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

Tuesday, November 25, 2025

The seamounts of Cape Verde: a biodiversity hotspot and a priority for marine conservation in the central-eastern Atlantic

Image Credit: Projecte Luso/iMirabilis2/iAtlantic

An international team led by Covadonga Orejas, a researcher at the Gijón Oceanographic Centre of the Spanish Institute of Oceanography (IEO-CSIC); Veerle Huvenne, a researcher at the UK National Oceanography Centre (NOC); and Jacob González-Solís, professor at the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona, has published the first comprehensive study on the seamounts of the Cape Verde archipelago, their biodiversity, ecological functionality and socio-economic relevance in the journal Progress in Oceanography.

These volcanic formations — at least 14 large mountains and numerous smaller elevations — act as veritable oases of life in the deep ocean, concentrating nutrients and modifying the circulation of underwater currents. This supports exceptional biodiversity, ranging from microorganisms to communities of deep-sea corals and sponges, as well as sharks, turtles, seabirds and cetaceans. Their position between the temperate waters of the North Atlantic and the tropical waters of the South, further enhances their productivity and ecological connectivity. 

Monday, November 24, 2025

Humpback Whales Are Making a Comeback – Here’s One Reason Why

Photo Credit: © Olga Filatova/SDU

When SDU whale researcher Olga Filatova set off on her first field trip in 2000, she spent five years looking for whales before she saw a humpback. 

“It was incredibly rare to spot one back then. Today, we see them almost every day when we’re in the field,” she says. “We don’t know exactly how many humpbacks there are now, but definitely many more than when I started.” 

A cautious estimate from the Endangered Species Coalition puts today’s population at around 80,000—up from just 10,000 at their lowest point. That makes humpbacks one of the great success stories of conservation. 

Friday, November 14, 2025

UH calculates survival needs of deep-diving Hawaiian pilot whales

An aerial view of Hawaiʻi short-finned pilot whales at the surface.
Photo Credit: HIMB Marine Mammal Research Program

For the first time, scientists have calculated a detailed “energetic budget” for Hawaiʻi‘s short-finned pilot whales, revealing what it takes to power their extreme, 800-meter (2,600-feet) dives for food.

A new study led by the University of Hawaiʻi at Mānoa’s Hawaiʻi Institute of Marine Biology (HIMB) found an average adult whale must eat 142 squid daily to survive, scaling up to 416 million squid annually for the entire population of short-finned pilot whales. This data, published in the Journal of Experimental Biology, provides a new benchmark for protecting the historically understudied marine mammals.

“Pilot whales are one of the only oceanic dolphins that regularly dive to extreme depths—up to 1,000 meters—to find prey,” said William Gough, Marine Mammal Research Program (MMRP) postdoctoral researcher and lead author of the study. “This deep-diving, high-risk foraging strategy requires a delicate balance between the energy they spend and the energy they acquire. Our study is the first step in quantifying that balance for this specific population.”

Severe impact of avian flu on southern elephant seals

Elephant seals on Lagoon Island near Ryder Bay, Adelaide Island.
Photo Credit: Steve Gibbs, BAS

New research reveals 47% decline in breeding female elephant seals at sub-Antarctic island of South Georgia following a highly pathogenic avian influenza outbreak. 

Scientists from the British Antarctic Survey (BAS) have documented the severe impact of highly pathogenic avian influenza (HPAI) on southern elephant seals at South Georgia, revealing a 47% decline in breeding females between 2022 and 2024. 

The research, published today in the journal Communications Biology, shows that the world’s largest population of southern elephant seals – which accounts for over half of the global population of breeding age – has suffered unprecedented losses following the arrival of HPAI H5N1 at the remote sub-Antarctic island in late 2023. 

Thursday, November 13, 2025

Carbon-rich waters are becoming even more acidic as atmospheric CO2 levels rise

Orange cup corals, pictured growing on rocks above, are native to the Pacific Ocean. As they grow, corals incorporate minerals from seawater, leaving a valuable historical record in their skeletons. In this University of Washington-led study, researchers compare preindustrial corals to modern specimens to show how quickly the ocean is acidifying.
Photo Credit: Alexander Vasenin
(CC BY-SA 4.0)

The waters bordering North America could soon be inhospitable to critical marine creatures if the Northeastern Pacific Ocean continues to acidify at the current rate, a new study shows.

Earth’s oceans have become approximately 30% more acidic since the industrial revolution began more than 200 years ago. Acidification changes marine chemistry and depletes key minerals that calcifying organisms, such as corals and clams, need to build their skeletons and shells. The Northeastern Pacific is naturally more acidic than other oceans, fueling debate about how much its chemistry will change in the coming decades.

The study, published in Nature Communications, shows that high baseline acidity makes the water more sensitive to additional carbon dioxide from human activities. Analyses of coral skeletons from the past century revealed that CO2 has been accumulating in North American waters faster than in the atmosphere, driving rapid acidification.

Drones Map Loggerhead Sea Turtle Nesting Site Hotspots

Graduate student and lead author, Summer Manestar, holding the UX11 unmanned aerial vehicle that was used in the study.
Photo Credit: Courtesy of  Florida Atlantic University

Researchers from the Charles E. Schmidt College of Science used drones and field surveys to study how environmental and human factors affect loggerhead sea turtle nest site selection on a high-density beach in Boca Raton. The team looked at beach slope, sand texture, and proximity to structures like dune stairs – wooden stairways that let people safely cross sand dunes without damaging them. Understanding these factors is important because where turtles nest directly affects hatchling survival and sex ratios.

The study found that successful nests were more likely on steeper parts of the beach and farther from dune stairs, while false crawls – when sea turtles come ashore but do not lay eggs – were more common in flatter areas or near stairs. These findings give researchers new tools for monitoring nesting activity and help guide efforts to protect Florida’s critical sea turtle habitats.

Wednesday, November 12, 2025

Hawaiian monk seals are far more ‘talkative’ than previously known

Two adult Hawaiian monk seals interacting under water.
Photo Credit: Krista Jaspers

A new study by researchers from the University of Hawaiʻi at Mānoa’s Hawaiʻi Institute of Marine Biology (HIMB) has revealed that endangered Hawaiian monk seals have a hidden vocal repertoire, using a complex range of sounds to call underwater.

Previously, scientists believed monk seals had a simple repertoire, identifying only six different calls based on seals in human care. In this study, the scientists analyzed thousands of hours of passive acoustic data from the wild, they discovered 25 distinct vocalizations.

Monday, November 10, 2025

Stranded Florida dolphins show Alzheimer’s-like brain changes linked to toxic algal blooms

Photo Credit: Oleksandr Sushko

A new study has discovered that dolphins living in Florida’s Indian River Lagoon show brain changes similar to Alzheimer’s disease. The collaborative study, which included scientists from the University of Miami Miller School of Medicine,  Hubbs-SeaWorld Research Institute (HSWRI), Brain Chemistry Labs, the Rosenstiel School of Marine, Atmospheric, and Earth Science and Blue World Research Institute, found that dolphins exposed to harmful algal blooms carried high levels of a toxin in their brains and showed warning signs of neurodegeneration.

The study is one of the first to connect neurotoxins found in algal blooms directly to brain changes associated with Alzheimer’s-like disease in a wild marine mammal. It also illustrates how warm water and nutrient pollution, which fuel these blooms, may impact wildlife health.

Friday, November 7, 2025

Deep-sea mining waste threatens life and food webs in  ocean’s dim “twilight zone”

Illustration showing midwater impacts of deep sea mining operations. Image credit: Dowd et al 2025 (Nature Communications)
Illustration Credit: Amanda Merritt

A new study led by researchers at the University of Hawai‘i (UH) at Mānoa is the first of its kind to show that waste discharged from deep-sea mining operations in the Pacific’s biodiverse Clarion-Clipperton Zone (CCZ) could disrupt marine life in the midwater “twilight zone” — a vital region 200-1,500 meters below sea level that supports vast communities of zooplankton, tiny animals that serve as the ocean’s basic food building blocks. Specifically, it finds that 53% of all zooplankton and 60% of micronekton, which feed on zooplankton, would be impacted by the discharge, which could ultimately impact predators higher up on the food web.  

“When the waste released by mining activity enters the ocean, it creates water as murky as the mud-filled Mississippi River. The pervasive particles dilute the nutritious, natural food particles usually consumed by tiny, drifting Zooplankton,” said Michael Dowd, lead author of the study and Oceanography graduate student in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “Micronekton, small shrimp, fish and other animals that swim, feed on zooplankton. Some migrate between the depths and near surface waters and they are consumed by fish, seabirds and marine mammals. Zooplankton’s exposure to junk food sediment has the potential  to disrupt  the entire food web.” 

Monday, November 3, 2025

Scientists Produce Powerhouse Pigment Behind Octopus Camouflage

An octopus camouflages itself with the seafloor. UC San Diego scientists have discovered a new way to produce large amounts of xanthommatin, a natural pigment used in animal camouflage, in a bacterium for the first time.
Photo Credit: Charlotte Seid

Scientists at UC San Diego have moved one step closer to unlocking a superpower held by some of nature’s greatest “masters of disguise.”

Octopuses, squids, cuttlefish and other animals in the cephalopod family are well known for their ability to camouflage, changing the color of their skin to blend in with the environment. This remarkable display of mimicry is made possible by complex biological processes involving xanthommatin, a natural pigment.

Because of its color-shifting capabilities, xanthommatin has long intrigued scientists and even the military, but has proven difficult to produce and research in the lab — until now.

Angling best practices are essential to promote shark survival

A male porbeagle shark caught off the coast of Scotland.
Photo Credit James Thorburn

Most sharks in UK waters survive catch-and-release fishing when angling best practices are followed, according to a new study.

University of Exeter researchers, working with partners, tagged almost 70 blue, porbeagle and tope sharks caught in recreational fishing in the British Isles, to track their behavior and survival afterwards.

Fewer than 5% – three sharks, one from each species – died.

“Our results suggest survival rates are high when sharks are caught and released within current best-practice guidelines,” said Francesco Garzon, from the University of Exeter.

Commenting on the sharks that died, Garzon added: “These deaths can’t be definitively attributed to any one aspect of being caught, as the sharks had no external wounds and were energetic when released.

Researchers in Japan Discover New Jellyfish Species Deserving of a Samurai Warrior Name

Physalia mikazuki sp. nov., a newly described Portuguese man-of-war collected from Gamo Beach, Sendai Bay. The gas-filled float and long trailing tentacles are characteristic of the Portuguese man-of-war. Runner-up names with a similar Sendai-oriented cultural flare included Physalia: zunda shake, blue dragon, and one-eyed dragon.
Image Credit: © Tohoku University / Cheryl Lewis Ames et al.

A student-led research group from Tohoku University has discovered a new species of the venomous Physalia (commonly known as Portuguese man-of-war) that has never been seen before in northeast Japan. This revelation suggests that warming coastal waters and shifting ocean currents are influencing the distribution of marine organisms in northeastern Japan.

"I was working on a completely different research project around Sendai Bay in the Tohoku region, when I came across this unique jellyfish I had never seen around here before," remarks second author Yoshiki Ochiai. "So, I scooped it up, put it in a ziplock bag, hopped on my scooter, and brought it back to the lab!"

Wednesday, October 29, 2025

Bowhead whales’ secret to long life may lie in a protein

University of Rochester biologists are considering ways to ramp up in humans the CIRBP protein, which plays a key role in repairing DNA in bowhead whales and other species.
Photo Credit: National Park Service / public domain

As humans age, we become more vulnerable to cancer and other diseases. Bowhead whales, however, can live for up to 200 years while staying remarkably disease resistant.

How does one of the largest animals on Earth stay healthy for centuries? And could their biology hold clues to help humans live longer too?

New research from scientists at the University of Rochester and their collaborators suggests one answer lies in a protein called CIRBP. The protein plays a key role in repairing double-strand breaks in DNA, a type of genetic damage that can cause disease and shorten lifespan in a variety of species, including humans. In a study published in Nature, the researchers—including URochester biology professors Vera Gorbunova and Andrei Seluanov and first authors Denis Firsanov, a postdoctoral researcher, and Max Zacher, a graduate student in their lab—found that bowhead whales have much higher levels of CIRBP than other mammals. The findings offer a new clue to how humans might one day enhance DNA repair, better resist cancer, and slow the effects of aging.

Wednesday, October 22, 2025

Retreating Glaciers May Send Fewer Nutrients to the Ocean

Northwestern Glacier in Alaska has retreated approximately 15 kilometers (nine miles) since 1950.
Photo Credit: Kiefer Forsch/Scripps Institution of Oceanography.

The cloudy, sediment-laden meltwater from glaciers is a key source of nutrients for ocean life, but a new study suggests that as climate change causes many glaciers to shrink and retreat their meltwater may become less nutritious. 

Led by scientists at UC San Diego’s Scripps Institution of Oceanography, the study finds that meltwater from a rapidly retreating Alaskan glacier contained significantly lower concentrations of the types of iron and manganese that can be readily taken up by marine organisms compared to a nearby stable glacier. These metals are scarce in many parts of the ocean including the highly productive Gulf of Alaska, and they are also essential micronutrients for phytoplankton, the microorganisms that form the base of most marine food webs.

Friday, October 10, 2025

Climate change may increase the spread of neurotoxin in the oceans

The researchers’ findings raise concerns about how climate change may affect the levels of methylmercury in fish and shellfish.
Photo Credit: Johnér Bildbyrå AB

Climate-driven oxygen loss in the Black Sea thousands of years ago triggered the expansion of microorganisms capable of producing the potent neurotoxin methylmercury. That is shown in a new study published in Nature Water, led by Eric Capo at Umeå University, which suggests that similar processes could occur in today’s warming oceans.

Methylmercury is a highly toxic compound that accumulates in fish and seafood, posing severe health risks to humans. It is formed when certain microbes convert inorganic mercury under low-oxygen conditions.

Today, climate change is causing such oxygen-depleted areas to expand in coastal marine environments, including parts of the Baltic Sea. Warmer and more stagnant waters mix less efficiently, and increased algal blooms contribute to oxygen loss in deeper layers, creating ideal conditions for these microbes.

Lessons from Ascension’s shark troubles could help boost conservation

Sharks at the coast of Ascension Island.
Photo Credit Kate Downes

Understanding people’s attitudes to interactions with sharks could help halt the global decline of shark numbers, according to new research carried out on Ascension Island.  

In 2017, there were two non-fatal shark attacks at Ascension – a UK territory in the South Atlantic with a population of about 800 people.

Large numbers of sharks – mostly silky and Galapagos sharks – have affected the island’s recreational fishers, who often lose tackle and hooked fish before they can be landed.

The research team, led by the University of Exeter and ZSL, interviewed 34 islanders to assess perceptions of sharks.

“We found that human-shark conflict is driven by lots of different factors beyond just attacks – and understanding this is vital if we want shark conservation to work,” said Dr Claire Collins, from ZSL and the University of Exeter.

Thursday, October 9, 2025

Critically endangered shark meat sold in US stores

Image Credit: Gillie Sibrian/UNC-Chapel Hill

Critically endangered shark meat is being sold at American grocery stores — often under misleading labels — according to a new study conducted by researchers at UNC-Chapel Hill.

The researchers purchased and DNA barcoded 29 shark meat products from stores in North Carolina; Washington, D.C.; Florida and Georgia and from online vendors. DNA testing revealed 11 different species of shark, yet 93% of the samples were ambiguously labeled as “shark” or “mako shark” at stores with no species-level identification.

Of the 11 species sold in stores, three are listed as critically endangered by the International Union for the Conservation of Nature — the great hammerhead, scalloped hammerhead and tope. Another species sold in stores, the shortfin mako shark, is listed as endangered by the IUCN.

The U.S. Food and Drug Administration only requires sellers to label shark meat as “shark,” with no specific species name required.

Sunday, October 5, 2025

Rare glimpse at understudied ecosystem prompts caution on deep-sea mining

Some of the animals identified in the deep-sea that spend their life in the benthic boundary layer.
Photo Credit: Gabrielle Ellis

An enormous but poorly understood region of the global ocean–referred to as the abyssal benthic boundary layer–lies a few meters above the seafloor and has only been sampled a handful of times. A study by oceanographers at the University of Hawaiʻi at Mānoa provided the first in-depth look at this habitat, revealing a dynamic community that may be more sensitive to seasonal changes than previously understood. The research, published in Limnology and Oceanography, also concluded that deep-sea mining could have significant and unavoidable impacts on biodiversity, regardless of the time of year.

“Given the remoteness of this environment, we have extraordinarily limited knowledge of the animals that inhabit this zone,” said Gabrielle Ellis, lead author of the study and recent oceanography graduate from the UH Mānoa School of Ocean and Earth Science and Technology. “This study represents a significant contribution to our understanding of the benthic boundary layer community, and it starts to unravel temporal dynamics in the abyss.”

What Is: Microplastics

Microplastic
Credit: Scientific Frontline

The Invisible Tide of Plastic


The modern era has been defined, in part, by the versatility and ubiquity of plastic. Yet, this celebrated 20th-century material has given rise to a paradoxical form of pollution—one so pervasive and minute that its scale was largely unrecognized until recently. Microplastics, the synthetic dust of our industrial age, represent a global environmental challenge of unprecedented complexity. These tiny particles, born from the fragmentation of larger debris and the intentional design of microscopic products, have infiltrated every corner of the planet. Scientific expeditions have confirmed their presence from the summit of Mount Everest to the abyssal depths of the Mariana Trench. More alarmingly, this invisible tide has crossed the final frontier, entering the human body itself, with researchers detecting microplastic particles in human blood, lung tissue, and even the placenta.

The ubiquity of microplastics signals a fundamental disruption of planetary systems. They are not merely inert debris but active agents in the environment, interacting with ecosystems and organisms in complex and often detrimental ways. Their journey spans the globe, carried by ocean currents, river systems, and atmospheric winds, connecting the most remote wilderness to the most densely populated urban centers in a shared system of contamination. This report provides a definitive, evidence-based synthesis of the current scientific understanding of microplastics. It aims to dissect the full scope of this issue, beginning with a fundamental definition of the pollutant and a detailed accounting of its myriad sources. It will then trace the environmental fate and transport of these particles through aquatic, terrestrial, and atmospheric systems. Finally, the report will conduct an exhaustive analysis of their multifaceted impacts on ecological integrity and human health, concluding with a critical evaluation of the policies, technologies, and strategies required to mitigate this pervasive threat.

Wednesday, October 1, 2025

3D-printed shelters increase baby coral survival rates

Researchers place the modules onto experimental tables in Kāneʻohe Bay.
Photo Credit: Jessica Reichert

To dramatically increase coral survival rates, scientists at the University of Hawaiʻi at Mānoa Hawaiʻi Institute of Marine Biology (HIMB) have developed innovative 3D-printed ceramic structures that provide crucial protection for baby corals. These new designs offer a low-cost and scalable solution to enhance reef recovery worldwide.

The discovery, published in Biological Conservation, addresses a critical challenge in reef restoration—the low settlement and survival rates of juvenile corals, which often die before adulthood due to predation, being overgrown by algae or being swept away by waves.

“We developed structures that help baby corals find safe homes in the reef,” said Josh Madin, principal investigator at HIMB’s Geometric Ecology Lab and co-author of the study. “Our new designs, with small spiral-shaped shelters called ‘helix recesses,’ give young corals the protection they need during this critical stage.”

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