Warm water has overlooked importance for cold-water fish, like salmon and trout

OREGON STATE UNIVERSITY

Research News

 

IMAGE: ARCTIC GRAYLING IN EPHEMERALLY WARM LAKE OUTLET, LITTLE TOGIAK RIVER, ALASKA. view more 

CREDIT: JONNY ARMSTRONG

CORVALLIS, Ore. - Warm river habitats appear to play a larger than expected role supporting the survival of cold-water fish, such as salmon and trout, a new Oregon State University-led study published today found.

The research has important implications for fish conservation strategies. A common goal among scientists and policymakers is to identify and prioritize habitat for cold-water fish that remains suitably cool during the summer, especially as the climate warms.

This implicitly devalues areas that are seasonally warm, even if they are suitable for fish most of the year, said Jonny Armstrong, lead author of the paper and an ecologist at Oregon State. He called this a "potentially severe blind spot for climate change adaptation."

"Coldwater fish like trout and salmon are the polar bears of river ecosystems - iconic species that are among the most vulnerable to climate change," Armstrong said. "A huge challenge for conservation is to figure out how to help these fish survive a warmer future. The conclusion is that we should not waste money on warm habitats and instead focus on saving the coldest places, such as high mountain streams, which are already the most pristine parts of basins. Most people agree we should give up on places that are warm in summer, but forget that these places are actually optimal for much of the year."

In the new paper, published in Nature Climate Change, Armstrong and collaborators at Oregon State and several federal agencies, show that warm river habitats, typically lower in basins, provide pulses of growth potential during the spring and fall, so-called shoulder seasons, when the rivers are not at peak summer temperatures. Foraging in these warm habitats can provide fish the needed energy to travel to cooler parts of the river during the summer and to reproduce.

"The synergy between cold water and warm water is really important," said Armstrong, an assistant professor in the Department of Fisheries and Wildlife in the College of Agricultural Sciences. "We're not saying cold water is not important. We're saying that warm portions of basins are also important because they grow fish during the shoulder seasons. Conserving this habitat is critical for unlocking the full potential of rivers to support fisheries.

"In a warmer future, many fish will need fish to take a summer vacation and move to cold places to survive the hottest months of the year. Their ability to do that could often depend on how much energy they can get in the spring and how well they can feed in the fall to bounce back. The places that are stressfully warm in summer are just right in spring and fall, and there is growing evidence that they can fuel fisheries"

For the study, the researchers used data from another team of scientists that used remote sensing technology to obtain river water temperature data across entire landscapes throughout the year. That team compiled data for 14 river basins in Oregon, Washington and Idaho.

The OSU-led team plugged these temperature data into a "bioenergetics model" that predicts fish growth potential based on equations derived from lab studies. This provided new insights into how growth opportunities shift across river basins throughout the year, and how a large fraction of total growth potential can accrue during the spring and autumn in places that are too hot during summer.

To explore how these warm habitats could contribute to fisheries, the team created a simulation model in which virtual rainbow trout were given simple behavior rules and allowed to forage throughout the year in a basin with cold tributaries and a warm, productive main-stem river. Their simulations showed the majority of fish moved into cooler waters in the summer and exhibited meager growth rates. However, outside summer, the simulation showed the fish resided primarily in seasonally warm downstream habitats, which fueled the vast majority of their growth.

"In conservation, we often judge streams by their summer conditions; this is when we traditionally do field work, and this is the season we focus on when planning for climate change," Armstrong said. "We place value on places that hold fish during summer and devalue those that don't. Our simulation showed why this can be a problem - the portions of rivers that contribute most to growth may not be the places where fish are found during summer, so they get written off."

The simulations reveal the synergy between seasonally warm and perennially cool habitats and that fish that lived in these two types of habitats grew much more than fish that were restricted to either habitat alone, Armstrong said.

"We think of things in this binary way - it's either warm-water habitat or its cold-water habitat," Armstrong said. "And we have definitions for fish - it's either a warm-water fish or a cold-water fish. But the places we think of as warm are, in fact, cold way more than they are warm."

He then mentioned an example using rivers in Oregon, including the Willamette, a tributary of the Columbia River that runs nearly 200 miles from Eugene to Portland.

"When it's warm enough for humans to swim, it's bad for cold-water fish. But there's only like six weeks of the year where it is comfortable to go swimming in Oregon," Armstrong said. "That speaks to the fact that we write off places because they get too hot through the lens of August. They're actually pretty nice for most of the year if you're a cold-water fish. And fish don't necessarily have to live there in August, just like you don't have to go swimming in the Willamette in December."

CAPTION

Westslope cutthroat trout and bull trout in Glacier National Park. An example of coldwater fish in summer habitat.

CREDIT

Jonny Armstrong

This research is continuing in the field at Upper Klamath Lake in Southern Oregon, where Armstrong and a team of researchers are tracking the movement and feeding behavior of redband trout as water temperature changes.

Co-authors of the paper are Aimee Fullerton and Chris Jordan of the National Oceanic and Atmospheric Administration Northwest Fisheries Science Center; Joseph Ebersole of the Environmental Protection Agency; James Bellmore, Brooke Penaluna and Gordon Reeves of the U.S. Forest Service Pacific Northwest Research Station; and Ivan Arismendi of Oregon State.

 

Tired of video conferencing? Research suggests you're right to question its effectiveness

A new study suggests that non-visual communication methods that better synchronize and boost audio cues are in fact more effective

CARNEGIE MELLON UNIVERSITY

Research News

 

In the year since the coronavirus pandemic upended how just about every person on the planet interacts with one another, video conferencing has become the de facto tool for group collaboration within many organizations. The prevalent assumption is that technology that helps to mimic face-to-face interactions via a video camera will be most effective in achieving the same results, yet there's little data to actually back up this presumption. Now, a new study challenges this assumption and suggests that non-visual communication methods that better synchronize and boost audio cues are in fact more effective.

Synchrony Promotes Collective Intelligence

Researchers from Carnegie Mellon's Tepper School of Business and the Department of Communication at the University of California, Santa Barbara, have studied collective intelligence--the ability of a group to solve a wide range of problems--and how synchrony in non-verbal cues helps to develop it. There are many forms of synchrony, but the common view is that synchrony occurs when two or more nonverbal behaviors are aligned. Essentially, conversation is what happens when at least two speakers take turns sharing their thoughts, and nonverbal cues are how they establish when and how to take these turns.

Previous research has shown that synchrony promotes collective intelligence because it improves joint problem solving. So it's not too far-fetched that many would assume that if a conversation can't take place face-to-face, it would be best simulated with both video and audio software.

The researchers focused on two forms of synchrony: facial expression synchrony and prosodic synchrony. Facial expression synchrony is pretty straightforward and involves the perceived movement of facial features. Prosodic synchrony, on the other hand, captures the intonation, tone, stress, and rhythm of speech. They hypothesized that during virtual collaboration, collective intelligence would develop through facial expression synchrony when the collaborators had access to both audio and visual cues. Without visual cues, though, they predicted that prosodic synchrony would enable groups to achieve collective intelligence instead.

Collective Intelligence Is Achievable With or Without Video, but Even More So Without

"We found that video conferencing can actually reduce collective intelligence," says Anita Williams Woolley, Associate Professor of Organizational Behavior and Theory at Carnegie Mellon's Tepper School of Business, who co-authored the paper. "This is because it leads to more unequal contribution to conversation and disrupts vocal synchrony. Our study underscores the importance of audio cues, which appear to be compromised by video access."

Woolley and her colleagues pulled together a large, diverse sample of 198 individuals and divided them into 99 pairs. Forty-nine of these pairs formed the first group, which were physically separated with audio capabilities but not video capabilities. The remaining 50 pairs were also physically separated but had both video and audio capabilities. During a 30-minute session, each duo completed six tasks designed to test collective intelligence. As Woolley points out, the results challenge the prevailing assumptions.

The groups with video access did achieve some form of collective intelligence through facial expression synchrony, suggesting that when video is available, collaborators should be aware of these cues. However, the researchers found that prosodic synchrony improved collective intelligence whether or not the group had access to video technology and that this synchrony was enhanced by equality in speaking turns. Most strikingly, though, was that video access dampened the pairs' ability to achieve equality in speaking turns, meaning that using video conferencing can actually limit prosodic synchrony and therefore impede upon collective intelligence.

Specifically, groups regulate speaking turns via a set of interaction rules, which include yielding, requesting, or maintaining turns. Collaborators often subtly communicate these rules through nonverbal cues such as eye contact or vocal cues, such as altering volume and rate. However, visual nonverbal cues appear to enable some collaborators to dominate the conversation. By contrast, the study shows that when groups have audio cues only, the lack of video does not prevent them from communicating these interaction rules but actually helps them to regulate their conversation more smoothly by engaging in more equal exchange of turns and by establishing improved prosodic synchrony.

What does this mean for organizations whose members are still physically separated by the COVID-19 pandemic? It might be worth it to disable the video function in order to promote better communication and social interaction during collaborative problem solving.

###

Summarized from "Speaking out of turn: How video conferencing reduces vocal synchrony and collective intelligence," by Tomprou, Maria (Carnegie Mellon University) Kim, Young Ji (University of California, Santa Barbara), Chikersal, Prerna (Carnegie Mellon University), Williams Woolley, Anita (Carnegie Mellon University), and Dabbish, Laura A. (Carnegie Mellon University). It appears in PLoS One, published by the Public Library of Science. Copyright 2021. All rights reserved.

Changes in ocean chemistry show how sea level affects global carbon cycle

New analysis of strontium isotopes reveals how the global carbon cycle has responded to changes in climate and sea level through geologic time

UNIVERSITY OF CALIFORNIA - SANTA CRUZ

Research News

 

IMAGE: THESE ILLUSTRATIONS SHOW HOW CHANGES IN SEA LEVEL AFFECT CARBONATE DEPOSITION AND OTHER PROCESSES IN THE GLOBAL CARBON CYCLE. view more 

CREDIT: ILLUSTRATIONS BY MADDISON WOOD

A new analysis of strontium isotopes in marine sediments has enabled scientists to reconstruct fluctuations in ocean chemistry related to changing climate conditions over the past 35 million years.

The results, published March 26 in Science, provide new insights into the inner workings of the global carbon cycle and, in particular, the processes by which carbon is removed from the environment through the deposition of carbonates.

"Strontium is very similar to calcium, so it gets incorporated into the calcium carbonate shells of marine organisms," explained lead author Adina Paytan, research professor in the Institute of Marine Sciences at UC Santa Cruz.

Paytan and her coauthors looked at the ratios of different isotopes of strontium, including radiogenic isotopes (produced by radioactive decay) and stable isotopes, which provide complementary information about geochemical processes. They found that the stable isotope ratio of strontium in the ocean has changed considerably over the past 35 million years, and it is still changing today, implying large changes in seawater strontium concentration.

"It's not in a steady state, so what's coming into the ocean and what's leaving don't match," Paytan said. "The strontium composition of seawater changes depending on how and where carbonates are deposited, and that is influenced by changes in sea level and climate."

The fluctuations in strontium isotope ratios analyzed in this study reflect the combined effect of shifts in the global balance of geologic processes including weathering of rocks on land, hydrothermal activity, and the formation of carbonate sediments in both deep-sea and shallow, nearshore marine environments.

Carbonate deposition in the open ocean comes from marine plankton like coccolithophores and foraminifera, which build their shells of the calcium carbonate mineral calcite. In shallow water on the continental shelves, hard corals are more abundant, and they build their skeletons of a different mineral of calcium carbonate, aragonite, which incorporates more strontium than calcite does.

"When corals form, they remove strontium, and when they are exposed, this strontium washes out and goes back into the ocean," Paytan said. "With changes in sea level, more or less of the continental shelf where corals grow is exposed, so that impacts the strontium composition of seawater."

Carbonate deposition also feeds back into the climate system, because the ocean absorbs carbon dioxide from the atmosphere, and carbonate deposition on geological timescales removes carbon from the system. The global carbon cycle and atmospheric carbon dioxide are tightly coupled to climate change, both in the long-term and during the recurring ups and downs of recent ice age cycles.

"The new type of information we can read from the stable strontium isotopes now allows us to take a close look at the business end of the global carbon cycle, when carbon is removed from the environment and laid down into marine carbonate beds," said coauthor Mathis Hain, assistant professor of Earth and planetary sciences at UCSC.

"These findings throw open a new window to let us see how the global carbon cycle adjusted to sea level and climate change through geologic time," he added. "We will need these insights in guiding our response to our current climate emergency and to mitigate the worst effects of ocean acidification."

The researchers were able to reconstruct a robust and detailed record of strontium isotope variations in seawater based on an analysis of marine barite extracted from deep-sea sediment cores.

"Records like this are critical to understanding how our earth operates over geologic times," said coauthor Elizabeth Griffith at Ohio State University. "Our international team worked together to both create this unique record and explain its significance through mathematical modeling, so we can reconstruct changes in the past when the climate conditions were different. The hope is to gain insight into how our blue planet might operate in the future."

CAPTION

Marine barite extracted from deep-sea sediment cores, seen here in a scanning electron microscope image, provides a record of variations in ocean chemistry over geologic time.

CREDIT

Adina Payta

In addition to Paytan, Hain, and Griffith, the coauthors of the paper include Anton Eisenhauer and Klaus Wallmann at the GEOMAR Helmholtz Center for Ocean Research in Germany, and Andrew Ridgwell at UC Riverside. This work was supported by the National Science Foundation.

BEFORE CRISPR

Plant gene found in insect, shields it from leaf toxins

CELL PRESS

Research News

 

IMAGE: THIS IMAGE SHOWS A WHITEFLY ON A LEAF view more 

CREDIT: JIXING XIA AND ZHAOJIANG GUO

Millions of years ago, aphid-like insects called whiteflies incorporated a portion of DNA from plants into their genome. A Chinese research team, publishing March 25th in the journal Cell, reveals that whiteflies use this stolen gene to degrade common toxins plants use to defend themselves against insects, allowing the whitefly to feed on the plants safely.

"This seems to be the first recorded example of the horizontal gene transfer of a functional gene from a plant into an insect," says co-author Ted Turlings (@FARCE_lab), a chemical ecologist and entomologist at the University of Neuchâtel, in Switzerland. "You cannot find this gene, BtPMaT1, which neutralizes toxic compounds produced by the plant, in any other insect species."

Scientists believe that plants probably use BtPMaT1 within their own cells to store their noxious compounds in a harmless form, so the plant doesn't poison itself. The team, led by Youjun Zhang from the Institute of Vegetables and Flowers at the Chinese Academy of Agricultural Sciences, used a combination of genetic and phylogenetic analyses, to reveal that roughly 35 million years ago, whiteflies stole this defense gene, granting the insect the ability to detoxify these compounds for themselves.

"We think a virus within the plant may have taken up this BtPMaT1 gene and, after ingestion by a whitefly, the virus then must have done something inside the insect whereby that gene was integrated into the whiteflies genome," says Turlings. "Of course, this is an extremely unlikely event, but if you think about millions of years and billions of individual insects, viruses, and plants across time, once in a while this could happen, and if the acquired gene is a benefit to the insects, then it will be evolutionarily favored and may spread."

Whiteflies have become a major agricultural pest worldwide, able to attack at least 600 different species of plants worldwide. "One of the questions we've been asking ourselves is how these insects acquired these incredible adaptations to circumvent plant defenses, and with this discovery we have revealed at least one reason as to why," Turlings says.

Using this knowledge, Turlings' Chinese colleagues created a strategy to undo the whiteflies' stolen superpower. They developed a small RNA molecule that interferes with the whiteflies' BtPMaT1 gene, making the whiteflies susceptible to the plant's toxic compounds.

"The most exciting step of this design was when our colleagues genetically manipulated tomato plants to start producing this RNA molecule" says Turlings. "Once the whiteflies fed on the tomatoes and ingested the plant-produced RNA, their BtPMaT1 gene was silenced, causing 100% mortality of the insect, but the genetic manipulation had no impact on the survival of other insects that were tested."

With focused efforts to produce genetically modified crops that are able to silence the whitefly gene, this could function as a targeted strategy for pest control to combat agricultural devastation caused by whitefly populations.

"There are definitely still some hurdles this method needs to get over, most notably the skepticism about using transgenic plants," he says "But in the future, I do see this as a very clear way of controlling whiteflies because now we know exactly the mechanism behind it, and we are equipped to deal with possible changes in the whitefly gene that may arise.

CAPTION

This image shows a whitefly feeding on a leaf

CREDIT

Jixing Xia and Zhaojiang Guo

This research was supported by the National Key R & D Program of China, the National Natural Science Foundation of China, the China Agriculture Research System, the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables, and the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences.

Cell, Xia et al.: "Whitefly hijacks a plant detoxification gene that neutralizes plant toxins" https://www.cell.com/cell/fulltext/S0092-8674(21)00164-1

Cell (@CellCellPress), the flagship journal of Cell Press, is a bimonthly journal that publishes findings of unusual significance in any area of experimental biology, including but not limited to cell biology, molecular biology, neuroscience, immunology, virology and microbiology, cancer, human genetics, systems biology, signaling, and disease mechanisms and therapeutics. Visit: http://www.cell.com/cell. To receive Cell Press media alerts, contact press@cell.com.

PFAS FOREVER CHEMICALS

Exposure to flame retardants early in pregnancy linked to premature birth

NYU LANGONE HEALTH / NYU SCHOOL OF MEDICINE

Research News

 Expectant women are more likely to give birth early if they have high blood levels of a chemical used in flame retardants compared with those who have limited exposure, a new study finds.

These polybrominated diphenyl ethers (PBDEs) are used in the manufacture of furniture, carpeting, and other products to reduce flammability. Previous studies have found that the substances can leach into household dust and build up in the body where they may interfere with the thyroid, an organ that secretes brain-developing hormones. Childhood exposure to PBDEs has been linked to learning disabilities, autistic symptoms, and behavioral issues, among other developmental problems.

In an investigation led by an NYU Long Island School of Medicine researcher, nearly all pregnant women enrolled in the study had detectable levels of PBDEs in their blood. The findings revealed that women with concentrations above 4 nanograms per milliliter of blood were roughly twice as likely to deliver their children early via cesarean section or intentionally induced labor due to safety concerns for the mother or infant. By contrast, there was no elevated risk for preterm birth among women with PBDE levels below that threshold.

"Our findings illustrate that flame retardants may have a tremendous impact on childbirth even if exposure occurred early on in the pregnancy," says study lead author Morgan Peltier, PhD. "Although PBDE chemicals are used with good intentions, they may pose a serious health concern that may have lasting consequences for children." Peltier is an associate professor in the departments of Clinical Obstetrics, Gynecology, and Reproductive Medicine at NYU Long Island School of Medicine, part of NYU Langone Health.

According to Peltier, preterm birth is a leading cause of newborn death and occurs annually in about 15 million pregnancies worldwide. Experts have linked the phenomenon to long-term neurological disorders including cerebral palsy, schizophrenia, and learning problems that can extend into adulthood. Earlier research has pointed to PBDE exposure as a possible culprit behind preterm birth. However, these investigations only looked at exposure to the chemicals late in pregnancy and only examined white and African-American mothers.

The new study, published online Dec. 1 in the Journal of Perinatal Medicine, is the first to explore the link between PBDE exposure in the first trimester of pregnancy, says Peltier. He notes that the investigation looked at a wider demographic group as well, adding Asian and Hispanic women to the analysis.

For the study, the research team analyzed blood samples from 3,529 California women, 184 of whom delivered their infants early. They measured the samples for levels of PBDE-47, a form of the chemical that commonly builds up in the household. The investigators then divided the mothers into four groups based on their amount of exposure.

The study also accounted for other risk factors linked to preterm birth, such as the mother's ethnicity, age, and whether she smoked during pregnancy.

Among the study findings, the group with the highest PBDE levels had a 75 percent increased risk for a spontaneous preterm birth compared with women who had the lowest exposure. Such births occur when women suddenly go into early labor after an otherwise normal pregnancy.

According to Peltier, the study findings also challenged previous beliefs about the role of thyroid hormones in the association between PBDEs and preterm birth. As part of the investigation, the researchers measured blood levels of thyroid stimulating hormone (TSH), a substance used to assess thyroid activity. If flame retardants indeed prevent the organ from working properly, thereby disrupting hormone function, then TSH levels should rise, says Peltier.

However, the study revealed that TSH levels remained normal, suggesting that another mechanism must be at work. Peltier says a possible explanation is that PBDEs may interfere with hormones in the placenta instead of the thyroid.

Peltier adds that the research team next plans to follow the children born to mothers in the study over time to explore how preterm birth linked to flame retardants may affect their long-term brain development.

He cautions that the findings do not prove a direct cause and effect, but strengthen the association between so-called endocrine disrupting chemicals and spontaneous premature birth.

###

Funding for the study was provided by National Institutes of Health grant R01 ES023116.

In addition to Peltier, other NYU Langone researchers included Yuko Arita, D.D.S., Ph.D; and Ali Mahfuz, MBA. Other study co-investigators are Michael Fassett, MD, at Kaiser Permanente Southern California-West Los Angeles Medical Center; Vicki Chiu, MS; Jiaxiao Shi, PhD; Harpreet Takhar MPH; Gildy Lopez, MPH; and Darios Getahun; MD, PhD, at Kaiser Permanente Southern California in Pasadena; and Ramkumar Menon, PhD, at the University of Texas in Galveston.

Media Inquiries

Gene required for jumping identified in rabbits

Experiments with a rare type of rabbit that can't jump pinpointed the necessary gene

PLOS

Research News

VIDEO: PATTERNS OF LOCOMOTION IN SAUTEUR RABBITS. FROM SAMUEL BOUCHER. view more 

CREDIT: CARNEIRO M ET AL., 2021, PLOS GENETICS

Rabbits and other hopping animals require a functional RORB gene to move around by jumping, according to a new study by Miguel Carneiro of the Universidade do Porto and Leif Andersson of Uppsala University published March 25th in PLOS Genetics.

Rabbits, hares, kangaroos and some rodent species all travel by jumping, but this type of movement is not well understood on a molecular and genetic level. In the new paper, researchers investigated jumping-related genes using an unusual breed of domesticated rabbit called the sauteur d'Alfort. Instead of hopping, it has a strange gait where it lifts its back legs and walks on its front paws. By breeding sauteur d'Alfort rabbits with another breed and comparing the offspring's genomes and jumping abilities, the researchers identified the cause of this developmental defect. They identified a specific mutation in the RAR related orphan receptor B (RORB) gene. Typically, the RORB protein is found in many regions of the rabbit nervous system, but the mutation leads to a sharp decrease in the number of neurons in the spinal cord that produce RORB. This change is responsible for the sauteur d'Alfort's weird walk.

The new study demonstrates that a functional RORB gene is necessary for rabbits and likely other hopping animals to perform their characteristic jumping gait. The findings build on previous studies in mice, showing that animals that lack the RORB gene had a duck-like walk. Additionally, this work advances our understanding of the different ways that animals with backbones move.

"This study provides a rare example of an abnormal gait behavior mapped to a single base change and the first description of a gene required for saltatorial locomotion," the authors conclude. "It further demonstrates the importance of the RORB protein for the normal wiring of the spinal cord, consistent with previous studies in mouse."

CAPTION

The sauteur d'alfort strain and associated phenotypes. (A) Typical posture of a sauteur rabbit (sam/sam) adopted when jumping (i.e., moving faster or across longer distances). Hindlegs are lifted from the ground, the body is held vertically, and locomotion is achieved through the alternate use of the forelegs. (B) Ocular malformations observed both in sam/sam and +/sam individuals include bilateral papillary colobomas, reduction in pupillary reflexes, bilateral cataracts with lesions in various components of the eye, glaucoma, and/or entropion and ectropion. Taken by (A) R. Cavignaux; (B) S. Boucher.

CREDIT

Carneiro M et al., 2021, PLOS Genetics

Research Article; Peer-reviewed; Experimental study; Animals

In your coverage please use this URL to provide access to the freely available article in PLOS Genetics: http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1009429

Citation: Carneiro M, Vieillard J, Andrade P, Boucher S, Afonso S, Blanco-Aguiar JA, et al. (2021) A loss-of-function mutation in RORB disrupts saltatorial locomotion in rabbits. PLoS Genet 17(3): e1009429. https://doi.org/10.1371/journal.pgen.1009429

Funding: This work was supported by the Fundação para a Ciência e Tecnologia (FCT, https://www.fct.pt/) through POPH-QREN funds from the European Social Fund and Portuguese MCTES (CEECINST/00014/2018/CP1512/CT0002 and IF/00283/2014/CP1256/CT0012); by FEDER funds through the COMPETE program and Portuguese national funds through FCT (projects PTDC/CVT/122943/2010 and PTDC/BIA-EVL/30628/2017); by the project NORTE-01-0145-FEDER-AGRIGEN, supported by the Norte Portugal Regional Operational Programme (NORTE2020) under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF); by grants from the Swedish Research Council (KK, LA), the Knut and Alice Wallenberg Foundation (LA), the Swedish Brain Foundation (KK) and the Swedish Foundation for Cooperation in Research and Higher Education (KK); and by travel grants to M.C. (COST Action TD1101). J.V. was supported by a postdoctoral contract from Stiftelsen Promobilia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

CTHULHU STUDIES
Octopuses sleep study finds they definitely change colors, maybe dream
By Katie Hunt, CNN 3/25/2021

With its eight legs wrapped around itself as if in a hug and its eye pupils narrowed to a slit, the octopus breathes evenly, its body a uniform whitish gray.

© Sylvia Medeiros/Federal University of Rio Grande do Norte

Moments later it begins to change color -- a mesmerizing shift between burnt orange and rust red. Its eyes, muscles and sucker pads twitching as if it may be experiencing a particularly vivid dream.

Brazilian scientists say the shifts in color, behavior and movement are evidence of a sleep cycle -- with the octopus switching between active and quiet sleep just as humans switch between deep sleep and REM sleep -- named for the rapid eye movements we experience in this state.
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The findings, published Thursday in the journal iScience, show how sleep may have evolved in a similar way in very different creatures and suggests that octopuses may experience something akin to a dream.

"It is not possible to affirm that octopuses dream because they cannot tell us that, but our results suggest that during 'Active sleep' the octopus experiences a state analogous to REM sleep, which is the state during which humans dream the most," said the study authors Sidarta Ribeiro and Sylvia Medeiros in an email.

Ribeiro is a professor of neuroscience at the Brain Institute of the Federal University of Rio Grande do Norte, and Medeiros is a doctoral student at the same university.

Scientists used to think that only mammals and birds experienced different sleep states -- think of a sleeping cat twitching as though it were chasing a bird in the backyard. More recent research, however, has revealed some reptiles and cuttlefish -- another cephalopod and relative of the octopus -- show non-REM and REM-like sleep.

Octopuses have a very different brain structure to humans, but they share some of the same functions as mammal brains. The creatures have special learning abilities -- including being able to solve problems and other sophisticated cognitive abilities, the authors said.

They said investigating octopus sleep was a "vantage point" for comparing them neurobiologically and psychologically with mammals -- with the sleep similarities likely a consequence of "the very taxing mental loads experienced by these separate groups of animals."

The octopus has long been a source of human fascination. Video footage from 2019 of an octopus called Heidi changing color as she slept in a tank had scientists wondering if the creatures could really dream. The Netflix documentary "My Octopus Teacher" has also showcased the creatures' unique abilities.

Dreaming in GIFs not movies

How were the researchers sure the octopuses they studied were asleep and not just resting? The researchers videoed four members of the Octopus insularis species in their lab and studied the animals' behavior over a period of more than 50 days. The octopuses were very sensitive to very weak stimuli when they were alert, but in both sleep states they needed a strong visual or tactile stimulus to evoke a behavioral response, the scientists said.

Octopuses usually change their skin color for camouflage or for communication but during sleep, environmental factors no longer trigger these patterns. The researchers inferred that the color changes during sleep results from independent brain activity.

The study found that the octopus experiences active sleep after a long episode of quiet sleep. In the case of an octopus, the long period is usually more than six minutes.

"If octopuses indeed dream, it is unlikely that they experience complex symbolic plots like we do. 'Active sleep' in the octopus has a very short duration (typically from a few seconds to one minute)," the authors said via email. "If during this state there is any dreaming going on, it should be more like small videoclips, or even gifs."

© Sylvia Medeiros/Federal University of Rio Grande do Norte Octopuses switch between active and quiet sleep just as humans switch between deep sleep and REM sleep, a new study has revealed.

© Sylvia Medeiros/Federal University of Rio Grande do Norte

ACTIVE DREAMING

VIDEO: THIS VIDEO SHOWS AN OCTOPUS IN QUIET SLEEP AND ACTIVE SLEEP. view more 

CREDIT: SYLVIA S L MADEIROS

Octopuses have two alternating sleep states, study shows

CELL PRESS

Research News

Octopuses are known to sleep and to change color while they do it. Now, a study publishing March 25 in the journal iScience finds that these color changes are characteristic of two major alternating sleep states: an "active sleep" stage and a "quiet sleep" stage. The researchers say that the findings have implications for the evolution of sleep and might indicate that it's possible for octopuses to experience something akin to dreams.

Scientists used to think that only mammals and birds had two sleep states. More recently, it was shown that some reptiles also show non-REM and REM sleep. A REM-like sleep state was reported also in cuttlefish, a cephalopod relative of the octopus.

"That led us to wonder whether we might see evidence of two sleep states in octopuses, too," says senior author Sidarta Ribeiro of the Brain Institute of the Federal University of Rio Grande do Norte, Brazil. "Octopuses have the most centralized nervous system of any invertebrate and are known to have a high learning capacity."

To find out, the researchers captured video recordings of octopuses in the lab. They found that during 'quiet sleep' the animals were still and quiet, with pale skin and eye pupils contracted to a slit. During 'active sleep,' it was a different story. The animals dynamically changed their skin color and texture. They also moved their eyes while contracting their suckers and body with muscular twitches.

"What makes it more interesting is that this 'active sleep' mostly occurs after a long 'quiet sleep'--generally longer than 6 minutes--and that it has a characteristic periodicity," Ribeiro says.

The cycle would repeat at about 30- to 40-minute intervals. To establish that these states indeed represented sleep, the researchers measured the octopuses' arousal threshold using visual and tactile stimulation tests. The results of those tests showed that in both 'active' and 'quiet sleep' states, the octopuses needed a strong stimulus to evoke a behavioral response in comparison with the alert state. In other words, they were sleeping.

The findings have interesting implications for octopuses and for the evolution of sleep. They also raise intriguing new questions.

"The alternation of sleep states observed in the Octopus insularis seems quite similar to ours, despite the enormous evolutionary distance between cephalopods and vertebrates, with an early divergence of lineages around 500 million years ago," says first author and graduate student Sylvia Medeiros of the Brain Institute of the Federal University of Rio Grande do Norte, Brazil.

"If in fact two different sleep states evolved twice independently in vertebrates and invertebrates, what are the essential evolutionary pressures shaping this physiological process?" she asks. "The independent evolution in cephalopods of an 'active sleep' analogous to vertebrate REM sleep may reflect an emerging property common to centralized nervous systems that reach a certain complexity."

Medeiros also says that the findings raise the possibility that octopuses experience something similar to dreaming. "It is not possible to affirm that they are dreaming because they cannot tell us that, but our results suggest that during 'active sleep' the octopus might experience a state analogous to REM sleep, which is the state during which humans dream the most," she says. "If octopuses indeed dream, it is unlikely that they experience complex symbolic plots like we do. 'Active sleep' in the octopus has a very short duration--typically from a few seconds to one minute. If during this state there is any dreaming going on, it should be more like small videoclips, or even gifs."

In future studies, the researchers would like to record neural data from cephalopods to better understand what happens when they sleep. They're also curious about the role of sleep in the animals' metabolisms, thinking, and learning.

"It is tempting to speculate that, just like in humans, dreaming in the octopus may help to adapt to environmental challenges and promote learning," Ribeiro says. "Do octopuses have nightmares? Could octopuses' dreams be inscribed on their dynamic skin patterns? Could we learn to read their dreams by quantifying these changes?"

###

This work was supported by the State University of Rio Grande do Norte (UERN), the Coordenação de Aperfeicoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and from the São Paulo Research Foundation (FAPESP) Center for Neuromathematics.

iScience, Medeiros et al.: "Cyclic alternation of quiet and active sleep states in the octopus" https://www.cell.com/iscience/fulltext/S2589-0042(21)00191-7

iScience (@iScience_CP) is an open access journal from Cell Press that provides a platform for original research and interdisciplinary thinking in the life, physical, and earth sciences. The primary criterion for publication in iScience is a significant contribution to a relevant field combined with robust results and underlying methodology. Visit http://www.cell.com/iscience. To receive Cell Press media alerts, contact press@cell.com.

Ocean's mammals at crucial crossroads

UNIVERSITY OF EXETER

Research News

 

IMAGE: HUMPBACK WHALE AND RESEARCHERS PICTURED FROM A DRONE. view more 

CREDIT: DUKE MARINE ROBOTICS AND REMOTE SENSING LAB

The ocean's mammals are at a crucial crossroads - with some at risk of extinction and others showing signs of recovery, researchers say.

In a detailed review of the status of the world's 126 marine mammal species - which include whales, dolphins, seals, sea lions, manatees, dugongs, sea otters and polar bears - scientists found that accidental capture by fisheries (bycatch), climate change and pollution are among the key drivers of decline.

A quarter of these species are now classified as being at risk of extinction (vulnerable, endangered or critically endangered on the IUCN Red List), with the near-extinct vaquita porpoise and the critically endangered North Atlantic right whale among those in greatest danger.

Conservation efforts have enabled recoveries among other species, including the northern elephant seal, humpback whale and Guadalupe fur seal.

The international research team - led by the University of Exeter and including scientists from more than 30 institutions in 13 countries - highlight conservation measures and research techniques that could protect marine mammals into the future.

"We have reached a critical point in terms of marine mammal conservation," said lead author Dr Sarah Nelms, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"Very few marine mammal species have been driven to extinction in modern times, but human activities are putting many of them under increasing pressure.

"Our paper examines a range of conservation measures - including Marine Protected Areas (MPAs), bycatch reduction methods and community engagement - as well as highlighting some of the species that are in urgent need of focus."

The researchers say 21% of marine mammal species are listed as "data deficient" in the IUCN Red List - meaning not enough is known to assess their conservation status.

This lack of knowledge makes it difficult to identify which species are in need of protection and what actions should be taken to save them.

Professor Brendan Godley, who leads the Exeter Marine research group, said: "To continue conservation successes and reverse the downward trend in at-risk species, we need to understand the threats they face and the conservation measures that could help.

"Technology such as drone and satellite imaging, electronic tags and molecular techniques are among the tools that will help us do this.

"Additionally, sharing best practice will empower us - and this is why we are so proud to be part of such a large and international group for this project."

The paper, published in the journal Endangered Species Research, is entitled: "Marine mammal conservation: Over the horizon."

CAPTION

Hawaiian spinner dolphins.

CREDIT

Rob Harcourt

CAPTION

Weddell seal.

CREDIT

Rob Harcourt