Data from selected U.S. Geological Survey National Stream Water-Quality Networks (WQN)

Alexander, Richard B.; Slack, James Richard; Ludtke, Amy S.; Fitzgerald, K.K.; Schertz, Terry L.; Briel, L.I.; Buttleman, Kim P.

doi:10.3133/ds37

Cited by 26 publications

(49 citation statements)

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“…Water-quality monitoring data-Regularly collected water-quality data were obtained from long-term monitoring stations in the U.S. Geological Survey's National Stream Quality Accounting Network (NASQAN; for details, see Alexander et al 1996;Hooper et al 2001). We selected 250 stations (see Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Water-quality records extend through 2001 at 27 of the stations, the latest year for which data were retrieved. The set of 250 stations provides a geographically representative description of the water quality of major rivers of the U.S. (Smith et al 1993;Alexander et al 1996; see Tables 1 and 2). Table 2 compares land use and population characteristics of the monitoring stations with those for the hydrologic cataloging units, a national set of officially defined watersheds (Seaber et al 1987) that are generally representative of the physiography, land use, and population in the drainage basins of large rivers of the United States (the characteristics of the monitoring station watersheds in Table 2 are generally similar to those reported for the national set of hydrologic cataloging units).…”

Section: Methodsmentioning

confidence: 99%

“…Detailed comparisons of the nutrient trends with contemporaneous changes in agricultural nutrient sources were made for the 24 monitoring stations located in predominantly agricultural watersheds. Changes in fertilizers (Alexander and Smith 1990;B. Ruddy pers.…”

Section: Methodsmentioning

confidence: 99%

“…Based on a review of available historical information on USGS field and laboratory methods (Schertz et al 1994;Alexander et al 1996), we evaluated the nutrient trends for the effects of possible measurement errors during the 1980 to 1986 period, related to the use of mercuric chloride tablets as a sample preservative. A previous study of laboratory blanks indicated that kjeldahl nitrogen measurements during this period potentially contained nitrogen contamination (Ͻ0.5 mg L Ϫ1 ) related to the use of a tablet form of a mercuric chloride preservative (Schertz et al 1994).…”

Section: Methodsmentioning

confidence: 99%

“…A previous study of laboratory blanks indicated that kjeldahl nitrogen measurements during this period potentially contained nitrogen contamination (Ͻ0.5 mg L Ϫ1 ) related to the use of a tablet form of a mercuric chloride preservative (Schertz et al 1994). In addition, semiannual laboratory analyses of spiked standard reference samples for dissolved substances, conducted as part of a regular external audit program, indicated a possible positive measurement error in phosphorus during 1980-1981(Alexander et al 1996. We assessed the effects of these potential measurement errors by testing the sensitivity of the nutrient trend results to the measurements reported for the 1980-1986 time period; in the analysis, we eliminated all total nutrient observations from the station records during the period 1980-1986 and retested the records for trends.…”

Section: Methodsmentioning

confidence: 99%

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Trends in the nutrient enrichment of U.S. rivers during the late 20th century and their relation to changes in probable stream trophic conditions

Alexander

Smith

2006

Limnology & Oceanography

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We estimated trends in concentrations of total phosphorus (TP) and total nitrogen (TN) and the related change in the probabilities of trophic conditions from 1975 to 1994 at 250 nationally representative riverine monitoring locations in the U.S. with drainage areas larger than about 1,000 km 2 . Statistically significant (p Ͻ 0.05) declines were detected in TP and TN concentrations at 44% and 37% of the monitoring sites, and significant increases were detected at 3% and 9% of the sites, respectively. We used a statistical model to assess changes in the probable trophic-state classification of the sites after adjusting for climate-related variability in nutrient concentrations. The probabilistic assessment accounts for current knowledge of the trophic response of streams to nutrient enrichment, based on a recently proposed definition of ''eutrophic,'' ''mesotrophic,'' and ''oligotrophic'' conditions in relation to total nutrient concentrations. Based on these trophic definitions, we found that the trophic state improved at 25% of the monitoring sites and worsened at fewer than 5% of the sites; about 70% of the sites were unchanged. Improvements in trophic-state related to declines in TP were more common in predominantly forested and shrubgrassland watersheds, whereas the trophic state of predominantly agricultural sites was unchanged. Despite the declines in TP concentrations at many sites, about 50% of all monitoring sites, and more than 60% of the sites in predominantly agricultural and urban watersheds, were classified as eutrophic in 1994 based on TP concentrations. Contemporaneous reductions in major nutrient sources to streams, related to wastewater treatment upgrades, phosphate detergent bans, and declines in some agricultural sources, may have contributed to the declines in riverine nutrient concentrations and associated improvements in trophic conditions.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Trends in the nutrient enrichment of U.S. rivers during the late 20th century and their relation to changes in probable stream trophic conditions

Alexander

Smith

2006

Limnology & Oceanography

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Assessing the Utility of Otolith Chemistry for Management of Six Freshwater Fishes from a River–Reservoir System

Radigan

Carlson

Graeb

et al. 2018

N American J Fish Manag

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Floodplain habitats often function as spawning, rearing, foraging, and refuge environments for riverine fishes. Although floodplain habitats are important for fish production and recruitment, their natal contributions may vary by species, a topic that has not been thoroughly investigated in large floodplain rivers. We evaluated the natal contributions of floodplain habitats to populations of six socioeconomically important sport fishes in Lake Sharpe, South Dakota, using otolith chemistry. Water samples and age‐0 and adult fishes were sampled from five habitat types (canal, embayment, main channel, stilling basin, tributary). Age‐0 fishes were classified to known natal habitats with 83% mean accuracy based on otolith Ba:Ca and Sr:Ca signatures, with 89% mean accuracy for Bluegill Lepomis macrochirus (89%), crappies Pomoxis spp. (88%), and Largemouth Bass Micropterus salmoides (91%). Floodplain habitats had substantial natal contributions to Bluegill (50%) and crappie (35%) populations. Despite spanning only 0.8% of Lake Sharpe by surface area, a specific floodplain habitat (Hipple Lake) contributed 15% of Largemouth Bass to the Lake Sharpe population—19 times greater than expected under a linear contribution–area relationship. Floodplain habitats had smaller natal contributions (0–5%) for reservoir‐oriented species such as Smallmouth Bass M. dolomieu and White Bass Morone chrysops than for centrarchids and Yellow Perch Perca flavescens. Given that floodplain habitats in Lake Sharpe, particularly Hipple Lake, are disproportionately important for sport fish populations relative to their size, maintaining river–floodplain connectivity is crucial for effective fisheries management. Otolith chemistry is a tool for sport fish management in Lake Sharpe as it reveals habitat‐specific natal contributions of diverse species and can be used to prioritize areas for floodplain protection and rehabilitation, harvest regulations, stock enhancement, and other fisheries management activities.

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Otolith‐Chemistry‐Based Discrimination of Wild‐ and Hatchery‐Origin Steelhead across the Lake Michigan Basin

Watson

Prichard

Jonas

et al. 2018

N American J Fish Manag

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Effective conservation and management of mixed-stock fisheries depends upon accurate stock identification of individual fish. We evaluated the utility of otolith chemical analysis as an approach to classify juvenile, premigratory steelhead Oncorhynchus mykiss collected in tributaries of Lake Michigan as either wild or hatchery origin. Two primary hypotheses proposed were that otolith chemistry can be used (1) to classify juvenile, hatchery-origin steelhead to the correct hatchery of origin and (2) to correctly classify stream-collected juvenile steelhead as wild or hatchery origin. Using laser-ablation inductively coupled plasma mass spectrometry, we analyzed the concentrations of seven elements (using 25 Mg, 55 Mn, 65 Cu, 66 Zn, 88 Sr, 137 Ba, 208 Pb) in the otoliths of juvenile steelhead collected from five hatcheries and 25 streams in the Lake Michigan basin. When discriminating among hatcheries, only 4.41% of fish misclassified to an alternate hatchery when subjected to the best random forest classification algorithm that included all elements as predictor variables. Distinct chemical signatures between fish of wild and hatchery origin supported 100% classification accuracies of known-wild, age-0 steelhead as wild origin for 19 of the 25 streams sampled. Misclassification of wild, age-0, and hatchery-origin fish, which tended to occur for streams that were located in close proximity to the hatchery, never exceeded 3.4% for a given stream. Our findings demonstrate highly successful discrimination of hatchery-origin and wild juvenile steelhead across a broad geographic range. Applying the classification algorithms developed herein to unknown-origin steelhead provides the ability to infer survival of year-classes from specific hatcheries. Further, the ability to differentiate hatchery-and wild-origin fish will assist in stock assessment efforts allowing for increased effectiveness of conservation and management of the species.

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Data from selected U.S. Geological Survey National Stream Water-Quality Networks (WQN)

Cited by 26 publications

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Trends in the nutrient enrichment of U.S. rivers during the late 20th century and their relation to changes in probable stream trophic conditions

Trends in the nutrient enrichment of U.S. rivers during the late 20th century and their relation to changes in probable stream trophic conditions

Assessing the Utility of Otolith Chemistry for Management of Six Freshwater Fishes from a River–Reservoir System

Otolith‐Chemistry‐Based Discrimination of Wild‐ and Hatchery‐Origin Steelhead across the Lake Michigan Basin

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