Effects of beaver dam analogs on stream ecosystem function of Crab Creek, Washington State

This study documents the effects of beaver dam analogs (BDAs) on nutrient transport, fish community composition, macroinvertebrate drift, and benthic macroinvertebrate communities of Crab Creek, WA, USA. In 2019, the U.S. Fish and Wildlife Service (USFWS), and Natural Resource Conservation Service (NRCS) placed 25 BDAs in Crab Creek on a section of private land near Harrington, WA. Beaver dam analogs are structures placed in streams to mimic the ecosystem effects of beaver activity and are increasingly used as a stream restoration technique. The primary goals of placing these BDAs in the stream was to impound sediment and create a new floodplain at the currently incised stream channel. While BDAs are increasingly used as a stream restoration technique, there is limited research on their impacts on stream ecosystem function. Investigating how BDAs effect nutrient retention, macroinvertebrate communities, and fish community composition will help inform practitioners about the effectiveness of this restoration strategy. Crab Creek had a significantly higher density of red sided shiners (Richardsonius balteatus) (p=0.00175) in the BDA reach compared to control reaches. When comparing the BDA reach to the control sites, there were no significant differences in nutrient retention in the BDA site. Macroinvertebrate community response had limited statistically significant differences when compared to the control sites. However, there were significant changes from 2009 to 2020 when comparing benthic macroinvertebrate assemblages, probably in response to factors other than BDA installation. Altogether, few effects of BDA installation were detected for nutrient retention, macroinvertebrate communities, and fish community composition. BDAs are a process-based restoration technique that requires a significant change in physical ecosystem parameters before any changes are likely to be seen in the biological community or ecosystem processes. Changes to geomorphology of the stream could potentially take time, as these restoration techniques require stream energy to alter the physical parameters of the stream. Since BDA installation in Crab Creek, no significant high flow events have occurred. Without early spring flood events, changes in the nutrient dynamics, and macroinvertebrates communities could be subtle, or undetectable. This research will ultimately contribute to the current limited understanding of the effects of BDAs on stream ecosystem function

Determination of molecular hydrocyanic acid in water and studies of the chemistry and toxicity to fish of metal-cyanide complexes

A reliable, easy, and inexpensive method for determination of molecular hydrocyanic acid (HCN) in solutions of simple and complex metal cyanides is described. The method was used to determine molecular HCN concentrations as low as 0.005 milligram per liter, and can be used for determination of even lower levels. It is a modification of a previously published method. A concentration column of glass beads coated with NaOH is employed, on which HCN displaced by air that has been bubbled through solutions under examination is trapped and concentrated for measurement of cyanide by a conventional analytical method. The apparatus could easily be modified for use in both field and laboratory situations where only limited facilities are available. Time periods required for attainment of equilibria upon dilution of solutions of metal-cyanide complexes, and also when metal salts and free cyanide are combined, were quite variable and ranged from several hours for the silver-cyanide complex to many months for iron-cyanide complexes kept in the dark. In solutions in which CuCN and NaCN were combined so that the molar ratio of CN to Cu was either 2.5 to 1 or 3 to 1, constancy of the HCN concentration usually was not attained even 110 days after preparation. The time to attainment of equilibrium through dissociation of the nickelocyanide complex ions generally was longer than that required for equilibrium to be attained in comparable experiments on complex formation, and it increased as the pH or the total cyanide concentration decreased; it is directly related to the percentage of total cyanide present as HCN at equilibrium. Results obtained at high total cyanide concentrations in nickelocyanide formation experiments were anomalous but verifiable by bioassay with fish. The HCN concentrations were at first unexpectedly low and then increased very slowly to the higher equilibrium levels. Cumulative dissociation constants (K[subscript D]) at 20°C for the Ag(CN)₂⁻, Cu(CN)₂⁻, Ni(CN)₄⁻², Fe(CN)₆⁻⁴, and Fe(CN)₆⁻³ complex ions, calculated from equilibrium levels of HCN, are 1.94 ± 2.82 x 10⁻¹⁹, 3.94 ± 1.75 x 10⁻²⁴, 1.00 ± 0.37 x 10⁻³¹, approximately 10⁻⁴⁷, and 10⁻⁵², respectively. The calculated constants for the tetracyanonickelate (II) and dicyanoargentate (I) complex ions inexplicably varied somewhat, increasing slightly with increase in total cyanide concentration and pH. Those for the tetracyanonickelate (II) and dicyanocuprate (I) complex ions showed close agreement with values recently reported in the literature, whereas the constants for the dicyanoargentate (I) and hexacyanoferrate (II) and (III) complex ions were materially different from presently accepted values. Possible unreliability of presently accepted stepwise constants for the cuprocyanide complex ions also was indicated. The acute toxicity of solutions of the different metal-cyanide complexes was generally found to be a function of the molecular HCN level, which increases with increase of total cyanide concentration and with decrease of pH. In some solutions however, a metal-cyanide complex ion per se was shown to be the major toxic component. The 48-hour median tolerance limits for bluegills of the dicyanoargentate (I) and dicyanocuprate (I) ions at 20°C were found to be approximately 9 and 4 mg/l as CN, respectively. The metallocyanide complex ions studied can be arranged in order of decreasing toxicity as follows: Cu(CN)₂⁻, Ag(CN)₂⁻, Ni(CN)₄⁻², and Fe(CN)₆⁻³ or Fe(CN)₆⁻⁴. A published empirical relationship between pH and 48-hour median tolerance limits of the nickelocyanide complex for a fish, determined without assurance that equilibria had been attained in test solutions, was compared with a calculated, theoretical relationship. Considerable divergence of the empirical and theoretical curves at pH values less than about 7.2 is ascribable mostly to the introduction of fish into test solutions long before equilibria had been attained in the solutions of low pH. Divergence at pH values greater than about 7.8 is attributable largely to moderate toxicity of the Ni(CN)₄⁻² complex ion itself. Slightly alkaline solutions of the silver cyanide complex, Ag(CN)₂⁻, become more toxic to sticklebacks with increase of chlorinity. The high toxicity in saline solutions, as compared with the toxicity in fresh water, is clearly attributable, at least in part or in some instances, to a molecular HCN content of the saline solutions much greater than that of comparable solutions prepared with fresh water. The two ligands CN⁻ and Cl⁻ compete for the silver ion, with which both ligands form complexes, and dissociation of the Ag(CN)₂⁻ ion, with production of HCN, consequently increases as the Cl⁻ ion concentration increases. Additional reasons for the observed increase of toxicity of solutions of the complex with increase of chlorinity can be an observed increase of the toxicity of HCN and a possible, similar increase of the toxicity of the complex ion. Experiments with ¹⁴C-labeled cyanide complexed with nickel showed that the complex does not penetrate readily into the body of a bluegill. The ¹⁴C accumulated in gill tissues much more markedly than it did in the blood and in tissues of internal organs sampled. When bluegills were exposed to solutions of the cyanide complexes of copper (I) and silver (I), considerable amounts of the metals accumulated in the blood and in tissues of internal organs, but little accumulation in gill tissues was observed. These results indicate that the cuprocyanide and silver-cyanide complexes enter the body of a bluegill much more readily than does the much less toxic nickelocyanide complex. The silver cation, however, apparently enters even more readily than does the silver-cyanide complex anion, the silver accumulating most markedly in the gill tissues of bluegills exposed to silver nitrate solutions, but also in their internal organ tissues

Zoo Boise Skull Identification: Building Bridges - Connecting Scientific Analysis to Public Education Through Mammalian Skulls

Animal skulls tell us a lot about an animal’s lifestyle and are commonly used for educational displays to inspire public interest. In mammals, features such as teeth, jaws, and cranial morphology provide markers for feeding habits and ecological roles. In this project, mammalogy students partnered with Boise Zoo to identify unknown skulls using dichotomous keys to research unique skull features and functions. The goal of skull identification is to inform and educate the Zoo Boise visitors on the traits found in particular skulls and how researchers can make deductions about the animal’s lifestyle. The product of this work will follow interpretive education best practices and be used in interpretive interactions at the zoo. We present our knowledge and findings using an interpretive display to help the zoo and its visitors gain insight into the organisms that they may encounter during their visit. The results will give us a better understanding of how the skull’s physical traits connect to their families and provide interesting information that will help visitors learn about the diversity of animal families in a more hands-on way

A River Continuum Analysis of an Anthropogenically-Impacted System: The Little Bear River, Utah

In September 2012 the Aquatic Ecology Practicum class from Utah State University studied the 51km river continuum of the Little Bear River located in northern Utah (Figure 1). The relatively pristine headwaters of the river begin in the Wasatch Mountain Range at an altitude of 1800 m. The river flows northward into Cache Valley where it terminates in Cutler Reservoir (1345 m elevation). Agricultural development and urbanization have modified the natural terrain and chemical characteristics of the river, and Hyrum Reservoir, located midway along the gradient causes a discontinuity in river processes. The results from analyses of stream condition indicators from up to eleven stations along the gradient were interpreted within the context of the River Continuum Concept (Vannote et al. 1980) and the Serial Discontinuity Hypothesis (Ward and Stanford 1983)

Toxicity evaluation of metal plating wastewater employing the Microtox® assay: A comparison with cladocerans and fish

The relative sensitivity of the Microtox assay is closely related to the type of toxicant, and hence its utility in biomonitoring effluents is better evaluated on a case-by-case basis. The Microtox® assay, employing the marine bacterium Vibrio fischeri , was evaluated for its applicability in monitoring metal plating wastewater for toxicity. The results of the Microtox assay after 5, 15, and 30 min of exposure, were compared with data obtained from conventional whole effluent toxicity testing (WET) methods that employed Daphnia magna , Ceriodaphnia dubia , and the fathead minnow ( Pimephales promelas ). The Microtox assay produced notably comparable EC50 values to the LC50 values of the acute fathead minnow toxicity test (<0.5 order of difference). The Spearman's rank correlation analyses showed that the bacterial assay, regardless of exposure duration, correlated better with the acute fish than the daphnid results ( p <0.05). These observations were consistent to other studies conducted with inorganic contaminants. The relative sensitivity of the 30-min Microtox assay was within the range of the two frequently used acute daphnid/fish toxicity tests. In conclusion, the Microtox assay correlated well with the acute fathead minnow data and is well suited for toxicity monitoring for these types of industrial wastes. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 136–141, 2001Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35240/1/1017_ftp.pd

Mid-Holocene Record of Lake Level Fluctuations and Episodic Eolian Activity, Lake Winnibigoshish North Central Minnesota

University of Minnesota M.S. thesis. October 2015. Major: Geology. Advisor: Howard Mooers. 1 computer file (PDF): v, 210 pages.Approximately 1000 to 1500 years ago the Mississippi River diverted its flow path to Lake Winnibigoshish. This change had a dramatic effect on lake conditions. Prior to the diversion, due to its large size and its few inputs and outputs, Lake Winnibigoshish was sensitve to evaporation. This is evident in the Sr/Ca ratio, and indicator of evaporative stress. The largest peak in Sr/Ca occurs at 8000 cal yr BP, and there are numerous oscillations in the Sr/Ca ratio that occur on timescales of 20-89 years. This suggests evaporative stress caused the lake level to drop and expose the nearshore lake sediment which eroded to form the large sand dunes on its SE shore. This means that diversion stabilized water levels and salinity. In addition, the new source of inflow induced a change in the nutrient budget.Broderius, Lisa. (2015). Mid-Holocene Record of Lake Level Fluctuations and Episodic Eolian Activity, Lake Winnibigoshish North Central Minnesota. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/180882