Geology topics

Research about Patuxent River

Source-linked reports with geographic coverage including Patuxent River.

8 recordsLinked to original sources

USGS2010

Herbivory by resident geese: The loss and recovery of wild rice along the tidal Patuxent River

Well known for a fall spectacle of maturing wild rice ( Zizania aquatica ) and migrant waterbirds, the tidal freshwater marshes of the Patuxent River, Maryland, USA, experienced a major decline in wild rice during the 1990s. We conducted experiments in 1999 and 2000 with fenced exclosures and discovered herbivory by resident Canada geese ( Branta canadensis ). Grazing by geese eliminated rice outside exclosures, whereas protected plants achieved greater size, density, and produced more panicles than rice occurring in natural stands. The observed loss of rice on the Patuxent River reflects both the sensitivity of this annual plant to herbivory and the destructive nature of an overabundance of resident geese on natural marsh vegetation. Recovery of rice followed 2 management actions: hunting removal of approximately 1,700 geese during a 4-year period and reestablishment of rice through a large-scale fencing and planting program.

Maryland↗

USGS2007

Soras in tidal marsh: Banding and telemetry studies on the Patuxent River, Maryland

From 1993 to 1999, we conducted banding and telemetry studies of fall migrant Soras ( Porzana carolina ) in the historic rail hunting and exceptional stopover habitat of the Wild Rice ( Zizania aquatica ) marshes of the tidal Patuxent River. Drift traps equipped with audio lures produced 3,897 Sora and 417 Virginia Rail ( Rallus limicola ) captures during the seven-year study. Sora captures were characterized by a high proportion (70% to 90%) of young-of-the year and a paucity of between-year recaptures (N = 12). Radio-telemetry studies depicted Soras as long-distance migrants with high stopover survival and a critical dependence on tidal freshwater marshes for migratory fattening. Here, the high productivity of Wild Rice, Smartweeds ( Polygonum spp.) and other seed-bearing annual plants seem intrinsically linked to Sora migratory fitness. A stopover period of >40 days and mean mass gain of +0.6g/d suggests Soras are accumulating large fat reserves for long-distance flight. Radio tracking confirmed Soras as strong flyers with a demonstrated overnight (ten h) flight range of 700-900+ km. Given the potential size of fat reserves and the ability to use tail winds, it is conceivable for Soras to make nonstop flights from the Patuxent River to Florida, the Bahamas, or even the Caribbean. Once a widely hunted species, a single sport-hunting recovery from our 3,900 bandings attests to the decline in popularity of the Sora as a game bird in the Atlantic Flyway. We suggest the few between-year recaptures observed in our bandings results from three possible factors: 1) the strong influence of wind drift on migration, 2) different migration chronology or flight path of AHY versus HY birds, and/or 3) high mortality of especially HY birds during Atlantic coastal and Gulf crossings. The critical dependence of Soras and other seed-dependent, fall-migrant waterbirds on highly productive yet limited tidal freshwater marsh habitats make conservation of such areas a priority mission within the Chesapeake Bay.

Maryland↗

USGS2004

Invasive herbivory: resident Canada geese and the decline of wild rice along the tidal Patuxent River

While concern grows over the increasing numbers of exotic mute swans ( Cygnus olor ) on the Chesapeake Bay, less attention seems to be given to the highly familiar and native Canada goose ( Branta canadensis ) which has over time developed unprecedented nonmigratory, or resident, populations. Although nuisance flocks of Canada geese have been well advertised at city parks, athletic fields, and golf courses over the past three decades, recent expansion of populations to an estimated one million birds in the Atlantic Flyway, and to over 100,000 in Maryland, carries a threat of broader ecological consequences.

Maryland↗

USGS1991

Stocking of hatchery-reared striped bass in the Patuxent River, Maryland: Survival, relative abundance, and cost‐effectiveness

Hatchery‐reared fingerlings of striped bass Morone saxatilis were tagged, stocked, and recovered in the Patuxent River, Maryland, to estimate their survival and abundance relative to wild young of the year and to compare the costs and benefits of stocking phase‐I (35–50 mm, total length) and phase‐II (150–200 mm) fish. About 100,000 phase‐I fingerlings were tagged and released each year during midsummer 1988 and 1989. Both tagged and untagged (wild) young of the year were recovered by alongshore seining in the river through 80 d poststocking. Mortality rates of wild and hatchery‐reared young of the year were not significantly different‐about 3%/d. Wild young of the year were more abundant in 1989 than in 1988. In 1988, phase‐I fingerlings composed 56% of all young‐of‐the‐year striped bass in the river. In 1989 wild young‐of‐the‐year striped bass outnumbered hatchery‐reared fingerlings by about 11 to 1. Whether phase‐I or phase‐II stocking was more cost‐effective depended on the relative magnitudes of fingerling survival and on hatchery production costs. The range of phase‐II survival (5–50%) observed among different hatcheries and years of production was too broad to support generalizations about cost‐effectiveness, given the fivefold difference in the unit costs of phase‐I and phase‐II production.

Maryland↗

USGS1970

Temperature and water-quality conditions of the Patuxent River estuary, Maryland, January 1966 through December 1967

The effect of power plant cooling water in raising natural water temperatures at a location near the power plant on the Patuxent River estuary is clearly evident from thermograph records. Surface temperature at a station 333 m (1,000 ft) downstream from the discharge canal was raised an average of about 4 C, and at times by as much as 8 C. Temperature rises were greatest during the winter. Infrared imagery showed that elevated surface temperatures could be detected about 5.5 km (3 nautical miles) upstream at flood tide. Temperature profiles obtained from airborne radiation equipment revealed a complicated surface temperature pattern and also showed the effects of density differences and wind action on the steam-electric station (S.E.S.) effluent plume. Mean annual salinity for a 5-year period (1963–1967) was highest in 1966, about 12.3 ‰, and lowest in 1967, about 9.9‰. Dissolved oxygen values for 1966–1967 ranged from 3.2 to 15.6 mg/l, and saturation ranged from 55 to 152%. Turbidity levels were inversely related to salinity, with the highest annual, mean of 28 JCU (Jackson Candle Units) occurring in 1967, the lowest salinity year. The extreme tide range was 2.1 m (6.7 ft); mean water levels at the Patuxent Bridge were highest in summer and lowest in winter. Water stages are more affected by wind speed and direction than by flow in the river.

Maryl↗

USGS1969

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.

Maryland↗

USGS1967

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.

Maryland↗

USGS1967

Temperature and water-quality conditions for the period July 1963 to December 1965, Patuxent River Estuary, Maryland

Graphs and tables obtained from continuous records of surface-water temperature from five stations for the period july 1963 through December 1965 and of surface, salinity, dissolved oxygen, turbidity, tide-stage, wind data and bottom temperature from a single station are presented herein. Effects of powerplant cooling water on water temperature were obvious at a station near the plant's discharge point. Surface-water density at the Patuxent River Bridge varied from 1.0033 to 1.0127 with least change during the period May to September. Salinity ranged from 3 to 16.5 parts per thousand. Average salinity in the spring of 1965 was double that of spring 1964. Turbidity was high during the winter, and peak values were obtained during prolonged periods of high wind velocities. Dissolved oxygen values ranged from 386 to 15.0 parts per million, and percentage saturation of oxygen from 49 to 144 percent. The extreme tidal range was 5.7 feet; mean water levels were highest in summer and lowest in winter and spring.

Maryl↗