC and microscopy results in freshwater systems. Understanding the effects of preservation and differences between IFC and microscopy will improve interpretation of these data and inform strategies to use IFC-based approaches in freshwater systems. Our study objectives were to compare IFC and phase contrast with epifluorescence microscopy as techniques for phytoplankton identification and enumeration, and the effects of sample preservation with an emphasis on taxa forming harmful cyanobacterial blooms (HCBs). During June through October 2020, samples were collected from 2 lakes in the Finger Lakes region of New York. Live and preserved samples were analyzed by laboratory-based IFC, and preserved samples were analyzed by microscopy. The IFC approach captured community dynamics while detecting potential cyanobacterial bloom-forming taxa earlier and at lower abundances than microscopy. Laboratory-based IFC allowed for an intermediate level of taxonomic information when compared to microscopy, gross techniques, such as extracted chlorophyll a or fluorescence sensors, and field-based operation of IFC approaches. The laboratory-based application of IFC in this study allowed receipt of results in 5 d or less, a substantial improvement over microscopy, which can be time-consuming to conduct. However, the laboratory-based IFC approach had some limitations. Imaging flow cytometry-estimated biovolume may be less accurate than microscopy for some taxa because of the algorithms used to calculate biovolume, particularly for chrysophytes and coccoid cyanobacteria. Colonial dissociation during preservation appeared to affect detection of Microcystis by IFC less than for other fragile bloom-forming taxa like chrysophytes. Our study results advance understanding of how IFC may translate to field-based approaches for early harmful algal bloom indicators in freshwater.

Lake and Reservoir Management↗