Geology topics
Research about Maryland
Source-linked reports with geographic coverage including Maryland.
Two species of Simuliidae (Diptera), Cnephia ornithophilia and Prosimulium vernale, from Maryland
The finding of Cnephia ornithophilia Davies, Peterson, & Wood and Prosimulium vernale Shewell for the first time at the Patuxent Wildlife Research Center, Laurel, Maryland, is described. Larvae of C. ornithophilia were collected Nov. 15, pupae Feb. 14, and adult flies Feb. 28. No immature or adult specimens were found between Apr. 2 and Nov. 14. The greatest number of immature stages was found in a 3- to 5-foot-wide stream several hundred feet long, 1-8 inches deep, with a stream flow between 0.49 and 3.30 feet per second. The water temperature varied from 0.5° to 4.0°C, the oxygen content was 10-13 ppm; and the p H varied from 6.9 to 7.4. Larvae of P. vernale were collected Nov. 30 through March, pupae from February through Apr. 1, and adult flies from Feb. 26 through Apr. 1. No immature or adult specimens were found between Apr. 2 and Nov. 29. The largest number of immature stages of P. vernale was found in a 6- to 16-foot-wide stream, 100 feet long, and 1.2 inches deep. The stream flow was between 0.92 and 1.36 feet per second. The water temperature was 0.5°C; p H was 6.7; and oxygen content was 7 ppm.
Geochemical balance of a small watershed and its geomorphic implications
A detailed input-output study of a small forested watershed draining the Wissahickon Formation in the Piedmont of Maryland revealed that chemical solution is five times as effective in removing material as is mechanical erosion. Solution weathering removes 16.9 tons/sq mi/yr of material compared with 3.2 tons/sq mi/yr by mechanical erosion. Plant activity during the growing season increased the concentration of silica, bicarbonate, calcium, and potassium, thus increasing total dissolved solids by one-third. Autumn leaf fall also caused a short-term increase of these ions. Rainfall does not simply dilute floodwaters as the concentration of sulfate, potassium, and calcium increases whereas silica and bicarbonate decrease in concentration during a flood cycle. Our data suggest that during the first half of a flood cycle, both the flood water and the dissolved solids in it come from an area in and immediately adjacent to the flood plain. The weathering model derived from our study suggests that on a long-term basis approximately one-half of the erosion of the Pond Branch watershed is caused by chemical solution of the silicate minerals kaolinite, vermiculite, biotite, and oligoclase. This contrasts to short-term ratio of solutional to mechanical weathering of five to one.
Propagation of captive American kestrels
A colony of kestrels ( Palco sparverius ) was established at the Patuxent Wildlife Research Center in 1964 in connection with work on pesticides. The kestrels were acquired from the wild, both as nestlings and as full-grown birds, and were housed in several rows of outdoor pens. Each 50 x 20 ft pen was covered with wire netting and had its long sides in common with adjacent pens. During the first two reproductive seasons, untreated parent birds (dosed birds are not included in this paper) ate eggs and young. Cannibalism virtually ceased after the diet was changed from ground beef or horsemeat supplemented with liver, vitamins, and minerals to one containing a finely ground mixture of laboratory rodents, chicken heads, skinned chicken necks, and supplements; hatching success thereafter generally equaled that of a wild population. In 1967, 16 pairs of untreated hawks (3-year-old females) laid clutches averaging 4.9 eggs, hatched 88 percent of their eggs, and fledged 88 percent of their young. In 1968, 10 pairs of this group (4-year-old females) laid clutches averaging 4.9 eggs, hatched 51 percent of their eggs, and fledged 85 percent of their young. Nine yearling pairs (hatched in captivity) laid clutches in 1968 averaging 5.1 eggs, hatched 87 percent of their eggs, and fledged all of their young.
A microsporidan (Protozoa: Cnidospora) in channel catfish (Ictalurus punctatus)
No abstract available.
An outbreak of fowl cholera in waterfowl on the Chesapeake Bay
An outbreak of fowl cholera ( Pasteurella multocida infection) occurred in waterfowl wintering on the Chesapeake Bay during February to March 1970. Losses were primarily confined to sea ducks: oldsquaws ( Clangula hyemalis ), white-winged scoters ( Melanitta deglandi ), golden-eyes ( Bucephala clangula ), and buffleheads ( Bucephala albeola ).
Glacial age marsh, Lafayette Park, Washington, D.C.
Organic sediments beneath historic Lafayette Park mark the site of a freshwater marsh which bordered the Potomac River when it was 15 meters above its present level. Plant microfossils and ice-rafted boulders indicate a climate much colder than now. The carbon-14 age of more than 45,000 years and palynological studies suggest an early Wisconsin age.
Epifauna and thermal additions in the upper Patuxent River estuary
In the upper Patuxent Estuary environmental changes in temperature, salinity, and turbidity over a 5-year period are linked to changes in epifaunal production and species distribution. During 1967 a series of monthly panels showed dry weight production averaged 2.8 times greater in a steam electric station heated effluent than in the intake. A downriver shift in epifanual production in 1967 and changes in species abundance was noted and attributed to natural changes in salinity and turbidity and man-induced changes in temperature.
Thermal additions and epifaunal organisms at Chalk Point, Maryland
Two sets of test panels, one in the intake and the other in the effluent canal of a steam-generating station, were submerged at monthly intervals in 1967. The panels were analyzed for epifaunal species composition, abundance, seasonal attachment, and total biomass production. The average surface-water temperature rose 6.3 C above ambient on the effluent side, and the biomass production of the epifaunal organisms found there increased nearly three times that of the intake. An earlier and larger set of some attached organisms occurred in the effluent, but there was little change in species composition between the intake and effluent canals. During the summer when high surface-water temperatures prevailed, there seemed to be a reduced number and/or disappearance of flatworms and colonial hydroids, along with increased barnacle growth.
Survival in wood duck broods
Mortality of wood ducklings ( Aix sponsa ) from hatching to 6 weeks of age averaged 47 percent during a 4-year study at the Patuxent Wildlife Research Center. Over 90 percent of the total mortality occurred during the first 2 weeks of life. Brood bonds began to dissolve after the fifth week. hlortality after 2 weeks was so low that Class I1 broods were believed to provide reliable estimates of production to flying age. Once-a-week brood censuses proved unreliable in estimating survival, but twice-a-xveek counts were accurate enough to estimate total broods and survival to Class II age.
A winter record of the Wilson's warbler at the Patuxent Wildlife Research Center, Laurel, Maryland
No abstract available.
Epifauna of the Patuxent River Estuary, Maryland, for 1963 and 1964
Methods of collection and analysis of epifaunal communities from six stations in the Patuxent estuary are described. The stations were distributed from Solomons near the mouth of the estuary , upstream to Lower Marlboro, near the limit of salt water intrusion. Species composition and abundance, seasons of attachment, and production of the epifaunal community were determined on material collected from panels submerged for 1, 3, and 12 month periods covering the years 1963 and 1964 . Salinity was highest downstream, as was the number of species. Salinity decreased rapidly between the Patuxent River Bridge station and Lower Marlboro, where the number of species was reduced to half. Seasons of attachment corresponded with seasonal temperature changes, with the greatest attachment taking place during the summer months. Over 40 species were identified with 7 of them comprising the bulk of the biomass produced. For the 7 most productive species, seasons of attachment and total numbers collected from areas of one square decimeter from monthly and quarterly panels from each station are shown. The seven species were the barnacle Balanus improvisus; the tunicate, Molgula manhattensis; the hydroids, Cordylophora lacustris and Bimeria franciscana; the amphipod, Corophium lacustre; the anemone Sagartia leucolena; the tubeworm, Polydora ligni. Their respective importance varied with seasons of attachment and location. Comments on the distribution and abundance of the less significant forms are included. Dry and ash-free dry weight (organic carbon) production of the epifaunal community varied from month to month depending on the seasons of attachment of the various species. The highest production for a single month was observed at the upriver station, Lower Marlboro, where barnacles and amphipods produced 2,754 g/m 2 /30 days dry weight and 351 g c /m 2 /30 days organic weight during August 1963 . At the same station, barnacles, amphipods, and hydroids produced, on quarterly panels, the highest yearly average weight of about 1150 g c /m 2 /yr organic carbon and on monthly panels, about 6,500 g/m 2 /yr dry weight or about 3.5 times the least organic weight and 8 times the least dry weight produced at the downriver Station, Queentree Landing.
Lead poisoning in a sample of Maryland mourning doves
A sick mourning dove ( Zenuidura macroura ) collected in Maryland with 2 lead shot in the gizzard showed acid-fast intranuclear inclusion bodies in the kidney tubular cells. The liver and the tibia contained 72 ppm and 187 ppm lead (wet weight) respectively. Four gizzards from 62 doves killed by hunters contained lead shot. The lead content of 43 dove livers ranged from 0.4-14.0 ppm (wet weight); 40 of these doves were collected by hunters, and the other 3 were dying of trichomoniasis.
Simple Bouguer gravity map of Baltimore County and Baltimore City, Maryland
No abstract available.
Nesting of hooded mergansers of the Patuxent Wildlife Research Center, Laurel, Maryland
The first known record of Hooded Mergansers ( Lophodytes cucullatus ) nesting on the coastal plain of Maryland was in 1961, when Mr. Francis Uhler (pers. comm) found two clutches in Wood Duck nest boxes in impoundments at the Patuxent Wildlife Research Center, about five miles southeast of Laurel, Maryland. R.E. Stewart and C.S. Robbins (“Birds of Maryland and the District of Columbia,” N. Amer. Fauna no. 62, 1958; see p. 102) reported two records of broods for Maryland, one for the Piedmont and one for the mountains.