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1. Smoke from regional wildfires alters lake ecology

   https://doi.org/10.1038/s41598-021-89926-6  

   Scordo, Facundo; Chandra, Sudeep; Suenaga, Erin; Kelson, Suzanne J.; Culpepper, Joshua; Scaff, Lucia; Tromboni, Flavia; Caldwell, Timothy J.; Seitz, Carina; Fiorenza, Juan E.; et al (December 2021, Scientific Reports)

   null (Ed.)

   Abstract Wildfire smoke often covers areas larger than the burned area, yet the impacts of smoke on nearby aquatic ecosystems are understudied. In the summer of 2018, wildfire smoke covered Castle Lake (California, USA) for 55 days. We quantified the influence of smoke on the lake by comparing the physics, chemistry, productivity, and animal ecology in the prior four years (2014–2017) to the smoke year (2018). Smoke reduced incident ultraviolet-B (UV-B) radiation by 31% and photosynthetically active radiation (PAR) by 11%. Similarly, underwater UV-B and PAR decreased by 65 and 44%, respectively, and lake heat content decreased by 7%. While the nutrient limitation of primary production did not change, shallow production in the offshore habitat increased by 109%, likely due to a release from photoinhibition. In contrast, deep-water, primary production decreased and the deep-water peak in chlorophyll a did not develop, likely due to reduced PAR. Despite the structural changes in primary production, light, and temperature, we observed little significant change in zooplankton biomass, community composition, or migration pattern. Trout were absent from the littoral-benthic habitat during the smoke period. The duration and intensity of smoke influences light regimes, heat content, and productivity, with differing responses to consumers. 

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2. Patchy and Pink: Dynamics of a Chlainomonas sp. ( Chlamydomonadales , chlorophyta) algal bloom on Bagley Lake, North Cascades, WA

   https://doi.org/10.1093/femsec/fiad106  

   van Hees, Dan; Hanneman, Clare; Paradis, Sophie; Camara, A G; Matsumoto, Maya; Hamilton, Trinity; Krueger-Hadfield, Stacy A; Kodner, Robin B (October 2023, FEMS Microbiology Ecology)

   Abstract Snow algal blooms frequently occur throughout alpine and polar environments during spring and summer months; however, our understanding of bloom dynamics is limited. We tracked a recurrent bloom of Chlainomonas sp. on Upper Bagley Lake in the North Cascade Mountains, USA, to assess the spatiotemporal dynamics in bloom color intensity, community photophysiology, and community composition over eight weeks. We found that the algae biomass had a dynamic patchy distribution over space and time, which was decoupled from changes in community composition and life-cycle progress averaged across the bloom. The proportional representation of Chlainomonas sp. remained consistent throughout the study while the overall community composition shows a progression through the bloom. We found that community photophysiology, measured by the maximum quantum yield of PSII (Fv/Fm), decreased on average throughout the bloom. These findings suggest that the Chlainomonas sp. community on Bagley Lake is not simply an algal bloom with rapid increase in biomass followed by a population crash, as is often seen in aquatic systems, though there is a physiological trajectory and sensitivity to environmental stress. These results contribute to our understanding of the biology of Chlainomonas sp. and its response to environmental stress, specifically an extreme warming event. 

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3. Aquatic macrophyte, snail, and crayfish abundance and richness data for ten lakes in Vilas County, WI, USA, 1987-2020

   https://doi.org/10.6073/pasta/f10681ca29a9a69e9597bcd77a06fbe5  

   Szydlowski, Daniel K; Elgin, Ashley K; Lodge, David M; Tiemann, Jeremy S; Larson, Eric R (January 2022, Environmental Data Initiative)

   {"Abstract":["Data accompanying the paper Szydlowski et al. "Macrophyte and snail community responses\n to 30 years of population declines of invasive rusty crayfish (Faxonius rusticus)."\n Macrophytes and snails were sampled in ten lakes in Vilas County, Wisconsin, USA during\n summer sampling events in 1987, 2002, 2011, and 2020. Lakes had varying levels of invasion\n by F. rusticus, which affected measures of macrophytes and snails. Macrophytes were sampled\n using a point-intercept transect method and snails were sampled using different sampler\n types which were dependent on substrate. Macrophytes were sampled at 6-14 sites per lake and\n snails were sampled at 16-31 sites per lake. Crayfish were regularly sampled at either 24 or\n 36 sites per lake between 1987 and 2020. Overall, this dataset provides abundance and\n richness data for over 25 species of snails and over 40 species of macrophytes in 10 north\n temperate lakes."]} 

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4. Elevated light and CO2 levels increase photosynthetic rates of diverse snow algal communities from the North Cascades

   https://doi.org/10.1111/nph.70332  

   Weigel, Brooke L; Castillo, Guadalupe; Pata, Honu K; Young, Jodi N; Kodner, Robin B (September 2025, New Phytologist)

   Microalgae adapted to near-zero temperatures and high light levels live on snowfields and glaciers worldwide. Snow algae have red-colored pigments that darken snow surfaces, lowering its albedo and accelerating snowmelt. Despite their importance to the cryosphere, we know little about controls on snow algal productivity and biomass. Here, we characterize photophysiology from diverse natural field-collected populations of alpine snow algae from the North Cascades of Washington, USA, where the major red-bloom producing genera Chlainomonas, Sanguina, and Rosetta were present. We tested short-term physiological responses of snow algae to light (0–3000 μmol m−2 s−1) and CO2 levels (0–1600 ppm), allowing us to determine the saturating light and CO2 levels for snow algal community net photosynthesis. All snow algal communities surveyed were adapted to extremely high light levels (3000 μmol m−2 s−1). In addition, photosynthesis rates of all the snow algal communities responded strongly to increasing CO2 levels. At current atmospheric CO2 levels (420 ppm), snow algal net photosynthesis rates were only c. 50% saturated. Together, these results suggest the primary productivity of important bloom-forming snow algal communities in alpine ecosystems will likely rise as atmospheric CO2 concentrations increase, regardless of potential changes in available light levels. 

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5. Dissolved organic matter in peat and marl marshes varies with nutrient enrichment and restored hydrology

   https://doi.org/10.1111/rec.13905  

   Anderson, Kenneth J.; Kominoski, John S.; Nocentini, Andrea; Hoffman, Sophia (April 2023, Restoration Ecology)

   Dissolved organic matter (DOM) drives biogeochemical processes in aquatic ecosystems. Yet, how hydrologic restoration in nutrient‐enriched ecosystems changes DOM and the consequences of those changes for the carbon cycle remain unclear. To predict the consequences of hydrologic restoration on carbon cycling in restored wetlands, we need to understand how local environmental factors influence production, processing, and transport of DOM. We collected surface water samples along transects in restored peat (organic‐rich, macrophyte‐dominated) and marl (carbonate, periphyton‐dominated) freshwater marshes in the Everglades (Florida, U.S.A.) that varied in environmental factors (water depth, phosphorus [P] concentrations [water, macrophytes, periphyton, and soil], and primary producer biomass) to understand drivers of dissolved organic carbon (DOC) concentrations and DOM composition. Higher water depths led to a “greening” of DOM, due to increasing algal contributions, with decreasing concentrations of DOC in peat wetlands, and a “browning” of DOM, due to increasing humic contributions, with increasing DOC concentrations in marl wetlands. Soil total P was positively correlated with DOC concentrations and microbial contributions to DOM in peat wetlands, and periphyton total P was positively correlated with algal contributions to DOM in marl wetlands. Despite large variations in both vegetation biomass and periphyton biovolume across transects and sites, neither were predictors of DOC concentrations or DOM composition. Hydrologic restoration differentially alters DOM in peat and marl marshes and interacts with nutrient enrichment to shift proportions of green and brown contributions to surface water chemistry, which has the potential to modify wetland food webs, as well as the processing of carbon by micro‐organisms. 

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