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Full-Text Articles in Physical Sciences and Mathematics

Effect Of Wind Changes During The Last Glacial Maximum On The Circulation In The Southern Ocean, John M. Klinck, David A. Smith Aug 1993

Effect Of Wind Changes During The Last Glacial Maximum On The Circulation In The Southern Ocean, John M. Klinck, David A. Smith

CCPO Publications

Present-day surface wind stress climatology is manipulated to simulate wind conditions during the last glacial maximum. These estimated wind fields force a one-layer, wind-driven numerical model of the southern ocean to determine if a change in the strength of the surface wind stress can shift the location of the Antarctic Polar Front, which is part of the Antarctic Circumpolar Current. A change in the forcing by a factor of 0.5-2.0 results in a change in the speed of the flow by an identical factor with no change in position. However, if the present-day wind climatology is shifted meridionally there is …


Data Report : Hypoxia In The James River, 1992, G. M. Sisson, A. Y. Kuo, Bruce Neilson, Nancy C. Wilson Aug 1993

Data Report : Hypoxia In The James River, 1992, G. M. Sisson, A. Y. Kuo, Bruce Neilson, Nancy C. Wilson

Reports

As part of the hypoxia program of the Virginia Chesapeake Bay Initiatives, the Department of Physical Sciences of the Virginia Institute of Marine Science (VIMS) conducted a series of measurements around the mouth of the James River estuary. The measurements were made in the summer of 1992. Two types of measurements were conducted: measurements at moored stations and measurements by slackwater surveys. The former collected data for investigation of dissolved oxygen (DO) variation, and associated physical parameters, in an intratidal time scale, as well as for studying the vertical distributions of the measured parameters. The latter collected data for spatial …


Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, With A Discussion Of Apparent Geographic Changes In Population Dynamics, Luiz R. Barbieri, Mark E. Chittenden Jr., Cynthia M. Jones Aug 1993

Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, With A Discussion Of Apparent Geographic Changes In Population Dynamics, Luiz R. Barbieri, Mark E. Chittenden Jr., Cynthia M. Jones

OES Faculty Publications

Atlantic croaker, Micropogonias undulatus, collected from commercial catches in Chesapeake Bay and in Virginia and North Carolina coastal waters during 1988-1991 (n=1,967) were aged from transverse otolith sections. Ages 1-8 were recorded, but eight-year-old fish were rare. Marginal increment analysis showed that for ages 1-7, annuli are formed once a year during the period April-May. Otolith age readings were precise: >99% agreement within and between readers. Observed lengths-at-age were highly variable and growth rate decreased after the first year. Despite the high variability in sizes-at-age, observed lengths for ages 1-7 fit the von Bertalanffy growth model (r2=0.99; n=753) well. …


Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1992 : A Report To The Virginia Department Of Environmental Quality, Kevin Curling, Rodney Jackson, Bruce Neilson Jul 1993

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1992 : A Report To The Virginia Department Of Environmental Quality, Kevin Curling, Rodney Jackson, Bruce Neilson

Reports

The Chesapeake Bay Water Quality Monitoring Program (WQMP) has three main objectives: (1) characterization of water quality conditions, (2) detection of temporal trends in water q1llality, and (3) crr.ation of a data base that furthers our understanding of the proceses that control water quality in the Chesapeake Bay system. The purpose of this report is to characterize water quality conditions in the Virginia portion of Chesapeake Bay during the 1992 water year, which runs from October 1991 through September 1992. These monitoring efforts have been conducted with funding from the US Environmental Protection Agency and the Commonwealth of Virginia.


Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1991 : A Report To The Virginia Water Control Board, Kevin Curling, Bruce Neilson Jun 1993

Water Quality In Chesapeake Bay : Virginia Portion, Water Year 1991 : A Report To The Virginia Water Control Board, Kevin Curling, Bruce Neilson

Reports

The purpose of this report is to characterize water quality conditions during the 1991 water year, October 1990 through September 1991. Most information is provided in graphical format and only data for the Virginia portion of Chesapeake Bay is included. No interpretation is included, since data analysis is the stated purpose of several other reports. This report and companion data reports provide to both scientists and managers ready access to a portion of the data. It is possible, for example, to quickly examine seasonal patterns, compare conditions at two stations, or see if surface and bottom conditions differ significantly. Trends, …


Data Base Development For Characterizing Contaminated Sediments In The Chesapeake Bay Region, Gary F. Anderson, Caroline Brouwer-Riel, Maynard M. Nichols Apr 1993

Data Base Development For Characterizing Contaminated Sediments In The Chesapeake Bay Region, Gary F. Anderson, Caroline Brouwer-Riel, Maynard M. Nichols

Reports

This project is one component of the U.S. Geological Survey's National Coastal Geology Program directed to polluted sediments. Its long-term aim is to develop a comprehensive database on estuarine contaminated sediments that provides a summary of information and a digital reference source of detailed and readily accessible data. It focuses on Chesapeake Bay because there is a wealth of data on bottom sediments and sedimentary contaminants. However, this data is fragmented, uncollated and dispersed in many papers, books, reports, files and documents, often local sources, outside the mainstream of national consideration and scientific knowledge. Without an organized body of data, …


Methanesulfonic Acid In Coastal Antarctic Snow Related To Sea‐Ice Extent, K. A. Welch, Paul Andrew Mayewski, S. I. Whitlow Mar 1993

Methanesulfonic Acid In Coastal Antarctic Snow Related To Sea‐Ice Extent, K. A. Welch, Paul Andrew Mayewski, S. I. Whitlow

Earth Science Faculty Scholarship

Proxy records of biogenic sulfur gas obtained from ice cores suggest that variability in marine biogenic sulfur emissions may reflect changes in climate [Saigne and Legrand, 1987; Legrand et al., 1988, Legrand et al., 1991; Anderson and Charlson, 1991]. Increased sea‐ice extent has previously been proposed as one cause of relatively high methanesulfonic acid (MSA) in glacial‐age ice core samples [Gibson et al., 1990]. We have analyzed MSA, one of the oxidation products of the biogenic sulfur gas dimethylsulfide [Hatakeyama et al., 1985], from snowpit samples recovered from a coastal site in Southern Victoria Land, Antarctica. Time series of MSA …


Carbon, Nitrogen, And Phosphorus Leaching Rates From Spartina Alterniflora Salt Marshes, R. Eugene Turner Jan 1993

Carbon, Nitrogen, And Phosphorus Leaching Rates From Spartina Alterniflora Salt Marshes, R. Eugene Turner

Faculty Publications

Annual carbon, nitrogen, and phosphorus leachate rates from live Spartina alterniflora Loisel in a Louisiana (USA) salt marsh were estimated to be 200, 14, and 3 g m-2, respectively, and to peak in summer and higher salinit~es. Leachate losses of P, N and C are equivalent to a turnover of live plant tissues of 10, 17 and 49 d, respectively, when submerged, and 148, 250 and 721 d, respectively, when unsubmerged. Plant leachate losses during marsh submergence and non-submergence are nearly equal because release rates are 15x greater during submergence. Nitrogen and carbon concentrations relative to phosphorus are proportionately 4x …


A Comparison Of Gulf Stream Sea Surface Height Fields Derived From Geosat Altimeter Data And Those Derived From Sea Surface Temperature Data, Tal Ezer, George L. Mellor, Dong-Shan Ko, Ziv Sirkes Jan 1993

A Comparison Of Gulf Stream Sea Surface Height Fields Derived From Geosat Altimeter Data And Those Derived From Sea Surface Temperature Data, Tal Ezer, George L. Mellor, Dong-Shan Ko, Ziv Sirkes

CCPO Publications

Two types of satellite data, Geosat altimeter data and sea surface temperature data (SST), are compared and evaluated for their usefulness in assimilation into a numerical model of the Gulf Stream region. Synoptic sea surface height (SSH) fields are derived from the SST data in the following way: first three-dimensional temperature and salinity analysis fields are obtained through the Optimum Thermal Interpolation System (OTIS), and then SSH fields are calculated using a primitive equation, free-surface, numerical model running in a diagnostic mode. The aforementioned SSH fields are compared with SSH fields obtained from the Geosat altimeter data. Use of Geosat …


Chesapeake Bay Wave Climate : Thimble Shoal Light Wave Station, Report And Summary Of Wave Observations, October 8, 1990 Through August 22, 1991 And Chesapeake Light Tower - Vims Star Gage Test Measurements And Evaluation, July, August, October 1991, John D. Boon, D. A. Hepworth, K. D. Suh, F. H. Farmer Jan 1993

Chesapeake Bay Wave Climate : Thimble Shoal Light Wave Station, Report And Summary Of Wave Observations, October 8, 1990 Through August 22, 1991 And Chesapeake Light Tower - Vims Star Gage Test Measurements And Evaluation, July, August, October 1991, John D. Boon, D. A. Hepworth, K. D. Suh, F. H. Farmer

Reports

This report also presents a description of a directional wave gaging system, known as a "Star" gage, that is designed for long-term, low-maintenance operation both within and immediately outside the Chesapeake Bay entrance area. This development was prompted by our dependence to date on the single-point, PUV-type directional wave gage described below. While ideally suited for short-term investigative studies at different sites, the PUV directional wave gage requires field service visits at monthly intervals to maintain adequate performance and uninterrupted operation. A prototype Star gage system was constructed and field tested to evaluate its potential use as a long-term and …


Sediment Processes Monitoring Data Report For Calendar Year 1989, Cheol Mo, Bruce Neilson, Richard L. Wetzel Jan 1993

Sediment Processes Monitoring Data Report For Calendar Year 1989, Cheol Mo, Bruce Neilson, Richard L. Wetzel

Reports

Pairs of particle interceptor traps were deployed at three depths - 3, 6, and 9 meters with deployment intervals typically lasting about two weeks. At times of deployment and retrieval, profiles of water temperature, salinity and dissolved oxygen content were made and water samples were collected at trap depths. Bottom sediments also were collected and a sub-sample of the surficial sediments taken. Water samples, bottom sediments, and the materials collected in the traps were returned to the Virginia Institute of Marine Sciences for analysis. The data collected during both 1988 and 1989 are presented in the appendices. Both 1988 and …


A Feasibility Study Of Detached Breakwater Designs Using A Combined Refraction/Diffraction Wave Model, Virginia Beach, Virginia, John D. Boon Jan 1993

A Feasibility Study Of Detached Breakwater Designs Using A Combined Refraction/Diffraction Wave Model, Virginia Beach, Virginia, John D. Boon

Reports

The Virginia Institute of Marine Science, together with management agencies in the commonwealth, has a continuing interest in the matter of beach preserva~ion along Virginia's Atlantic coastline. This interest is particularly acute along the coastline fronting the resort city of Virginia Beach, Virginia, where some 225,000 cubic meters of artificial sand nourishment are required each year to maintain recreational beaches. Wright et al.(1987), in their detailed report on beach dynamics from Cape Henry to False Cape, have stated that offshore loss of sand is a major cause of shoreline erosion in the Virginia Beach sector. Because of the narrowness and …


Spatial And Temporal Occurrence Of Spanish Mackerel Scomberomorus Maculatus In Chesapeake Bay, Mark E. Chittenden Jr., Luiz R. Barbieri, Cynthia M. Jones Jan 1993

Spatial And Temporal Occurrence Of Spanish Mackerel Scomberomorus Maculatus In Chesapeake Bay, Mark E. Chittenden Jr., Luiz R. Barbieri, Cynthia M. Jones

OES Faculty Publications

No abstract provided.


Benthic Microalgal Production At Stellwagen Bank, Massachusetts Bay, Usa, Lawrence B. Cahoon, Guy R. Beretich Jr., Carrie J. Thomas, Amy M. Mcdonald Jan 1993

Benthic Microalgal Production At Stellwagen Bank, Massachusetts Bay, Usa, Lawrence B. Cahoon, Guy R. Beretich Jr., Carrie J. Thomas, Amy M. Mcdonald

OES Faculty Publications

Benthic microalgal chlorophyll a and production were measured at 3 sites at Stellwagen Bank, a cold temperate continental shelf habitat in Massachusetts Bay, USA, during August 1991. Benthic microalgal chlorophyll a averaged 39.8 Mg M-2, vs average integrated phytoplankton chlorophyll a of 25.9 mg m-2. Gross benthic microalgal production, measured by oxygen exchange in clear and opaque benthic chambers, averaged 20.9 mg C m-2 h-1. This production was supported by average daily light fluxes to the bottom that never exceeded 1 % of surface incident radiation and were as low as 4.7 μE …


Seasonal Relationships Between Phytoplankton Composition, Abundance, And Primary Productivity In Three Tidal Rivers Of The Lower Chesapeake Bay, Harold G. Marshall, Kneeland K. Nesius Jan 1993

Seasonal Relationships Between Phytoplankton Composition, Abundance, And Primary Productivity In Three Tidal Rivers Of The Lower Chesapeake Bay, Harold G. Marshall, Kneeland K. Nesius

Biological Sciences Faculty Publications

The seasonal abundance and successional patterns of phytoplankton, including autotrophic picoplankton, are compared to spring, summer, and fall primary production maxima that occurred in three tidal rivers. The tidal freshwaters were dominated by diatoms, chlorophytes, and cyanobacteria during a late spring through early fall period of maximum growth. In contrast, downstream assemblages were dominated by estuarine diatoms, dinoflagellates, and cryptomonads which developed spring pulses and a protracted summer-fall maximum. Autotrophic picoplankton produced a major summer pulse at all river stations with reduced abundance during other seasons. The mean annual productivity rates for the tidal James, Rappahannock, and York rivers were …


Changes In The Sea-Ice Brine Community During The Spring-Summer Transition, Mcmurdo Sound, Antarctica .2. Phagotrophic Protists, Diane K. Stoecker, Kurt R. Buck, Mary Putt Jan 1993

Changes In The Sea-Ice Brine Community During The Spring-Summer Transition, Mcmurdo Sound, Antarctica .2. Phagotrophic Protists, Diane K. Stoecker, Kurt R. Buck, Mary Putt

OES Faculty Publications

The land-fast sea-ice brine contains a diverse phagotrophic protist assemblage consisting of < 5 mum heterotrophic flagellates, Cryothecomonas spp., heterotrophic dinoflagellates, and heterotrophic and mixotrophic ciliates. Fine-scale horizontal spatial variability is a feature of this assemblage; samples taken within 1 m of each other can be dominated by different heterotrophic protists. Many of the larger heterotrophic protists found in the brine are also found in the water column. The photosynthetic ciliate Mesodinium rubrum is also common. In mid to late austral spring, the heterotrophic assemblage accounts for ca 10% of the total protist biomass in the brine and is dominated by Cryothecomonas spp. This flagellate …


A Reproductive-Resting Stage In An Harpacticoid Copepod, And The Significance Of Genetically Based Differences Among Populations, D. J. Lonsdale, P. Weissman, Fred C. Dobbs Jan 1993

A Reproductive-Resting Stage In An Harpacticoid Copepod, And The Significance Of Genetically Based Differences Among Populations, D. J. Lonsdale, P. Weissman, Fred C. Dobbs

OES Faculty Publications

Dormancy is an important life-history strategy which allows copepods to increase their fitness by delaying growth and reproduction until harsh environmental conditions have ameliorated. For marine species, the primary strategies identified to date include the production of dormant eggs by shallow-water species, and copepodite overwintering in deep-water species. Herein, we describe a third strategy in which fertilized adult females enter a “reproductive-resting” stage during the late fall that allows them to overwinter and provide a first source of spring naupliar recruitment. This strategy has been observed in the estuarine copepod Coullana canadensis, but may also occur in other species. …


Age, Growth, And Reproduction Of Tautog Tautoga Onitis (Labridae: Perciformes) From Coastal Waters Of Virginia, E. Brian Hostetter, Thomas A. Munroe Jan 1993

Age, Growth, And Reproduction Of Tautog Tautoga Onitis (Labridae: Perciformes) From Coastal Waters Of Virginia, E. Brian Hostetter, Thomas A. Munroe

Biological Sciences Faculty Publications

Tautog Tautoga onitis are gaining popularity in Virginia's coastal waters as a recreational and food fish. Adult tautog are seasonally abundant on inshore hard-bottom habitats (1-10 m) and inhabit offshore areas (10-75 m) year-round. Juveniles, especially newly-settled recruits, inhabit vegetated areas in shallow water (usually < 1 m). From March 1979 to July 1986, tautog were collected in lower Chesapeake Bay and nearby coastal waters to examine age, growth, and sexual maturation. Age estimates were determined from annular marks on opercle bones: 82% of the fish were age-10 or younger, 18% exceeded age-10, and 1% were age-20 or older. Marginal increment analysis revealed that annuli formed concurrent with a protracted spawning season (April-July). The von Bertalanffy growth equation, derived from back-calculated mean lengths-at-age, was l(t) = 742 [1-e-0.085 (t-1.816)]. Tautog are long-lived (25+ yr) and attain relatively large sizes (672 mm TL) slowly (K for sexes combined = 0.085). Growth rates of both sexes are similar, although males grow slightly faster (K = 0.090 vs. 0.085 for females). Maturity occurs at age-3 in both sexes. Growth rates for tautog from Virginia are similar to those reported nearly 25 years ago for tautog in Rhode Island. Growth rates for tautog are similar to those of other reef fishes, such as snappers and groupers. Habitat restriction, slow growth, great longevity, and increasing popularity by user groups may contribute to over-exploitation of this species in Virginia waters.