Publications by authors named "Mary Power"

Article Synopsis
  • Climate change is creating problems for California's rivers, lakes, and wetlands, which are important habitats for many living things.
  • Native plants and animals are struggling due to issues like water diversion, pollution, and new species taking over.
  • To fix these problems, we need to learn more about how these ecosystems work, work together with different groups, and prepare the next generation to protect the environment.
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Nearshore (littoral) habitats of clear lakes with high water quality are increasingly experiencing unexplained proliferations of filamentous algae that grow on submerged surfaces. These filamentous algal blooms (FABs) are sometimes associated with nutrient pollution in groundwater, but complex changes in climate, nutrient transport, lake hydrodynamics, and food web structure may also facilitate this emerging threat to clear lakes. A coordinated effort among members of the public, managers, and scientists is needed to document the occurrence of FABs, to standardize methods for measuring their severity, to adapt existing data collection networks to include nearshore habitats, and to mitigate and reverse this profound structural change in lake ecosystems.

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The relative importance of separation by distance and by environment to population genetic diversity can be conveniently tested in river networks, where these two drivers are often independently distributed over space. To evaluate the importance of dispersal and environmental conditions in shaping microbial population structures, we performed genome-resolved metagenomic analyses of benthic Microcoleus-dominated cyanobacterial mats collected in the Eel and Russian River networks (California, USA). The 64 Microcoleus genomes were clustered into three species that shared >96.

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Advances in next-generation sequencing have enabled the widespread measurement of microbiome composition across systems and over the course of microbiome assembly. Despite substantial progress in understanding the deterministic drivers of community composition, the role of historical contingency remains poorly understood. The establishment of new species in a community can depend on the order and/or timing of their arrival, a phenomenon known as a priority effect.

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Synthetic threads through the web of life.

Proc Natl Acad Sci U S A

June 2021

CRISPR-Cas gene editing tools have brought us to an era of synthetic biology that will change the world. Excitement over the breakthroughs these tools have enabled in biology and medicine is balanced, justifiably, by concern over how their applications might go wrong in open environments. We do not know how genomic processes (including regulatory and epigenetic processes), evolutionary change, ecosystem interactions, and other higher order processes will affect traits, fitness, and impacts of edited organisms in nature.

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Article Synopsis
  • Predation plays a crucial role in ecosystems, impacting food webs, energy flow, and nutrient cycling, though most research has focused on larger predators rather than microscopic ones like bacteria.
  • This study found that obligate predatory bacteria exhibited significantly higher growth and carbon uptake (36% and 211% more, respectively) compared to nonpredatory bacteria across various environments, while facultative predators showed only slightly enhanced rates.
  • The research indicates that increased energy flow in microbial communities boosts the role of predatory bacteria, suggesting that more productive environments lead to stronger predatory influence on lower trophic levels.
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  • - Researchers discovered hundreds of bacteriophage genomes over 200 kilobases, including the largest known at 735 kb, showing that phages can have significantly larger genetic material than previously thought.
  • - Many of these phages possess unique genetic elements, such as previously unidentified CRISPR-Cas systems and various tRNA-related genes, hinting at complex interactions with their bacterial hosts.
  • - The study classifies major groups of these large phages from various ecosystems around the world, suggesting they play a key role in microbial interactions and could influence microbial diversity across different environments.
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  • Recent studies highlight the harmful impacts of riverine benthic cyanobacterial mats, particularly their distribution and biosynthetic abilities.
  • Metagenomic sequencing of 22 microbial mats from the Eel River revealed that these mats are largely dominated by cyanobacteria, with oxygenic photosynthesis as the main metabolic process and limited anaerobic pathways.
  • Four novel Microcoleus species were identified, including one with anatoxin-a biosynthesis genes, and their presence was linked to higher nitrogen levels and specific microbial associations, prompting further research into their ecological roles.
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Animals experience varying levels of predation risk as they navigate heterogeneous landscapes, and behavioral responses to perceived risk can structure ecosystems. The concept of the landscape of fear has recently become central to describing this spatial variation in risk, perception, and response. We present a framework linking the landscape of fear, defined as spatial variation in prey perception of risk, to the underlying physical landscape and predation risk, and to resulting patterns of prey distribution and antipredator behavior.

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  • * Removal of hippopotamuses led to reduced grassland height and increased grass leafiness, while also impacting soil nutrient levels, though it did not significantly affect plant species diversity.
  • * Findings suggest that the loss of hippos, due to their ecological importance, could lead to significant changes in the ecosystem, emphasizing the need to protect this vulnerable species.
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  • Benthic algae play a crucial role in river ecosystems by supporting food webs and biogeochemical processes, but can become dominated by toxic cyanobacteria, posing risks to water quality and public health.
  • In the Eel River, since 2000, there have been multiple dog deaths linked to cyanotoxins, prompting research into the distribution of these toxins.
  • A study from 2013-2015 found that anatoxin-a levels were significantly higher than microcystins in cyanobacterial mats, with a notable presence of anatoxin-a in over half of the sampled mats, highlighting a concerning trend of toxic cyanobacteria in North American waterways.
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Cross-boundary transfers of nutrients can profoundly shape the ecology of recipient systems. The common hippopotamus, , is a significant vector of such subsidies from terrestrial to river ecosystems. We compared river pools with high and low densities of to determine how subsidies shape the chemistry and ecology of aquatic communities.

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Little is known about the importance of food-web processes as controls of river primary production due to the paucity of both long-term studies and of depositional environments which would allow retrospective fossil analysis. To investigate how freshwater algal production in the Eel River, northern California, varied over eight decades, we quantified siliceous shells (frustules) of freshwater diatoms from a well-dated undisturbed sediment core in a nearshore marine environment. Abundances of freshwater diatom frustules exported to Eel Canyon sediment from 1988 to 2001 were positively correlated with annual biomass of surveyed over these years in upper portions of the Eel basin.

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Benthic cyanobacteria in rivers produce cyanotoxins and affect aquatic food webs, but knowledge of their ecology lags behind planktonic cyanobacteria. The buoyancy of benthic Anabaena spp. mats was studied to understand implications for Anabaena dispersal in the Eel River, California.

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Robert T. Paine, who passed away on 13 June 2016, is among the most influential people in the history of ecology. Paine was an experimentalist, a theoretician, a practitioner, and proponent of the "ecology of place," and a deep believer in the importance of natural history to ecological understanding.

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The liberalization of marijuana policies, including the legalization of medical and recreational marijuana, is sweeping the United States and other countries. Marijuana cultivation can have significant negative collateral effects on the environment that are often unknown or overlooked. Focusing on the state of California, where by some estimates 60%-70% of the marijuana consumed in the United States is grown, we argue that (a) the environmental harm caused by marijuana cultivation merits a direct policy response, (b) current approaches to governing the environmental effects are inadequate, and

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Article Synopsis
  • Animal migrations play a vital role in connecting different ecosystems, as demonstrated by the mayfly, Ephemerella maculata, which migrates from productive river mainstems to cooler, less productive tributaries where it lays eggs.
  • This migration significantly boosts the insect population in the tributary, tripling the food availability for local predators during the summer.
  • The study shows that the mayfly influx substantially enhances the growth of young steelhead trout, highlighting the importance of aquatic insect migrations in supporting predator resilience in warming river systems.
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Purpose: To develop and conduct feasibility testing of an evidence-based and theory-informed model for facilitating performance feedback for physicians so as to enhance their acceptance and use of the feedback.

Method: To develop the feedback model (2011-2013), the authors drew on earlier research which highlights not only the factors that influence giving, receiving, accepting, and using feedback but also the theoretical perspectives which enable the understanding of these influences. The authors undertook an iterative, multistage, qualitative study guided by two recognized research frameworks: the UK Medical Research Council guidelines for studying complex interventions and realist evaluation.

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  • Mercury, especially in its organic form methylmercury (MeHg), is prevalent in the environment and can accumulate in food webs, affecting both aquatic and terrestrial organisms.
  • A study analyzed stable isotope ratios of MeHg in various species, revealing significant differences in MeHg sources between benthic invertebrates and terrestrial invertebrates, while steelhead trout predominantly obtained MeHg from aquatic sources.
  • The research indicates that terrestrial invertebrates contribute to MeHg bioaccumulation in aquatic predators, highlighting the importance of direct terrestrial input into headwater streams for the transfer of methylmercury.
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Overfishing and environmental change have triggered many severe and unexpected consequences. As existing communities have collapsed, new ones have become established, fundamentally transforming ecosystems to those that are often less productive for fisheries, more prone to cycles of booms and busts, and thus less manageable. We contend that the failure of fisheries science and management to anticipate these transformations results from a lack of appreciation for the nature, strength, complexity, and outcome of species interactions.

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Living nature can be thought of as a tapestry, defined not only by its constituent parts but also by how these parts are woven together. The weaving of this tapestry is a metaphor for species interactions, which can be divided into three broad classes: competitive, mutualistic, and consumptive. Direct interactions link together as more complex networks, for example, the joining of consumptive interactions into food webs.

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Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood-drought cycles; thus, their likelihood of persistence may decrease in response to disruption of the seasonal synchrony between stable low-flow conditions and reproduction. We evaluated whether altered flow regimes affected 2 native frogs in California and Oregon (U.

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Wetlands are among the most productive and economically valuable ecosystems in the world. However, because of human activities, over half of the wetland ecosystems existing in North America, Europe, Australia, and China in the early 20th century have been lost. Ecological restoration to recover critical ecosystem services has been widely attempted, but the degree of actual recovery of ecosystem functioning and structure from these efforts remains uncertain.

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