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  • Title

    Monitoring and Evaluation of the North Delta Food Subsidies and Colusa Basin Drain Study

    Lead California Department of Water Resource [DWR]
    Description The North Delta Food Subsidies – Colusa Basin Drain Study monitors and evaluates the effects of the North Delta Flow Action on the Delta food web.
    Science topics Delta Smelt, Fish, Flows, Water management
    Updated June 13, 2024
  • Title

    Delta Regional Monitoring Program Mercury Monitoring

    Lead Delta Regional Monitoring Program [RMP]
    Description Monitoring of sport fish and water was conducted by the Delta Regional Monitoring Program (Delta RMP) from August 2016 to April 2017 to begin to address the highest priority information needs related to implementation of the Sacramento–San Joaquin Delta Estuary Total Maximum Daily Load (TMDL) for Methylmercury (Wood et al. 2010). Two species of sport fish, largemouth bass (Micropterus salmoides) and spotted bass (Micropterus punctulatus), were collected at six sampling locations in August and September 2016. The length-adjusted (350 mm) mean methylmercury (measured as total mercury, which is a routinely used proxy for methylmercury in predator fish) concentration in bass ranged from 0.15 mg/kg or parts per million (ppm) wet weight at Little Potato Slough to 0.61 ppm at the Sacramento River at Freeport. Water samples were collected on four occasions from August 2016 through April 2017. Concentrations of methylmercury in unfiltered water ranged from 0.021 to 0.22 ng/L or parts per trillion. Concentrations of total mercury in unfiltered water ranged from 0.91 to 13 ng/L. Over 99% of the lab results for this project met the requirements of the Delta RMP Quality Assurance Program Plan, and all data were reportable. This data report presents the methods and results for the first year of monitoring. Historic data from the same or nearby monitoring stations from 1998 to 2011 are also presented to provide context. Monitoring results for both sport fish and water were generally comparable to historic observations. For the next several years, annual monitoring of sport fish will be conducted to firmly establish baseline concentrations and interannual variation in support of monitoring of long-term trends as an essential performance measure for the TMDL. Monitoring of water will solidify the linkage analysis (the quantitative relationship between methylmercury in water and methylmercury in sport fish) in the TMDL. Water monitoring will also provide data that will be useful in verifying patterns and trends predicted by numerical models of mercury transport and cycling being developed for the Delta and Yolo Bypass by the California Department of Water Resources (DWR).
    Science topics Biosentinels, Fish, Methylmercury, Restoration, Water
    Updated November 17, 2022
  • Title

    Operation Baseline Project 2B: Phytoplankton, CSU Maritime Academy

    Lead California State University Maritime Academy
    Description Planned upgrades to the Sacramento Regional wastewater treatment plant (Regional San) between 2019 and 2021 will reduce total nitrogen inputs by >60% and shift the dominant form of nitrogen entering the Delta from ammonium (NH4) to nitrate (NO3). These changes will affect the Delta in ways unforeseeable with existing knowledge. The focus of this project is to quantify the links between wastewater nitrogen and phytoplankton standing stock, community composition and carbon and nitrogen production. Working in collaboration with the other two Operation Baseline projects, we will: 1. validate in situ monitoring approaches for phytoplankton standing stock and community composition (i.e. using size-fractionated chlorophyll-a and diagnostic phytopigments via HPLC) and 2. provide estimates of ambient and nitrogen-saturated phytoplankton NH4 and NO3 uptake rates as well as C uptake. Phytoplankton N and C uptake rates will be made along spatial gradients in nitrogen and water residence time (Task 1) and in three wetland habitats with varying influence from wastewater nitrogen (Task 3). Together with the other proposals, this project will provide much needed baseline characterization of nutrient processes in the Delta prior to Regional San upgrades.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Operation Baseline Project 2C: Zooplankton, Romberg Tiburon Center, SFSU

    Lead San Francisco State University [SFSU]
    Description This project will examine responses of zooplankton (copepods) to variations in the foodweb attributable to nutrient sources. At each wetland site we will determine spatial abundance patterns and rates of reproduction, growth, and mortality. These will be integrated with information on phytoplankton and physical dynamics to determine how population dynamics responds to nutrient conditions. Stable isotopes will be used to assess nutrient source contributions to growth.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Do light, nutrient, and salinity interactions drive the “bad Suisun” phenomenon? A physiological assessment of biological hotspots in the San Francisco Bay-Delta

    Lead University of California - Santa Cruz [UCSC]
    Description This project assessed the physiological basis for reduced phytoplankton growth in Suisun Bay, prior to the major upgrade at the Sacramento Regional Wastewater Treatment Plant (SRWTP), which is responsible for 90% of the nitrogen released into the bay. The work involved analyzing almost three decades of historical eld data from the bay-delta and using it to build a model to evaluate environmental drivers of phytoplankton biomass. Discoveries from the eld data were then tested through laboratory culturing experiments. By illuminating the interacting e ects of bottom- up drivers (light, nutrients, salinity) on phytoplankton, this research helps provide a fundamental understanding of this complex ecosystem.
    Science topics Ammonia, Flushing rates, Light, Open water, Pelagic fish, Phytoplankton, Salinity, Wastewater discharge, Water temperature
    Updated November 17, 2022
  • Title

    Defining habitat quality for young-of-year longfin smelt: Historical otolith-based reconstructions of growth and salinity history in relation to geography, climate, and outflow

    Lead University of California - Davis [UC Davis]
    Description This project aimed to use experiments to develop new otolith-based tools for longfin smelt and to then apply them to an extensive collection of archived wild Longfin Smelt specimens, to build a better understanding of longfin smelt life history, habitat use, and the interactions between stressors and abundance. In addition, the project aims to improve the understanding of how longfin smelt populations are affected by freshwater outflow. The project also aims to provide tools to support and evaluate habitat restoration, and facilitate development of a plan to recover this threatened species.
    Science topics Longfin Smelt, Outflow, Salinity
    Updated November 17, 2022
  • Title

    Operation Baseline Project 1: Conceptual Framework

    Lead Delta Stewardship Council
    Description A multidisciplinary team will develop a thorough conceptual model that will describe current conditions and consider changes from the WWTP upgrade. The model will be used to identify the highest priority science questions and investigations to pursue before, during, and after the plant upgrade.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Operation Baseline Project 2A1: USGS Pilot Studies

    Lead U.S. Geological Survey [USGS]
    Description Two pilot studies were funded to establish a baseline in open water and shallow wetland habitats prior to the WWTP upgrade. Study 1: Nutrient concentrations, transformation rates, and links to the foodweb. Study 2: Method to improve monitoring using fixed stations coupled with high-speed boat measurements
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Operation Baseline Project 2A2: USGS Pilot Studies - Isotopes

    Lead U.S. Geological Survey [USGS]
    Description Evaluate the usefulness of stable isotopes to trace nutrients form effluent water
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen / ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Quantifying the contribution of tidal flow variations to survival of juvenile Chinook salmon

    Lead U.S. Geological Survey [USGS]
    Description The purpose of this project is to quantify how tides in the Delta influence survival of juvenile salmon. Juvenile salmon survival increases when there is more flow and the river is less tidally influenced. We hypothesize that the increase in survival is because of reduced travel times causing less exposure to predators. This project will test this hypothesis using multiple models including ones that can predict how management actions that modify tidal patterns affect juvenile salmon survival.
    Science topics Chinook Salmon, Salmon migration, Surface water / flow, Tides, Water management
    Updated June 17, 2024
  • Title

    Assessing Sediment Nutrient Storage and Release in the Delta: Linking Benthic Nutrient Cycling to Restoration, Aquatic Vegetation, Phytoplankton Productivity, and Harmful Algal Blooms

    Lead U.S. Geological Survey [USGS]
    Description Nutrients in sediment play a large role in influencing food webs, harmful algal blooms, aquatic vegetation, and drinking water quality. This study will investigate the amount, types, and dynamics of nutrients in Delta sediments. It will also examine sediment microbial communities that mediate these processes. Results of this study will help determine how the planned reduction in nutrient inputs to the Delta will effect sediment nutrients and microbial communities following the upgrade of the Sacramento Regional County Sanitation District’s wastewater treatment plant. Data will also inform how wetland restoration and invasive aquatic vegetation influence sediment nutrients and microbial communities. These data will contribute to improving computer models that inform large-scale nutrient management actions.
    Science topics Aquatic vegetation, Benthic, Cyanobacteria, Harmful algal blooms HAB, Nitrogen, Nitrogen / ammonia, Nutrients, Phytoplankton, Sediments
    Updated May 14, 2024
  • Title

    Resolving Contradictions in Foodweb Support for Native Pelagic Fishes

    Lead San Francisco State University [SFSU]
    Description Much research in the Delta has focused on foodweb dynamics, stimulated by evidence that low productivity of plankton is linked to declines in several fish species including the endangered delta smelt. Pseudodiaptomus forbesi is the most abundant copepod (small crustaceans) in the Delta in summer. It is an important food source for many fishes and makes up about half of the food of delta smelt. This study focuses on the feeding, reproduction, and growth of copepods as essential foodweb support for fishes. This work investigates four diverse habitats including two open-water channels and two shallow habitats. The researchers will measure copepods´ feeding rates on microscopic plants and animals, and relate feeding to their rates of growth and reproduction. Computer models will be used to estimate their movement and death rates. These results will show the sources of nutrition used for growth and reproduction of these key organisms. Results will inform how food webs respond to large scale changes in the Delta ecosystem, for example, restoration and the Sacramento wastewater treatment plant upgrade.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Evaluating Juvenile Salmonid Behavioral Responses to Hydrodynamic Conditions in the Sacramento-San Joaquin Delta

    Lead State Water Contractors [SWC]
    Description This study combines detailed model predictions with salmonid tracking data to inform how river flows affect steelhead movement through the Delta. This project leverages an existing 6-year data set to support analysis of salmonid behavioral responses across a broad range of water years. The study will evaluate behavior relative to flow under existing regulatory requirements (Old and Middle River Flow and the Inflow to Export ratio), evaluate five new potential water management metrics identified by the Collaborative Adaptive Management Team Salmonid Scoping Team, and improve the understanding of what conditions affect survival.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Impact of Temperature and Contaminants on Chinook Salmon Survival: A Multi-Stressor Approach

    Lead National Marine Fisheries Service [NMFS]
    Description The decline of native salmon species has resulted in their protection under the U.S. Endangered Species Act and the California Endangered Species Act. Disease and predation are primary drivers of mortality as salmon migrate. Multiple stressors, such as exposure to contaminants and elevated temperature, can impact rates of disease and predation of salmon as they migrate to the ocean. This study examines how contaminant exposures at different temperatures affects salmon health. Specifically, the study investigates the sensitivity of salmon to a contaminant mixture of bifenthrin (a pyrethoid pesticide) and triclosan (an antibacterial added to personal care products). Both contaminants can alter fish swimming behavior and critical physiological functions. Similarly, temperature stress can impact fish physiology and behavior, as well as exacerbate the adverse effects of contaminants.
    Science topics None specified
    Updated April 29, 2022
  • Title

    An Evaluation of Sublethal and Latent Pyrethroid Toxicity Across a Salinity Gradient in Two Delta Fish Species

    Lead Oregon State University
    Description Pyrethroids are a type of insecticide frequently detected in the San Francisco Bay and Delta (SFBD). They are highly toxic to fishes and may contribute to their decline. The Central Valley Water Resources Control Board has adopted regulations for many pyrethroids. These concentration goals for Delta surface waters are quite stringent. However, they do not take into account non-lethal effects in fishes, particularly during the early life stages and at the salinity conditions we see in the SFBD. Understanding non-lethal effects in fish is vital to influencing population health. This study investigates pyrethroid toxicity on Delta smelt and Inland Silverside embryos, while accounting for changing SFBD salinity and other factors such as sediment. Results will inform the development of pesticide regulation criteria and control efforts, furthering the protection of SFBD fishes.
    Science topics None specified
    Updated April 29, 2022
  • Title

    Phytoplankton and cyanobacteria growth and response to stressors

    Lead University of California - Davis [UC Davis]
    Description Pesticide and nutrient inputs from human activities are present in the Sacramenot-San Joaquin Bay-Delta, but the impact of these stressors together on algae is not well known. This research will examine the impacts of herbicides and nutrients on the growth and stress responses of phytoplankton and cyanobacteria present in the San Francisco Estuary. The algae in the delta are diverse with critical ecological effects, ranging from toxin-producing cyanobacteria that form hazardous algal blooms to benthic diatoms and green algae that make up the bulk of the aquatic food web. Contaminants and herbicides can cause changes in algae cellular health which may impact population growth. Understanding algal sub-lethal stress responses will improve our understanding of stressors on the bay-delta food web and bloom formation.
    Science topics Phytoplankton, Cyanobacteria
    Updated April 29, 2022
  • Title

    Estuarine fish community responses to climate, flow, and habitat

    Lead University of California - Berkeley [UC Berkeley]
    Description The goal of this research is to better understand how climate change will affect fishes with different life histories and habitat associations across the San Francisco Estuary. Existing datasets will be incorporated in synthetic analyses and cutting-edge statistical models to identify fish community responses to climate, flows, and habitats along the estuarine salinity gradient. This synthesis-science project will use rich long-term datasets that have been collected by Bay-Delta researchers for decades that will then be analyzed in a reproducible and open science framework. It will also support efforts by the Interagency Ecological Program’s Climate Change Project Work Team.
    Science topics Estuaries
    Updated April 29, 2022
  • Title

    The effect of temperature on predation of juvenile salmonids

    Lead University of California - Davis [UC Davis]
    Description This study will investigate fish swim performance in response to temperature, using salmon and two of its known predators: largemouth bass and Sacramento pikeminnow. The researcher will assess swim performance metrics and predation risk inside and outside the ideal thermal range of each species to determine if a temperature advantage predicts salmon survival in predation scenarios. This project’s results will provide a mechanistic understanding of how temperature stress may influence mortality risk of juvenile Chinook salmon through predation, which will offer a more holistic perspective on the management of this species
    Science topics Temperature
    Updated April 29, 2022
  • Title

    Using existing datasets to understand multi-scale changes in and controls on biogeochemistry in the SF Bay-Delta

    Lead University of California - Santa Cruz [UCSC]
    Description In collaboration with the United States Geological Survey, this research will explore temporal and spatial variability of carbon and nitrogen biogeochemistry across the San Francisco Bay-Delta. This science synthesis will capitalize on existing multi-year isotope datasets to gain new insights useful for understanding future changes in the system. The results generated from this two-year data synthesis project will be useful for improving our current understanding of factors driving changes in SF Bay-Delta biogeochemical processes. Results will also be informative for understanding the imminent changes coming to the from the Sacramento Regional Wastewater Treatment Plant upgrade.
    Science topics Nitrogen
    Updated November 17, 2022
  • Title

    Nitrogen cycling and ecosystem metabolism before and after regulatory action

    Lead Stanford University
    Description This project focuses on nitrogen and carbon cycling within the Bay-Delta, both before and after planned 2021 upgrades to the Sacramento Regional Wastewater Treatment Plant (SRWTP). We will measure in situ benthic nitrate (NO3- ) and oxygen (O2) fluxes using a new non-invasive technique, which provides high frequency continuous data over a much larger sediment surface area than traditional methods. The SRTWP currently represents one of the largest point sources of nitrogen to the Bay-Delta, with the upgrades projected to cut nitrogen outputs from the plant by ~65%. This project will help assess the efficacy of this major management action and our results will add to biogeochemical models for the Bay-Delta.
    Science topics Nitrogen / ammonia
    Updated April 29, 2022
  • Title

    Science for adaptive management of juvenile spring-run Chinook salmon in the San Joaquin River

    Lead University of California - Davis [UC Davis]
    Description Spring-run Chinook salmon rehabilitation efforts are intensifying on the San Joaquin River. Over the last three years, UC Davis has successfully tracked movement, behavior, reach-specific survival, and route selection for reintroduced juvenile spring-run Chinook salmon in this ecosystem. In 2019, information on salmon tracking was combined with state-of-art habitat (fast limnological automated measurements or “FLAMe”) and physiological (e.g. fish condition, survival and transcriptomic) approaches. Results from this work are ongoing but have yielded actionable information on key habitats and management strategies for promoting salmon life-cycles in the San Joaquin River and central Delta. Now UC Davis will further explore promising recent findings. First, the analysis of an additional year of juvenile salmon tracking will occur to glean more survival information across different water year conditions. This information would be married with expanded FLAMe surveys in space and time along with a second year of physiological assays using caged fish. UC Davis will also evaluate the ‘transport effect’ on salmon, in an attempt to explain consistently high losses of JSATS-tagged salmon through the restoration area. Numerous other synergies exist with new and ongoing telemetry work that will be benefitted by a continuation of this work. The goal is to provide actionable science, and open access data, with a high potential to facilitate adaptive management in the San Joaquin River and central Delta.
    Science topics Chinook Salmon, Endangered species, Estuaries, Fish, Habitat restoration
    Updated October 3, 2023
  • Title

    Impact of Temperature and Contaminants on Chinook salmon survival: A Multi‐Stressor Approach

    Lead National Oceanic and Atmospheric Administration [NOAA]
    Description This project will examine how contaminant exposures at different temperatures impact a number of critical physiological functions and the associated genes that maintain salmon fitness. The project will determine the sensitivity of fall‐run Chinook salmon to a mixture of bifenthrin, a pyrethoid pesticide, and triclosan, an antibacterial added to personal care products, at optimal and high temperatures that Chinook salmon encounter during their outmigration through the Sacramento and San Joaquin rivers. The hypothesis is that these stressors will impact salmon predator and disease susceptibility and will interact, such that the cumulative effect on salmon could not be predicted from multiple single exposures. To test the hypothesis, fall‐run Chinook salmon parr will be exposed to sublethal concentrations of bifenthrin, triclosan, and a mixture of bifenthrin and triclosan at different temperatures. The impacts of these exposures on salmon will be assessed with the following endpoints: (1) predator susceptibility through altered response latencies and escape velocities;  (2) disease susceptibility in response to a disease challenge; and (3) differential gene expression by high‐throughput sequencing of the Chinook salmon transcriptome.
    Science topics Pesticides
    Updated September 28, 2023
  • Title

    From Microbes to Zooplankton, What Defines a Beneficial Wetland?

    Lead San Francisco State University, Estuary & Ocean Science Center
    Description Our study will characterize species diversity at multiple levels of biological organization in the water column of restoring wetlands in the upper San Francisco Estuary and Delta (SFE), from bacteria to fishes. In doing so, we will also describe the foodweb benefits being provided to larval fishes, including longfin smelt, through additional dietary DNA analysis. We will use the species diversity we find in the water column to identify a subset of biota that are indicative of the conditions present in wetlands in different stages of restoration (early, intermediate, and mature) and identify connections between those indicators to the foodweb resources being provided to higher trophic levels. We will study 3-4 wetlands in each of 3 stages: early (unvegetated), intermediate (partially vegetated and partially channelized), and mature (fully vegetated and channelized) wetlands.
    Science topics Crustaceans, Cyanobacteria, Estuaries, Fish, Food webs, Habitat, Habitat restoration, Insects, Invertebrates, Longfin Smelt, Other species, Other zooplankton, Pelagic fish, Phytoplankton, Predation, Restoration, Salinity, Saltwater / freshwater marshes, Tidal wetlands, Wetlands, Zooplankton
    Updated January 31, 2024
  • Title

    Impacts of predation and habitat on Central Valley Chinook smolt survival

    Lead University of Vermont, USGS Vermont Cooperative Fish and Wildlife Research Unit
    Description The Sacramento River in California’s Central Valley has been highly modified over the past 150 years due to mining, urbanization, and impoundment/diversion of river flow to provide water for municipal, industrial, and agricultural needs. Land use changes combined with high levels of harvest have been accompanied by drastic declines in native salmon populations, including the once abundant Chinook salmon (Oncorhynchus tshawytscha). Further, the region has been subject to the introduction and widespread establishment of non-native fish species, some of which are predators of juvenile salmon. Of the four historic ecotypes of Chinook salmon (fall, late-fall, winter, and spring runs), winter- and spring-runs have been most impacted and are currently listed as endangered and threatened respectively under the US Endangered Species act. Past research has illustrated how smoltification of juvenile salmon and outmigration from freshwater to the ocean is a time of increased mortality, and reduced survival at this life stage can impact the number of reproducing adults returning to the system in subsequent years. While these studies have provided valuable information on how habitat and environmental conditions experienced by migrating Chinook salmon smolts can affect survival, they have primarily focused on individual ecotypes during the portion of the year where downstream migrations occur. However, variation in smolt size and migration timing among ecotypes can expose migrating fish to differing environmental conditions and levels of exposure to predation, which can present distinct risks for outmigration survival. To identify the areas and environmental conditions which have the greatest relative impact on juvenile survival for each ecotype, this project will use over ten years of data (2012-2022) from acoustically tagged smolts representing all four Chinook salmon ecotypes in the Sacramento River/Central Valley. Combining these data will increase sample size relative to previous studies, the range of environmental conditions (e.g., temperature, flow, and predator abundance) modeled, the range of fish sizes, and thus, the statistical power of our analyses. We hypothesize that each ecotype will have different factors that will be the primary drivers of mortality experienced during outmigration. To test our hypotheses, we will implement Cormack-Jolly-Seber (CJS) mark-recapture models to estimate both the probability of survival through reaches of the Sacramento River delineated by acoustic receivers, and the detection probability in each reach. Survival will be modeled as a function of individual, release group, reach-specific, and time-varying covariates. Further, to examine the relative impact of predation on smolt survival, we will include an additional covariate representing predator-prey encounter rates using the Mean Free-path Length model. Finally, model selection will be applied to a series of CJS models to assess the relative impact of each covariate on smolt survival for each of the four Chinook ecotypes.
    Science topics Chinook Salmon, Environmental drivers, Fish, Flows, Habitat, Predation, Salmon migration, Water temperature
    Updated February 2, 2024
  • Title

    The Relative Contributions of Contaminants to Ecological Risk in the Upper San Francisco Estuary

    Lead Delta Stewardship Council - Delta Science Program
    Description This project developed methods to calculate risk of mixtures of pesticides for the Upper San Francisco Estuary (USFE). We used curve fitting to estimate the exposure-response curves for each individual chemical and then the mixture. For the mixtures, the models were normalized for specific ECx values. In that way, the curve fitting was optimized for effects that are comparable to most threshold values. A Bayesian network was built that incorporated five different pesticides and mercury. The input distributions of the contaminants were measured amounts from each of the six risk regions. We also explored three different methods of combining the results of the three pathways – additive, average, and expert judgement. The initial result was the BN model’s Predicted Fish Mortality (%). The Sensitivity analysis (mutual information) identified the most important components of the Bayesian network in determining the toxicity. The top two pathways were the Malathion/Diazinon Mortality pathway and the Mercury Mortality pathway. For the individual nodes Mercury, Bifenthrin and Season were key. Currently, we are completing the risk assessment network by adding Chinook salmon and Delta smelt population pathways to estimate risk to the six Risk Regions. A major accomplishment was the demonstration that curve fitting using additive models for mixtures can be used to estimate fish toxicity in this proof-of-concept model. Bifenthrin, the specific risk region, and season were the inputs that were most important to the calculation. Factors determining macroinvertebrate community structure were identified using multivariate tools. Water quality parameters were the most important in determining clusters of similar macrobenthic communities. Because contaminants were not statistically significant in determining these patterns, further analysis of macroinvertebrate community structure was postponed. At this time, the techniques applied in this program appear applicable to estimating risk due to the variety of chemicals and other stressors to the multiple endpoints under management in the USFE.
    Science topics None specified
    Updated January 24, 2024