Life Sciences Commons^™

Modern And Holocene Formanifera In The Chesapeake Bay Region, Robert L. Ellison, Maynard M. Nichols

VIMS Books and Book Chapters

Estuaries are highly variable coastal ecosystems. Some of the variation is seasonal and some is longitudinal along the environmental gradient from the river to the sea. Foraminifera are tuned to the periodicity, and a progressive change in the composition and structure of foraminiferal faunas parallels the longitudinal ecocline, identified by the gradient in salinity.

In marshes and tributary estuaries where water is fresh, thecamoebinids comprise the microfauna. Three other marsh faunas are composed chiefly of the agglutinate species: Ammoastuta salsa, Miliammina fusca, Arenoparrella mexicana, Alllmobaculites crassus and species of Haplophragmoides and Trochammina. Their distribution is influenced by salinity and exposure. …

Changes In Salinity Structure Of The James, York And Rappahannock Estuaries Resulting From The Effects Of Tropical Storm Agnes, Paul V. Hyer, Evon P. Ruzecki

VIMS Books and Book Chapters

The peak effect of the flood waters produced by Tropical Storm Agnes was seen on June 25 in the James, June 26 in the Rappahannock, and June 30 in the York. Recovery toward normal salinity conditions after the high runoffs proceeded discontinuously, with alternating periods of vertical stratification and destratification. During strongly stratified stages, saline water advanced upstream along the bottom. In the York and James Rivers, the most dramatic stratification occurred about July 20- 25. This event resulted in bottom salinity values exceeding normal ambient values and, at the river mouths, reaching values hitherto unobserved. This event was apparently …

The Effects Of Tropical Storm Agnes On Fishes In The James, York, And Rappahannock Rivers Of Virginia, Walter J. Hoagman, Woodrow L. Wilson

VIMS Books and Book Chapters

Intensive trawl surveys during and after Tropical Storm Agnes were mounted on the James, York, and Rappahannock Rivers to measure the effects of the floodwaters on the distribution and abundance of fish. The direct effect of Agnes on the fish populations was minor and temporary. The normal zone was extended downriver. A substantial portion of the lower-river (marine) species was also displaced downstream and into Chesapeake Bay, but had returned by the follow-up surveys. No adult mortalities due to Agnes were detected. Although we know vast quantities of fish larvae and other plankton were swept into Chesapeake Bay, the overall …

Effects Of Tropical Storm Agnes On Zooplankton In The Lower Chesapeake Bay, George C. Grant, Burton B. Bryan, Fred Jacobs, John E. Olney

VIMS Books and Book Chapters

Sampling techniques in use since August 1971 were employed to study effects of Tropical Storm Agnes on lower Chesapeake Bay zooplankton following the storm's passage on June 21, 1972. Mean catches of copepods, cladocerans, barnacle larvae, decapod larvae, chaetognaths, and fish eggs and larvae were calculated for the entire study area and six subareas from 8" bongo net collections. A single subarea was selected for specific identifications within major taxa of zooplankton.

Patterns Of Distribution Of Estuarine Organisms And Their Response To A Catastrophic Decrease In Salinity, Peter F. Larsen

VIMS Books and Book Chapters

The occurrence of Tropical Storm Agnes during an ongoing study on the community structure of the macrobenthos associated with the James River oyster reefs provided a unique opportunity to document the responses of this assemblage to such a disturbance. The spatial and temporal patterns of abundance of 18 important taxa are examined in this paper. Eight species exhibited limited up estuary penetration, six were most successful in the upper part of the estuarine segment studied, two were most abundant in the mid-section of the study area, and two were ubiquitous. In the post-Agnes period, .six species exhibited reduced population levels, …

The Effect Of Tropical Storm Agnes On Oysters, Hard Clams, Soft Clams, And Oyster Drills In Virginia, D. S. Haven, W. J. Hargis Jr., J. G. Loesch, J. P. Whitcomb

VIMS Books and Book Chapters

Tropical Storm Agnes had a major effect on the molluscan fisheries of Virginia. One effect was the direct mortality of oysters, Crassostrea virginiaa, in the upper parts of many estuaries. Typical losses on leased bottoms were: the James River, 10%; the York River, 2%; the Rappahannock River, 50%; and the Potomac River tributaries (Virginia) 70%. Economic loss was in excess of 7.9 million dollars. There was a nearly complete absence of oyster larvae attachment (setting) in 1972. Other effects of Agnes included a nearly complete loss of soft clams, Mya arenaria, in the Rappahannock River. Hard clams, Meraenaria meraenaria, were …

Public Health Aspects Of Tropical Storm Agnes In Virginia's Portion Of Chesapeake Bay And Its Tributaries, M. P. Lynch, J. Claiborne Jones

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All Virginia waters within Chesapeake Bay were closed for the taking of shellfish for direct consumption on 23 June 1972. This initial closing was in anticipation of high microorganism levels accompanying flood waters moving downstream. Various areas beginning with the lower portion of Chesapeake Bay were reopened beginning )n 20 July 1972. By 5 October 1972 all areas closed as a result )f Tropical Storm Agnes were reopened. No increased incidents of infectious diseases caused by waterborne microorganisms were noted in Virginia which could be attributed to Tropical Storm Agnes.

The Displacement And Loss Of Larval Fishes From The Rappahannock And James Rivers, Virginia, Following A Major Tropical Storm, Walter J. Hoagman, John V. Merriner

VIMS Books and Book Chapters

Two days after Tropical Storm Agnes, the Virginia Institute of Marine Science (VIMS) established an anchor station at Mile 15 in the Rappahannock and Mile 10 in the James River. Both stations were in mainstream, manned constantly for 10 days, and took continuous current data from meters placed at 0, 6, 8, and 15 min the Rappahannock and 0, 4, 5, 8, and 14 min the James. Concurrently, 0.85 m diameter plankton nets of No. 1 nylon mesh were hung in the flowing surface water for 10 minutes hourly. A small collection of midwater (4 m) plankton samples was obtained …

Effect Of Tropical Storm Agnes On Setting Of Shipworms At Gloucester Point, Virginia, Marvin L. Wass

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Surveillance of shipworm infestation at Gloucester Point, Va., began in 1958. Borer attack by Bankia gouldi occurred in July to early October each year until the passage of Agnes greatly reduced setting. Populations returned to near normal in 1975. Salinity was shown to vary with watershed rainfall.

The Effect Of Tropical Storm Agnes On The Benthic Fauna Of Eelgrass, Zostera Marina, In The Lower Chesapeake Bay, Robert J. Orth

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Tropical Storm Agnes caused major changes in the macroinvertebrate assemblages of both epifauna and infauna in eelgrass, Zostera marina, beds. Species abundance and density of infauna declined by one-third to one-half of values found prior to Agnes. Typical members of the infaunal community such as the amphipods, Ampelisca spp. and Lysianassa alba, the polychaetes Sabella microphthalma and Exogone dispar, ostracods and gastropods were either absent or rare following Agnes. Epifaunal density was much higher than that recorded before Agnes but the number of species was reduced. This high density was attributed to several species, e.g. Molgula manhattensis, which appeared to …