Nutrients in the Swan-Canning Estuary  ||  Stream restoration of Wilson Creek
Ohio River ecosystem study  ||  James River ecosystem study

James River ecosystem study

In August of 2004 I moved my laboratory from the University of Louisville to Virginia Commonwealth University. VCU is in the process of building a program in river science, which is my primary area of research interest. The university’s initiative in this area coincides with the development of the VCU Inger and Walter Rice Center for Environmental Life Sciences as a base for research activities on the James River. The information below provides some background on the current state of the river and outlines preliminary ideas for starting a research program focusing on ecosystem processes.

Map of the James River basin showing the locations of the city of Richmond, VCU’s Rice Center and USGS gauging stations.

VCU’s Rice Center: A 342-acre parcel on the tidal freshwater James River donated to VCU in October 2000.

The river
The James River is the nation’s most historic river. It served as the site of the first English colonial settlements and the earliest stages of export agriculture and industrial activity. The river drains a large portion of Virginia, originating in the Appalachian Mountains and flowing eastward for 540 km before entering the Chesapeake Bay. The James is the third largest tributary of Chesapeake Bay, contributing 12 percent of discharge, 5 percent of total N and 20 percent of total P inputs (source: USGS report by Sprague et al. 2000). The river plays an important role in the regional economy by serving as a major transportation artery and a drinking-water source for a growing population. The economic importance of the river also is due to its ecological status as a designated Scenic River, premier recreational fishery and famous white-water destination. Water quality and biotic resources are well characterized, particularly nutrients and fish, although little work has been done to investigate lower trophic levels (plankton) or ecosystem processes. Current land use in the basin is predominantly forest (67 percent) with 22 percent in agriculture and six percent in urban development (population = 2.6 million). Agricultural and urban areas contribute a disproportionate fraction of nutrient loading to the James relative to catchment area. Analyses for the 1985-98 period show that agriculture accounts for one-third of N inputs to the river but that this fraction is declining due to reductions in acreage (Sprague et al. 2000). In contrast, N delivery from urban areas is increasing and this source now contributes nearly as much N as agriculture. Agriculture accounts for 50 percent of P inputs to the river and this fraction has not changed substantially despite reductions in acreage and implementation of best management practices (BMPs). Substantial increases in P loading from point sources have occurred during this period. Current spending on nutrient management in the Chesapeake Bay is $1 billion per year, and it is anticipated that an additional $14 billion will be required over the next six years to meet projected targets.

I view the James River ecosystem study as an opportunity to (1) provide timely data on nutrients and plankton processes in the James and (2) introduce innovative ecosystem modeling techniques into a high-profile management effort.

Research overview
My research focuses on ecosystem attributes that are directly linked to important aspects of valuation. Rivers provide an array of goods and services that fulfil societal needs – drinking-water, fisheries, maintenance of biodiversity – and justify expenditures for ecosystem management. One of my areas of interest is the sources of energy that support riverine food webs. Rivers transport particulate organic matter, seston, which serves as the primary energy source for a diverse array of consumers. Seston predominantly is comprised of decomposed terrestrial plant material that is of low nutritive quality. Phytoplankton constitute a small (10 percent) but ecologically significant fraction of seston that is rich in mineral nutrients and biochemicals essential to animal growth and reproduction. I plan to conduct experiments to (1) assess nutrient-light constraints on phytoplankton production in the James River and (2) quantify growth rates of key phytoplankton consumers (zooplankton) to assess their response to changes in the algal fraction of seston. Results from these experiments will enable us to model phytoplankton and consumer responses to changes in river nutrient concentrations. Algal production is linked directly to economic valuation (drinking-water quality, river aesthetics) and indirectly through higher trophic levels (diversity maintenance, fisheries).

VCU faculty member Dr. Paul Bukaveckas and graduate student Christina Lynchesky measure solar energy below the surface of the James River aboard the Chesapeake.  Measurements of solar energy at depth are used to characterize the transparency of the water and to model the timing and location of algal blooms.  Photo by William Portlock (Chesapeake Bay Foundation).

Getting Started

On Friday, November 11, 2005 we completed our first data collection cruise on the James River. The cruise spanned the lower portion of the James River beginning near Richmond and extending to Newport News (within 20 miles of Chesapeake Bay). Working aboard the Chesapeake (operated by the Chesapeake Bay

VCU graduate student Amy Macdonald (Biology) processes samples aboard the Chesapeake. Water samples were collected at various stations along the lower James River to characterize the dissolved and particulate materials that control the absorption and scattering of light within the water column. Photo by Christina Baker (VCU).

Foundation) we collected data on the optical properties of the river in order to understand the processes that regulate water transparency. Water clarity is an important determinant of where and when algal blooms may occur as well as habitat conditions for the establishment and growth of submerged aquatic vegetation such as eelgrass. Future cruises will examine how variation in river flow affects water clarity in the lower James River.