. Scientific Frontline: Marine Biology
Showing posts with label Marine Biology. Show all posts
Showing posts with label Marine Biology. Show all posts

Wednesday, March 13, 2024

Menopause explains why some female whales live so long

Orcas
Photo Credit: NOAA

Females of some whale species have evolved to live drastically longer lives so they can care for their families, new research shows.

The study focused on five whale species that – along with humans – are the only mammals known to go through menopause.

The findings show that females of these whale species that experience menopause live around 40 years longer than other female whales of a similar size.

By living longer without extending their “reproductive lifespan” (the years in which they breed), these females have more years to help their children and grandchildren, without increasing the “overlap” period when they compete with their daughters by breeding and raising calves at the same time.

This new research shows that – despite being separated by 90 million years of evolution – whales and humans show remarkably similar life histories, which have evolved independently.

The study was carried out by the universities of Exeter and York, and the Center for Whale Research.

“The process of evolution favors traits and behaviors by which an animal passes its genes to future generations,” said lead author Dr Sam Ellis, from the University of Exeter.

Marine heat waves disrupt the ocean food web in the northeast Pacific Ocean

Pyrosomes.
Photo Credit: Mark Farley, Hatfield Marine Science Center, Oregon State University.

Marine heat waves in the northeast Pacific Ocean create ongoing and complex disruptions of the ocean food web that may benefit some species but threaten the future of many others, a new study has shown.

The study, just published in the journal Nature Communications, is the first of its kind to examine the impacts of marine heat waves on the entire ocean ecosystem in the northern California Current, the span of waters along the West Coast from Washington to Northern California.

The researchers found that the biggest beneficiary of marine heat waves is gelatinous zooplankton – predominantly cylindrical-shaped pyrosomes that explode in numbers following a marine heat wave and shift how energy moves throughout the food web, said lead author Dylan Gomes, who worked on the study as a postdoctoral scholar with Oregon State University’s Marine Mammal Institute.

“If you look at single species interactions, you’re likely to miss a lot,” Gomes said. “The natural effects of a disturbance are not necessarily going to be straightforward and linear. What this showed us is that these heat waves impact every predator and prey in the ecosystem through direct and indirect pathways.”

The project was a collaboration by Oregon State University and the National Oceanic and Atmospheric Administration. Joshua Stewart, an assistant professor with the Marine Mammal Institute, mentored Gomes and co-authored the paper.

Tuesday, March 12, 2024

Range-shifting fishes are climate-change losers, according to new research

Pouting (Trisopterus luscus)
Photo Credit: Diego Delso
(CC BY-SA 4.0 DEED)

The warming of the Earth’s oceans due to climate change is affecting where the world’s fishes live, eat and spawn — and often in ways that can negatively impact their populations. That’s according to a new paper in the journal Nature Ecology and Evolution.

The researchers write that populations that experience rapid-range shift decline noticeably, up to 50 per cent over a decade. The populations affected most are those living on the northern poleward edges of their species’ range.

“There is a conventional wisdom among many climate-change biologists that species that shift their ranges quickly by moving northward should provide a mechanism to sustain healthy populations — that shifting species should be climate-change winners. Our results show the exact opposite,” says paper co-author Jean-Philippe Lessard, a professor in the Department of Biology.

“Species that are shifting their range quickly experience little change in their population size in their core range. But some of them experience a major collapse in their populations at the northern edges.

“In fact, the population collapse is mostly driven by the northern poleward populations,” he adds. “We were expecting that many individuals from the core of the range would be moving up north due to climate change and maintain these northern populations. But the northern-edge populations are the ones most likely to collapse.”

Maternal obesity may promote liver cancer

Obese mice pass on an altered microbiome to their offspring, which has an impact on liver health in adulthood and increases the risk of liver cancer. Normalising the intestinal microbiome reduces the risk of cancer. Specific families of bacteria are linked to tumour burden and liver inflammation.
Image Credit: Toso, Moeckli et al. 2024
CC-by-nc-nd

A team from the UNIGE and the HUG has revealed the role of the microbiota in the increased risk of developing liver disease in the offspring of mothers suffering from obesity.

Obesity, which could reach 50% of the population in certain developed countries by 2030, is a major public health concern. It not only affects the health of those who suffer from it, but could also have serious consequences for their offspring. Scientists at the University of Geneva (UNIGE) and the Geneva University Hospitals (HUG) have studied the impact of maternal obesity on the risk of developing liver disease and liver cancer. Using an animal model, the team discovered that this risk was indeed much higher in the offspring of mothers suffering from obesity. One of the main causes was the transmission of a disturbed intestinal microbiota from the mother, resulting in a chronic liver disease whose effects became apparent in adulthood. These results, which have yet to be confirmed in humans, are a warning signal and a call for action to limit the deleterious effect of obesity on children. This research is published in the journal JHEP Reports.

History repeats as Coral Bay faces mass loss of coral and fish life

Photo Credit: Nico Smit

A perfect storm of environmental factors has seen a monumental loss of fish and coral life at a popular area of Ningaloo Reef in Western Australia’s Gascoyne region — however Curtin University research into the event shows there is hope it will recover.

In March 2022, during the annual coral spawning event, calm weather and limited tidal movement combined to trap the coral’s eggs within Bills Bay, at the town of Coral Bay.

This led to an excess of nutrients in the water which consumed more oxygen than usual — causing massive numbers of fish and corals to die from asphyxiation.

Study lead Associate Professor Zoe Richards, from Curtin’s School of Molecular and Life Sciences, said a lack of oxygen is a well-known risk for tropical coral reefs.

“Severely low oxygen levels in the ocean can create ‘dead zones’ where almost nothing can live, causing a lot of harm to nature and, in tourist areas such as Coral Bay, this can also impact the economy and community,” Associate Professor Richards said.

Monday, March 11, 2024

Unprecedented heatwaves revealed by marine lab’s historic data

Photo Credit: Courtesy of University of Auckland

A unique record at the University of Auckland's Leigh marine lab shows dramatic change in the Hauraki Gulf.

A thermometer dipped in a bucket of sea water on New Year’s Day in 1967 began a unique record which shows the dramatic intensification of warming in the Hauraki Gulf.

Sea-surface readings at the Leigh Marine Laboratory north of Auckland since that time indicate the “unprecedented nature of recent marine heatwaves,” according to Dr Nick Shears of the University of Auckland, Waipapa Taumata Rau.

The number of marine heatwave days and their cumulative intensity has increased sharply since 2012, Shears and his co-authors write in a paper published in the New Zealand Journal of Marine and Freshwater Research.

In past decades, some years had no heatwaves, but that hasn’t happened since 2012. Sponges `melting,’ becoming detached from rocks and dying, along with seaweed and kelp die-offs, are among temperature effects.

Especially warm autumns and winters have likely facilitated an increase in subtropical and tropical species such as the long-spined sea urchin Centrostephanus rodgersii, a voracious herbivore which can lay waste to deep reef environments.

Friday, March 8, 2024

Marine algae implants could boost crop yields

Discovery could lead to more sustainable food supply
Photo Credit: Oktavianus Mulyadi

Scientists have discovered the gene that enables marine algae to make a unique type of chlorophyll. They successfully implanted this gene in a land plant, paving the way for better crop yields on less land. 

Finding the gene solves a long-standing mystery amongst scientists about the molecular pathways that allow the algae to manufacture this chlorophyll and survive. 

“Marine algae produce half of all the oxygen we breathe, even more than plants on land. And they feed huge food webs, fish that get eaten by mammals and humans,” said UC Riverside assistant professor of bioengineering and lead study author Tingting Xiang. “Despite their global significance, we did not understand the genetic basis for the algae’s survival, until now.”

The study, published in Current Biology, also documents another first-of-its-kind achievement: demonstrating that a land plant could produce the marine chlorophyll. Tobacco plants were used for this experiment, but in theory, any land plant may be able to incorporate the marine algae gene, allowing them to absorb a fuller spectrum of light and achieve better growth. 

Wednesday, February 28, 2024

Aerial surveys reveal ample populations of rays in southeast Florida

The giant manta ray is designated as threatened under the U.S. Endangered Species Act and is protected in Florida waters.
Photo Credit: Steve Kajiura, Florida Atlantic University

The whitespotted eagle ray (Aetobatus narinari) and the giant manta ray (Mobula birostris) are rapidly declining globally. Both species are classified by the International Union for Conservation of Nature as endangered worldwide and the giant manta ray is designated as threatened under the United States Endangered Species Act.

In Florida waters, giant manta rays and whitespotted eagle rays are protected species. To provide effective management for these species, it is necessary to gather information on their distribution and abundance.

Using aerial surveys, Florida Atlantic University researchers conducted a unique long-term (2014 to 2021) study to quantify the spatial (latitude) and temporal (month, year) abundance of the whitespotted eagle rays and giant manta rays in Southeast Florida. The researchers conducted 120 survey flights between January 2014 and December 2021 along the Atlantic Coast from Miami north to the Jupiter Inlet. They reviewed the video footage from the flights to quantify the number of rays of each species.

New Fish Species Discovered at Remote Islands Off Mexico’s Pacific Coast

Two females of the newly discovered species, Halichoeres sanchezi or the tailspot wrasse. The males are larger and have different coloration.
Photo Credit: Allison & Carlos Estape

A team of scientists including Ben Frable of UC San Diego’s Scripps Institution of Oceanography have discovered a new species of tropical fish during an expedition to the remote islands of the Revillagigedo Archipelago off Mexico’s Pacific coast. The fish is likely endemic to these islands, meaning it is found no place else on Earth. The Revillagigedos are sometimes called the “Mexican Galapagos” for their trove of marine biodiversity and rugged beauty. 

The researchers describe the new species, dubbed Halichoeres sanchezi or the tailspot wrasse, in a paper published Feb. 28 in the journal PeerJ. Halichoeres sanchezi was named in honor of marine scientist Carlos Armando Sánchez Ortíz of the Universidad Autónoma de Baja California Sur (UABCS) who collected the first specimen and who organized the 2022 expedition that led to the fish’s discovery.

The eight specimens of the new species collected by the team range in size from around an inch long to nearly six inches. The smaller females of the species are mostly white with reddish horizontal stripes along their top half and black patches on their dorsal fin, behind their gills, and just ahead of their tail fin. Frable described the males as “orangy red up top fading to a yellow belly with a dark band at the base of the tail.” 

Halichoeres sanchezi is a member of the wrasse family, a highly diverse and colorful group of more than 600 species. Most wrasse are less than seven inches long, such as the bluestreak cleaner wrasse (Labroides dimidiatus), but some get much larger like the California sheephead (Semicossyphus pulcher) or the massive humphead wrasse (Cheilinus undulatus), which can reach seven feet in length.

Researchers encountered the new wrasse species inhabiting an underwater field of volcanic rubble at a depth of around 70 feet near San Benedicto Island.

Tuesday, February 27, 2024

‘Janitors’ of the Sea: Overharvested Sea Cucumbers Play Crucial Role in Protecting Coral

Photo Credit: Cody Clements

Corals are foundational for ocean life. Known as the rainforests of the sea, they create habitats for 25% of all marine organisms, despite only covering less than 1% of the ocean’s area. 

Coral patches the width and height of basketball arenas, used to be common throughout the world’s oceans. But due to numerous human-generated stresses and coral disease, which is known to be associated with ocean sediments, most of the world’s coral is gone.

“It’s like if all the pine trees in Georgia disappeared over a period of 30 to 40 years,” said Mark Hay, Regents’ Chair and the Harry and Anna Teasley Chair in Environmental Biology in the School of Biological Sciences at the Georgia Institute of Technology. “Just imagine how that affects biodiversity and ecosystems of the ocean.”

In first-of-its-kind research, Hay, along with research scientist Cody Clements, discovered a crucial missing element that plays a profound role in keeping coral healthy — an animal of overlooked importance known as a sea cucumber.

Monday, February 26, 2024

New study uncovers the importance of deepwater ecosystems for endangered species

Hawksbills typically forage on coral reefs where their diet is predominantly sponges.
Photo Credit: Jeanne A Mortimer

Using tracking data, a new study has revealed for the first time that hawksbill turtles feed at reef sites much deeper than previously thought.

Critically endangered hawksbill turtles are found in every ocean and are the most tropical of sea turtles. Adult hawksbills have long been considered to have a close association with shallow (less than 15 meters depth) seas where coral reefs thrive.

Young hawksbills drift in currents during their open water phase of their development before they move to seabed habitats. Hawksbills are usually seen foraging in coral reefs where their diet is predominantly sponges.

To study their feeding habits in more detail, researchers at Swansea, Florida and Deakin universities used high-accuracy GPS satellite tags to track 22 adult female hawksbills from their nesting site on Diego Garcia in the Chagos archipelago in the Indian Ocean to their foraging grounds.

Friday, February 23, 2024

Research reveals new insights into marine plastic pollution

Photo Credit: Lucien Wanda

A groundbreaking study led by researchers at the University of Stirling has uncovered the crucial role of bacteria living on plastic debris.

The research also identifies rare and understudied bacteria that could assist in plastic biodegradation, offering new insights for tackling plastic pollution.

Plastic pollution is a worldwide problem, with up to two million tons estimated to enter oceans every year, damaging wildlife and ecosystems.

In a pioneering study, experts at the University of Stirling’s Faculty of Natural Sciences and the University of Mons (Belgium) analyzed the proteins in plastic samples taken from Gullane Beach in Scotland.

Unlike previous studies carried out in warmer climates that focus on the genetic potential of biofilms inhabiting plastics, this research led by Dr Sabine Matallana-Surget took a unique approach by analyzing the proteins expressed by active microorganisms.

Their findings have unveiled a remarkable discovery of enzymes actively engaged in degrading plastic. Moreover, the team has pioneered new methodologies for enhanced predictions in marine microbiology research.

Wednesday, February 21, 2024

Baleen whales evolved a unique larynx to communicate

humpback whales
Image Credit: Jeanette Atherton AI generated.

The new results also make it clear that human noise in the oceans severely restricts the animals

The iconic baleen whales, such as the blue, gray and humpback whale, depend on sound for communication in the vast marine environment where they live. However, ever since whale song were first discovered more than 50 years ago, it remained unknown how baleen whales produce their complex vocalizations – until now. A team led by the voice scientists Coen Elemans from the University of Southern Denmark and Tecumseh Fitch from the University of Vienna has now for the first time found that baleen whales evolved novel structures in their larynx to make their vast array of underwater songs. The study was published in the prestigious journal Nature. 

Baleen whales are the largest animals to have ever roamed our planet and as top predators play a vital role in marine ecosystems. To communicate across vast distances and find each other, baleen whales depend critically on the production of sounds that travels far in murky and dark oceans. 

A new study in the prestigious journal Nature reports that baleen whales evolved unique structures in their larynx that enable their low-frequency vocalizations, but also limit their communication range.

"The toothed and baleen whales evolved from land mammals that had a larynx serving two functions: protecting the airways and sound production. However, their transition to aquatic life placed new and strict demands on the larynx to prevent choking underwater.", says Tecumseh Fitch. 

Wednesday, February 14, 2024

Compounds released by bleaching coral reefs promote bacteria

Field site in Moʻorea, French Polynesia.
Photo Credit: Milou Arts of NIOZ

On healthy reefs, corals, algae, fishes and microbes live interconnected and in balance—exchanging nutrients, resources and chemical signals. New research led by the University of Hawaiʻi at Mānoa and the Royal Netherlands Institute for Sea Research (NIOZ) revealed that when coral bleaching occurs, corals release unique organic compounds into the surrounding water that not only promote bacterial growth overall, but also promote bacteria that may further stress reefs and pose the risk for more damage.

“Our results demonstrate how the impacts of both short-term thermal stress and long-term bleaching may extend beyond coral and into the water column,” said Wesley Sparagon, co-lead author, postdoctoral researcher in the UH Mānoa College of Tropical Agriculture and Human Resources and previous doctoral student with the UH Mānoa School of Ocean and Earth Science and Technology (SOEST).

The research team, which included scientists from UH Mānoa, NIOZ, Scripps Institution of Oceanography and University of California, Santa Barbara, conducted experiments on bleached and unbleached corals gathered during a bleaching event in Moorea, French Polynesia in 2019.

“Although coral bleaching is a well-documented and increasingly widespread phenomenon in reefs across the globe, there has been relatively little research on the implications for reef water column microbiology and biogeochemistry,” said Craig Nelson, senior author on the study and professor in SOEST.

Tuesday, February 13, 2024

Satellites unveil the size and nature of the world’s coral reefs

A satellite photo from the Allen Coral Atlas showing shallow coral reefs off Fiji
Image Credit: Courtesy of Allen Coral Atlas

University of Queensland-led research has shown there is more coral reef area across the globe than previously thought, with detailed satellite mapping helping to conserve these vital ecosystems.

Dr Mitchell Lyons from UQ’s School of the Environment, working as part of the Allen Coral Atlas project, said scientists have now identified 348,000 square kilometers of shallow coral reefs, up to 20-30 meters deep.

“This revises up our previous estimate of shallow reefs in the world’s oceans,” Dr Lyons said.

“Importantly, the high-resolution, up-to-date mapping satellite technology also allows us to see what these habitats are made from.

“We’ve found 80,000 square kilometers of reef have a hard bottom, where coral tends to grow, as opposed to soft bottom like sand, rubble or seagrass.

Concordia researchers identify a decline in microbial genetic richness in the western Arctic Ocean

With the warming and freshening of the Arctic Ocean comes a decrease of nutrients that are important for photosynthesis
Photo Credit: Davide Cantelli

The Arctic region is experiencing climate change at a much faster rate than the rest of the world. Melting ice sheets, runoff from thawing permafrost and other factors are rapidly changing the composition of the Arctic Ocean’s water. And that change is being experienced all the way down to the microbial level.

In a Concordia-led study published in the journal ISME Communications, researchers analyzed archival samples of bacteria and archaea populations taken from the Beaufort Sea, bordering northwest Canada and Alaska. The samples were collected between 2004 and 2012, a period that included two years — 2007 and 2012 — in which the sea ice coverage was historically low. The researchers looked at samples taken from three levels of water: the summer mixed layer, the upper Arctic water below it and the Pacific-origin water at the deepest level.

The study examined the microbes’ genetic composition using bioinformatics and statistical analysis across the nine-year time span. Using this data, the researchers were able to see how changing environmental conditions were influencing the organisms’ structure and function.

The researchers found subtle but statistically significant changes in the communities they studied.

Sunday, December 24, 2023

Octopus DNA solves mystery of ice sheet’s past

Octopus, probably Pareledone species, from 500m depth on the Bellingshausen Sea continental shelf.
Photo Credit: British Antarctic Survey

Scientists, including from British Antarctic Survey, have used octopus DNA to discover that the West Antarctic Ice Sheet (WAIS) likely collapsed during the Last Interglacial period around 120,000 years ago – when the global temperatures were similar to today.

This provides the first empirical evidence that the tipping point of this ice sheet could be reached even under the Paris Agreement targets of limiting warming to 1.5-2oC.

The study, published in the journal Science, was led by Professor Jan Strugnell, Chief Investigator, and Dr Sally Lau, Postdoctoral Research Fellow from ARC Securing Antarctica’s Environmental Future at James Cook University.

Octopus, probably Pareledone species, from 500m depth on the Bellingshausen Sea continental shelf. BAS.

Wednesday, December 20, 2023

Toxic chemicals found in oil spills and wildfire smoke detected in killer whales

Orcas (killer whales)
Photo Credit: Bart van Meele

Toxic chemicals produced from oil emissions and wildfire smoke have been found in muscle and liver samples from Southern Resident killer whales and Bigg’s killer whales.

A study published in Scientific Reports is the first to find polycyclic aromatic hydrocarbons (PAHs) in orcas off the coast of B.C., as well as in utero transfer of the chemicals from mother to fetus.

“Killer whales are iconic in the Pacific Northwest—important culturally, economically, ecologically and more. Because they are able to metabolically process PAHs, these are most likely recent exposures. Orcas are our canary in the coal mine for oceans, telling us how healthy our waters are,” said senior author Dr. Juan José Alava, principal investigator of the UBC Ocean Pollution Research Unit and adjunct professor at Simon Fraser University.

PAHs are a type of chemical found in coal, oil and gasoline which research suggests are carcinogenic, mutagenic, and have toxic effects on mammals. Their presence in the ocean comes from several sources, including oil spills, burning coal and forest fire smoke particles.

Researchers analyzed muscle and liver samples from six Bigg’s, or transient, killer whales and six Southern Resident killer whales (SRKWs) stranded in the northeastern Pacific Ocean between 2006 and 2018. They tested for 76 PAHs and found some in all samples, with half the PAHs appearing in at least 50 per cent of the samples. One compound, a PAH derivative called C3-phenanthrenes/anthracenes, accounted for 33 per cent of total contamination across all samples. These forms of PAHs, known as alkylated PAHs, are known to be more persistent, toxic, and to accumulate more in the bodies of organisms or animals than parental PAHs.

Monday, December 18, 2023

Some coral species might be more resilient to climate change than previously thought

OSU coral researcher Alex Vompe off the north shore of Mo'orea
Photo Credit: Mackenzie Kawahara

Some coral species can be resilient to marine heat waves by “remembering” how they lived through previous ones, research by Oregon State University scientists suggests.

The study also contains evidence that the ecological memory response is likely linked to the microbial communities that dwell among the corals.

The findings, published today in Global Change Biology, are important because coral reefs, crucial to the functioning of planet Earth, are in decline from a range of human pressures including climate change, said the study’s lead author, Alex Vompe.

“It is vital to understand how quickly reefs can adapt to ever more frequent, repeated disturbances such as marine heat waves,” said Vompe, a doctoral student who works in the lab of microbiology professor Rebecca Vega Thurber. “The microbiomes living within their coral hosts might be a key component of rapid adaptation.”

Heat waves are likely to increase in frequency and severity because of climate change, he added. Slowing down the rate of coral cover and species loss is a major conservation goal, and predicting and engineering heat tolerance are two important tools.

Tuesday, November 7, 2023

30-foot whale shark spotted off Kāneʻohe Bay by UH researchers


University of Hawaiʻi at Mānoa researchers spotted the world’s largest fish species, a 30-foot whale shark, a mile off Kāneʻohe Bay near Kualoa Ranch on November 2.

Researchers from the Hawaiʻi Institute of Marine Biology (HIMB) Shark Research Lab were returning from conducting field work when they spotted seabirds flying over what they suspected was a bait ball, where small fish swarm in a tightly packed spherical formation near the surface while being pursued and herded by predators below.

Mark Royer, a HIMB shark researcher, went into the water to see what sealife had gathered to feed and was surprised to see the whale shark.

“It is surprising,” said Royer. “[Whale sharks] are here more often than we think, however they are probably hard to come across, because I didn’t see this animal until I hopped in the water.”

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