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1. Environmental justice and drinking water: A critical review of primary data studies

   https://doi.org/10.1002/wat2.1653  

   Karasaki, Seigi ; Goddard, Jessica J. ; Cohen, Alasdair ; Ray, Isha ( May 2023 , WIREs Water)

   Though safe drinking water for all is a global public health goal, disparities in access persist worldwide. We present a critical review of primary‐data based environmental justice (EJ) studies on drinking water. We examine their findings in relation to the broader EJ and drinking water literatures. Using pre‐specified protocols to screen 2423 records, we identified 33 studies for inclusion. We organized our results using the following questions: (1) what sampling and data collection methods are used; (2) how is (un)just access to water defined and measured; (3) what forms of environmental injustice are discussed; (4) how are affected communities resisting or coping; and (5) what, if any, mechanisms of redress are advocated? We find that while many studies analyze the causes and persistence of environmental injustices, most primary‐data studies on drinking water are cross‐sectional in design. Many such studies are motivated by health impacts but few measure drinking water exposures or associated health outcomes. We find that, while distinct types of injustice exist, multiple types are either co‐produced or exacerbate one another. Recognitional injustice is emerging as an undergirding injustice upon which others (distributional or procedural) can take hold. Tensions remain regarding the role of the state; redress for inequitable water access is often presumed to be the state's responsibility, but many EJ scholars argue that the state itself perpetuates inequitable conditions. The accountability for redress under different forms of water governance remains an important area for future research.

   This article is categorized under:

   Human Water > Methods

    

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2. Incorporating investigations of environmental racism into middle school science

   https://doi.org/10.1002/sce.21824  

   Bradford, Allison ; Gerard, Libby ; Tate, Erika ; Li, Rui ; Linn, Marcia C. ( November 2023 , Science Education)

   To promote a justice‐oriented approach to science education, we formed a research‐practice partnership between middle school science teachers, their students, curriculum designers, learning scientists, and experts in social justice to co‐design and test an environmental justice unit for middle school instruction. We examine teacher perspectives on the challenges and possibilities of integrating social justice into their standards‐aligned science teaching as they participate in co‐design and teach the unit. The unit supports students to investigate racially disparate rates of asthma in their community by examining pollution maps and historical redlining maps. We analyze interviews and co‐design artifacts from two teachers who participated in the co‐design and taught the unit in their classrooms. Our findings point to the benefits of a shared pedagogical framework and an initial unit featuring local historical content to structure co‐design. Findings also reveal that teachers can share similar goals for empowering students to use science knowledge for civic action while framing the local socio‐political factors contributing to the injustice differently, due in part to different institutional supports and constraints. Student interviews and a pre/postassessment illustrate how the unit facilitated students' progress in connecting socio‐political and science ideas to explain the impacts of particulate matter pollution and who is impacted most. Analyses illuminate how teachers' pedagogical choices may influence whether and how students discuss the impact of systemic racism in their explanations. The findings inform refinement of the unit and suggest supports needed for co‐design partnerships focused on integrating social justice and science.

    

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3. Xylem form and function under extreme nutrient limitation: an example from California's pygmy forest

   https://doi.org/10.1111/nph.16405  

   Cary, Katharine L. ; Ranieri, Gina M. ; Pittermann, Jarmila ( February 2020 , New Phytologist)

   Xylem anatomy and function have large implications for plant growth as well as survival during drought, but the impact of nutrient limitation on xylem is not fully understood. This study examines the pygmy forest in California, a plant community that experiences negligible water stress but is severely stunted by low‐nutrient and acidic soil, to investigate how nutrient limitation affects xylem function.

   Thirteen key anatomical and hydraulic traits of stems of four species were compared between pygmy forest plants and nearby conspecifics growing on richer soil.

   Resistance to cavitation (P₅₀), a critical trait for predicting survival during drought, had highly species‐specific responses: in one species, pygmy plants had a 26% decrease in cavitation resistance compared to higher‐nutrient conspecifics, while in another species, pygmy plants had a 56% increase in cavitation resistance. Other traits responded to nutrient limitation more consistently: pygmy plants had smaller xylem conduits and higher leaf‐specific conductivity (K_L) than conspecific controls.

   Edaphic stress, even in the absence of water stress, altered xylem structure and thus had substantial impacts on water transport. Importantly, nutrient limitation shifted cavitation resistance in a species‐specific and unpredictable manner; this finding has implications for the assessment of cavitation resistance in other natural systems.

    

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4. Opportunities, challenges and pitfalls in characterizing plant water‐use strategies

   https://doi.org/10.1111/1365-2435.13945  

   Kannenberg, Steven A. ; Guo, Jessica S. ; Novick, Kimberly A. ; Anderegg, William R. L. ; Feng, Xue ; Kennedy, Daniel ; Konings, Alexandra G. ; Martínez‐Vilalta, Jordi ; Matheny, Ashley M. ( October 2021 , Functional Ecology)

   Classifying the diverse ways that plants respond to hydrologic stress into generalizable ‘water‐use strategies’ has long been an eco‐physiological research goal. While many schemes for describing water‐use strategies have proven to be quite useful, they are also associated with uncertainties regarding their theoretical basis and their connection to plant carbon and water relations. In this review, we discuss the factors that shape plant water stress responses and assess the approaches used to classify a plant's water‐use strategy, paying particular attention to the popular but controversial concept of a continuum from isohydry to anisohydry.

   A generalizable and predictive framework for assessing plant water‐use strategies has been historically elusive, yet recent advances in plant physiology and hydraulics provide the field with a way past these obstacles. Specifically, we promote the idea that many metrics that quantify water‐use strategies are highly dynamic and emergent from the interaction between plant traits and environmental conditions, and that this complexity has historically hindered the development of a generalizable water‐use strategy framework.

   This idea is explored using a plant hydraulics model to identify: (a) distinct temporal phases in plant hydraulic regulation during drought that underpin dynamic water‐use responses, and (b) how variation in both traits and environmental forcings can significantly alter common metrics used to characterize plant water‐use strategies. This modelling exercise can bridge the divide between various conceptualizations of water‐use strategies and provide targeted hypotheses to advance the understanding and quantification of plant water status regulation across spatial and temporal scales.

   Finally, we describe research frontiers that are necessary to improve the predictive capacity of the plant water‐use strategy concept, including further investigation into the below‐ground determinants of plant water relations, targeted data collection efforts and the potential to scale these concepts from individuals to whole regions.

   A freePlain Language Summarycan be found within the Supporting Information of this article.

    

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5. Anatomical and hydraulic responses to desiccation in emergent conifer seedlings

   https://doi.org/10.1002/ajb2.1517  

   Miller, Megan L. ; Roddy, Adam B. ; Brodersen, Craig R. ; McElrone, Andrew J. ; Johnson, Daniel M. ( August 2020 , American Journal of Botany)

   The young seedling life stage is critical for reforestation after disturbance and for species migration under climate change, yet little is known regarding their basic hydraulic function or vulnerability to drought. Here, we sought to characterize responses to desiccation including hydraulic vulnerability, xylem anatomical traits, and impacts on other stem tissues that contribute to hydraulic functioning.

   Larix occidentalis,Pseudotsuga menziesii, andPinus ponderosa(all ≤6 weeks old) were imaged using x‐ray computed microtomography during desiccation to assess seedling biomechanical responses with concurrently measured hydraulic conductivity (k_s) and water potential (Ψ) to assess vulnerability to xylem embolism formation and other tissue damage.

   In non‐stressed samples for all species, pith and cortical cells appeared circular and well hydrated, but they started to empty and deform with decreasingΨwhich resulted in cell tearing and eventual collapse. Despite the severity of this structural damage, the vascular cambium remained well hydrated even under the most severe drought. There were significant differences among species in vulnerability to xylem embolism formation, with 78% xylem embolism inL. occidentalisbyΨof −2.1 MPa, but only 47.7% and 62.1% inP. ponderosaandP. menziesiiat −4.27 and −6.73 MPa, respectively.

   Larix occidentalisseedlings appeared to be more susceptible to secondary xylem embolism compared to the other two species, but all three maintained hydration of the vascular cambium under severe stress, which could facilitate hydraulic recovery by regrowth of xylem when stress is relieved.

    

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