Publications

No abstract available.

The effects of acid deposition on surface waters in eastern United States watersheds having similar size, physiography, climate and land use are related to the composition of the underlying bedrock. Watersheds developed on greenstone, calcareous shale, sandstone, granite, and schist differ in their ability to neutralize acid deposition. Surface waters in watersheds developed on greenstone and calc

Certain geologic media are known to have small permeability; subsurface environments composed of these media and lacking well developed secondary permeability have groundwater flow sytems with many distinctive characteristics. Moreover, groundwater flow in these environments appears to influence the evolution of certain hydrologic, geologic, and geochemical systems, may affect the accumulation of

Detrended correspondence analysis (DCA) was evaluated for its effectiveness in displaying factors controlling the spatial distribution of benthic insects in an oligotrophic stream where an experimental gradient (copper) that selectively affects population abundances was imposed. DCA proved to be highly sensitive to differences among samples and consistently provided ecologically meaningful species

A controlled and renewable release fertilization system is proposed that employs NH4 saturated clinoptilolite to aid in the dissolution of phosphate rock (apatite), and thereby to release soluble N, P, and exchangeable Ca for uptake by plants. The system is based on the principle that exchangers can sequester Ca ions released by the dissolution of apatite, thereby leading to further dissolution of

Effects of Zn (0-1 mu M total Zn(II)) and orthophosphate (8-12 mu M total P) additions on growth indices for the chlorophyte Selenastrum capricornutum were examined in a medium containing 50 mg liter-1 colloidal titania. Over the Zn(II) concentration range used, detrimental growth and yield effects were observed. Addition of P to a synthetic growth medium increased stationary phase cell density, b

Selenastrum capricornutum Printz, growing in a chemically defined medium, was used as a model for studying adaptation of algae to a toxic metal (copper) ion. Cells exhibited lag‐phase adaptation to 0.8 μM total Cu (10−12 M free ion concentration) after 20 generations of Cu exposure. Selenastrum adapted to the same concentration when Cu was gradually introduced over an 8‐h period using a specially

Gas-film coefficients for the volatilization of ethylene dibromide (EDB) and water were determined in the laboratory as a function of wind speed and temperature. The ratio of the coefficients was independent of wind speed and increased slightly with temperature. Use of this ratio with an environmentally determined gas-film coefficient for the evaporation of water permits determination of the gas-f

No abstract available.

Determinations of the aqueous solubilities of kaolinite at pH 4, and of five smectite minerals in suspensions set between pH 5 and 8, were undertaken with mineral suspensions adjusted to approach equilibrium from over- and undersaturation. After 1,237 days, Dry Branch, Georgia kaolinite suspensions attained equilibrium solubility with respect to the kaolinite, for which Keq = (2.72 ± 0.35) × 107.

Analysis of water-level fluctuations in about 30 observation wells and 5 lakes in the Crescent Lake National Wildlife Refuge in the sandhills of Nebraska indicates water-table configuration beneath sand dunes in this area varies considerably, depending on the configuration of the topography of the dunes. If the topography of an interlake dunal area is hummocky, ground-water recharge is focused at

Detrended correspondence analysis (DCA) was evaluated for its usefulness in elucidating relationships among samples and among species of periphyton in an oligotrophic stream, and for its effectiveness in displaying major gradients where an experimental gradient (copper) affecting species composition was imposed. It was highly sensitive to differences among samples and consistently provided ecologi