Tests uncover unexpected humpback sensitivity to high-frequency noise

Photo Credit: Mike Doherty

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Humpback whales demonstrate unexpected sensitivity to high-frequency sounds, reacting to frequencies significantly higher than prior anatomical predictions suggested.
• Methodology: Researchers employed behavioural observation audiometry (BOA) over four migration seasons, broadcasting frequency-modulated upsweeps to migrating groups and recording behavioral changes such as course deviation or speed adjustment.
• Key Data: The study confirmed a hearing range extending from 80 Hz to 22 kHz, with specific reactions at the 22 kHz threshold proving sensitivity at the upper end of the human hearing range.
• Significance: This finding overturns the long-held assumption that baleen whales are exclusively low-frequency specialists and validates that wild-setting experiments can match the precision of captive studies.
• Future Application: These insights will refine strategies for mitigating human-induced noise pollution along migration routes, thereby enhancing conservation and protection protocols.
• Branch of Science: Marine Biology and Environmental Science.
• Additional Detail: The research generated the first data-driven audiogram for humpback whales, visually mapping their sensitivity across the tested frequency spectrum.

Silky Shark Study Reveals Deadly Gaps in Marine Protected Areas

The Silky Shark (Carcharhinus falciformis)
Photo Credit: Alex Chernikh
(CC BY-SA 4.0)

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Silky sharks predominantly migrate west and northwest from the Galápagos Marine Reserve into unprotected high-seas corridors, exposing them to industrial fishing fleets despite the existence of nearby Marine Protected Areas.
• Methodology: Researchers deployed fin-mounted satellite tags on 40 adult silky sharks (33 females and 7 males) off Wolf and Darwin Islands, tracking their movements and residence times within protected versus unprotected zones for up to 1.75 years.
• Key Data: The tagged sharks spent more than 50% of the study duration outside Marine Protected Areas, with one individual traveling a record 27,666 kilometers; global populations of the species have declined by 47% to 54% in the last 40 years.
• Significance: The study reveals a critical misalignment between current conservation boundaries and shark behavior, as the animals rarely use the recently established eastern protected areas, preferring instead to travel into high-risk fishing zones.
• Future Application: Conservation planners can utilize this migration data to shift or expand Marine Protected Areas toward the west and northwest to cover the actual pelagic pathways used by the species.
• Branch of Science: Marine Ecology and Conservation Biology
• Additional Detail: Silky sharks are the second-most common species found in the international fin trade, driving their classification as vulnerable with a high risk of extinction.

Arctic seas are getting louder as ice melts, posing risks

Photo Credit: Наталья Коллегова

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Current international regulatory frameworks for monitoring Arctic underwater noise are insufficient as they rely on narrow low-frequency "shipping bands" that miss modern, higher-frequency noise sources like snowmobiles and small vessels.
• Methodology: Researchers analyzed over a decade of acoustic measurements from a community observatory in Cambridge Bay, Nunavut, correlating soundscapes with seasonal ice dynamics to evaluate noise pollution beyond standard satellite tracking.
• Key Data: The study utilized 10 years of continuous data and highlights that the Arctic is warming three times faster than the global average, necessitating region-specific rather than generic European open-water noise models.
• Significance: Inadequate monitoring poses severe risks to marine wildlife that rely on sound for navigation and communication, while also threatening the subsistence hunting practices of Indigenous communities by making prey harder to locate.
• Future Application: International bodies must revise environmental policy frameworks to monitor a wider range of sound frequencies and incorporate seasonal ice cover variables into noise regulation thresholds.
• Branch of Science: Underwater Acoustics and Environmental Physics
• Additional Detail: The research demonstrates that "satellite-invisible" human activities, such as small boat traffic, generate distinct acoustic signatures that significantly alter the soundscape but remain undetected by current tracking systems.

Study finds fisheries management—not predator recovery—drives catch levels in the North Sea

Harbour seals (Phoca vitulina) basking on a rocky shore. Recent data shows these charismatic marine mammals have surged in the past few decades. However, new research suggests this increased population size remains compatible with sustainable fisheries.
Photo Credit: Jeremy Kiszka, Ph.D., Florida International University.

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Anthropogenic fishing effort, driven by management decisions, serves as the primary determinant of fishery yields in the North Sea rather than predation pressure from recovering large marine mammal populations.
• Methodology: Researchers constructed a comprehensive ecosystem model of the southern North Sea and eastern English Channel, integrating data from 12 commercial fishing fleets and the complete marine food web, ranging from microscopic plankton to apex predators like gray seals and harbor porpoises.
• Key Data: The model synthesized extensive real-world datasets, including predator diet studies, fish stock assessments, and historical fisheries catch records, to accurately simulate the interplay between ecological dynamics and human harvest rates.
• Significance: This analysis demonstrates that the conservation of protected predator species is compatible with sustainable seafood production, challenging the prevailing assumption that recovering predator populations inevitably compromise commercial fishery viability.
• Future Application: Findings support the broader implementation of ecosystem-based fisheries management (EBFM) strategies that prioritize regulating human fishing pressure to balance economic objectives with ecological recovery.
• Branch of Science: Marine Ecology and Fisheries Management.
• Additional Detail: Published in the Canadian Journal of Fisheries and Aquatic Sciences, the study indicates that while total consumption by predators increased alongside their population growth, its impact on fish stocks remained subordinate to the volume of biomass removed by commercial fleets.

Positive Interactions Dominate Among Marine Microbes, Six-Year Study Reveals

Lead study author Ewa Merz conducting maintenance on a pump below the Scripps Pier, which brings seawater to the surface for sampling.
Photo Credit: Riley Hale

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Marine microbial communities are driven primarily by positive, mutually beneficial interactions rather than competition, a trend that intensifies during periods of elevated ocean temperature.
• Methodology: Scientists utilized a six-year time series of high-frequency seawater sampling from Scripps Pier combined with DNA sequencing and computational analysis to map interactions among 162 abundant microbial taxa.
• Key Data: Analysis revealed that 78% of microbial associations were positive; specifically, warmer waters caused a 33% drop in total interactions but drove an 11% shift toward facilitation among the remaining connections.
• Significance: These findings challenge the traditional ecological emphasis on competition and predation, suggesting that cooperative networks are critical for microbiome stability and ecosystem function.
• Future Application: Integrating these positive interaction dynamics into climate models will enhance the accuracy of predictions regarding carbon cycling and food web stability in warming oceans.
• Branch of Science: Marine Microbial Ecology
• Additional Detail: The study identified specific "keystone" microbes that disproportionately influence community structure, noting that the identity of these critical species shifts in response to temperature changes.

Seawater microbes offer new, non-invasive way to detect coral disease

This brain coral shows the effects of stony coral tissue loss disease. The brown areas are healthy, the white areas are newly dead from the disease, and the light yellow areas are dead and colonized by endolithic algae.
Photo Credit: Amy Apprill ©WHOI

Scientific Frontline: "At a Glance" Summary

• Main Discovery: Microorganisms in seawater immediately surrounding corals act as superior, non-invasive biomarkers for detecting diseases like Stony Coral Tissue Loss Disease (SCTLD) compared to microbes within the coral tissue.
• Methodology: Researchers performed a four-year longitudinal analysis (2020–2024) of brain coral (Colpophyllia natans) in the U.S. Virgin Islands, using genetic sequencing to compare microbial shifts in coral tissue versus adjacent seawater throughout a disease outbreak.
• Key Data: Microbial communities in seawater remained stable near healthy corals but shifted dramatically during disease infection, whereas internal coral tissue microbiomes varied inconsistently regardless of health status.
• Significance: This approach overcomes the limitations of traditional visual assessments by enabling non-destructive, presymptomatic detection of reef health declines, allowing for timely intervention.
• Future Application: Development of automated, rapid genetic monitoring systems to provide early warning signals for reef managers to mitigate disease spread.
• Branch of Science: Marine Microbiology and Coral Ecology.
• Additional Detail: The study, published in Cell Reports Sustainability, suggests seawater microbes respond to specific materials released by diseased corals, offering a clear signal even before visual lesions appear.

Bristol scientists discover early sponges were soft

Xestospongia muta, the barrel sponge, may live for 100 years and grow to over 6 feet tall. While populations have declined at sites throughout the Caribbean, they appear to be quite healthy on Little Cayman Island. Caribbean Sea, Cayman Islands.
Photo Credit: NOAA
(Public Domain)

Sponges are among earth’s most ancient animals, but exactly when they evolved have long puzzled scientists. Genetic information from living sponges, as well as chemical signals from ancient rocks, suggests that sponges evolved at least 650 million years ago. 

This evidence has proved highly controversial as it predates the fossil record of sponges by a minimum of 100 million years. Now an international team of scientists led by Dr M. Eleonora Rossi, from the University of Bristol’s School of Biological Sciences, has solved this conflict by examining the evolution of sponge skeletons.  The research was published in Science Advances. 

Living sponges have skeletons composed of millions of microscopic glass-like needles called spicules. These spicules also have an extremely good fossil record, dating back to around 543 million years ago in the late Ediacaran Period. Their absence from older rocks has led some scientists to question whether earlier estimates for the origin of sponges are accurate. 

A molecular switch that controls transitions between single-celled and multicellular forms

The marine yeast Hortaea werneckii switches between unicellular and multicellular forms depending on food availability. These microscope images show (left to right): individual cells dividing on their own, fully connected multicellular chains that develop directly from single cells, and multicellular forms transitioning back by producing unicellular offspring. This flexibility helps the yeast adapt to changing ocean conditions.
Image Credit: Gakuho Kurita, Sugashima Marine Biological Laboratory, Nagoya University

How did multicellular life evolve from single cells? Nagoya University researchers have identified genes in marine yeast that may help answer this fundamental question. 

Scientists at Nagoya University in Japan have identified the genes that allow an organism to switch between living as single cells and forming multicellular structures. This ability to alternate between life forms provides new insights into how multicellular life may have evolved from single-celled ancestors and eventually led to complex organisms like animals and plants. 

Published in Nature, the study represents an exceptionally detailed molecular explanation of how clonal multicellularity, where all cells descend from a single ancestor, can be achieved and controlled at the genetic level. 

Manta rays create mobile ecosystems

Juvenile Atlantic manta ray swimming over sandflat with remora symbionts in South Florida. 
Photo Credit: Bryant Turffs

A new study from the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science and the Marine Megafauna Foundation finds that young Caribbean manta rays (Mobula yarae) often swim with groups of other fish, creating small, moving ecosystems that support a variety of marine species.

South Florida—particularly along Palm Beach County—serves as a nursery for juvenile manta rays. For nearly a decade, the Marine Megafauna Foundation has been studying these rays and documenting the challenges they face from human activities near the coast, such as boat strikes and entanglement in fishing gear, which can pose significant threats to juvenile mantas

Identical micro-animals live in two isolated deep-sea environments. How is that possible?

The researchers traveled on the research vessel Polarstern to South Sandwich Trench where they collected sediment samples.
Photo Credit: ©Anni Glud/SDU

Halalaimus is a microscopic nematode genus commonly found in sediment on the seafloor. It lives 1–5 cm below the sediment surface and grazes on bacteria or organic materials in the sediment. 

It does so in the Aleutian Trench as well, which lies in the northern Pacific Ocean, near the Bering Sea. We now know this because PhD Yick Hang Kwan from Danish Center for Hadal Research at the Department of Biology has isolated its eDNA in sediment samples collected from the depths of the Aleutian Trench. 

“But we also found its eDNA in sediment samples from the South Sandwich Trench, which lies 17,000 km away in the South Atlantic. And that inevitably makes you ask: How is it possible that the same nematode genus exists in such extremely isolated deep-sea environments so far apart, when it has a very limited ability to move – and when the trenches are up to eight kilometers deep?” Kwan asks rhetorically. 

New deep-sea species discovered during mining test

A small marine bristle worm. The group from the University of Gothenburg has been working with this species. It is one of the few species that is slightly more common in this area. The animal is about 1-2 mm long.
Photo Credit: Natural History Museum, London & Göteborgs Universitet

There is a high demand globally for critical metals, and many countries want to try extracting these sought-after metals from the seabed. An international study, which has discovered large numbers of new species at a depth of 4,000 meters, shows that such mining has less of a negative impact than expected. However, species diversity declined by a third in the tracks of the mining machine. 

In a major research project, marine biologists from several countries have attempted to map life in one of the least explored places on Earth: the deep-sea floor of the Pacific Ocean. 

New marine sponges provide clues about animal evolution

Paco Cárdenas and Julio A. Díaz have described new sponges found off the coast of Spain. The researchers discovered that the sponges produce a substance of potential interest for drug development.
 Photo Credit: Mikael Wallerstedt

A completely new order of marine sponges has been found by researchers at the Museum of Evolution, Uppsala University. The sponge order, named Vilesida, produces substances that could be used in drug development. The same substances support the hypothesis that sponges – and therefore animals – emerged 100 million years earlier than previously thought. 

Sponges are among the most challenging animals in the tree of life to identify and classify. For this reason, many sponges lack a formal name, which is unusual in other animal groups. While the discovery by scientists of new species of marine invertebrates is an everyday occurrence, it is far less common to identify entirely new genera or families. The discovery of a completely new order is rare: only twelve new animal orders have been described in the last five years. 

The mystery of the missing deep ocean carbon fixers

Alyson Santoro Associate Professor Ecology, Evolution, and Marine Biology
Alyson Santoro's research focuses on microbes involved in nutrient cycling in the ocean, especially of the element nitrogen. This research combines laboratory experiments with field observations, and to date has used genomics, transcriptomics, proteomics and stable isotope geochemistry as tools to uncover the activity of microbes in the mesopelagic ocean.
Photo Credit: Courtesy of University of California, Santa Barbara

In a step toward better understanding how the ocean sequesters carbon, new findings from UC Santa Barbara researchers and collaborators challenge the current view of how carbon dioxide is “fixed” in the sunless ocean depths. UCSB microbial oceanographer Alyson Santoro and colleagues, publishing in the journal Nature Geoscience, present results that help to reconcile discrepancies in accounting for nitrogen supply and dissolved inorganic carbon (DIC) fixation at depth.

“Something that we’ve been trying to get a better handle on is how much of the carbon in the ocean is getting fixed,” Santoro said. “The numbers work out now, which is great.”  

Marine Biology: In-Depth Description

Photo Credit: Neeraj Pramanik

Marine Biology is the scientific study of organisms in the ocean and other brackish bodies of water. This discipline encompasses a vast spectrum of life forms, ranging from microscopic picoplankton to the blue whale, the largest animal on Earth. It is an integrative field that combines elements of geology, chemistry, physical oceanography, and biology to understand the physiology, behavior, and ecological roles of marine organisms, as well as their complex interactions with the high-salinity environment.

Counting salmon is a breeze with airborne eDNA

A male Coho salmon, featuring the characteristic hooked nose, returns to spawn from the Oregon Coast.
Photo Credit: NOAA Fisheries

During the annual salmon run last fall, University of Washington researchers pulled salmon DNA out of thin air and used it to estimate the number of fish that passed through the adjacent river. Aden Yincheong Ip, a UW research scientist of marine and environmental affairs, began formulating the driving hypothesis for the study while hiking on the Olympic Peninsula.

“I saw the fish jumping and the water splashing and I started thinking — could we recover their genetic material from the air?,” he said.

The researchers placed air filters at several sites on Issaquah Creek, near the Issaquah Salmon Hatchery in Washington. To their amazement, the filters captured Coho salmon DNA, even 10 to 12 feet from the river. Scientists collect environmental DNA, or eDNA, to identify species living in or passing through an area, but few have attempted to track aquatic species by sampling air.

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. 

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. 

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. 

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.