What goes up must come down – scientists unearth “universal thermal performance curve” that shackles evolution

HEAT DEATH OF THE UNIVERSE 

Trinity College Dublin

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From lizards running on a treadmill, to sharks swimming in the ocean, and cell division rates in bacteria — the universal thermal performance curve applies to all species and dictates how they respond to temperature change. Once things get too hot, performance tails off rapidly. Data collapse, and models converge, onto this Universal Thermal Performance Curve (UTPC), which only requires optimal and critical temperatures as parameters. 

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Credit: Prof. Andrew Jackson, Trinity College Dublin

Scientists from Trinity College Dublin have unearthed a “universal thermal performance curve” (UTPC) that seemingly applies to all species and dictates their responses to temperature change. This UTPC essentially “shackles evolution” as no species seem to have broken free from the constraints it imposes on  how temperature affects performance.

All living things are affected by temperature, but the newly discovered UTPC unifies tens of thousands of seemingly different curves that explain how well “species work” at different temperatures. And not only does the UTPC seem to apply to all species, but also to all measures of their performance with regard to temperature variation – whether you are measuring lizards running on a treadmill, sharks swimming in the ocean, or recording cell division rates in bacteria.

Crucially, the new UTPC shows that as all organisms warm: 

1. performance slowly increases until they reach an optimum (where performance is greatest),
2. but then with further warming performance quickly declines. 
3. The rapid decline above optimum temperatures means overheating can be dangerous, risking physiological failure or even death.

One obvious takeaway from the work, just published in leading international journal PNAS, is that species may be more constrained than feared when it comes to their ability to adapt to global climate change, given that in most places temperatures are rising.

Andrew Jackson, Professor in Zoology in Trinity’s School of Natural Sciences, and co-author, said: “Across thousands of species and almost all groups of life including bacteria, plants, reptiles, fish and insects, the shape of the curve that describes how performance changes with temperature is very similar. However, different species have very different optimal temperatures, ranging from 5oC to 100oC, and their performance can vary a lot depending on the measure of performance being observed and the species in question.”

“That has led to countless variations on models being proposed to explain these differences. What we have shown here is that all the different curves are in fact the same exact curve, just stretched and shifted over different temperatures. And what’s more, we have shown that the optimal temperature and the critical maximum temperature at which death occurs are inextricably linked.” 

“Whatever the species, it simply must have a smaller temperature range at which life is viable once temperatures shift above the optimum.”

Senior author, Dr Nicholas Payne, from Trinity’s School of Natural Sciences, added:  “These results have sprung forward from an in-depth analysis of over 2,500 different thermal performance curves, which comprise a tremendous variety of different performance measures for a similarly tremendous variety of different species – from bacteria to plants, and from lizards to insects.” 

“This means the pattern holds for species in all major groups that have diverged massively as the tree of life has grown throughout billions of years of evolution. Despite this rich diversity of life, our study  shows basically all life forms remain remarkably constrained by this ‘rule’ on how temperature influences their ability to function. The best evolution has managed is to move this curve around – life hasn’t found a way to deviate from this one very specific thermal performance shape.” 

“The next step is to use this model as something of a benchmark to see if there are any species or systems we can find that may, subtly, break away from this pattern. If we find any, we will be excited to ask why and how they do it – especially given forecasts of how our climate is likely to keep warming in the next decades.”

Biological performance across the tree of life collapses onto the Universal Thermal Performance Curve (UTPC). Shown are approx. 30,000 performance measurements derived from seven kingdoms, 39 phyla and 2710 experiments. Performance is represented by diverse rates including metabolism, individual growth, foraging intensity, voluntary activity, and population growth.

Credit

Credit authors Prof. Nicholas Payne and Prof. Andrew Jackson, Trinity College Dublin. Originally published in PNAS.

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2513099122 

eoht.info/page/Literature thermodynamics

 

Commercially important fish found congregating at methane seep off Chile

Scientists spot nearly 50 red cusk-eels burrowed into a tubeworm bush at a methane seep in a new-to-science observation

University of California - San Diego

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A red cusk-eel burrowed in among tubeworms at a methane seep off the coast of El Quisco in central Chile. Credit: Schmidt Ocean Institute

 

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Credit: Credit: Schmidt Ocean Institute

A team of scientists from Chile and the United States discovered dozens of red cusk-eels, fish prized in Chilean seafood markets and celebrated in a poem by renowned Chilean poet Pablo Neruda, embedded in a bushy thicket of tubeworms at a methane seep off the coast of central Chile. 

This is the first time this commercially important species has been documented using methane seeps as habitat. It’s not yet clear what drew the fish to the methane seep, but some evidence suggests the fish may have been receiving a parasite cleaning from resident spider crabs.

“Methane seeps are important places for deep-sea biodiversity,” said Lisa Levin, co-author of a study detailing the discovery and professor emeritus at UC San Diego’s Scripps Institution of Oceanography. “Our findings show these seeps are not just home to communities of obscure creatures that are cut off from the rest of the deep sea. They are also important for commercially fished species and may be much more connected to the rest of the ocean than one might expect.”

The discovery places the cusk-eels among a small but growing list of other commercially significant species using methane seeps. The study was published Oct. 18 in the journal Ecology. The research was supported by the Schmidt Ocean Institute and funded by the National Science Foundation.

Red cusk-eels (Genypterus chilensis) can reach lengths of 1.6 meters (five feet) and are usually found near the bottom at depths up to 350 meters (1,100 feet) from northern Peru to southern Chile. They are not true eels but their long slender body shape and undulating swimming style make it easy to understand how they got their name. In 2022, Chilean fishers hauled up roughly 2,000 tons of red cusk-eel (known locally as "congrio colorado"), and the fish features prominently in coastal restaurant menus. Research suggests the species is being overfished, with a 2003 study finding that 75% of the catch had not yet reached sexual maturity. 

Methane seeps are where methane and hydrogen sulfide emerge from the seafloor. Thousands of these seeps have been discovered around the world, typically near continental margins. The seeps provide food for microbes that specialize in converting the leaking chemicals into energy through a process called chemosynthesis. These microbes form the base of thriving ecosystems that exist largely apart from the sun. Methane seeps have gained recognition as critical habitats for some species targeted by commercial fishing fleets, including thornyhead rockfish, Chilean seabass (also known as Patagonian toothfish) and deep-sea snow crabs. 

An October 2024 oceanographic expedition aboard the Schmidt Ocean Institute’s Research Vessel Falkor (too) set out to map and explore methane seeps off the coast of central and south Chile and to study the unique ecosystems they support.

The research team used a combination of shipboard sonar and expertise from collaborating geologists to locate mounds on the seafloor that were potential methane seeps. The team then deployed Schmidt Ocean Institute’s ROV SuBastian to explore and film these sites. 

The team discovered a large mound roughly 18 kilometers (11 miles) off the coast of El Quisco, a small town about 85 kilometers (53 miles) south of Valparaíso. On a dive to survey the mound some 435 meters (1,427 feet) below the surface, the team was impressed by the size and density of tubeworms attached to the mound’s surface. Tubeworms, which flourish via a symbiotic relationship with the seep’s chemosynthetic bacteria, form cylindrical tubes to protect their soft bodies, and large numbers of them create tangled bushes on the seafloor. 

“At first we were amazed by the size of the tubeworm bush,” said Levin. “Eventually we noticed all these fish with their heads poking out from inside the bush.”

The team sent the ROV down to the mound twice over the course of two days and counted 46 to 48 red cusk-eels nestled within a large, dense tubeworm bush on this single mound. Researchers observed the fish swimming backwards into their hiding spots. Video also showed cusk-eels receiving what looked like a parasite cleaning from spider crabs that live in the tubeworm bushes. Levin said the fish could also be congregating to feed, reproduce or seek refuge.

“The presence of this important fishery resource on a methane seep ecosystem close to the coast where it faces pressure from fishing and pollution forces us to think about measures to protect and conserve these habitats,” said Eulogio Soto, a researcher at the University of Valparaíso in Chile who served as a chief scientist of the expedition and co-authored the study. “Our discovery took place over the course of just two days, so we don't know what life exists or what is happening at other times of the year. We must go back.”

The mound appeared to be singular in its appeal to the fish, with surveys of eleven other nearby mounds turning up only three fish in total. The surrounding seafloor near the methane seeps was littered with lost nets and other fishing gear, suggesting this location may be known to local fishers. The findings could inform the management of the red cusk-eel fishery, perhaps serving as the basis for protecting the site and others like it from fishing.  

The study authors said future research should explore whether these aggregations represent spawning sites, feeding grounds, refuges or parasite cleaning stations.

“Almost every time we visit these ecosystems, we find something new,” said Levin. “There is so much more for us to learn, and we need to keep exploring and studying them.”

In addition to Levin and Soto, the study was co-authored by Yerko Castillo of the University  of Valparaiso, Patricia Esquete from the University of Aveiro and Jeffrey Marlow of Boston University.

Red cusk-eels embedded in a tubeworm bush at a methane seep off central Chile. Credit: Schmidt Ocean Institute   

Credit

Credit: Schmidt Ocean Institute

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Journal

Ecology

DOI

10.1002/ecy.70237 

Article Title

Congregation of cusk-eels (Genypterus chilensis, Ophidiiformes) at a deep-sea methane seep off Chile

Article Publication Date

18-Oct-2025

Crop-killing pathogen found to disable plant ‘alarm system’

University of York

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Scientists have discovered how one of the world’s most destructive plant diseases manages to slip past crops’ defenses - a breakthrough that could help farmers grow stronger, more resilient plants.

The new research, published in Nature Communications, describes a family of enzymes produced by a microorganism called Phytophthora infestans, the infamous causative agent of the Irish potato famine and a recurrent threat to potato and tomato crops worldwide.

Led by biologists and chemists from the University of York, in collaboration with The James Hutton Institute and Université Libre de Bruxelles, the international team discovered that this pathogen employs special enzymes, called AA7 oxidases, to disable the plants’ early warning system, weakening their defenses before they can respond. 

The team also showed that disabling the genes that encode these enzymes rendered the pathogen incapable of infecting the host.

Dr Federico Sabbadin, from the Biology Department’s Centre for Novel Agricultural Products (CNAP), said: “It’s like burglars cutting the wires to your home alarm before breaking in. The trick is that the pathogen has evolved the same kind of enzyme activity that plants themselves use to keep their alarm signals under control. 

“By attacking these alarm molecules, the pathogen switches them off before the plant can react - it’s as if the microbe has learned the plant’s own language and uses it against it. When we disabled the genes for these enzymes, the microbes became much weaker at infecting plants.”

As climate change fuels more extreme weather and disrupts farming, crops are left more vulnerable to pests and disease. With global demand for food rising, every lost harvest deepens the risk of shortages and higher prices.

By uncovering this hidden microbial strategy, scientists have opened the door to new ways of protecting crops. Blocking the AA7 enzymes could keep plants’ defenses switched on, helping farmers safeguard yields in an increasingly uncertain climate.

Dr Stephen Whisson, from The James Hutton Institute, said: “We need better strategies for protecting our food if we are to secure global food supplies in the future, and so this latest discovery is a real step forward in doing that.  These enzymes are conserved across major plant pathogens, and their discovery paves the way for powerful new strategies in crop protection.”

The research is part of the project “Berberine bridge enzyme-like proteins as key virulence factors in plant pathogens” running from 2024 to 2027, and is supported with a £870k grant from the Biotechnology and Biological Sciences Research Council, part of UK Research and Innovation (UKRI).

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Journal

Nature Communications

 

Population decline of Franklin’s bumble bee wasn’t due to pathogens, museum genomic research shows

University of California - Davis

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A specimen of Franklin's bumblebee photographed by Robin Thorp. The rare bee, now thought to be extinct, was limited to a few counties in northern California and southern Oregon. A study of DNA from museum specimens shows that the bee's decline was likely due to population bottlenecks compounded by environmental factors rather than diseases. 

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Credit: Robin Thorp, UC Davis

The mysterious population decline of the imperiled Franklin’s bumble bee, which once flourished in a small area of northern California and southern Oregon, was not due to pathogens, but most likely to population bottlenecks and environmental issues such as fire and drought, according to research published Oct. 20 in the Proceedings of the National Academy of Sciences.

A team led by conservation geneticist Rena Schweizer of the USDA Agricultural Research Services Pollinating Insects Research Unit, Logan, Utah, collected whole-genome sequence data from museum specimens of Bombus franklini, spanning more than four decades, to reconstruct 300,000 years of the bee’s genetic history.

Most of the specimens are from the Bohart Museum of Entomology at the University of California, Davis. UC Davis Distinguished Emeritus and bumble bee conservationist Professor Robbin Thorp of the UC Davis Department of Entomology and Nematology monitored the B. franklini population and collected specimens from 1998 until his death in 2019. He was instrumental in obtaining species protection under the U.S. Endangered Species Act.

“Understanding what was happening to Franklin's bumble bee was Robbin Thorp's last major project before his death,” said Distinguished Professor Emeritus Lynn Kimsey, who directed the Bohart Museum for 34 years until her retirement in 2024. She is a co-author of the paper.

Franklin’s bumble bee has not been sighted in the wild since 2006 and is feared extinct. Its range, a 13,300-square-mile area confined to Siskiyou and Trinity counties in California and Jackson, Douglas and Josephine counties in Oregon, is thought to be the most limited geographic distribution of any bumble bee in North America and possibly the world.

The team described the bumble bee as a “rare U.S. pollinator” that “exemplifies the challenges of studying species with small ranges and declining populations that are no longer found in the wild. Using advanced genomic techniques on historical museum specimens, we reconstructed the species’ evolutionary history, revealing critically low genetic diversity and significant population declines since the late Pleistocene.”

“We found that, contrary to previous hypotheses, pathogens likely did not drive initial declines; rather, its extinction vulnerability may have arisen from population bottlenecks and environmental stochasticity over the last 100,000 years,“ the authors wrote. “This study underscores the significance of museum collections in unraveling species’ historical population dynamics before modern anthropogenic influences, thereby contributing to understanding extinction risk and helping guide conservation actions.”

“An analysis of 25 female museum specimens revealed evidence of very low genetic diversity and historical inbreeding,” the authors said. “We found evidence of a steep decrease in population size beginning in the late Pleistocene era, with further decline detected between 200 to 300 years ago, prior to human impact and the introduction of pathogens.

The scientists concluded that “a combination of historically low effective population size and genetic diversity along with environmental stochasticity heightened this species’ extinction vulnerability prior to recent anthropogenic stressors. This study demonstrates the utility of museum collections for clarifying genetic and demographic dynamics of rare species and suggests that B. franklini may have already been on a trajectory of decline prior to human impacts.”

In emphasizing the significance of the research, the authors noted that “Pollinator declines globally threaten ecosystem stability and agricultural productivity. Reconstructing pollinator historic demographies provides an evolutionary perspective to understand contemporary population declines.”

“The global decline of insect pollinators such as bees, beetles, butterflies, and flies is an issue of significant ecological and economic concern as they play an irreplaceable role in the reproduction of many plant species, including an estimated 35% of the crops essential for humans,” they wrote. “Bumble bees are among the most well-studied bee fauna, with many species observed to be in decline, considered at risk for extinction, or even putatively extinct. This is alarming given that wild bumble bees are critical pollinators in natural and agricultural landscapes and are vital to the production of agricultural crops. Assessing the status of bumble bees and other pollinator species and determining the drivers of their declines have become critical research areas.”

Between 1998 and 2005, the number of sightings of B. franklini declined precipitously from 94 individuals in 1998 to 20 in 1999, nine in 2000 and one in 2001. Although 20 were found in 2002 only three were sighted in 2003, all at a single locality. None were found in 2004 and 2005, and a single worker was sighted in 2006. This was at the same locality, Mt. Ashland, where the last B. franklini were found in 2003. No individuals were found in 2007 or 2008.

B. franklini was named for Henry J. Franklin, who monographed the bumble bees of North and South America in 1912-13. In a UC Davis interview, Thorp said that Franklin's bumble bee frequents California poppies, lupines, vetch, wild roses, blackberries, clover, sweet peas, horsemint and mountain penny royal during its flight season, from mid-May through September. It collects pollen primarily from lupines and poppies and gathers nectar mainly from mints.

The authors said the project could not have been completed without the work of Thorp and the approval of Kimsey to extract DNA from the specimens. They were able to genomically sample museum specimens at the Bohart for use in their study, with specimens ranging in age from 1950-1998, the only observations after this point. This allowed us to peek into the genetic history of the species both during the 1950-1998 period,” they said, “and thousands of years prior, using population genomics techniques.”

In addition to Kimsey, co-authors are Michael Branstetter (UC Davis doctoral alumnus), Diana Cox-Foster and Jonathan Uhuad Koch, all of USDA-ARS, Logan, Utah; Jared Grummer, University of Montana, Missoula; Kerrigan Tobin, Marquette University, Milwaukee; and Renee Corpuz and Scott Geib of USDA-ARS, Hilo, Hawaii.

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2509749122 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Museum genomics suggests long-term population decline in a putatively extinct bumble bee

Article Publication Date

20-Oct-2025