Sarah Ellen Johnson

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Se is an essential element for animals. In man low dietary Se intakes are associated with health disorders including oxidative stress-related conditions, reduced fertility and immune functions and an increased risk of cancers. Although the reference nutrient intakes for adult females and males in the UK are 60 and 75 microg Se/d respectively, dietary Se(More)
One of the chemical breakdown products of nonylphenol ethoxylates, 4-nonylphenol (4-NP), accumulates in organisms and is of concern as an environmental pollutant due to its endocrine disrupting effects. We measured 4-NP levels in the seawater, sediment, and twelve organisms within the California estuary, Morro Bay, and examined biomagnification of 4-NP(More)
Legacy data provide valuable baselines for assessing ecological changes. Excellent baseline data for Wisconsin's plant communities exist because of the surveys conducted by J.T. Curtis and colleagues (the Wisconsin Plant Ecology Laboratory or PEL) in the 1940s and 1950s. They surveyed > 2,000 sites to test how plant community composition varies along(More)
Temperate North American forest communities have changed considerably in response to logging, fragmentation, herbivory, and other global change factors. Significant changes in the structure and composition of seemingly undisturbed Wisconsin forest communities have occurred over the past 50 years, including widespread declines in alpha and beta species(More)
Dams, levees, and water withdrawals disrupt hydrologic regimes and associated floodplain forests. Because these forests are also responding to changes in land use, species invasions, and climate change, the relative effects of these factors are hard to disentangle. Most studies of floodplain forests lack historic data, requiring us to rely on recent data or(More)
Legacy data provide valuable baselines for assessing ecological changes. Excellent baseline data for Wisconsin's plant communities exist because of the surveys conducted by J.T. Curtis and colleagues (the Wisconsin Plant Ecology Laboratory or PEL, GIVD ID NA-US-008) in the 1940s and 1950s. They surveyed >2,000 sites to test how plant community composition(More)
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