Graham Raby
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graham-raby.bsky.social
Graham Raby
@graham-raby.bsky.social
45 followers 63 following 9 posts

Associate Professor at Trent University (Canada).

www.rabylab.com

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Environmental science 65%
Geography 17%
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Reposted by Graham D. Raby

plosbiology.org
PLOS Biology @plosbiology.org · 6d
Oxygen limitation is considered a key mechanism of #ThermalTolerance. @dianasmadeira.bsky.social explores how a @plosbiology.org study challenges this idea, showing minimal protective effects of O2 supersaturation in heat-stressed #aquatic #ectotherms 🧪 Paper: plos.io/43hzMQa Primer: plos.io/3XeUtbS
The effects of temperature on organismal performance are depicted using thermal performance curves, where performance is greatest at the optimal temperature and starts to decrease toward cooler or warmer temperatures, reflecting the thermal window (tolerable range of temperatures) of the species. Briefly, the Oxygen and Capacity Limited Thermal Tolerance hypothesis proposes that oxygen limitation explains the performance decline at high temperatures and sets the first boundary for thermal limits across ectotherms. This is due to a mismatch between the oxygen demand of the organism and the capacity of the cardiorespiratory system to supply oxygen to tissues when the organism is under warming. This concept is central to predict species responses to warming. As oxygen supersaturation in water has been shown to alleviate oxygen supply limitations by increasing maximum rates of oxygen transport in blood, Raby and colleagues (2025) tested the effects of oxygen supersaturation on thermal tolerance across 14 aquatic species. The authors found that it had negligible effects on upper thermal limits, challenging the oxygen limitation hypothesis as a universal mechanism underpinning thermal tolerance of aquatic ectotherms. The authors highlight that oxygen supersaturation in water, a naturally occurring phenomenon in shallow waters, may not protect aquatic species from the effects of extreme heat.

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · 6d
Very exciting to finally have this work out there. Thanks to the team at @plosbiology.org for being willing to publish null results!
plosbiology.org PLOS Biology @plosbiology.org · 6d
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.

Reposted by Graham D. Raby

plosbiology.org
PLOS Biology @plosbiology.org · 6d
Oxygen limitation is considered a key mechanism of #ThermalTolerance. @dianasmadeira.bsky.social explores how a @plosbiology.org study challenges this idea, showing minimal protective effects of O2 supersaturation in heat-stressed #aquatic #ectotherms 🧪 Paper: plos.io/43hzMQa Primer: plos.io/3XeUtbS
The effects of temperature on organismal performance are depicted using thermal performance curves, where performance is greatest at the optimal temperature and starts to decrease toward cooler or warmer temperatures, reflecting the thermal window (tolerable range of temperatures) of the species. Briefly, the Oxygen and Capacity Limited Thermal Tolerance hypothesis proposes that oxygen limitation explains the performance decline at high temperatures and sets the first boundary for thermal limits across ectotherms. This is due to a mismatch between the oxygen demand of the organism and the capacity of the cardiorespiratory system to supply oxygen to tissues when the organism is under warming. This concept is central to predict species responses to warming. As oxygen supersaturation in water has been shown to alleviate oxygen supply limitations by increasing maximum rates of oxygen transport in blood, Raby and colleagues (2025) tested the effects of oxygen supersaturation on thermal tolerance across 14 aquatic species. The authors found that it had negligible effects on upper thermal limits, challenging the oxygen limitation hypothesis as a universal mechanism underpinning thermal tolerance of aquatic ectotherms. The authors highlight that oxygen supersaturation in water, a naturally occurring phenomenon in shallow waters, may not protect aquatic species from the effects of extreme heat.

Reposted by Graham D. Raby

plosbiology.org
PLOS Biology @plosbiology.org · 6d
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · 6d
Special thanks to @dianasmadeira.bsky.social for authoring this thoughtful primer about the study we published this week in @plosbiology.org Good suggestions about all the work we still need to do to unveil the mechanisms underlying variation in thermal tolerance.

journals.plos.org/plosbiology/...

Reposted by Graham D. Raby

plosbiology.org
PLOS Biology @plosbiology.org · 7d
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.

Reposted by Graham D. Raby

plosbiology.org
PLOS Biology @plosbiology.org · 7d
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.

Reposted by Graham D. Raby

jutfelt.bsky.social
Fredrik Jutfelt 🐠 @jutfelt.bsky.social · 7d
Oxygen supersaturation has been reported to protect aquatic animals from heat waves. We tested this in a large collaborative experiment on many species of fish and crustaceans. Our new paper in @plosbiology.org shows that the effect of hyperoxia on thermal tolerance is negligible. Unfortunately.

Reposted by Graham D. Raby

cars-afs.bsky.social
cars-afs.bsky.social @cars-afs.bsky.social · 10d
CONGRATULATIONS!
Larkin Award, PhD Winner
#BradleyHowell
🪼
[Graham Raby, #TrentUniversity & Steven Cooke, #CarletonUniversity]
🪼
Bradley’s research focuses on using telemetry and respirometry data to assess #predatorprey interactions and movement patterns that raise predation risk.

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · 20d
Boat salad

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · 27d
We have the most photogenic campus

Reposted by Graham D. Raby

Reposted by Graham D. Raby

garyburness.bsky.social
Gary Burness @garyburness.bsky.social · Oct 1
Excited about a new preprint from PhD candidate Megan Heft, showing that nestling provisioning rates in male tree swallows are not limited by the male's risk of overheating (in contrast with previous studies of females) 🧪 #ornithology #science
www.biorxiv.org/content/bior...
www.biorxiv.org

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · Sep 26
If you're a fish tracking nerd you know and love the sight of this pink foam

Reposted by Graham D. Raby

Reposted by Yasheng Huang, Benjamin Hansen, Graham D. Raby

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · Sep 8
Caught a couple northern sunfish in a beach seine today; first time ever seeing these for me (in the Otonabee River near Trent U).

Reposted by Graham D. Raby

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · Sep 4
tick tock

Reposted by Graham D. Raby

Reposted by Graham D. Raby

Reposted by Graham D. Raby

Reposted by Graham D. Raby

methodsinecoevol.bsky.social
Methods in Ecology and Evolution @methodsinecoevol.bsky.social · Aug 25
📖Published📖

Raby et al. provide a comprehensive, practical guide for designing and conducting experiments to measure critical thermal limits, with an emphasis on CTmax 🌍 🧪 👇

buff.ly/iZN6Xdg
Diagram of a template design for a CTmax apparatus. Aeration, mixing mechanisms (pump), and heating elements are in an ‘equipment section’ that is physically separated with a screen from the part of the arena containing the animals (‘animal arena’; here with fish). A submerged temperature sensor (or data logger) is used to log temperatures, in addition to a temperature sensor with a display that is used to score CTmax in real time. The time and temperature should only be visible to the data recorder (and/or video camera), not to the person observing animals for end points.

Reposted by Graham D. Raby

Reposted by Graham D. Raby

thefsbi.bsky.social
The FSBI @thefsbi.bsky.social · Aug 23
#JFB: Validation of a new acoustic telemetry transmitter for the study of predation events in small fishes doi.org/10.1111/jfb.15827 #FishSci
doi.org

graham-raby.bsky.social
Graham Raby @graham-raby.bsky.social · Aug 22
is this what the discovery grant panel looks like