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Research about Mississippi

Source-linked reports with geographic coverage including Mississippi.

At least 163 records · Page 9Linked to original sources
USGS1998

Soil, environmental, and watershed measurements in support of carbon cycling studies in northwestern Mississippi

Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about carbon cycling in agricultural and forest ecosystems to understand the potential role of erosion and deposition in the sequestration of soil organic carbon in upland soils. The question of whether soil erosion and burial constitutes an important net sink of atmospheric carbon dioxide is one hypothesis that the MBCP is evaluating to better understand carbon cycling and climate change. This report contains discussion of methods used and presents data for the period December 1996 through March 1998. Included in the report are ancillary data provided by the U.S. Department of Agriculture (USDA) ARS National Sedimentation Laboratory and U.S. Forest Service (USFS) Center for Bottomland Hardwoods Research on rainfall, runoff, sediment yield, forest biomass and grain yield. Together with the data collected by the USGS these data permit the construction of carbon budgets and the calibration of models of soil organic matter dynamics and sediment transport and deposition. The U.S. Geological Survey (USGS) has established cooperative agreements with the USDA and USFS to facilitate collaborative research at research sites in northwestern Mississippi.

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USGS1998

Concentrations and loads of nitrogen and phosphorus in the Yazoo River, northwestern Mississippi, 1996-97

Increased nutrient loading to the Gulf of Mexico from off-continent flux has been identified as contributing to the increase in the areal extent of the low dissolved-oxygen zone that develops annually off the coast of Louisiana and Texas. The proximity of the Yazoo River Basin in northwestern Mississippi to the Gulf of Mexico, and the intensive agriculture in the basin have lead to speculation that the Yazoo River Basin contributes a disproportionate amount of nitrogen and phosphorus to the Mississippi River and ultimately the Gulf of Mexico. Water samples from the Yazoo River were collected during 1996 and 1997 and were analyzed for total nitrogen, nitrate as nitrogen, total phosphorus, and orthophosphorus as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. These data were used to compute annual loads of nitrogen and phosphorus discharged from the Yazoo River for 1996 and 1997. Annual loads of nitrogen and phosphorus were calculated by two methods. The first used multivariate regression and the second multiplied the mean annual concentration by the total annual flow. Load estimates based on the product of the mean annual concentration and the total annual flow were within the 95 percent confidence interval for the load calculated by multivariate regression in all cases. The Yazoo River loads, compared to long-term annual loads in the Mississippi River, indicated that the Yazoo River was contributing 2.3 percent or less of the total nitrogen load, 5.7 percent or less of the total phosphorus load, and 1 percent or less of the nitrate load in 1996 and 1997. The total nitrogen load from the Yazoo River Basin into the Mississippi River and ultimately the Gulf of Mexico was proportional to its discharge, the nitrate load was less than expected, whereas the total phosphorus load was slightly higher than expected based on discharge.

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USGS1997

Body-mass, survival, and pairing consequences of winter-diet restriction in wood ducks

We conducted feeding experiments with captive, wild-strain wood ducks ( Aix sponsa ) during winters 1990-91 and 1991-92 to test effects of increasing levels of food restriction on body mass dynamics, mortality, and pair formation. Male and female wood ducks fed restricted diets (i.e., 5, 10, 15, or 20% less food [g] than consumed on the previous day by a control group fed ad libitum) weighed less ( P ≤ 0.037) than birds fed ad libitum; those on 15 and 20% restricted diets weighed least. Increased mortality and decreased pair formation occurred only within the 20% restricted group ( P ≤ 0.049). We concluded that food restriction ranging between 15 and 20% of ad libitum intake may signify a threshold above which survival and reproduction of captive wood ducks may be impaired. Because energy costs of free living are greater than in captivity, a lower threshold may exist for wild wood ducks. Research is needed to validate the threshold theory for free-ranging wood ducks and other waterfowl, and to evaluate its potential application for conservation of winter foraging habitat. Conservation of bottomland hardwood ecosystems, which provide important foraging habitat for migrating and wintering wood ducks, should be encouraged to prevent potential negative effects on wood duck life-cycle events.

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USGS1997

Water resources data, Mississippi, water year 1996

Water resources data for the 1996 water year for Mississippi consist of records of surface water and ground water in the State. Specifically, it contains: (1) Discharge records for 88 streamflow-gaging stations, stage records for 19 of these gaging stations, discharge records for 66 partial-record or miscellaneous streamflow stations, including 7 flood hydrograph partial-record stations, 53 crest-stage partial-record stations, and 6 special study and miscellaneous sites; (2) stage only at 4 gaging stations; (3) water-quality records for 21 streamflow-gaging stations, 1 ungaged stream site, 2 partial-record or miscellaneous sites, 64 short-term study sites, and 26 wells; and (4) water-level records for 46 observation wells. Records obtained from water-resources investigations are also included in special sections of the report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey, and cooperating local, State, and Federal agencies in Mississippi.

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USGS1996

Sediment mass-flow processes on a depositional lobe, outer Mississippi Fan

SeaMARC 1A sidescan-sonar imagery and cores from the distal reaches of a depositional lobe on the Mississippi Fan show that channelized mass flow was the dominant mechanism for transport of silt and sand during the formation of this part of the fan. Sediments in these flows were rapidly deposited once outside of their confining channels. The mass flows most likely originated from slope failure at the head of the Mississippi Canyon or on the outer continental shelf and flowed approximately 500 km to the distal reaches of the fan, with debris flow being the dominant flow type.

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USGS1996

Selected reports of the U.S. Geological Survey on Water Resources in Mississippi, 1990-96

Results of water-resources data-collection programs and interpretive hydrologic studies conducted by the U.S. Geological Survey (USGS) are published in reports and are made available to universities, State and local agencies, other Federal agencies, and the public. The following is a list of selected USGS reports on water resources in Mississippi published since 1990 and categorized according to the major emphasis of the report; these reports are available for inspection at the Mississippi District Office in Pearl, Mississippi.

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USGS1996

Susceptibility of ground water to surface and shallow sources of contamination in Mississippi

Ground water, because of its extensive use in agriculture, industry, and public-water supply, is one of Mississippi's most important natural resources. Ground water is the source for about 80 percent of the total freshwater used by the State's population (Solley and others, 1993). About 2,600 Mgal/d of freshwater is withdrawn from aquifers in Mississippi (D.E. Burt, Jr., U.S. Geological Survey, oral commun., 1995). Wells capable of yielding 200 gal/min of water with quality suitable for most uses can be developed nearly anywhere in the State (Bednar, 1988). The U.S. Geological Survey (USGS), in cooperation with the Mississippi Department of Environmental Quality, Office of Pollution Control, and the Mississippi Department of Agriculture and Commerce, Bureau of Plant Industry, conducted an investigation to evaluate the susceptibility of ground water to contamination from surgace and shallow sources in Mississippi. A geographic information system (GIS) was used to develop and analyze statewide spatial data layers that contain geologic, hydrologic, physiographic, and cultural information.

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USGS1996

Water resources data, Mississippi, water year 1995

Water resources data for the 1995 water year for Mississippi consist of records of surface water and ground water in the State. Specifically, it contains: (1) Discharge records for 86 streamflow-gaging stations, stage records for 20 of these gaging stations, discharge records for 80 partial-record or miscellaneous streamflow stations, including 8 flood hydrograph partial-record stations, 54 crest-stage partial-record stations, and 18 special study and miscellaneous sites; (2) stage only at 6 gaging stations; (3) water-quality records for 22 streamflow-gaging stations, 1 ungaged stream site, 9 partial-record or miscellaneous sites, 50 short-term study sites, and 72 wells; and (4) water-level records for 47 observation wells. Records obtained from water-resources investigations are also included in special sections of the report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey, and cooperating local, State, and Federal agencies in Mississippi.

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USGS1996

Location and depth of sand and clay intervals in Jackson County, Mississippi

Driller's logs and geophysical logs from various sources were used to compile information on the location and depth of water-bearing sands and intervening clays in Jackson County, southeastern Mississippi. Each log was checked for accuracy of location and for adequate description of subsurface materials. Generally, data for sand intervals greater than about 20 feet in thickness and less than 2,000 feet below land surface were compiled. Data from more than 1,600 logs were compiled. Well logs generally showed two or three sand intervals, but as many as seven were reported. Compiled sand intervals averaged about 48 feet in thickness, and well depths averaged about 417 feet below land surface. Data determined from each log were entered into a geographic information system (GIS) data base. A graphical representation of each well log is presented.

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USGS1995

Geometry of sandy deposits at the distal edge of the Mississippi Fan, Gulf of Mexico

Sidescan sonar provides a map of the seafloor that has greatly improved the understanding of depositional processes on modern deep-sea fans (e.g. Mutti and Normark 1991). Here, we present a sidescan-sonar mosaic from the eastern Gulf of Mexico that images the distal reaches of a channel on the Mississippi Fan and the deposits associated with it (Fig. 41.1). This area is one of several deep-sea fan systems that had not previously been imaged by high-resolution sidescan systems. The mosaic highlights the complexity of the spatial relationships of channels and deposits at ends of channels on this large, modern, passive-margin deep-sea fan (Figs 41.2 and 41.3).

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USGS1995

Factors affecting visibility rate of aerial waterfowl surveys in the Mississippi alluvial valley

Because visibility bias can confound attempts to detect changes in abundance, we evaluated factors that affect visibility rate in aerial surveys of wintering waterfowl. We placed waterfowl decoys in 32 2- x 0.25-km strip transects in the Mississippi Alluvial Valley (MAV) during February 1990 and 1991 and observed the decoys under different experimental conditions. Visibility rate was influenced ( P < 0.10) by habitat, transect width, and decoy group size. We simulated variation in use of habitat and found that changes in use between open and wooded wetlands would cause changes in visibility rate and affect the power to detect a change in abundance. The effect of changes in visibility rate on likelihood of detecting population change depended on the magnitude and direction of population change and precision of the population index. For transect surveys of wintering ducks in the MAV we recommend reducing transect width from 250 to 150 m on each side of the aircraft and restricting comparisons between years when 70% of the population is likely to be distributed in open wetlands. Improved techniques for estimating abundance of wintering waterfowl are also needed so use of questionable population indices can be avoided.

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