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Field measurements of canopy structure and species composition are related to spectral reflectance measurements taken with a radiometer over a number of marsh sites. Marsh vegetation types are discussed in terms of their characteristic canopy structure and phenology; the influence of these characteristics on spectral reflectance will be examined. Vegetation...

No abstract available....

The apparent imbalance between relative sea-level rise and vertical marsh accretion is frequently cited as a major factor in the problem of wetland loss in Louisiana. Rates of relative sea-level rise are high in Louisiana due to high rates of subsidence. Although marsh accretion rates are also high, they are...

This report consolidates and synthesizes information on Quaternary faulting, folding, and volcanism in Utah and characterizes recent tectonic activity throughout the state. The primary purpose is to provide a comprehensive reference on faultspecific seismic sources and surface rupture to facilitate the evaluation of earthquake hazards in Utah. Two 1:500,000-scale maps...

Recent examinations of competition matrices for transitivity (species A > species B > species C) have used techniques that can be subject to certain biases. First, recent theoretical and empirical analyses have shown that traditional measures of competitive performance are biased in favor of the larger species. It is argued...

Monthly behavioral observations of Northern Pintails (Anas acuta) were conducted on five leased tracts of nonhunted private land, each including 60 ha of flooded rice fields, in southwest Louisiana during November-February 1988-1989. Pintails spent 52% of diurnal time resting, 21% feeding, 16% in comfort activities, 6% in locomotion, 4% courting...

No abstract available....

This volume presents over 25 papers containing the proceedings of a symposium held at the 122nd annual meeting of the American Fisheries Society in September 1992. The symposium was organised to review the status of fish and wildlife resources and restoration planning for the Mississippi river ecosystem. The objectives of...

No abstract available....

Many of the high-Ti quartz-normative tholeiitic intrusive sheets in the early Mesozoic rift basins of the Eastern USA exhibit lateral differentiation from mafic cumulate units, through diabase, to relatively evolved iron-rich rock types. We have investigated a representative example in detail, the York Haven sheet in the Gettysburg basin of...

Addresses the significance of changes in summer thermal stratification patterns of Adirondack lakes affected by acidification to cold-water fish populations inhabiting these sensitive lakes. Brook trout Salvelinus fontinalis is the primary cold-water fish species indigenous to acid-sensitive lakes in the Adirondack region of N New York State; the ability of these lakes to sustain...

Although acid deposition is not considered a problem in the western United States, surface waters in high elevations and fish inhabiting these waters may be vulnerable to acidification. This study examined the sensitivity of a western salmonid to acid and aluminum stress. Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri; YSC) were...

Aquatic organisms accumulated selenium (Se) from inorganic and organic Se species via aqueous and food-chain exposure routes. We measured aqueous and food-chain Se bioaccumulation from selenate, selenite, and seleno-L-methionine in a laboratory food chain of algae (Chlamydomonas reinhardtii), daphnids (Daphnia magna), and fish (bluegill, Lepomis macrochirus). Selenium concentrations were monitored radiometrically...

Measurement of the rate and direction of ground water flow beneath Wollaston Beach, Quincy, Massachusetts by use of a heat-pulsing flowmeter shows a mean velocity in the bulk sediment of 40 cm d−1. The estimated total discharge of ground water into Quincy Bay during October 1990 was 1324–2177 m3 d−1,...

Two geodetic airborne laser altimeter (ALA) systems coupled to Global Positioning System receivers acquired submeter-resolution topographic profiles of the lower parts of Breidamerkurjökull and Skeidarárjökull, Iceland, in May 1989 and September 1991 (Skeidarárjökull) and of Jakobshavns Isbræ, Greenland, in April 1992. Maximum...

Single-channel seismic reflection profiles show evidence for areas of significant gas accumulation at the head of the Cape Fear Slide on the continental rise oft North Carolina. Gas accumulation appears to occur beneath a gas hydrate seal in landward-dipping strata and in domed strata associated with diapirism. In addition, gas...

No abstract available....

Approximately 2550 km of single-channel high-resolution seismic reflection profiles have been interpreted and calibrated with lithological and geochronological information from four representative piston cores and one grab sample to provide a regional stratigraphie framework for the subbottom deposits of Lake Ontario. Five units overlying Paleozoic bedrock were identified and mapped....

No abstract available....

A three-dimensional lithostratigraphic model of the central block of Yucca Mountain, Nevada, illustrates how some activities can serve both site characterization and design and construction of the Exploratory Studies Facility (ESF). Site-characterization activities supported by this model include characterizing the three-dimensional geometry of lithologic units and faults, and providing boundary...