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1999 Progress Report: Spatial and Temporal Trends in Water Quality
EPA Grant Number: R825433C057Subproject: this is subproject number 057 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: EERC - Center for Ecological Health Research (Cal Davis)
Center Director: Rolston, Dennis E.
Title: Spatial and Temporal Trends in Water Quality
Investigators: Jassby, Alan D.
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: October 1, 1996 through September 30, 2000
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
RFA: Exploratory Environmental Research Centers (1992)
Research Category: Center for Ecological Health Research , Targeted Research
Description:
Objective:To develop methods for analyzing and displaying water quality data and investigate historical water quality databases to uncover mechanisms of spatial and temporal variability.
Progress Summary:Activity during the last year centered on describing primary food resources for fish and shellfish in the Sacramento-San Joaquin Delta. This investigation is motivated by the role of food limitation in the decline of certain fish populations over the last few decades. The specific objective of the first phase is to determine the most important food sources and characterize their year-to-year variability. We have now completed this phase. Primary producers include phytoplankton, tidal marsh export, macrophytes, and benthic microalgae. The main source of primary production is phytoplankton, although tidal marsh export and aquatic macrophytes such as Egeria densa can be locally important. Allochthonous sources include tributary loading from the Sacramento, San Joaquin, and "east side" rivers, agricultural drainage, wastewater discharge, and urban runoff. The main allochthonous source is tributary loading, although even agricultural drainage is comparable to phytoplankton production in terms of total organic carbon loading. The primary production sources, however, cannot be directly compared to allochthonous sources. The primary production sources are largely in the form of particles that can be consumed directly by primary consumers. The allochthonous sources, on the other hand, are largely dissolved and must first be transformed to particles before they can enter the "macroscopic" food web. A further refinement is therefore necessary, which takes into account the lability of the organic matter, the time course of decomposition, the residence time of organic matter in the Delta, and the efficiency of conversion to microheterotroph biomass. Taking into account these refinements, phytoplankton production is a major source in spring and summer and a significant source in other seasons. Many other interesting observations resulted from our analyses of the last year and they are incorporated into a manuscript that will be submitted for publication shortly.
In the next phase of this study, we are focusing on the mechanisms underlying interannual variability in the main food sources, namely, phytoplankton production and tributary loading. Variability in the latter can be almost completely explained by year-to-year changes in climate and river flow, and a discussion is included in the aforementioned manuscript. The phytoplankton production issues are subtler and require consideration in a separate paper now in preparation. Our historical reconstruction of phytoplankton productivity was surprising, in that Delta-wide production was relatively invariant from year to year, despite the wild swings at individual stations. It appears that different locations compensate for each other to a large extent. Total production therefore has not been declining and is unlikely to underlie species changes at higher levels. There have been large changes in species composition, however. Different taxa are of different nutritional value. A current view is that the highly unsaturated fatty acid content determines not only their food value but also the extent to which detrital organic matter can be used. We have developed a class-dependent nutritional index to characterize how the food value has changed over the past few decades. We expect this work to characterize the role-or lack of one-of phytoplankton in species declines.
Our research has been supplemented with funding from CALFED, the federal-state consortium charged with overseeing Bay-Delta rehabilitation, and is a collaboration with several other institutions, including the USGS Water Resources Division (Menlo Park), Virginia Institute of Marine Sciences, and Stanford University. We are also working with colleagues at these institutions on other aspects of the primary food supply.
Future Activities:The development of organic carbon budgets for the Delta described above also touches on issues of importance to municipal drinking water supply in at least two ways.
First, phytoplankton often contributes to taste and odor problems in Delta water supplies, as well as filter clogging problems. These problems develop at high concentrations. The processes underlying bloom formation in the Delta are therefore of interest. Historical analysis suggests that hydrological forces, including those that can be managed in the Delta, play an important role. There is every indication from statistical analysis that bloom formation can be predicted with adequate certainty. We are approaching prediction using statistical spatial-temporal series modeling. One issue is the role that benthic macroinvertebrates play, because the data for them in the Delta are inadequate. Our current view is that this lack of data will prevent accurate prediction at lower levels of phytoplankton but may not hamper predictions of timing and magnitude of larger bloom events. The other necessary variables-insolation, temperature, water chemistry, flow, and zooplankton-are well-represented in the historical data set.
A second interface between our organic matter budgets and drinking water is in total organic carbon (TOC) concentrations and loading. TOC is an important issue for municipalities because of the potential for interacting with disinfectants in the water treatment process and forming carcinogenic disinfection byproducts. Because of this potential, federal regulations set limits for TOC in raw water. TOC levels can be lowered in raw water through expensive treatment processes but obviously there is a great interest in limiting raw water TOC through watershed management. We will refine our Delta-wide TOC budgets to characterize the sources near municipal water intakes. We are also examining the TOC data sets available from different programs in the Delta to describe quantitatively how climate and water management-through their effects on hydrological processes-affect seasonal and interannual variability in TOC levels near municipal water intakes. We expect our results will enable a more accurate assessment of the feasibility of watershed management to improve TOC levels in raw water.
Supplemental Keywords:Ecosystem Protection/Environmental Exposure & Risk, Water, INTERNATIONAL COOPERATION, Scientific Discipline, Waste, RFA, ECOSYSTEMS, Water & Watershed, Restoration, Aquatic Ecosystem Restoration, Aquatic Ecosystems & Estuarine Research, Terrestrial Ecosystems, Aquatic Ecosystem, computing technology, Biochemistry, Environmental Microbiology, Fate & Transport, Watersheds, Monitoring/Modeling, Ecology and Ecosystems, water quality, ecological impact, contaminant transport models, computer simulation modeling, aquatic, fate and transport, watershed management, watershed restoration, database, computer science, data management, decision support systems, ecological research, ecology assessment models, aquatic modeling, alternative mechanistic models, hydrological transport model, analytical models, material transport, GIS, ambient particle properties, aquatic ecosystems, data analysis, ecosystem assessment, environmental stress, sediment transport, watershed sustainablility, hydrology, modeling, watershed influences, restoration strategies, ecosystem stress, ecological models, biodiversity, habitat, integrated watershed model
Progress and Final Reports:
Original Abstract
2000 Progress Report
Final Report
Main Center Abstract and Reports:
R825433 EERC - Center for Ecological Health Research (Cal Davis)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
R825433C002 Sacramento River Watershed
R825433C003 Endocrine Disruption in Fish and Birds
R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
R825433C005 Fish Developmental Toxicity/Recruitment
R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
R825433C009 Modeling Ecosystems Under Combined Stress
R825433C010 Mercury Uptake by Fish
R825433C011 Clear Lake Watershed
R825433C012 The Role of Fishes as Transporters of Mercury
R825433C013 Wetlands Restoration
R825433C014 Wildlife Bioaccumulation and Effects
R825433C015 Microbiology of Mercury Methylation in Sediments
R825433C016 Hg and Fe Biogeochemistry
R825433C017 Water Motions and Material Transport
R825433C018 Economic Impacts of Multiple Stresses
R825433C019 The History of Anthropogenic Effects
R825433C020 Wetland Restoration
R825433C021 Sierra Nevada Watershed Project
R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
R825433C025 Regional Movement of Toxics
R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
R825433C031 Pre-contact Forest Structure
R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
R825433C035 Border Rivers Watershed
R825433C036 Toxicity Studies
R825433C037 Watershed Assessment
R825433C038 Microbiological Processes in Sediments
R825433C039 Analytical and Biomarkers Core
R825433C040 Organic Analysis
R825433C041 Inorganic Analysis
R825433C042 Immunoassay and Serum Markers
R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
R825433C045 Microbial Community Assays
R825433C046 Cumulative and Integrative Biochemical Indicators
R825433C047 Mercury and Iron Biogeochemistry
R825433C048 Transport and Fate Core
R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
R825433C053 Currents in Clear Lake
R825433C054 Data Integration and Decision Support Core
R825433C055 Spatial Patterns and Biodiversity
R825433C056 Modeling Transport in Aquatic Systems
R825433C057 Spatial and Temporal Trends in Water Quality
R825433C058 Time Series Analysis and Modeling Ecological Risk
R825433C059 WWW/Outreach
R825433C060 Economic Effects of Multiple Stresses
R825433C061 Effects of Nutrients on Algal Growth
R825433C062 Nutrient Loading
R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
R825433C064 Chlorinated Hydrocarbons
R825433C065 Sierra Ozone Studies
R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
R825433C067 Terrestrial - Agriculture
R825433C069 Molecular Epidemiology Core
R825433C070 Serum Markers of Environmental Stress
R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
R825433C072 Molecular Monitoring of Microbial Populations
R825433C073 Aquatic - Rivers and Estuaries
R825433C074 Border Rivers - Toxicity Studies