School of Marine Science History and Current Status

This presentation opened the VIMS 75th Anniversary Alumni Research Symposium. Dr. Linda Schaffner, VIMS Alumnus and Associate Dean of Academic Studies for the Virginia Institute of Marine Science and the School of Marine Science, College of William and Mary, presents history and current state of the school. As part of the year-long 75th anniversary celebration, this symposium brings together presentations from both alumni and current students to provide a historical and forward-looking perspective on the impacts that members of the VIMS community have made to the world

Ecology of the benthos of the lower Chesapeake Bay (Maryland)

The spatially complex lower Chesapeake Bay estuary is characterized by a variety of bottom types and hydrodynamic regimes. to account for this physically-induced variability a benthic habitat delineation scheme was developed based on existing knowledge of physical and geological characteristics. Within the context of this scheme a series of studies were conducted to identify biotic response to and interactions with the physical, chemical and geological gradients that characterize the lower Chesapeake Bay. These studies characterized organism distribution and abundance patterns within the lower bay and identified processes controlling those patterns. The biological community of the polyhaline basin habitat, an area characterized by moderate tidal, but little wave-induced bottom disturbance was defined and described for the first time. This community is characterized by large tube and burrow builders, epifaunal and commensal organisms, shallowly-distributed, short-lived species and deeply-dwelling predators. The basin is also the preferred habitat of overwintering blue crabs and an area where biotic sediment reworking generally exceeds physical reworking. The results of these studies suggest that within the lower Chesapeake Bay estuarine system, the relative importance of biological versus physical processes in maintaining the structure and dynamics of estuarine benthic communities will be greatest in the basin habitat

Baltimore Harbor and channels aquatic benthos investigations at the Wolf Trap alternate disposal site in lower Chesapeake Bay : final report

The disposal of dredged material from channel deepening projects is a major anthropogenic process influencing· benthic communities of coastal aquatic systems. Such activities are important because benthic subsystems and component organisms play major roles in the functioning of estuarine ecosystems. Benthic invertebrates are major prey items in the diets of fishes and crabs (Arntz and Brunswig 1975, Virnstein 1977, Arntz 1978, Blundon and Kennedy 1982, Lunz and Kendall 1982, Moeller et al. 1985, Pihl et al. 1992). As secondary producers capable of utilizing trophic resources from a variety of sources (e.g. detritus, algae, bacteria), they provide important links to higher trophic levels. From microbes to macrofauna, benthic organisms also have major impacts on the cycling of nutrients (Diaz and Schaffner 1990, Mayer et al. in review), contaminants (Lee and Swartz 1980, Diaz and Schaffner 1990, and Schaffner et al. 1992), and sediments (Rhoads and Boyer 1982, Diaz and Schaffner 1990). Macrobenthic organisms exhibit many properties that make them good indicators of environmental conditions (e.g. limited mobility, a variety of life histories, a range of physiological tolerances). Numerous studies have demonstrated that spatial and temporal comparisons of the kinds and abundances of benthic organisms are sensitive and important methods for assessing dredge material disposal effects on aquatic systems. This study documents changes in the structure of lower Chesapeake Bay macrobenthic communities affected by dredged material disposal. The Corps is completing an assessment of changes in benthic resource value at the Wolf Trap Alternate Disposal Site using the Benthic Resource Assessment Technique (BRAT)

Population biology and secondary production of the suspension feeding polychaete Chaetopterus cf. variopedatus: Implications for benthic-pelagic coupling in lower Chesapeake Bay

Benthic suspension feeders are functionally important components of many shallow estuarine and coastal ecosystems. Their relative importance in material and energy cycling depends on physical and biological factors, of which population dynamics of individual species are a key feature, We studied the demographics and secondary production of a population of the tubicolous, suspension feeding polychaete, Chaetopterus cf. variopedatus, of southern Chesapeake Bay, Virginia, to better understand its functional role in an estuarine ecosystem. Average worm densities in the study region ranged from 30 to \u3e 1000 individuals m(-2) and were greatest after the summer recruitment period. Recruitment success varied threefold between 1994 and 1995. A two-cohort model (juveniles and adults) with seasonality best described the data. High secondary production (18 g C m(-2) yr(-1) in 1994, 34 g C m(-2) yr(-1) in 1995) was mainly due to rapid growth and maturation of new recruits during summer and tube production. An interannual difference in production was associated with the interannual difference in recruitment success. General temporal trends of primary production and worm production were similar, and the worm population required 35%-100% of the estimated annual net water column community production per m(2) for this region of the estuary. Chaetopterus cf. variopedatus is an important component of the lower bay ecosystem and should be considered when modeling carbon, nutrient, and energy flow. Our results further demonstrate that temporal variations in population dynamics lead to significant temporal variability in the relative importance of benthic suspension feeder effects for ecosystem function

Local demographics of the polychaete Chaetopterus pergamentaceus within the lower Chesapeake Bay and relationships to environmental gradients

Chaetopterus pergamentaceus is an abundant and functionally important species within the soft sediment, subtidal benthic community of lower Chesapeake Bay. The present study elucidates spatial relationships in density, individual ash-free dry weight, total station ash-free dry weight and growth rates for juveniles and adults from 2 yrs of sampling (1994, 1995) at 12 stations in the lower Chesapeake Bay. A strong inverse relationship (r(2) = 0.69) was observed between growth rates and total density for juveniles when data from a low(1994) and high(1995) recruitment year were considered. Common parameters among stations characterized by high density/low growth were: (1) depth (maximum for region); (2) proximity to the center of a major circulation eddy; (3) proximity to a channel; (4) higher food concentration (indexed by chi-a in surface sediment layer); and (5) higher physical energy in the benthic boundary layer region. The study provides evidence that spatial variation in population processes, concordant with major environmental gradients, strongly influences population dynamics. The effects of these environmental parameters on the population dynamics of this polychaete cannot yet be clearly resolved because the parameters are confounded

Comparison of Sediment Landscapes in Chesapeake Bay as Seen by Surface and Profile Imaging

The sediment-water interface is the boundary layer between the water column and sediments. It is involved in virtually all processes and cycles within aquatic and estuarine ecosystems. Interactions and reactions at the sediment-water interface are of particular importance in regulating processes involving nutrient regeneration-remineralization (Boynton and Kemp 1985), fate of toxicants (Olsen, Cutshall and Larsen 1982), development of hypoxia-anoxia (Garber 1987), sediment mixing (Schaffner et al. 1987a, b), and sediment transport (Wright et al. 1987). Much effort has and is being expended to provide details of these processes which will eventually be used in management plans for water quality, sediment quality, and fisheries resources.https://scholarworks.wm.edu/vimsbooks/1162/thumbnail.jp

Geological and benthic evaluation of sand resources in the lower Chesapeake Bay, Report 2, Tail of the Horseshoe : Final Report v.1

This is the second of two reports concerning the resources of sand in the lower portions of Chesapeake Bay. The first, Geotechnical and Benthic Evaluation of Sand Resources in the Lower Chesapeake Bay (Kimball and others, 1989), presents a study of the resources in Thimble Shoal. The present work is a study of the area known as Tail of the Horseshoe which is just east of Thimble Shoal (Figure 1). The deposits of sand described in this report will be of most interest to the communities of Norfolk and Virginia Beach

Geological and benthic evaluation of sand resources in the lower Chesapeake Bay, Report 2, Tail of the Horseshoe : Appendix

Appendices to the final report with data and core information: York Spit Channel Sand Inventory Data Thimble Shoals Channel Tail of the Horseshoe Cape Henry Channel data from benthic evaluation listing of species collected in quantitative box cores sediment profile imagery station location

Resource use by Amphipoda (Crustacea: Peracarida) on the outer continental shelf of the Middle Atlantic Bight: Implications to community structure

Benthic communities on the outer continental shelf of the Middle Atlantic Bight are characterized by abundant populations of amphipods in the families Ampeliscidae and Corophiidae. Members of these families occupy tubes at or near the sediment surface and, thus, potentially compete with each other for spatial and trophic resources. This study examines the spatial, temporal and trophic resource use of six numerically dominant species in these families as a means of assessing the relative importance of competition as a structuring force in outer shelf benthic communities. Analysis of abundance data and the use of discriminant analysis to relate abundance to measured environmental parameters indicated that habitat partitioning was of major importance within the ampeliscid group. Spatial partitioning appeared to be of little importance within the corophiid group. Between group patterns suggest that only one species, the corophiid Unciola irrorata, was able to coexist in deep swales with the ampeliscid Ampelisca agassizi. Seasonal abundance patterns were exhibited by all corophiids, but the high degree of temporal overlap in abundance suggests that this was not an important partitioning mechanism. Similarly, persistent abundances over· time (!. agassizi) or variation in a non-seasonal manner suggests that temporal partitioning of resources was not important within the ampeliscid group. Differences in body size which might facilitate differential spatial or trophic resource use among species were observed. These differences were most strongly pronounced in closely related species which frequently co-occured. The use of trophic resources was indirectly assessed by comparing mouthpart morphologies and known feeding behaviors of each species. Quantitative morphological differences among species were evident which relate well to observed habitat preferences. A complex set of physical and biological factors were found to govern the distribution and abundance of these species within the outer shelf zone. In outer shelf swale habitats the ampeliscid, A. agassizi, effectively excludes the other members of this family. This may be the result of the species superior abilities to utilize spatial or trophic resources. Outside . of swale habitats the abundances of Ampelisca vadorum and Byblis serrata may be limited by the availability of trophic resources. The corophiids show little evidence of resource partitioning, although some differences in microhabitat distribution may facilitate coexistence among ·the species in this family, as well as between families. Populations · of these species may be held below the levels at which competitive interactions become important by benthic predators. The corophiids are known to comprise a major portion of the diet of benthic fishes on the outer shelf