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Publications

Read publications and other informational products to learn more about USGS science occurring in the Mississippi Basin.

Filter Total Items: 5579

Metamorphosis of two amphibian species after chronic cadmium exposure in outdoor aquatic mesocosms Metamorphosis of two amphibian species after chronic cadmium exposure in outdoor aquatic mesocosms

Amphibian larvae at contaminated sites may experience an alteration of metamorphic traits and survival compared to amphibians in uncontaminated conditions. Effects of chronic cadmium (Cd) exposure on the metamorphosis of American toads (Bufo americanus) and southern leopard frogs (Rana sphenocephala) were determined. The two species were reared separately from shortly after hatching...
Authors
S.M. James, E. E. Little, R. D. Semlitsch

A method for measuring total thiaminase activity in fish tissues A method for measuring total thiaminase activity in fish tissues

An accurate, quantitative, and rapid method for the measurement of thiaminase activity in fish samples is required to provide sufficient information to characterize the role of dietary thiaminase in the onset of thiamine deficiency in Great Lakes salmonines. A radiometric method that uses 14C-thiamine was optimized for substrate and co-substrate (nicotinic acid) concentrations...
Authors
James L. Zajicek, Donald E. Tillitt, Dale C. Honeyfield, Scott B. Brown, John D. Fitzsimons

Amphibian ecotoxicology Amphibian ecotoxicology

No abstract available.
Authors
R. D. Semlitsch, C.M. Bridges

Does biofilm contribute to diel cycling of Zn in High Ore Creek, Montana? Does biofilm contribute to diel cycling of Zn in High Ore Creek, Montana?

Concentrations of metals cycle daily in the water column of some mining-impacted streams in the Rocky Mountains of the western USA. We hypothesized that biofilm in High Ore Creek, Montana, USA, sorbs and releases Zn on a diel cycle, and this uptake-and-release cycle controls the total and dissolved (0.45-μm filtered) Zn concentrations. We collected water samples from three sites...
Authors
J.M. Morris, D. A. Nimick, A.M. Farag, J.S. Meyer

Spartina alterniflora genotype influences facilitation and suppression of high marsh species colonizing an early successional salt marsh Spartina alterniflora genotype influences facilitation and suppression of high marsh species colonizing an early successional salt marsh

Genetically based phenotypic and ecotypic variation in a dominant plant species can influence ecological functions and patterns of recruitment by other species in plant communities. However, the nature and degree of importance of genotypic differences is poorly understood in most systems.The dominant salt marsh species, Spartina alterniflora, is known to induce facilitative and...
Authors
C.E. Proffitt, R.L. Chiasson, A.B. Owens, K.R. Edwards, S.E. Travis

Effects of flooding regime and seedling treatment on early survival and growth of nuttall oak Effects of flooding regime and seedling treatment on early survival and growth of nuttall oak

Effects of flooding on survival and growth of three different types of Nuttall oak (Quercus texana Buckl.) seedlings were observed at the end of third and fifth growing seasons at Yazoo National Wildlife Refuge, Mississippi, U.S.A. Three types of seedlings were planted in January 1995 in a split‐plot design, with four replications at each of two elevations on floodprone, former cropland...
Authors
V.R. Burkett, R.O. Draugelis-Dale, H.M. Williams, S.H. Schoenholtz

Thiamine and thiaminase status in forage fish of salmonines from Lake Michigan Thiamine and thiaminase status in forage fish of salmonines from Lake Michigan

Dietary sources of thiamine (vitamin B1) and thiamine-degrading enzymes (thiaminases) are thought to be primary factors in the development of thiamine deficiency among Great Lakes salmonines. We surveyed major forage fish species in Lake Michigan for their content of thiamine, thiamine vitamers, and thiaminase activity. Concentrations of total thiamine were similar (P ≤ 0.05) among most...
Authors
D. E. Tillitt, J.L. Zajicek, S.B. Brown, L. R. Brown, J.D. Fitzsimons, D. C. Honeyfield, M.E. Holey, G.M. Wright

Development of thiamine deficiencies and early mortality syndrome in lake trout by feeding experimental and feral fish diets containing thiaminase Development of thiamine deficiencies and early mortality syndrome in lake trout by feeding experimental and feral fish diets containing thiaminase

We conducted a laboratory investigation on the consequences of feeding predatory salmonids either experimental diets low in thiamine or diets containing alewife Alosa pseudoharengus. In experiment 1, adult lake trout Salvelinus namaycush were fed experimental diets containing bacterial thiaminase. In experiment 2, adult lake trout were fed natural prey species, alewives, and bloaters...
Authors
D. C. Honeyfield, J. P. Hinterkopf, J.D. Fitzsimons, D. E. Tillitt, J.L. Zajicek, S.B. Brown

Variation in mangrove forest structure and sediment characteristics in Bocas del Toro, Panama Variation in mangrove forest structure and sediment characteristics in Bocas del Toro, Panama

Mangrove forest structure and sediment characteristics were examined in the extensive mangroves of Bocas del Toro, Republic of Panama. Forest structure was characterized to determine if spatial vegetation patterns were repeated over the Bocas del Toro landscape. Using a series of permanent plots and transects we found that the forests of Bocas del Toro were dominated by Rhizophora mangle...
Authors
C. E. Lovelock, Ilka C. Feller, K.L. McKee, R. Thompson

Selenium in the Blackfoot, Salt, and Bear River Watersheds Selenium in the Blackfoot, Salt, and Bear River Watersheds

Nine stream sites in the Blackfoot River, Salt River, and Bear River watersheds in southeast Idaho, USA were sampled in May 2001 for water, surficial sediment, aquatic plants, aquatic invertebrates, and fish. Selenium was measured in these aquatic ecosystem components, and a hazard assessment was performed on the data. Water quality characteristics such as pH, hardness, and specific...
Authors
S. J. Hamilton, K.J. Buhl
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