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Research about Maryland

Source-linked reports with geographic coverage including Maryland.

At least 361 records · Page 20Linked to original sources
USGS1975

Incidence of ingested lead shot in sora rails

Gizzards of 934 sora rails ( Porzana carolina ) collected in Maryland (767) and Missouri (167) were examined for ingested shot. Ingested shot were found in 12.3 percent of the Maryland sample and 1.8 percent of the Missouri birds. Individual Maryland birds had ingested up to 28 pellets. None of the lead pellets examined was larger than a No. 7 1/2 shot. Maryland ingestion rates did not differ by age or sex, but significant differences between collection areas, groups of years, and collection periods within years were indicated. This exploratory work points out a potential lead poisoning problem among sora rails.

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USGS1975

Effects of sediment control on sediment transport in the northwest branch Anacostia River basin, Montgomery County, Maryland

Streamflow and sediment were monitored in an urbanizing drainage basin in southeastern Montgomery County, Md., from 1962 to 1972. During this period, urban construction areas averaged about 3 percent of the 21.1 mi 2 (54.6 km 2 ) basin. Urban land increased from 3.5 percent in 1959 to 20 percent in 1971. Virtually all the suspended sediment was transported during storms; three-fourths of it, during large storms. High sediment yields were observed in February, March, June, and August; and low yields, generally from September through January. The decrease in sediment discharge in the latter half of the study period is attributed to a sediment-control program. Sediment discharge decreased 35 percent between 1967 and 1972, when effective control measures were installed on about half the construction sites.

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USGS1974

Changes in oxygen and primary production of the Patuxent estuary, Maryland, 1963 through 1969

From 1963 through 1969, the U.S. Geological Survey operated a water-quality monitor system in the upper-middle Patuxent estuary, near Benedict, Maryland. Over the period of record, a pronounced change occurred in the diel (24 hr.) oxygen measurement, particularly during the months of July, August, and September. Annual variations of dissolved oxygen ranged from 3.6 to 15.0 mg liter −1 in 1964 and from 2.3 to 16.5 mg liter −1 in 1969 with percentage saturation varying from 60 to 130 percent in 1964 and from 30 to 184 percent in 1969. The magnitude of diel summer oxygen variation changed from about 3 to 7 mg liter −1 day −1 over the same period. From hourly values of temperature, oxygen, and conductivity, gross primary production (GP) and respiration (R) were estimated. Data representing greatest daily change for spring, summer, and autumn of each year and “average” values for each month of years 1964 and 1969 were analyzed for GP and R. From the seasonal data, GP ranged from about 3 to 25 g O 2 m −2 day −1 , and R ranged from about 4 to 32 g O 2 m −2 day −1 . From the “average” days, GP ranged from 2 to 10 g O 2 m −2 day −1 in 1964 and from 1 to 16 in 1969. In 1964, daily average GP was 5.2 g O 2 m −2 day −1 as compared to 6.1 in 1969, and respiration was 6.1 g O 2 m −2 day −1 in 1964 versus 10.2 g O 2 m −2 day −1 in 1969, increases of 20 and 16 percent, respectively. Ratios of GP/R averaged 0.84 in 1964 versus 0.60 in 1969, reflecting a larger respiration in 1969 and suggesting a trend towards community instability. Productivity estimates by other investigators showed a two-to threefold increase in production over the same period of time. The increases in production were attributed to upstream domestic waste loading. If the present trend increases, metabolic imbalance and anaerobic conditions may develop.

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USGS1974

Water quality in Rhode River at Smithsonian Institution Pier near Annapolis, Maryland, April 1970 through December 1973

Water temperature, salinity (computed from specific conductance data), turbidity, dissolved oxygen, pH, and water level data were collected by a continuously recording water quality monitor located in the Rhode River, at the Smithsonian Institution's pier near Annapolis, Md., from April 1970 through December 1973. Data, as presented in this report, consist of daily maximum and minimum values summarized by week to give weekly averages and extremes. Temperatures showed an overall range from 0.7 to 32.6°C. The water temperature data indicate successively warmer winters. Salinity ranged from 1.05 to 14.03 parts per thousand. In June 1972, salinity dropped markedly as fresh water from tropical storm Agnes entered the Rhode River from Chesapeake Bay. Most of the fresh water entering upper Chesapeake Bay as a result of tropical storm Agnes came from the Susquehanna River. Turbidity was usually low, averaging about 14 Jackson Turbidity Units; however, during spring and early summer of 1972, values averaged about 23 Jackson Turbidity Units. This increase in turbidity was due to the high Susquehanna River flows during that period. Extremes of turbidity ranged from about 5 to 80 Jackson Turbidity Units. Dissolved oxygen ranged from 0.0 to 19.8 milligrams per litre. Large daily changes in oxygen indicated a high state of biological metabolism. Values of pH ranged from 6.8 to 10.1 and daily changes coincided with oxygen changes. Tide-dominated water levels had an overall range of 5.9 feet (1.8 metres) and a mean tidal range of 1.5 feet (0.46 metres).

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USGS1974

Salmonellosis in a captive heron colony

Salmonellosis caused by Salmonella typhimurium was one of several factors responsible for losses among young herons being held at the Patuxent Wildlife Research Center. The infection was demonstrated in five black-crowned night herons ( Nycticorax nycticorax ), three common egrets ( Casmerodius albus ), two little blue herons ( Florida caerulea ), one cattle egret ( Bubulcus ibis ), one snowy egret ( Leucophoyx thula ) and one Louisiana heron ( Hydranassa tricolor ). The disease was characterized by emaciation, focal liver necrosis, and frequently by a caseo-necrotic enteritis.

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USGS1973

River channel change with time : An example

Monumented channel cross sections were resurveyed over a period of 20 yrs (1953 to 1972) to determine the amount and kind of change of channel area and position on a 3.7-sq-mi basin, Watts Branch near Rockville, Maryland. For the first 12 yrs, the channel progressively but slowly became smaller as urbanization of the basin gradually proceeded. After 1966, a threshold of change apparently was passed and, probably as a result of an increased rate of land alteration upstream, large amounts of sediment were deposited within the channel and overbank. The number of floods exceeding channel capacity increased dramatically from an average of two to more than ten per year. Simultaneously, the channel area began to increase. Despite the trend toward increasing cross-sectional area, the net result after 20 yrs was a channel smaller by 20 percent than it had been originally. Urbanization did not alter the rate of channel migration.

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USGS1973

Role of water in urban planning and management

Concentrations of people in urban areas intensify water problems such as flooding and pollution, but these deleterious effects on water resources can be minimized or corrected by comprehensive planning and management. Such planning of the water resources of an urban area must be based on adequate hydrologic data. Through the use of a matrix, urban water problems can be evaluated and availability of data assessed. The Washington-Baltimore metropolitan area is used as a case study. The completed matrix provides both a means for developing a meaningful dialogue between the hydrologist and the urban planner and a method for developing a work plan to insure consideration of water-resources data in urban planning.

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USGS1972

Some physiologic blood values of wild diving ducks

Blood samples were obtained from 54 canvasbacks ( Aythya valisineria ), 30 lesser scaup ( A. affinis ), 3 ring-necks ( A. collaris ), and 3 buffleheads ( Bucephala albeola ), which were wintering on Chesapeake Bay. These blood samples were used for: red blood cell counts (cans. 2.56 × 10 6 /mm 3 ; scaup 2.45 × 10 6 /mm 3 ; ring-necks 2.50 × 10 6 /mm 3 ; bufflehead 2.64 × 10 6 /mm 3 ), packed cell volume (cans. 52.2%; scaup 57.1%; ring-neck 49.1%; buffleheads 54.3%), total protein (cans. 4.4 g/100 ml; scaup 4.4 g/100 ml; ring-neck 3.5 g/100 ml; bufflehead 3.8 g/100 ml), erythrocyte measurements, and electrophoretic analysis of plasma and serum. Variations between individuals of the same species and sex were slight but a possible difference between male and female erythrocyte numbers and packed cell volumes was evident in the canvasback and scaup samples.

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USGS1971

A further revision of the stratigraphic nomenclature of the Wissahickon Formation in Maryland

The Wissahickon Formation, the thickest and most extensive unit of the Glenarm Series, was divided into lithofacies several years ago. We suggest revision of two of these lithofacies and addition of another. We also suggest that the term lithofacies be shortened to facies. The added facies, the quartzite facies, is distinguished by metamorphosed orthoquartzites and protoquartzites. It corresponds in part to the former Peters Creek quartzite.

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USGS1971

A starling-deterrent wood duck nest box

In many parts of the United States, the starling ( Sturnus vulgaris ) has I become a serious competitor for nest boxes erected for wood ducks ( Aix sponsa ). Research at the Patuxent Wildlife Research Center and at Eastern Neck National Wildlife Refuge near Rock Hall, Maryland, demonstrated that horizontal nest structures with semicircular entrance holes 11 inches in diameter were acceptable to nesting wood ducks but discouraged nesting by starlings. Starlings seemed to prefer boxes in open impoundments to those in wooded impoundments, whereas wood ducks seemed to show no preference.

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USGS1971

Nesting by a yearling Canada goose

A free-flying Canada goose ( Branta canadensis interior ), known to be just under a year old, laid a clutch of four eggs at the Patuxent Wildlife Research Center. At least half of the 2-year-old females nest at Patuxent, and almost all of the 3-year-olds nest. As far as we know, this is the first record of nesting by a yearling Canada goose.

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