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Eldridge SLC, Wood TM. 2019. Annual variation in microcystin occurrence in Upper Klamath Lake, Oregon, based on high-throughput DNA sequencing, qPCR, and environmental parameters. Lake Reserv Manag...

Seasonal phytoplankton blooms dominated by cyanobacteria in Upper Klamath Lake, Oregon, produce toxic microcystins at concentrations that may be detrimental to local wildlife. In 2009, water column, sediment trap, and surficial sediment samples were collected to relate the occurrences of microcystins in these samples to other environmental variables. Microcystin concentrations in sediment trap and surficial sediment samples were lower than in water column samples, and sediment trap samples contained higher concentrations than surficial sediment samples, with a peak in one sample (1107 μg/g) that exceeded the maximum concentration measured in any other water or sediment sample from this area. Concentrations of microcystins and cells of Microcystis aeruginosa increased following the decline of the first bloom dominated by non-microcystin-producing Aphanizomenon flos-aquae in response to an increase in nitrogen and phosphorus concentrations. Results of this study also show that nitrogen fixation by ...

Radiotelemetry was used to investigate the summer distribution and diel habitat associations of endangered adult Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris in northern Upper Klamath Lake, Oregon. From 2002 to 2004, Lost River and shortnose suckers were tracked by boat, and water depth and water quality were measured at each fish location. A series of water quality monitors were deployed in northern Upper Klamath Lake to provide temporal information on ambient temperature, pH, and dissolved oxygen, and water samples were collected to assess chlorophyll a concentration. Suckers moved into northern Upper Klamath Lake during June and began to leave in late September each year. Kernel density estimates revealed differences in the distribution in the northern portion of Upper Klamath Lake in 2002 and 2004. In 2003, however, both Lost River and shortnose suckers were commonly located within and offshore from Pelican Bay, a shallow (1.0-2.0 m), groundwater-influenc...

Removing dams and levees to restore hydrologic connectivity and enhance ecosystem services such as nutrient removal has been an increasingly common management practice. In the present study, the authors assessed geochemical and biological changes following engineered levee breaches that reconnected eutrophic Upper Klamath Lake and Agency Lake, Oregon, USA, to an adjacent, historic wetland that had been under agricultural use for the last seven decades. Over the three-year study, the reconnected wetland served as a benthic source for both macronutrients (dissolved organic carbon [DOC], soluble reactive phosphorus [SRP], and ammonia) and micronutrients (dissolved iron and manganese). The magnitude of those benthic sources was similar to or greater than that of allochthonous sources. The highest DOC benthic flux to the water column occurred immediately after rewetting occurred. It then decreased during the present study to levels more similar to the adjacent lake. Dissolved ammonia fluxes, initially negative after the levee breaches, became consistently positive through the remainder of the study. Nitrate fluxes, also initially negative, became negligible two years after the levee breaches. In contrast to previous laboratory studies, SRP fluxes remained positive, as did fluxes of dissolved iron and manganese. Our results indicate that the timescales of chemical changes following hydrologic reconnection of wetlands are solute-specific and in some cases extend for multiple years beyond the reconnection event. During the present study, colonization of the reconnected wetlands by aquatic benthic invertebrates gradually generated assemblages similar to those in a nearby wetland refuge and provided further evidence of the multiyear transition of this area to permanent aquatic habitat. Such timescales should be considered when developing water-quality management strategies to achieve wetland-restoration goals.

A new numerical model for the fate and transport of nonconservative metals in an estuarine environment is introduced. ELAmet solves the depth-averaged advection/dispersion/transformation equation on a two-dimensional grid using a finite element formulation in an Eulerian-Lagrangian framework. The model incorporates aqueous speciation and adsorption/desorption. Adsorption to any number of solid types can take place through linear (partitioning) reactions or nonlinear (complexation) reactions. The model accommodates chemical equilibria and kinetics simultaneously. Rate constants can span any range of time scales, as the computational time step for solving the chemical transformation equations has been decoupled from that dictated by the circulation. Verification of the model is included for a one-dimensional channel and up to 15 chemical species. Preliminary applications are included which illustrate the concept of diagnostic modeling for a synthetic estuarine system in which the effects of source location, chemical kinetics, and sediment deposition on the mixing plot are examined.

Geographical variations in the variance and cross-correlation of monthly mean sea surface temperature (SST), outgoing longwave radiation (OLR, a proxy for deep convection and vertical motion), and convergence of winds at the surface and at 850 mb across the tropical Indian and Pacific oceans are examined. Within about 10° of the equator at most longitudes the variance of these quantities associated with the seasonal cycle is less than the variance associated with anomalies from the seasonal cycle. Largest variances in the SST and surface convergence data occur across the eastern near-equatorial Pacific, whereas OLR and 850 mb convergence variances are largest across the western Pacific. OLR anomalies are significantly correlated with collocated SST and surface convergence anomalies from the date line eastward to the South American coast, but are uncorrelated west of the. date line. The OLR and 850 mb convergence anomalies are significantly correlated from about 120°W westward but are uncorrelated...

The hydrodynamics in the Upper Klamath Lake (UKL) plays a significant role in the water quality conditions of the lake. In order to provide a quantitative evaluation of the impacts of hydrodynamics on water quality in UKL, a detailed hydrodynamic model was implemented using an unstructured grid 3-D hydrodynamic model known as the UnTRIM model. The circulation in UKL is driven primarily by wind. Wind speed and direction time-series records were used as input, the numerical model reproduced the wind set-up and set-down at down wind and upwind ends of the lake, respectively. Of the two acoustic Doppler current profiler (ADCP) records, the UnTRIM model reproduced the measured velocity at the deep station. At the shallow station, the model results showed diurnal patterns that correlated well with wind variations, but the measured velocity showed water velocity sustained at 3 to 5 cm/sec or above. Discrepancies between the model results and observations at the shallow ADCP station is discussed on the basis of correct physics. If the field measurements are inconsistent with the known physics, there exists the possibility that the field data are suspect or the field data are revealing some physical processes that are not yet understood.

For additional information contact: Copies of this report can bepurchased from:District ChiefU.S. Geological Survey USGS Information Services10615 S.E. Cherry Blossom Drive Box 25286, Federal CenterPortland, OR 97216-3159 Denver, CO 80225-0286E-mail: info-or@usgs.gov Telephone: 1-888-ASK-USGSInternet: http://oregon.usgs.govSuggested citation:Wood, T.M., 2001, Sediment oxygen demand in Upper Klamath and Agency Lakes, Oregon, 1999:U.S. Geological Survey Water-Resources Investigations Report 01–4080, 13 p.

This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Oregon Department of Transportation (ODOT), to evaluate the effects of the highway deicing material, calcium magnesium acetate (CMA), on the water quality of Bear Creek, in the Cascade Range of Oregon. ODOTO began using CAM (an alternative deicer that has fewer adverse environmental effects than road salt) in the mid-1990s and began this study with the USGS to ensure that there were no unexpected effects on the water quality of Bear Creek. Streamflow, precipitation, dissolved oxygen, pH, specific conductance, and water temperature were measured continuously through the 1998-99 winter.

A laterally averaged, two-dimensional model was used to simulate discharge, temperature, and water quality in the Tualatin River during the summers (May-October) of 1991, 1992, and 1993. During low-flow periods, the lower main stem of the Tualatin River (river miles 38.4 to 3.4) is characteristic of a long, slow-moving lake. Water-quality problems encountered during the summer include intermittent violations of the State of Oregon minimum dissolved oxygen and maximum pH standards, exceedances of the action level for nuisance phytoplankton growth, and impairment of several of its designated beneficial uses (aesthetics, aquatic life, and water-contact recreation). This river was modeled with a modified version of CE-QUAL-W2, a U.S. Army Corps of Engineers reservoir model that is appropriate for use on the lower main stem of the Tualatin River. Eighteen water-quality constituents were simulated: chloride, suspended solids, dissolved solids, dissolved organic matter, phytoplankton, detritus, soluble orthophosphate, ammonia, nitrate, dissolved oxygen, bottom sediment, total inorganic carbon, carbonate alkalinity, pH, carbon dioxide, bicarbonate, carbonate, and zooplankton; total phosphorus and carbonaceous biochemical oxygen demand were simulated by using a combination of these constituents. The model was calibrated for 18 months of data: May through October in each of 1991, 1992, and 1993. Only six calibration parameters were used for the water-quality routines in the model; of these, the model was most sensitive to the maximum algal growth rate and the zooplankton mortality rate. Values for most of the parameters required by the model were either independently measured or taken from the available literature. The maximum algal growth rate was varied over the summer in accordance with observed patterns in measured primary productivity rates. The zooplankton mortality rate was kept constant throughout each summer but was calibrated to different values for each year due to differences in observed zooplankton population levels. The calibration process resulted in a model that performed very well; it captured the dynamics of the most important water-quality processes in the lower main-stem Tualatin River during each of three hydrologically distinct summers. Accuracy in day-to-day fluctuations was sacrificed somewhat in order to more accurately simulate the overall cycle of algal growth for these 18 months while varying the calibration parameters only as absolutely necessary. This level of accuracy was sufficient to simulate the interactions among nitrogen, phosphorus, phytoplankton, zooplankton, and dissolved oxygen, but was insufficient to accurately simulate pH during every algal bloom. The ability to extrapolate beyond the calibrated conditions of the model, however, was determined to be more important than accurately simulating the pH during the shorter time scales of individual algal blooms; therefore, this calibration philosophy was retained, and the further calibration of pH was not pursued. Using the model as a diagnostic tool, a number of general conclusions were made during the calibration process: (1) Water quality in the lower main-stem Tualatin River is dominated by three physical constraints and conditions-residence time, air temperature, and insolation. dissolved oxygen standard, the phytoplankton were found to be important both in their presence and their absence. Violations of the standard in midsummer were usually associated with the crash of a large algal bloom; such violations were normally of short duration although the minimum dissolved oxygen concentration associated with a large crash may be less than 4 mg/L. Violations of the standard during September and October, on the other hand, were normally associated with small populations of phytoplankton. The CBOD and SOD consumed more oxygen during those periods than the small populations of phytoplankton were able to produce through photosynthesis.

In recent years, it has been well established that the (axial) angular momentum of the atmosphere and that of the solid earth are closely related on a variety of time scales. On the subseasonal scale, for example, 30–50 day atmospheric fluctuations are strongly mirrored in the rotation of the earth (Langley et al., 1981). On seasonal scales, annual and semiannual cycles in the momentum of the atmosphere are matched by those of the earth (Rosen and Salstein, 1985). At inter- annual time scales, features such as the El Nino-Southern Oscillation (ENSO) and the stratospheric quasi-biennial oscillation have been shown to be related to the earth’s rotation rate (Rosen et al., 1984; Chao, 1989). However, on the very shortest and longest time scales the atmospheric and geodetic momentum series appear to diverge, even when measured by the most recent techniques. The purpose of this note is to outline the character of the disagreement at these two time scales. A fuller discussion, including details of our analysis methods, appears in Rosen et al. (1990).

Modern geodetic and atmospheric data sets have demonstrated that changes in the solid earth's rotation rate are closely coupled to changes in the atmosphere's angular momentum over a range of subseasonal through interannual time scales. Nevertheless, limits to the correspondence between changes in the momenta of the two bodies exist at both ends of the spectrum resolvable by the data. It is shown that, at high frequencies, changes in the length of day as short as a fortnight can now be attributed almost entirely to atmospheric forcing; more rapid fluctuations in the length of day, however, cannot be shown to coincide with atmospheric behavior, a result blamed mostly on errors remaining in both the geodetic and atmospheric series rather than on the neglect of some other component of the momentum budget. On the decadal time scale, nonatmospheric processes, believed primarily to involve core-mantle coupling, dominate the global momentum budget.