Fresh Water Studies Commons^™

Presence Of The Cyanotoxin Microcystin In Arctic Lakes Of Southwestern Greenland, Jessica Trout-Haney, Zachary Wood, Kathryn Cottingham

Dartmouth Scholarship

Cyanobacteria and their toxins have received significant attention in eutrophic temperate and tropical systems where conspicuous blooms of certain planktonic taxa release toxins into fresh water, threatening its potability and safe use for recreation. Although toxigenic cyanobacteria are not confined to high nutrient environments, bloom-forming species, or planktonic taxa, these other situations are studied les often studied. For example, toxin production in picoplankton and benthic cyanobacteria—the predominant photoautotrophs found in polar lakes—is poorly understood. We quantified the occurrence of microcystin (MC, a hepatotoxic cyanotoxin) across 18 Arctic lakes in southwestern Greenland. All of the focal lakes contained detectable levels of …

Fecal Indicator Bacteria In Knitting Mill Creek With A Comparison Of Methods Used To Enumerate E. Coli, Manju Nagarajan

OES Theses and Dissertations

This research seeks to evaluate the impact of an urban, multi-use neighborhood on the bacteriological quality of water in Knitting Mill Creek, a blind arm of the Lafayette River, a sub-estuary of the lower Chesapeake Bay. A principal objective was to determine the effects of rainfall, a surrogate for run-off, on water-column concentrations of fecal-indicator bacteria (FIB). I collected water samples weekly (September 2009-December 2010) and biweekly (January 2010-December 2011) at a storm-sewer outfall and a nearby marina and quantified their E. coli and enterococci concentrations using Colilert-18 and Enterolert, most-probable-number assays. In addition, I took monthly samples for these …

Sulfur-Oxidizing Bacteria In Soap Lake (Washington State), A Meromictic, Haloalkaline Lake With An Unprecedented High Sulfide Content, Dimitry Y. Sorokin, Mirjam Foti, Holly C. Pinkart, Gerard Muyzer

All Faculty Scholarship for the College of the Sciences

Culture-dependent and -independent techniques were used to study the diversity of chemolithoautotrophic sulfur-oxidizing bacteria in Soap Lake (Washington State), a meromictic, haloalkaline lake containing an unprecedentedly high sulfide concentration in the anoxic monimolimnion. Both approaches revealed the dominance of bacteria belonging to the genus Thioalkalimicrobium, which are common inhabitants of soda lakes. A dense population of Thioalkalimicrobium (up to 10⁷ cells/ml) was found at the chemocline, which is characterized by a steep oxygen-sulfide gradient. Twelve Thioalkalimicrobium strains exhibiting three different phenotypes were isolated in pure culture from various locations in Soap Lake. The isolates fell into two groups …

Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson

Publications (WR)

The response to periodic desiccation of periphyton communities developed in eddy environments or in areas exposed to variable, direct current was examined. Algal communities were incubated on clay tiles for between 2 and 12 weeks in the Colorado River, directly below Hoover Dam from October, 1983 - January, 1984. Mean daily discharge from the dam decreased over this period. To assess the influence of these discharge changes on community dynamics, samples collected over the first 12 weeks of the investigation were compared to samples of the same age collected over the final 8 weeks.

The small diatom taxon Achnahthes spp …

Report On Wastewater Disposal To Board Of County Commissioners, Clark County Nevada, Clair N. Sawyer

Publications (WR)

This report is concerned with the management of waste-waters and subsurface drainage from the City of Las Vegas and its environs and the BMI complex, all in Clark County, Nevada. The prime objective is to recommend a plan of action which will utilize the natural resources of the area in the least costly manner and still protect Lake Mead for recreational purposes and use as a public water supply, At this writing, conditions in the upper Las Vegas arm of Boulder Basin are quite unsatisfactory for some recreational purposes due to the extensive blooms of algae which develop. Experience at …

Preliminary Report: Monolayer Behavior Studies, 1959, Bureau Of Reclamation

Publications (WR)

During the fall of 1959, monolayer behavior studies were made on two lakes in the southwest; Boulder Basin of Lake Mead, Nevada, and Lake Sahuaro near Phoenix, Arizona.

These studies were made to evaluate the effect of geographical and climatological conditions on movement and behavior of monolayers. The Lake Sahuaro tests also were used to provide data for design and development of improved methods of application and maintenance of a film on this lake in anticipation of full scale, evaporation-reduction tests to be performed there during the summer of I960.

The Lake Mead studies produced the following general points of …