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1. Nitrate Reductase Knockout Uncouples Nitrate Transport from Nitrate Assimilation and Drives Repartitioning of Carbon Flux in a Model Pennate Diatom

   https://doi.org/10.1105/tpc.16.00910  

   McCarthy, James K. ; Smith, Sarah R. ; McCrow, John P. ; Tan, Maxine ; Zheng, Hong ; Beeri, Karen ; Roth, Robyn ; Lichtle, Christian ; Goodenough, Ursula ; Bowler, Chris P. ; et al ( August 2017 , The Plant Cell)
2. Social Disparities in the Duration of Power and Piped Water Outages in Texas After Winter Storm Uri

   https://doi.org/10.2105/AJPH.2022.307110  

   Grineski, Sara E. ; Collins, Timothy W. ; Chakraborty, Jayajit ; Goodwin, Eric ; Aun, Jacob ; Ramos, Kevin D. ( January 2023 , American Journal of Public Health)

   We assessed sociodemographic disparities in basic service disruptions caused by Winter Storm Uri in Texas. We collected data through a bilingual telephone survey conducted in July 2021 (n  = 753). Being Black, having children, and renting one’s residence were associated with longer power outage durations; being Black was also associated with longer water outages. Our findings highlight the need to plan for and ameliorate inequitable service outages and their attendant health risks in climate change–related extreme weather events such as Uri. (Am J Public Health. 2023;113(1):30–34. https://doi.org/10.2105/AJPH.2022.307110 ) 

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3. Extended day length in late winter/early spring, with a return to natural day length of shorter duration, increased plasma testosterone and sexual performance in rams with or without melatonin implants

   https://doi.org/10.1111/rda.12988  

   Abecia, JA ; Chemineau, P ; Keller, M ; Delgadillo, JA ( October 2017 , Reproduction in Domestic Animals)
4. Labile carbon release from oxic–anoxic cycling in woodchip bioreactors enhances nitrate removal without increasing nitrous oxide accumulation

   https://doi.org/10.1039/d1ew00446h  

   McGuire, Philip M. ; Dai, Valentina ; Walter, M. Todd ; Reid, Matthew C. ( November 2021 , Environmental Science: Water Research & Technology)

   Denitrification in woodchip bioreactors (WBRs) treating agricultural drainage and runoff is frequently carbon-limited due to the recalcitrance of carbon (C) in lignocellulosic woodchip biomass. Recent research has shown that redox fluctuations, achieved through periodic draining and re-flooding of WBRs, can increase nitrate removal rates by enhancing the release of labile C during oxic periods. While dying–rewetting (DRW) cycles appear to hold great promise for improving the performance of denitrifying WBRs, redox fluctuations in nitrogen-rich environments are commonly associated with enhanced emissions of the greenhouse gas nitrous oxide (N 2 O) due to inhibition of N 2 O reduction in microaerophilic conditions. Here, we evaluate the effects of oxic–anoxic cycling associated with DRW on the quantity and quality of C mobilized from woodchips, nitrate removal rates, and N 2 O accumulation in a complementary set of flow-through and batch laboratory bioreactors at 20 °C. Redox fluctuations significantly increased nitrate removal rates from 4.8–7.2 g N m −3 d −1 in a continuously saturated (CS) reactor to 9.8–11.2 g N m −3 d −1 24 h after a reactor is drained and re-saturated. Results support the theory that DRW conditions lead to faster NO 3 − removal rates by increasing mobilization of labile organic C from woodchips, with lower aromaticity in the dissolved C pool of oxic–anoxic reactors highlighting the importance of lignin breakdown to overall carbon release. There was no evidence for greater N 2 O accumulation, measured as N 2 O product yields, in the DRW reactors compared to continuously saturated reactors. We propose that greater organic C availability for N 2 O reducers following oxic periods outweighs the effect of microaerophilic inhibition of N 2 O reduction in controlling N 2 O dynamics. Implications of these findings for optimizing DRW cycling to enhance nitrate removal rates in denitrifying WBRs are discussed. 

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5. Anion Exchange Capacity Explains Deep Soil Nitrate Accumulation in Brazilian Amazon Croplands

   https://doi.org/10.1007/s10021-022-00747-8  

   Huddell, Alexandra ; Neill, Christopher ; Palm, Cheryl A. ; Nunes, Darlisson ; Menge, Duncan N. L. ( April 2022 , Ecosystems)

   Deep tropical soils with net anion exchange capacity can adsorb nitrate and might delay the eutrophication of surface waters that is often associated with many temperate croplands. We investigated anion exchange capacity and soil nitrate pools in deep soils in the Southern Brazilian Amazon, where conversion of tropical forest and Cerrado to intensive fertilized soybean and soybean-maize cropping expanded rapidly in the 2000s. We found that mean soil nitrate pools in the top 8 m increased from 143 kg N ha⁻¹in forest to 1,052 in soybean and 1,161 kg N ha⁻¹in soybean-maize croplands. This nitrate accumulation in croplands aligned with the estimated N surpluses in the croplands. Soil anion exchange capacity explained the magnitude of nitrate accumulation. High nitrate retention in soils was consistent with current low levels of streamwater nitrate exported from croplands. Soil exchange sites were far from saturation, which suggests that nitrate accumulation can continue for longer under current cropping practices, although mechanisms such as competition with other anions and preferential water flowpaths that bypass exchange sites could reduce the time to saturation.

    

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