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Status and Trends in Water Quality and Living Resources in the Virginia Chesapeake Bay: 1985-1997

Water quality and living resource monitoring in the Virginia Mainstem and tributaries began in 1984 and has continued for a total of 13 years. Recently, a detailed assessment of the status of water quality and living resources conditions and long term trends in water quality and living resources in Chesapeake Bay and its tributaries was conducted (Carpenter and Lane., 1998; Dauer, 1997; Dauer et al., 1998; Lane et al.,1998, Marshall et al., 1998). An attempt was made to determine if there was concordance in or causality between current conditions of and long-term changes in water quality and living resources. The purpose of this project was to reassess the results of these studies by re-conducting the analyses after adding data collected during 1997. This report describes the status of water quality and living resource conditions for the Virginia Mainstem and tributaries, summarizes major long-term trends in water quality and measures of living resource community health, and identifies any changes in status and long term trends in water quality and living resources that have occurred as a result of an additional year of monitoring.

Water Quality Status and Trends in the Virginia Tributaries and Chesapeake Bay: 1985-1996

The objectives of the present investigation are: 1) to describe the status of water quality conditions for the lower Chesapeake Bay mainstem and the Virginia tributaries for the last three years of monitoring (1994 to 1996); 2) to summarize major long-term trends in water quality that have occurred during the 12-year period from 1985 to 1996; and 3) to compare the results of trend analyses conducted on the original water quality data with data that has been corrected for natural effects such as freshwater flow in order to determine if trends in the original data were the result of anthropogenic or natural effects.

Zooplankton Status and Trends in Virginia Tributaries and the Chesapeake Bay: 1985-1996

The zooplankton community of the Virginia portion of the Chesapeake Bay and its watershed has been systematically monitored for more than 12 years. This report summarizes status and trends in the zooplankton community of Chesapeake Bay over the period of 1984-1996. All bioindicators were calculated using zooplankton abundance and biomass data collected at the Virginia and Maryland plankton monitoring stations from the beginning of the respective monitoring programs through December of 1996. Zooplankton bioindicators used for these analyses included estimates of total mesozooplankton (excluding copepod nauplii) and microzooplankton community abundance and biomass, the ratio of microzooplankton to mesozooplankton abundance (decimal percent), mesozooplankton community species diversity (Margalef index), the deviation of mesozooplankton abundance from the grand mean mesozooplankton abundance (decimal percent), the ratio of calanoid copepods to cyclopoids and cladocerans, and the percentage of total mesozooplankton community abundance represented by Bosmina spp.

Resource Limitation of Phytoplankton in the Virginia Chesapeake Bay and Tributaries Using Nutrient-Addition Bioassays

Nutrient-addition bioassays were conducted periodically in the James, York and Rappahannock Rivers and the mainstem lower Chesapeake Bay from 1985 through early 1993 for the purpose of describing temporal and spatial patterns of nutrient limitation of phytoplankton growth and abundance in these tidally influenced aquatic systems.

Phytoplankton Status and Trends in Virginia Tributaries and the Chesapeake Bay: 1985-1996

Phytoplankton represent the microscopic plant community within the Chesapeake Bay estuarine system. They are the primary food producers within these waters, with both microbial and metazoan linkages. In addition, they represent the major source of oxygen in this Bay.

Alterations in phytoplankton composition, or trends depicting the increased presence or absence of certain algal components, are indicative of changes in the trophic, or general health status within the estuary (Marshall and Alden, 1990b; 1997). These flora may be considered a bellwether community for associating these responses to conditions or trends within the system.

An Index of Biological Integrity (IBI) was established for the phytoplankton community and is included in this report. It is based on the abundance and biomass of major algal components, and several ratio sets within this group, plus surface chlorophyll a concentrations (Alden et al., 1997). It is understood that certain patterns in increasing (or decreasing) abundance or biomass may be considered favorable (good) or unfavorable (poor). Trends based on significant patterns (p<0.02) from July 1985 through December 1996 are also indicated, with the current status based on data sets over the last three years of this period. The IBI and status of different variables were evaluated as being "good", "fair", or "poor."

Phytoplankton Indicators within the Chesapeake Bay Monitoring Program

The phytoplankton community is the primary producer and major source of oxygen within freshwater and estuarine habitats. It also represents a complex and diverse assemblage of species that differ in size, morphology and in their response to environmental conditions. The initial phase of this investigation is to identify specific relationships between various sub-sets of the phytoplankton community and specific water quality parameters within different salinity regimes of the Chesapeake Bay system. Emphasis is placed on the tidal freshwater and salinity regions of several major tributaries. The second phase of this study is the application of these results to establish a phytoplankton index that would use specific phytoplankton metrics as indicators in defining the health status within different sections of these tributaries.

Virginia Chesapeake Bay Water Quality and Living Resources Monitoring Programs: Executive Report, 1985-1996

This document represents a synthesis of the overall findings of water quality and living resources data generated over the first 12 years (1985 through 1996) of the Virginia Chesapeake Bay Monitoring Program. In this report, patterns of water quality and living resources for Virginia's tributaries and the Virginia Chesapeake Bay are examined. Patterns of nutrient loadings are examined for the entire watershed of each river; however, status and trends in water quality and living resources are presented only for the tidal portion of each river.

2000 Biennial Report of Monitoring Results

(This file is a "zipped" WordPerfect 6.1 document. The zipped document size is 482KB.)

The linked report is part of an ongoing effort to measure progress toward Chesapeake Bay restoration and to assess the quality of Virginia's rivers and streams. As we look at water quality trends across the Bay and its tributaries, we see some water quality indices are improving and, in certain areas, we are beginning to get a grasp on the more difficult problems such as nonpoint source pollution. As a result of management actions, we have also seen a number of improvements on a larger scale - such as the strong rebound of the striped bass population and a reduction to nutrient levels in some segments. However, in many other instances, the localized improvements have not yet translated into larger systemic improvements due to the natural lag (or response) time associated with the Chesapeake Bay's complex ecosystem.

Chemical and Toxicological Characterization of Tidal Freshwater Areas

(This file is a PDF document, requiring Adobe Acrobat to read)

Ambient toxics monitoring was initiated in the fall of 2000 and to date has focused on the Tidal James River from Jamestown Island to the I-95 bridge in Richmond. Monitoring in this program includes: the simultaneous assessment of river mud for chemical contaminants, evaluation for toxicity from chemical contaminants that may be present, and screening of the bottom dwelling animals. This approach, often referred to as the Sediment Quality Triad, takes into account all three pieces of information, adding considerable strength to the toxics assessment. The results provide a clearer picture for the system being evaluated on the historic and present day inputs of chemical contaminants and how animals that live there may be affected.