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1. Contrasting responses of black fly species (Diptera: Simuliidae) to experimental whole‐stream warming

   https://doi.org/10.1111/fwb.13583  

   Nelson, Daniel; Benstead, Jonathan P.; Huryn, Alexander D.; Cross, Wyatt F.; Hood, James M.; Johnson, Philip W.; Junker, James R.; Gíslason, Gísli M.; Ólafsson, Jón S. (July 2020, Freshwater Biology)

   Abstract As global temperatures continue to rise, assessment of how species within ecological communities respond to shifts in temperature has become increasingly important. However, such assessments require detailed long‐term observations or ecosystem‐level manipulations that allow for interactions among species and the potential for species dispersal and exchange with the regional species pool.We examined the effects of experimental whole‐stream warming on a larval black fly assemblage in southwest Iceland. We used a paired‐catchment design, in which we studied the warmed stream and a nearby reference stream for 1 year prior to warming and 2 years during warming and estimated population abundance, biomass, secondary production, and growth rates for larvae of three black fly species.Experimental warming by 3.8°C had contrasting effects on the three black fly species in the assemblage. The abundance, biomass, growth, and production ofProsimulium ursinumdecreased in the experimental stream during the warming manipulation. Despite increasing in the reference stream, the abundance, biomass, and production of another species,Simulium vernum, decreased in the experimental stream during warming.In contrast, warming had an overall positive effect onSimulium vittatum. While warming had little effect on the growth of overwintering cohorts ofS. vittatum, warming led to an additional cohort during the summer months and increased its abundance, biomass, and production. Overall, family‐level production was enhanced by warming, despite variation in species‐level responses.Our study illustrates that the effects of climate warming are likely to differ even among closely related species. Moreover, our study highlights the need for further investigation into the uneven effects of warming on individual species and how those variable effects influence food web dynamics and ecosystem function. 

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2. Egg laying during stress-induced sleep of Caenorhabditis elegans is reduced due to behavioral quiescence and fertility defects

   https://doi.org/10.17912/micropub.biology.001735  

   Subramanian, Sanjita; Diya, Nikki; Nelson, Matthew D (January 2025, microPublication biology)

   Sleep is a reversible state, characterized by the inhibition of periodic behaviors that occur during waking hours. Caenorhabditis elegans demonstrates stress-induced sleep following exposure to environmental stressors, like noxious heat or ultraviolet irradiation. During this time, animals inhibit movement, feeding, and defecation, behavioral quiescence largely controlled by neuropeptide signaling from the ALA and RIS sleep interneurons. Here, we tested whether egg retention and/or production which occurs during suboptimal environmental conditions, is regulated by the ALA and/or RIS, or other neuropeptides. We find that during stress-induced sleep, worms reduce egg-laying behavior and egg production (i.e., fertility). While the behavior is modestly modified in the absence of the ALA and RIS, as well as some neuropeptides, fertility is regulated by other mechanisms. 

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3. Senescence-driven solubilization of biomass is the main source of kelp-derived dissolved organic carbon to the coastal ocean

   https://doi.org/10.1038/s42003-025-08477-y  

   English, Chance J; Bell, Tom W; Opalk, Keri; Siegel, David A; Carlson, Craig A (December 2025, Communications Biology)

   Abstract Kelp forests form some of the most productive areas on earth and are proposed to sequester carbon in the ocean, largely in the form of released dissolved organic carbon (DOC). Here we investigate the role of environmental, seasonal and age-related physiological gradients on the partitioning of net primary production (NPP) into DOC by the canopy forming giant kelp (Macrocystis pyrifera). Rates of DOC production were strongly influenced by an age-related decline in physiological condition (i.e. senescence). During the mature stage of giant kelp development, DOC production was a small and constant fraction of NPP regardless of tissue nitrogen content or light intensity. When giant kelp entered its senescent phase, DOC production increased substantially and was uncoupled from NPP and light intensity. Compositional analysis of giant kelp-derived DOC showed that elevated DOC production during senescence was due to the solubilization of biomass carbon, rather than by direct exudation. We coupled our incubation and physiological experiments to a novel satellite-derived 20-year time series of giant kelp canopy biomass and physiology. Annual DOC production by giant kelp varied due to differences in standing biomass between years, but on average, 74% of the annual DOC production by giant kelp was due to senescence. This study suggests DOC may be a more important fate of macroalgal NPP than previously recognized. 

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4. A cortical network processes auditory error signals during human speech production to maintain fluency

   https://doi.org/10.1371/journal.pbio.3001493  

   Ozker, Muge; Doyle, Werner; Devinsky, Orrin; Flinker, Adeen (February 2022, PLOS Biology)

   Bizley, Jennifer K. (Ed.)

   Hearing one’s own voice is critical for fluent speech production as it allows for the detection and correction of vocalization errors in real time. This behavior known as the auditory feedback control of speech is impaired in various neurological disorders ranging from stuttering to aphasia; however, the underlying neural mechanisms are still poorly understood. Computational models of speech motor control suggest that, during speech production, the brain uses an efference copy of the motor command to generate an internal estimate of the speech output. When actual feedback differs from this internal estimate, an error signal is generated to correct the internal estimate and update necessary motor commands to produce intended speech. We were able to localize the auditory error signal using electrocorticographic recordings from neurosurgical participants during a delayed auditory feedback (DAF) paradigm. In this task, participants hear their voice with a time delay as they produced words and sentences (similar to an echo on a conference call), which is well known to disrupt fluency by causing slow and stutter-like speech in humans. We observed a significant response enhancement in auditory cortex that scaled with the duration of feedback delay, indicating an auditory speech error signal. Immediately following auditory cortex, dorsal precentral gyrus (dPreCG), a region that has not been implicated in auditory feedback processing before, exhibited a markedly similar response enhancement, suggesting a tight coupling between the 2 regions. Critically, response enhancement in dPreCG occurred only during articulation of long utterances due to a continuous mismatch between produced speech and reafferent feedback. These results suggest that dPreCG plays an essential role in processing auditory error signals during speech production to maintain fluency. 

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5. High productivity in hybrid-poplar plantations without isoprene emission to the atmosphere

   https://doi.org/10.1073/pnas.1912327117  

   Monson, Russell K.; Winkler, Barbro; Rosenstiel, Todd N.; Block, Katja; Merl-Pham, Juliane; Strauss, Steven H.; Ault, Kori; Maxfield, Jason; Moore, David J. P.; Trahan, Nicole A.; et al (January 2020, Proceedings of the National Academy of Sciences)

   Hybrid-poplar tree plantations provide a source for biofuel and biomass, but they also increase forest isoprene emissions. The consequences of increased isoprene emissions include higher rates of tropospheric ozone production, increases in the lifetime of methane, and increases in atmospheric aerosol production, all of which affect the global energy budget and/or lead to the degradation of air quality. Using RNA interference (RNAi) to suppress isoprene emission, we show that this trait, which is thought to be required for the tolerance of abiotic stress, is not required for high rates of photosynthesis and woody biomass production in the agroforest plantation environment, even in areas with high levels of climatic stress. Biomass production over 4 y in plantations in Arizona and Oregon was similar among genetic lines that emitted or did not emit significant amounts of isoprene. Lines that had substantially reduced isoprene emission rates also showed decreases in flavonol pigments, which reduce oxidative damage during extremes of abiotic stress, a pattern that would be expected to amplify metabolic dysfunction in the absence of isoprene production in stress-prone climate regimes. However, compensatory increases in the expression of other proteomic components, especially those associated with the production of protective compounds, such as carotenoids and terpenoids, and the fact that most biomass is produced prior to the hottest and driest part of the growing season explain the observed pattern of high biomass production with low isoprene emission. Our results show that it is possible to reduce the deleterious influences of isoprene on the atmosphere, while sustaining woody biomass production in temperate agroforest plantations. 

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