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1. Groundwater residence time estimates obscured by anthropogenic carbonate

   https://doi.org/10.1126/sciadv.abf3503  

   Seltzer, Alan M.; Bekaert, David V.; Barry, Peter H.; Durkin, Kathryn E.; Mace, Emily K.; Aalseth, Craig E.; Zappala, Jake C.; Mueller, Peter; Jurgens, Bryant; Kulongoski, Justin T. (April 2021, Science Advances)

   null (Ed.)

   Groundwater is an important source of drinking and irrigation water. Dating groundwater informs its vulnerability to contamination and aids in calibrating flow models. Here, we report measurements of multiple age tracers ( 14 C, 3 H, 39 Ar, and 85 Kr) and parameters relevant to dissolved inorganic carbon (DIC) from 17 wells in California’s San Joaquin Valley (SJV), an agricultural region that is heavily reliant on groundwater. We find evidence for a major mid-20th century shift in groundwater DIC input from mostly closed- to mostly open-system carbonate dissolution, which we suggest is driven by input of anthropogenic carbonate soil amendments. Crucially, enhanced open-system dissolution, in which DIC equilibrates with soil CO 2 , fundamentally affects the initial 14 C activity of recently recharged groundwater. Conventional 14 C dating of deeper SJV groundwater, assuming an open system, substantially overestimates residence time and thereby underestimates susceptibility to modern contamination. Because carbonate soil amendments are ubiquitous, other groundwater-reliant agricultural regions may be similarly affected. 

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2. Residence time structures microbial communities through niche partitioning

   https://doi.org/10.1101/2024.08.22.609267  

   Mueller, Emmi A; Lennon, Jay T (August 2024, bioRxiv)

   ABSTRACT Much of life on Earth is at the mercy of currents and flow. Residence time (τ) estimates how long organisms and resources stay within a system based on the ratio of volume (V) to flow rate (Q). Short residence times promote immigration but may prevent the establishment of species that cannot quickly reproduce, or resist being washed out. In contrast, long residence times reduce resource input, selecting for species that can survive on a low supply of energy and nutrients. Theory suggests that these opposing forces shape the abundance, diversity, and function of flowing systems. In this study, we subjected chemostats inoculated with a complex lake microbial community to a residence time gradient spanning seven orders of magnitude. Microbial abundance, richness, and evenness increased with residence time, while functions like productivity and resource consumption decreased along the gradient. Microbial taxa were non- randomly distributed, forming distinct clusters of short-τ and long-τ specialists, reflecting a pattern of niche partitioning. Consistent with theoretical predictions, we demonstrate that residence time shapes assembly processes with direct implications for biodiversity and community function. These insights are crucial for understanding and managing flowing environments, such as animal gut microbiomes, soil litter invertebrate communities, and plankton in freshwater and marine ecosystems. 

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3. A multi-tracer model approach to estimate reef water residence times: A multi-tracer residence time model

   https://doi.org/10.4319/lom.2012.10.1078  

   Venti, A.; Kadko, D.; Andersson, A. J.; Langdon, C.; Bates, N. R. (December 2012, Limnology and Oceanography: Methods)
4. Lysine-Targeting Reversible Covalent Inhibitors with Long Residence Time

   https://doi.org/10.1021/jacs.1c12702  

   Reja, Rahi M.; Wang, Wenjian; Lyu, Yuhan; Haeffner, Fredrik; Gao, Jianmin (January 2022, Journal of the American Chemical Society)
5. Simulation-based Real-time Production Control with Different Classes of Residence Time Constraints

   https://doi.org/10.1109/CASE49997.2022.9926676  

   Wang, Feifan; Ju, Feng (August 2022, 2022 IEEE 18th International Conference on Automation Science and Engineering (CASE))