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At least 613 records · Page 34Linked to original sources
USGS1997

Practical considerations for measuring hydrogen concentrations in groundwater

Several practical considerations for measuring concentrations of dissolved molecular hydrogen (H2) in groundwater including 1 sampling methods 2 pumping methods and (3) effects of well casing materials were evaluated. Three different sampling methodologies (a downhole sampler, a gas- stripping method, and a diffusion sampler) were compared. The downhole sampler and gas-stripping methods gave similar results when applied to the same wells, the other hand, appeared to The diffusion sampler, on overestimate H2 concentrations relative to the downhole sampler. Of these methods, the gas-stripping method is better suited to field conditions because it is faster (~ 30 min for a single analysis as opposed to 2 h for the downhole sampler or 8 h for the diffusion sampler), the analysis is easier (less sample manipulation is required), and the data computations are more straightforward (H2 concentrations need not be corrected for water sample volume). Measurement of H2 using the gas-stripping method can be affected by different pumping equipment. Peristaltic, piston, and bladder pumps all gave similar results when applied to water produced from the same well. It was observed, however, that peristaltic-pumped water (which draws water under a negative pressure) enhanced the gas-stripping process and equilibrated slightly faster than either piston or bladder pumps (which push water under a positive pressure). A direct current(dc) electrically driven submersible pump was observed to produce H2 and was not suitable for measuring H2 in groundwater. Measurements from two field sites indicate that iron or steel well casings, produce H2, which masks H2 concentrations in groundwater. PVC-cased wells or wells cased with other materials that do not produce H2 are necessary for measuring H2 concentrations in groundwater.Several practical considerations for measuring concentrations of dissolved molecular hydrogen in groundwater including sampling methods, pumping methods, and effects of well casing materials were evaluated. The downhole sampler and gas-stripping methods gave similar results when applied to the same wells. The diffusional sampler appears to overestimate H2 concentrations relative to the downhole sampler. Gas-stripping method is better for a single analysis and the data computations are more straightforward. Measurement of H2 using the gas-stripping method can be affected by different pumping equipment.

Environmental Science & Technology↗
USGS2011

A history of paleoflood hydrology in the United States

The origins of paleoflood hydrology in the United States can be traced back to the beginning of the 19th century, when windgaps and watergaps in the Applachians were believed to have been eroded by extraordinary floods as large lakes that were ponded behind the ridges rapidly drained. Sediment evidence for extraordinary floods was evoked several decades later when glacial sediments in New England were interpreted as deposits from the great Biblical deluge, and estimates of the depth and velocity of the great flood were attempted. The popularization of the glacial origins of drift by Agassiz by 1840 resulted in strong beliefs in uniformitarianism and waning interests in paleoflood investigations. The documentation of the origins of the channeled scablands in eastern Washington by catastrophic glacial outbreak floods, begun by Bretz in the early 1920s, led to renewed interest in paleoflood hydrology. Subsequent efforts to reconstruct hydraulic variables of past floods used conventional open channel flow equations applied to other enormous Pleistocene floods. The elevation of sediments was used as a paleostage estimator in the 1880s, and botanical techniques for estimating paleoflood frequency and magnitude were well documented by the mid-1960s. Since 1970, an exponential expansion has occurred in the recognition and use of paleoflood hydrology in the United States.

Eos, Earth and Space Science News↗
USGS2011

Use of hydrologic and hydrodynamic modeling for ecosystem restoration

Planning and implementation of unprecedented projects for restoring the greater Everglades ecosystem are underway and the hydrologic and hydrodynamic modeling of restoration alternatives has become essential for success of restoration efforts. In view of the complex nature of the South Florida water resources system, regional-scale (system-wide) hydrologic models have been developed and used extensively for the development of the Comprehensive Everglades Restoration Plan. In addition, numerous subregional-scale hydrologic and hydrodynamic models have been developed and are being used for evaluating project-scale water management plans associated with urban, agricultural, and inland costal ecosystems. The authors provide a comprehensive summary of models of all scales, as well as the next generation models under development to meet the future needs of ecosystem restoration efforts in South Florida. The multiagency efforts to develop and apply models have allowed the agencies to understand the complex hydrologic interactions, quantify appropriate performance measures, and use new technologies in simulation algorithms, software development, and GIS/database techniques to meet the future modeling needs of the ecosystem restoration programs.

Florida↗
USGS2025

Centering voices of scientists from marginalized backgrounds to understand experiences in climate adaptation science and inform action

Identifying and building solutions to help people and ecosystems adapt to climate change requires participation of all people; however, Science, Technology, Engineering, and Mathematics (STEM) fields, including environmental sciences, continue to lack diversity. To address this issue, many institutions have increased programming to recruit and retain people from historically marginalized backgrounds in STEM fields. Institutions use surveys to evaluate the experiences of community members and identify areas for improvement; however, surveys often summarize and reflect majority perspectives and disregard voices of historically marginalized individuals. In June 2021, a survey of graduate students, postdocs, faculty, staff, and researchers affiliated with the Northeast Climate Adaptation Science Center (NE CASC) evaluated their experiences of diversity, equity, inclusion, and justice (DEIJ) using Likert-based and long-answer questions. We analyzed the results as a whole, but also focused on the responses of people who self-identified as members of a marginalized group (“marginalized respondents”) in climate adaptation science to center their voices. Marginalized respondents reported being motivated to enter climate adaptation science to improve society and the environment rather than for intellectual curiosity, which motivated one third of non-marginalized respondents. Once in science, marginalized respondents reported feeling less supported and comfortable at work and were more likely to have considered leaving science and academia in the last year. Long-answer responses of marginalized respondents indicated distrust in the ability of leadership and existing DEIJ initiatives to effectively tackle systemic issues and emphasized the importance of focusing on equity and inclusion before recruitment. Marginalized respondents identified additional funding to support existing DEIJ efforts and undergraduates as priorities. By allowing participants to self-identify as part of a marginalized group, we were able to highlight experiences and needs without risking exposure based on race, gender, disability status, or sexual orientation. This approach can be applied to other small organizations with limited demographic diversity.

PLoS ONE↗
USGS2019

New and interesting species of the genus Muelleria (Bacillariophyta) from the Antarctic region and South Africa

During a survey of the terrestrial diatom flora of some sub-Antarctic islands in the southern Indian and Atlantic Oceans and of the Antarctic continent, more than 15 taxa belonging to the genus Muelleria were observed. Nine of these taxa are described as new species using light and scanning electron microscopy. Comments are made on their systematic position and how they are distinguished from other species in the genus. Additionally, two previously unrecognized taxa within the genus were discovered in samples from South Africa. One of these, Muelleria taylorii Van de Vijver & Cocquyt sp. nov., is new to science; the other, Muelleria vandermerwei (Cholnoky) Van de Vijver & Cocquyt nov. comb., had been included in the genus Diploneis. The large number of new Muelleria taxa on the (sub)-Antarctic locations is not surprising. Species in Muelleria occur rarely in collections; in many habitats, it is unusual to find more than 1-2 valves in any slide preparation. As a result, records are scarce. The practice of "force-fitting" (shoehorning) specimens into descriptions from common taxonomic keys (and species drift) results in European species, such as M. gibbula and M. linearis, being applied to Antarctic forms in ecological studies. Finally, the typical terrestrial habitats of soils, mosses and ephemeral water bodies of most of these taxa have been poorly studied in the past.

Phycologia↗
USGS2001

Our evolving conceptual model of the coastal eutrophication problem

A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplankton-derived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5 questions that will guide coastal science in the early 21st century: (1) How do system-specific attributes constrain or amplify the responses of coastal ecosystems to nutrient enrichment? (2) How does nutrient enrichment interact with other stressors (toxic contaminants, fishing harvest, aquaculture, nonindigenous species, habitat loss, climate change, hydrologic manipulations) to change coastal ecosystems? (3) How are responses to multiple stressors linked? (4) How does human-induced change in the coastal zone impact the Earth system as habitat for humanity and other species? (5) How can a deeper scientific understanding of the coastal eutrophication problem be applied to develop tools for building strategies at ecosystem restoration or rehabilitation?

Marine Ecology Progress Series↗
USGS1983

Ages estimated from a diffusion equation model for scarp degradation

The diffusion equation derived from the continuity equation for hillslopes is applied to scarp erosion in unconsolidated materials. Solutions to this equation allow direct calculation of the product of the rate coefficient and the age of the scarp from measurements of scarp morphology. Where the rate coefficient can be estimated or can be derived from scarps of known age, this method allows direct calculation of unknown ages of scarps.

Science↗
USGS2026

CoralCache: A virtual coral core repository for transparent and reproducible annual growth rate analyses

As science fields enter the Big Data revolution, open-access repositories are essential for addressing larger-scale questions than are possible for single researchers by making data findable, accessible, interoperable, and reusable (FAIR). Furthermore, transparent data and code are increasingly important for reproducible research, especially for data types that inherently require subjective human interpretations. These ideas are applicable to coral sclerochronology, as the field has long been characterized by individual researchers collecting and analyzing coral skeletal cores from their study sites without substantial data sharing or archiving of the core images to meet FAIR principles. Here, we present CoralCache, a virtual coral core repository that not only archives image datasets (i.e., digitized X-rays and computed tomography scans), but also observer interpretations of the density banding patterns. CoralCache is linked to a graphical user interface, CoralCT, which together offer a way forward for coral growth rate analysis that is reproducible and collaborative. The data organization systems presented here could also be readily applied to related archives such as tree rings or bivalve shells.

Earth System Science Data↗
USGS2009

Investigation of uptake and retention of atmospheric Hg(II) by boreal forest plants using stable Hg isotopes

Although there is now a general consensus among mercury (Hg) biogeochemists that increased atmospheric inputs of inorganic Hg(II) to lakes and watersheds can result in increased methylmercury (MeHg) concentrations in fish, researchers still lack kinetic data describing the movement of Hg from the atmosphere, through watershed and lake ecosystems, and into fish. The use of isotopically enriched Hg species in environmental studies now allows experimentally applied new Hg to be distinguished from ambient Hg naturally present in the system. Four different enriched stable Hg(II) isotope “spikes” were applied sequentially over four years to the ground vegetation of a microcatchment at the Experimental Lakes Area (ELA) in the remote boreal forest of Canada to examine retention of Hg(II) following deposition. Areal masses of the spikes and ambient THg (all forms of Hg in a sample) were monitored for eight years, and the pattern of spike retention was used to estimate retention of newly deposited ambient Hg within the ground vegetation pool. Fifty to eighty percent of applied spike Hg was initially retained by ground vegetation. The areal mass of spike Hg declined exponentially over time and was best described by a first-order process with constants ( k ) ranging between 9.7 × 10 −4 day −1 and 11.6 × 10 −4 day −1 . Average half-life ( t 1/2 ) of spike Hg within the ground vegetation pool (±S.D.) was 704 ± 52 days. This retention of new atmospheric Hg(II) by vegetation delays movement of new Hg(II) into soil, runoff, and finally into adjacent lakes. Ground-applied Hg(II) spikes were not detected in tree foliage and litterfall, indicating that stomatal and/or root uptake of previously deposited Hg (i.e., “recycled” from ground vegetation or soil Hg pools) were likely not large sources of foliar Hg under these experimental conditions.

Environmental Science & Technology↗
USGS1967

Biodegradation of dichlorodiphenyltrichloroethane: Intermediates in dichlorodiphenylacetic acid metabolism by Aerobacter aerogenes

The final product of dichlorodiphenyltrichloroethane (DDT) degradation by vertebrates is commonly considered to be dichlorodiphenylacetic acid, DDA (J. E. Peterson and W. H. Robison, Toxicol. Appl. Pharmacol. 6:321, 1964). Recently, certain organisms (A. S. Perry, S. Miller, and A. J. Buckner. J. Agr. Food Chem. 11:457, 1963; J. D. Pinto, M. N. Comien, and M. S. Dunn. J. Biol. Chem. 240:2148, 1965) have been found to degrade further DDA to dichlorobenzophenone (DBP), but the possibility that such degradation was due to microbial action could not be excluded. Significantly, dichlorobenzhydrol (DBH), dichlorophenylmethane (DPM), and dichlorodiphenylethylene (DDE) have been tentatively identified in rats fed DDA (Pinto et al., J. Biol. Chem. 240:2148, 1965). Since DDA as well as DDT is degraded by the ubiquitous microorganism Aerobacter aerogenes (G. Wedemeyer, Appl. Microbiol. 15:569, 1967; J. L. Mendel, and M. S. Walton, Science 151:1527, 1966), it seemed reasonable that the intestinal microflora might be involved in DBP formation, DPM and DBH being intermediates in its pathway from DDA. Since DDA is a (3,y-unsaturated acid, ketone formation via an alkene and an alcohol would be expected (S. G. Waley, Mechanisms of Organic and Enzymatic Reactions, Oxford University Press, London, England 1962).

Applied Microbiology↗
USGS1996

Overview of the limnology of crater lake

Crater Lake occupies the collapsed caldera of volcanic Mount Mazama in Crater Lake National Park, Oregon. It is the deepest lake (589 m) in the United States and the 7th deepest lake in the world. The water column mixes to a depth of about 200 m in winter and spring from wind energy and cooling. The deep lake is mixed in winter and early spring each year when relatively cold water near the surface sinks and exchanges positions with water in the deep basins of the lake. The lake becomes thermally stratified in summer and early fall. The metalimnion extends to a depth of about 100 m; thus most of the water column is a cold hypolimnion. Secchi disk clarity measurements typically are in the upper-20-m range to the low-30-m range in summer and early fall. Concentrations of nutrients are low, although conductivity is relatively high owing to the inflow of hydrothermal fluids. Total chlorophyll is low in concentration, but typically maximal at a depth of 120 m during periods of thermal stratification. Primary production also is low, with the maximum levels occurring between the depth of 40 and 80 m. Phytoplankton taxa are spatially segregated from each other within the water column to a depth of 200 m in summer and early fall. The same generalization applies to the Zooplankton taxa. Water level, clarity, concentrations of total chlorophyll, primary production, and abundances of zooplankton and introduced kokanee salmon exhibit long-term fluctuations. Based primarily on a recent 10-year study of the lake, the lake is considered to be pristine, except for the consequences of fish introductions. ?? 1996 by the Northwest Scientific Association. All rights reserved.

Northwest Science↗
USGS2021

Techniques to improve ecological interpretability of black box machine learning models

Statistical modeling of ecological data is often faced with a large number of variables as well as possible nonlinear relationships and higher-order interaction effects. Gradient boosted trees (GBT) have been successful in addressing these issues and have shown a good predictive performance in modeling nonlinear relationships, in particular in classification settings with a categorical response variable. They also tend to be robust against outliers. However, their black-box nature makes it difficult to interpret these models. We introduce several recently developed statistical tools to the environmental research community in order to advance interpretation of these black-box models. To analyze the properties of the tools, we applied gradient boosted trees to investigate biological health of streams within the contiguous USA, as measured by a benthic macroinvertebrate biotic index. Based on these data and a simulation study, we demonstrate the advantages and limitations of partial dependence plots (PDP), individual conditional expectation (ICE) curves and accumulated local effects (ALE) in their ability to identify covariate–response relationships. Additionally, interaction effects were quantified according to interaction strength (IAS) and Friedman’s H 2 "> H 2 statistic. Interpretable machine learning techniques are useful tools to open the black-box of gradient boosted trees in the environmental sciences. This finding is supported by our case study on the effect of impervious surface on the benthic condition, which agrees with previous results in the literature. Overall, the most important variables were ecoregion, bed stability, watershed area, riparian vegetation and catchment slope. These variables were also present in most identified interaction effects. In conclusion, graphical tools (PDP, ICE, ALE) enable visualization and easier interpretation of GBT but should be supported by analytical statistical measures. Future methodological research is needed to investigate the properties of interaction tests. Supplementary materials accompanying this paper appear on-line.

Journal of Agricultural, Biological, and Environme↗
USGS2006

The Model Parameter Estimation Experiment (MOPEX): Its structure, connection to other international initiatives and future directions

The Model Parameter Estimation Experiment (MOPEX) is an international project aimed at developing enhanced techniques for the a priori estimation of parameters in hydrological models and in land surface parameterization schemes connected to atmospheric models. The MOPEX science strategy involves: database creation, a priori parameter estimation methodology development, parameter refinement or calibration, and the demonstration of parameter transferability. A comprehensive MOPEX database has been developed that contains historical hydrometeorological data and land surface characteristics data for many hydrological basins in the United States (US) and in other countries. This database is being continuously expanded to include basins from various hydroclimatic regimes throughout the world. MOPEX research has largely been driven by a series of international workshops that have brought interested hydrologists and land surface modellers together to exchange knowledge and experience in developing and applying parameter estimation techniques. With its focus on parameter estimation, MOPEX plays an important role in the international context of other initiatives such as GEWEX, HEPEX, PUB and PILPS. This paper outlines the MOPEX initiative, discusses its role in the scientific community, and briefly states future directions.

IAHS-AISH Publication↗
USGS2021

Cyprosulfamide: Analysis of the herbicide safener and two of its degradates in surface water and groundwater from the Midwestern United States

Herbicide safeners are commonly included in herbicide formulations to selectively protect crops from herbicide toxicity but are poorly understood in terms of their environmental occurrence and fate. This study established an analytical method for a newer safener, cyprosulfamide, and two of its degradates, cyprosulfamide desmethyl and N -cyclopropyl-4-sulfamoylbenzamide, in water via solid-phase extraction and liquid chromatography with tandem mass spectroscopy. To evaluate the potential for off-field transport and transformation of cyprosulfamide, the method was used to analyze groundwater and surface water samples collected near cornfields in the midwestern United States where cyprosulfamide had been applied. All three compounds were detected in surface water samples ( N = 34); N -cyclopropyl-4-sulfamoylbenzamide was most frequently detected (56%), followed by cyprosulfamide (25%) and cyprosulfamide desmethyl (19%). Maximum concentrations ranged from 22.0 to 5185.9 ng/L, with the highest concentrations and detection rates during the growing season. None of our target analytes were detected in groundwater.

ACS Agricultural Science and Technology↗
USGS2025

An approach to urban waterway assessment using holistic values and reciprocity

Current aquatic ecosystem assessment methods and tools often focus on physical, chemical, and biological indicators of ecosystem health. This approach to ecosystem assessment is not always straightforward to execute in urban environments and ignores potential connectivity between social and environmental outcomes. During a workshop at the Symposium on Urbanization and Stream Ecology in Brisbane, Australia in 2023 (SUSE6), we developed an approach to urban aquatic ecosystem assessment that incorporates a holistic perspective. Specifically, our approach considers both environmental (biological, chemical, and physical integrity) and social (community connection, human safety, resource use) values of urban waterways. This approach is inclusive of Indigenous perspectives, such as the concept of reciprocity, whereby consideration of both the environment and society leads to a healthy ecosystem. To highlight how this holistic assessment approach could be used, we present real-world examples that included assessing both environmental and societal values informed by reciprocity or balanced perspectives. This approach can be broadly applied and adapted to specific aquatic ecosystem conditions and projects, providing an inclusive, community-centered approach for assessing the health of waterways in urban environments.

Freshwater Science↗
USGS2026

An improved empirical model for predicting postfire debris-flow volume in the western United States

Reliable estimates of debris-flow volume can be used to help predict the magnitude of debris-flow hazards following wildfire in the western United States. In this study, we compiled and used a database of 227 postfire debris-flow volumes that were collected across the western United States to develop a multiple linear regression model for predicting postfire debris-flow volume. We explored 36 predictor variables related to rainfall, terrain, and fire characteristics, and selected the model with the combination of variables that yielded the most accurate predictions of debris-flow volume. We evaluated model performance against the entire volume database, as well as against four subsets of volume data from southern California, the Intermountain West, the Southwest, and regions with limited volume data, such as northern California and Washington. We also compared model performance against 3 existing postfire debris-flow volume models that were developed for use in southern California, the Intermountain West, and the Southwest. We demonstrate that the new volume model performs as well as the regional models in the regions for which they were developed and outperforms existing models when applied to volumes from data-limited regions in the western United States. These results indicate that the debris-flow volume model introduced in this study can be used to improve postfire hazard assessments across the western United States, especially outside of southern California.

Arizona, California, Colorado, New Mexico, Utah, W↗
USGS2024

Boundary spanning increases knowledge and action on invasive species in a changing climate

Challenges associated with global change stressors on ecosystems have prompted calls to improve actionable science, including through boundary-spanning activities, which aim to build connections and communication between researchers and natural resource practitioners. By synthesizing and translating research and practitioner knowledge, boundary-spanning activities could support proactive, research-informed conservation practice, but the success of these efforts is rarely evaluated. Using repeat survey data from the Northeast Regional Invasive Species and Climate Change (NE RISCC) Management Network, a boundary-spanning organization, we evaluate whether participating in NE RISCC affected practitioners' knowledge, actions and priorities related to invasive species management under a changing climate. Our survey results suggest that practitioners who participate in NE RISCC have greater knowledge about invasive species and climate change and are incorporating climate change in more ways into their invasive species management. We also found NE RISCC membership affected the perceived usefulness of informational resources, with NE RISCC members more frequently identifying research syntheses and targeted workshops (both are common products used by NE RISCC to translate science into practice and share manager knowledge) as useful compared to non-members. Practitioners who participate in NE RISCC also identified somewhat different research priorities, with non-members and short-term members more frequently identifying range-shifting neonative species and their impacts on native communities as higher priorities compared to long-term NE RISCC members. NE RISCC research activities and outreach materials have consistently framed range-shifting neonative species as comparatively low risk, suggesting that this information has influenced practitioner's perception of risk. Practical implication : Although real-world impacts of applied ecology are notoriously difficult to quantify, this analysis illustrates that if research results are actively translated, they can affect the knowledge and actions of natural resource practitioners. These impacts illustrate the potential for boundary-spanning efforts to address other global change challenges to conservation.

Ecological Solutions and Evidence↗
USGS2003

Quantitative PCR analysis of CYP1A induction in Atlantic salmon (Salmo salar)

Environmental pollutants are hypothesized to be one of the causes of recent declines in wild populations of Atlantic salmon (Salmo salar) across Eastern Canada and the United States. Some of these pollutants, such as polychlorinated biphenyls and dioxins, are known to induce expression of the CYP1A subfamily of genes. We applied a highly sensitive technique, quantitative reverse transcription-polymerase chain reaction (RT-PCR), for measuring the levels of CYP1A induction in Atlantic salmon. This assay was used to detect patterns of CYP1A mRNA levels, a direct measure of CYP1A expression, in Atlantic salmon exposed to pollutants under both laboratory and field conditions. Two groups of salmon were acclimated to 11 and 17??C, respectively. Each subject then received an intraperitoneal injection (50 mg kg-1) of either ??-naphthoflavone (BNF) in corn oil (10 mg BNF ml-1 corn oil) or corn oil alone. After 48 h, salmon gill, kidney, liver, and brain were collected for RNA isolation and analysis. All tissues showed induction of CYP1A by BNF. The highest base level of CYP1A expression (2.56??1010 molecules/??g RNA) was found in gill tissue. Kidney had the highest mean induction at five orders of magnitude while gill tissue showed the lowest mean induction at two orders of magnitude. The quantitative RT-PCR was also applied to salmon sampled from two streams in Massachusetts, USA. Salmon liver and gill tissue sampled from Millers River (South Royalston, Worcester County), known to contain polychlorinated biphenyls (PCBs), showed on average a two orders of magnitude induction over those collected from a stream with no known contamination (Fourmile Brook, Northfield, Franklin County). Overall, the data show CYP1A exists and is inducible in Atlantic salmon gill, brain, kidney, and liver tissue. In addition, the results obtained demonstrate that quantitative PCR analysis of CYP1A expression is useful in studying ecotoxicity in populations of Atlantic salmon in the wild. ?? 2003 Elsevier Science B.V. All rights reserved.

Aquatic Toxicology↗