Seasonal Temperature Preference of Adult Mountain Whitefish, Prosopium williamsoni

Temperatures selected seasonally by adult mountain whitefish were measured in the laboratory in a horizontal gradient. Final preferendum estimates, based on acute (3-hour) preference tests conducted with fish acclimated to 5, 10, and 15 C each season, were 17.7 C (pre-spawning), 11.9 C (post-spawning), 9.9 C (winter), and 16.3 C (spring). Seasonal influence on temperature selection was evident on the basis of differences in final preferenda, covariance analysis of responses of laboratory-acclimated fish, and temperature selection by fish held at ambient river temperatures. Post-spawning and winter groups selected lower temperatures than did pre-spawning and spring groups. Pre-spawnine fish selected temperatures unsuitable for embryo survival. Reproductive status as reflected by gonad size was evidently not a factor that influenced seasonal temperature selection of adult whitefish

Reconnaissance of Sediment-Phosphorus Relationships in Some Utah Reservoirs

Introduction: Phosphorus inputs to lakes and reservoirs from tributary streams and non-point sources are well-known contributors to nuisance algal growths that degrade water quality for potable and recreational uses in lakes and reservoirs. However, phosphours inputs to the euphotic zone may also occur from within the lake itself, as a result of releases from both oxic and anoxid sediments. Such releases may originate from phosphorus inputs to a lake or reservoir during high runoff periods in the previous winder or spring, or they may represent phosphorus trapped in the sediment many years earlier, when phosphorus contributions from natural or anthropogenic sources were higher that at present. Whatever their origin, phophours loading from sediments may exacerbate the eutrophication process or delay the recovery of a eutrophic lake or reservoir following reductions in external phosphous loading aimed at water quality restoration (Begtsson 1978, Larsen et al, 1975, 1981). This phenomenon has been graphically linkened to the memory of a lake for its previous trophic state: oligotrophic, lakes tend to trap phophorus in their sediments, thus remaining oligotrophic, while eutrophic lakes mine their sediments for phosphorus during summer stratification and further contribute to the production of late summer and fall phytoplankton blooms (Imboden 1974). Virtually no information is availabe on the extent to which internal phosphorus loading is important in reservoirs in the Intermountain West, or on the factors controlling phosphous uptake or release in these sediments. in fact, there reaims considerable debate over the accuracy of the simple paradigm outlined above for all lakes and reservoirs. Under certain circumstances, oxic release rates of phosphorus from some sediments can be substantial, while anoxic release rates may be relatively low (Holdren and Armstrong 1980). A series of studies on sediments in several reservoirs in the Intermountain West is being conducted at the Utah Water Research Laboratory, Utah State University, in order to further our understanding of important sediment-water interactsion in the phosphorus cycles of such reservoirs. The data reported here represent preliminary results from the first field season of these studies. They relate to the phosphorus chemistry of the sediments themselves, and to P release simulations carried out on intact sediment cores incubated in the laboratory. The aim of the discussion that follows is to compare the chemistry and release rates of cores from several reservoirs, and to suggest some implications of these results regarding the potential for further eutrophication or the potential for recovery of the reservoirs under study. Because the inferences are drawn from preliminary data, the conclusions should be regarded as tentative. Messer et al. (1983) has presented a rationale for related such sediment release data to the impact on the overlying water column

Sediment-Phosphorus Relationships in Deer Creek Reservoir

Summary and Conclusions: Laboratory analyses of sediment samples recovered from Deer Creek Reservoir showed the sediments to have amoderate potential for serving as a source of phosphorus (P) for the overlying water solumn under anaerobic conditions. This source could account for the occurrence or exacerbation of blue-green algal blooms in the upper end of the reservoir when the sediment surface becomes anaerobic late in the summer. It could also delay the response of the reservoir to programs that decrease external P loading, if the upper end of the reservoir still has large enough algal blooms to render the sediment-water interface anaerobic. The redox cycle of Fe is closely associated with P release in the reservoir sediments, and aerobic P release rates are probably insignificant in the phosphorus budget of the reservoir. Sediment profiles indicate that the tropich state of the lake has probably not changed significantly since the reservoir was first filled. The profiles do indicate, however, that much of the P input to the lake may be in the relatively unreactive apatite-P traction, and attempts at reducing P loading from external sources should take into account the degree of availability of the P thus removed

Reconnaissance of Sediment-Phosphorus Relationships in Upper Flaming Gorge Reservoir

Executive Summary: A reconnaissance-level study was conducted in Flaming Gorge Reservoir, Wyoming, during the late summer of 1982 in order to determine the possible importance of the sediment sin exacerbating the blue-green algal blooms that occur in summer in the upper reservoir. Sediments can affect phytoplankton dynamics in reservoirs on an annual basis by delyaing the availability of particulate P associated with spring runoff until late summery, when the warm water temperatures and the light climate favor the growth of blue-green algae. Over the longer term, however, sediments that historically have served as a trap for part of the annual phosphous load entering the system may release some of this stored P in response to decreased P concentrations in the overlying water. The decreased concentrations may result from unusally wet water years or, more importantly from a management standpoint, from restoration strategies aimed at reducing inputs of P from the watershed. The resulting internal P loading can delay the anticipated recovery of a reservoir for may years, relative to the recovery rate that owuld be predicted in its absence. The study of lacustrine sediments is helpful in predicting the potential for internal P loading from a particular sediment, as well as the factors more important in controlling P releas

Effects of Cadmium on Streams and Irrigated Agriculture in the Presence and Absence of Oil Shale Leachate

Artificial streams, soil perfusion columns, and potted plants were exposed to 20 ug Cd/l in the presence and absence of unretorted oil shale leachate. High cadmium accumulations occurred in the stream biota, but did not measurably affect community structure or function. The presence of oil shale leachate had no effect on bioaccumulation or ecosystem structure or function. Nitrification in soil columns was enhanced by the presence of the organic fraction of oil shale leachate, but this effect was not observed when cadmium was present. Crop accumulation of cadmium was somewhat higher in alfalfa and radishes irrigated with leachate, but did not cause plant concentrations that would be hazardous to livestock or human consumers

Resistance to paclitaxel in a cisplatin-resistant ovarian cancer cell line is mediated by P-glycoprotein

The IGROVCDDP cisplatin-resistant ovarian cancer cell line is also resistant to paclitaxel and models the resistance phenotype of relapsed ovarian cancer patients after first-line platinum/taxane chemotherapy. A TaqMan low-density array (TLDA) was used to characterise the expression of 380 genes associated with chemotherapy resistance in IGROVCDDP cells. Paclitaxel resistance in IGROVCDDP is mediated by gene and protein overexpression of P-glycoprotein and the protein is functionally active. Cisplatin resistance was not reversed by elacridar, confirming that cisplatin is not a P-glycoprotein substrate. Cisplatin resistance in IGROVCDDP is multifactorial and is mediated in part by the glutathione pathway and decreased accumulation of drug. Total cellular glutathione was not increased. However, the enzyme activity of GSR and GGT1 were up-regulated. The cellular localisation of copper transporter CTR1 changed from membrane associated in IGROV-1 to cytoplasmic in IGROVCDDP. This may mediate the previously reported accumulation defect. There was decreased expression of the sodium potassium pump (ATP1A), MRP1 and FBP which all have been previously associated with platinum accumulation defects in platinum-resistant cell lines. Cellular localisation of MRP1 was also altered in IGROVCDDP shifting basolaterally, compared to IGROV-1. BRCA1 was also up-regulated at the gene and protein level. The overexpression of P-glycoprotein in a resistant model developed with cisplatin is unusual. This demonstrates that P-glycoprotein can be up-regulated as a generalised stress response rather than as a specific response to a substrate. Mechanisms characterised in IGROVCDDP cells may be applicable to relapsed ovarian cancer patients treated with frontline platinum/taxane chemotherapy