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1. Coping with seasons: evolutionary dynamics of gene networks in a changing environment

   https://doi.org/10.1145/3583133.3590744  

   Petak, Csenge; Frati, Lapo; Pespeni, Melissa Helen; Cheney, Nick (July 2023, Proceedings of the Companion Conference on Genetic and Evolutionary Computation)

   In environments that vary frequently and unpredictably, bet-hedgers can overtake the population. Diversifying bet-hedgers have a diverse set of offspring so that, no matter the conditions they find themselves in, at least some offspring will have high fitness. In contrast, conservative bet-hedgers have a set of offspring that all have an in-between phenotype compared to the specialists. Here, we use an evolutionary algorithm of gene regulatory networks to de novo evolve the two strategies and investigate their relative success in different parameter settings. We found that diversifying bet-hedgers almost always evolved first, but then eventually got outcompeted by conservative bet-hedgers. We argue that even though similar selection pressures apply to the two bet-hedger strategies, conservative bet-hedgers could win due to the robustness of their evolved networks, in contrast to the sensitive networks of the diversifying bet-hedgers. These results reveal an unexplored aspect of the evolution of bet-hedging that could shed more light on the principles of biological adaptation in variable environmental conditions. 

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2. Seasons of Syn

   https://doi.org/10.1002/lno.11374  

   Hunter‐Cevera, Kristen R.; Neubert, Michael G.; Olson, Robert J.; Shalapyonok, Alexi; Solow, Andrew R.; Sosik, Heidi M. (November 2019, Limnology and Oceanography)

   Abstract Synechococcusis a widespread and important marine primary producer. Time series provide critical information for identifying and understanding the factors that determine abundance patterns. Here, we present the results of analysis of a 16‐yr hourly time series ofSynechococcusat the Martha's Vineyard Coastal Observatory, obtained with an automated, in situ flow cytometer. We focus on understanding seasonal abundance patterns by examining relationships between cell division rate, loss rate, cellular properties (e.g., cell volume, phycoerythrin fluorescence), and environmental variables (e.g., temperature, light). We find that the drivers of cell division vary with season; cells are temperature‐limited in winter and spring, but light‐limited in the fall. Losses to the population also vary with season. Our results lead to testable hypotheses aboutSynechococcusecophysiology and a working framework for understanding the seasonal controls ofSynechococcuscell abundance in a temperate coastal system. 

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3. Linking climate niches across seasons to assess population vulnerability in a migratory bird

   https://doi.org/10.1111/gcb.15639  

   Ruegg, Kristen; Anderson, Eric C.; Somveille, Marius; Bay, Rachael A.; Whitfield, Mary; Paxton, Eben H.; Smith, Thomas B. (May 2021, Global Change Biology)

   Abstract Global loss of biodiversity has placed new urgency on the need to understand factors regulating species response to rapid environmental change. While specialists are often less resilient to rapid environmental change than generalists, species‐level analyses may obscure the extent of specialization when locally adapted populations vary in climate tolerances. Until recently, quantification of the degree of climate specialization in migratory birds below the species level was hindered by a lack of genomic and tracking information, but recent technological advances have helped to overcome these barriers. Here we take a genome‐wide genetic approach to mapping population‐specific migratory routes and quantifying niche breadth within genetically distinct populations of a migratory bird, the willow flycatcher (Empidonax traillii), which exhibits variation in the severity of population declines across its breeding range. While our sample size is restricted to the number of genetically distinct populations within the species, our results support the idea that locally adapted populations of the willow flycatcher with narrow climatic niches across seasons are already federally listed as endangered or in steep decline, while populations with broader climatic niches have remained stable in recent decades. Overall, this work highlights the value of quantifying niche breadth within genetically distinct groups across time and space when attempting to understand the factors that facilitate or constrain the response of locally adapted populations to rapid environmental change. 

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4. Finding the seasons in tree ring stable isotope ratios

   https://doi.org/10.1002/ajb2.1083  

   Monson, Russell K.; Szejner, Paul; Belmecheri, Soumaya; Morino, Kiyomi A.; Wright, William E. (May 2018, American Journal of Botany)
5. Potential Thiamine Deficiency of Phytoplankton Across a Productivity Gradient and Seasons in Ohio Lakes

   https://doi.org/10.1111/fwb.70134  

   Rowland, Freya_E; Vanni, Michael_J; Hayes, Nicole_M; Kraft, Clifford_E (November 2025, Freshwater Biology)

   ABSTRACT Although nitrogen and phosphorus deficiency of algal blooms have been the focus of substantial attention, organic nutrients can limit algal growth in aquatic systems. Growing evidence indicates thiamine (vitamin B₁) can influence the community of primary producers in marine systems, but comparatively little is known about the effect of thiamine on freshwater algal productivity.We conducted 106 nutrient deficiency experiments with water from 39 Ohio lakes of varying trophic status during the growing seasons (April–October) of 2008–2009. Specifically, we tested the response of phytoplankton biomass (as chlorophylla, chl‐a) relative to controls to added nitrogen (N), phosphorus (P), thiamine (Th), or combinations of N + P and N + P + Th. Next, we compared the chl‐agrowth response of treatment/control to published thresholds based on frequentist approaches and compared the conclusions with Bayesian model results that focused on probability of a response.Although N + P addition was consistently associated with the largest chl‐aresponse, we found evidence of a thiamine influence on phytoplankton growth in some experiments. The Bayesian approach suggested thiamine may become more limiting as the growing season progresses. By late in the growing season, there was an 85% probability of a positive algal growth response to thiamine addition.Understanding the role of thiamine or other overlooked nutrients is not likely to alter the prevailing understanding of nutrient deficiency in freshwater ecosystems. However, we present evidence that freshwater phytoplankton may experience thiamine deficiency and suggest limnologists consider thiamine when exploring resource deficiencies. 

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