Stuart G. Fisher

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Recovery of a desert stream after an intense flash flooding event is described as a model of temporal succession in lotic ecosystems. A late summer flood in Sycamore Creek, Arizona, virtually eliminated algae and reduced invertebrate standing crop by 98%. Physical and morphornetric conditions typical of the preflood period were restored in 2 d and the biota(More)
Metabolism of a Sonoran Desert stream was investigated by both enclosure and whole system oxygen techniques. We used recirculating chambers to estimate surface sediment metabolism and measured deep sediment respiration in isolated sediment cores. Metabolism of the stream ecosystem was determined for a 30-m reach as dark and light oxygen change with and(More)
Stream ecosystems consist of several subsystems that are spatially distributed concentrically, analogous to the elements of a simple telescope. Subsystems include the central surface stream, vertically and laterally arrayed saturated sediments (hyporheic and parafluvial zones), and the most distal element, the riparian zone. These zones are hydrologically(More)
Riparian zones effectively remove nitrogen (N) from water flowing through riparian soils, particularly in agricultural watersheds. The mechanism of N removal is still unclear, especially the role of vegetation. Uptake and denitrification are the two most commonly studied mechanisms. Retention of groundwater N by plant uptake is often inferred from(More)
Stream research has contributed only modestly to general ecological theory. Moreover, the rate of generation of new ideas in stream ecology may have slowed recently. These shortcomings might be remedied by a more deliberate effort to generate new, creative ideas about streams that will enhance their use in developing general theory. The creative process has(More)
Dissolved organic carbon (DOC) dynamics were examined over five years (1989–1993) in Sycamore Creek, a Sonoran Desert stream, specifically focusing on DOC concentration in surface and hyporheic waters, and rates of export. In 1989 and 1990, the years of lowest stream discharge (0.08 and 0.04 m3 s−1 annual mean of daily discharge, respectively), DOC was(More)
We conducted a manipulative field experiment to examine individual and interactive effects of scour and short-term nutrient enrichment (4 h exposure) on postspate recovery of benthic algae in a desert stream. We then compared recovery from these simulated-spate conditions to algal recovery patterns following a natural spate that increased water-column(More)
Hydrologic flow and connectivity act as important determinants of ecological pattern and process in heterogeneous landscapes. Here we examine how the routing of water through the drainage network of an upper Sonoran Desert basin influences landscape patterns of soil respiration (SR) at both seasonal and event-based timescales. At seasonal timescales, SR(More)
The distribution and movement of water can influence the state and dynamics of terrestrial and aquatic ecosystems through a diversity of mechanisms. These mechanisms can be organized into three general categories wherein water acts as (1) a resource or habitat for biota, (2) a vector for connectivity and exchange of energy, materials, and organisms, and (3)(More)
Primary production and ecosystem respiration of the Fort River ecosystem, a medium size (mean discharge 1.4 m3/sec) lowland stream in central Massachusetts, U.S.A., were measured using diurnal oxygen techniques from May 1972 to November 1973. During the summer of 1973, vascular hydrophyte production was measured with a modified cropping technique. Whole(More)