DNA from discarded whale bones suggests loss of genetic diversity due to commercial whaling

Abandoned whaling stations on South Georgia Island
Photo Credit: Courtesy of Oregon State University

Commercial whaling in the 20th century decimated populations of large whales but also appears to have had a lasting impact on the genetic diversity of today’s surviving whales, new research from Oregon State University shows.

Researchers compared DNA from a collection of whale bones found on beaches near abandoned whaling stations on South Georgia Island in the south Atlantic Ocean to DNA from whales in the present-day population and found strong evidence of loss of maternal DNA lineages among blue and humpback whales.

“A maternal lineage is often associated with an animal’s cultural memories such as feeding and breeding locations that are passed from one generation to the next,” said the study’s lead author, Angela Sremba, who conducted the research as part of her doctoral studies at Oregon State University’s Marine Mammal Institute. “If a maternal lineage is lost, that knowledge is likely also lost.”

The findings were published recently in the Journal of Heredity.

Good news for the world’s rarest marine dolphin?

Māui dolphins.
Photo Credit: University of Auckland/Department of Conservation

The tiny population – only about 54 Māui dolphins remain – lives off the west coast of the North Island.

Once seen from Cook Strait to north of Kaipara, the dolphins’ range is now considerably smaller, with most sightings between Muriwai and Raglan.

The creatures' median age dropped by about a year over the course of a decade, according to research from the University of Auckland – Waipapa Taumata Rau, Oregon State University and University of California Los Angeles.

It could be good news: a population with younger dolphins will produce more calves than an older population, ultimately increasing the population size, which is vital for the dolphins' future.

“The population may be getting younger because individuals born after 2008, the year a marine sanctuary was introduced off the west coast of the North Island, have better chances of survival, since they are less likely to be accidentally caught in fishing nets,” suggests Professor Rochelle Constantine.

However, it’s also possible that older dolphins aren’t living to expected maximum ages of about 20 years.

Biochemistry innovation to aid reef restoration, management

Close-up of coral shows individual polyps.
Photo Credit: Ty Roach

Using an innovative new approach to sampling corals, researchers at the University of Hawaiʻi at Mānoa are now able to create maps of coral biochemistry that reveal with unprecedented detail the distribution of compounds that are integral to the healthy functioning of reefs. The study was published in Communications Biology.

“This work is a major step in understanding the coral holobiont [the coral animal and all of its associated microorganisms], which is critical for reef restoration and management,” said lead author Ty Roach, who conducted this study as a postdoctoral researcher at the Hawaiʻi Institute of Marine Biology (HIMB) in the UH Mānoa School of Ocean and Earth Science and Technology.

Despite occupying a tiny fraction of the ocean, coral reefs are one of the most diverse and productive ecosystems on the planet and provide critical habitats for many species and protection for coastal communities.

Biochemicals, such as amino acids, compounds that affect development and growth, and others that have antibacterial or antioxidant properties, have a direct relation to how resilient coral will be in the face of stressors, such as warmer ocean temperatures and ocean acidification.

Why Are Killer Whales Harassing and Killing Porpoises Without Eating Them

A killer whale in the Salish Sea is observed harassing a porpoise, a behavior that has long perplexed scientists. A study from Wild Orca and UC Davis’ SeaDoc Society investigates what may be behind it.
 Photo Credit: Courtesy Wild Orca

For decades, fish-eating killer whales in the Pacific Northwest have been observed harassing and even killing porpoises without consuming them — a perplexing behavior that has long intrigued scientists.

A study published today in Marine Mammal Science, co-led by Deborah Giles of Wild Orca and Sarah Teman of the SeaDoc Society, a program of the UC Davis School of Veterinary Medicine, looked at more than 60 years of recorded interactions between Southern Resident killer whales and porpoises in the Salish Sea to better understand why they exhibit this behavior.

Southern Resident killer whales are an endangered population, numbering only 75 individuals. Their survival is intimately tied to the fortunes of chinook salmon — also an endangered species. Without enough chinook salmon, these whales are in danger of extinction.

“I am frequently asked, why don’t the Southern Residents just eat seals or porpoises instead?” said Giles. “It's because fish-eating killer whales have a completely different ecology and culture from orcas that eat marine mammals — even though the two populations live in the same waters. So we must conclude that their interactions with porpoises serve a different purpose, but this purpose has only been speculation until now.”

Atlantic walrus more vulnerable than ever to Artic warming

Photo Credit: Rod Long

Past cycles of climate change, along with human exploitation, have led to only small and isolated stocks of Atlantic walrus remaining. The current population is at high risk of the same issues affecting them severely, according to a new study led by Lund University in Sweden.

Today, the last remaining stocks of Atlantic walrus are more at danger than ever, due to a combination of Arctic warming and a long history of devastating human exploitation. Rising global temperatures are significantly impacting Arctic marine ecosystems and their inhabitants. However, little is known about exactly how this combination of stress factors will impact Arctic species.

Now, researchers have examined how walrus coped with past cycles of climate change. Using breakthroughs in ancient genomics, the team was able to extract, sequence and interpret ancient genetic information contained in teeth and bone that survive well in the Arctic’s frozen archaeological sites. These DNA results were integrated with modern genetic samples, enabling them to reconstruct how the genetic diversity of Atlantic walrus had changed under earlier cycles of global warming.

Gravity foundations: A marine-friendly future for wind turbines

Photo Credit: Tom Swinnen

Gravity-base structures may offer a porpoise and dolphin-friendly construction alternative to traditional pile-driven wind turbine foundations, new research suggests.

Marine scientists from Newcastle University investigated short- and long-term impacts of this new wind turbine installation method on cetaceans off Blyth, Northumberland. The response of dolphins and harbor porpoises was investigated using cetacean echolocation recorders over a three-year period, covering one year before, during and after the installation.

The findings revealed that wind turbine installation using gravity-base foundations had no long-term effects on the occurrence of dolphins or porpoises.

“Our findings are important in light of the global expansion of offshore wind farms and the need to find installation methods that have less impact to the marine environment”, says lead author and master’s graduate Kelsey Potlock. “These findings are promising for conservationists, marine environmental managers, and for the future of offshore renewable energy.”

A marine mystery: finding the link between climate change and sea sponge loss

The latest findings suggest that thermal stress disturbs sponge-microbes symbiosis, which likely causes the sponge to die.
Photo Credit: Heidi Luter.

Microbes could hold the key to explaining how climate change affects sea sponges, warn scientists from UNSW Sydney. 

Sea sponges are essential to marine ecosystems. They play critical roles in the ocean, as they provide shelter and food to a plethora of marine creatures, recycle nutrients by filtering thousands of liters of sea water daily, and are hosts to microbes that may be the key to some of the most pressing medical challenges we face today. 

Now, scientists from UNSW have discovered that when a tropical sea sponge is exposed to warmer temperatures, it loses an important microbe, which could explain why the sponge tissue dies.  

The latest study, published in ISME Communications, has revealed that by exposing sea sponges to a temperature increase of 3°C, one essential microbe abandons the sponge, potentially causing tissue poisoning.   

The collaboration between researchers from UNSW, Heidi Luter from the Australian Institute of Marine Science and James Bell from the Victoria University of Wellington, has added an important piece to the puzzle on the impact of climate change on sponge populations around the world. 

Twenty species of sea lettuce found along the coasts

Sea lettuce, which is a type of green alga, grows along the coasts and is interesting as potential food source. A new survey shows that there are 20 different species of sea lettuce along the Swedish coast.
Photo Credit: Sophie Steinhagen

The number of species of the green alga sea lettuce in the Baltic Sea region and Skagerak and is much larger than what was previously known. Researchers at the University of Gothenburg have surveyed 10,000 kilometers of coast and found twenty species of sea lettuce.

Green macroalgae of the genus Ulva, also known as sea lettuce, are almost ubiquitous in the wider Baltic Sea region and can be found from the Atlantic waters all the way up to the Bay of Bothnia in the Baltic Sea. Sea lettuce reproduces easily and grows quickly, which makes it interesting for an expanding aquaculture industry. Research is ongoing both in Sweden and abroad for utilizing sea lettuce in the food industry and for different biochemical applications.

There are multiple species, but until now it has not been known how many there are and previously only a handful had been identified.

When Water Temperatures Change, the Molecular Motors of Cephalopods Do Too

Doryteuthis opalescens, otherwise known as market squid, helped UC San Diego researchers discover the animals’ ability to recode RNA in cells to improve their functioning in different water temperatures.
 Credit: UC San Diego/Sea Grant California.

Cephalopods are a large family of marine animals that includes octopuses, cuttlefish and squid. They live in every ocean, from warm, shallow tropical waters to near-freezing, abyssal depths. More remarkably, report two scientists at University of California San Diego in a new study, at least some cephalopods possess the ability to recode protein motors within cells to adapt “on the fly” to different water temperatures.    

Writing in the June 8, 2023 edition of Cell, first author Kavita J. Rangan, PhD, a postdoctoral researcher in the lab of senior author Samara L. Reck-Peterson, PhD, a professor in the departments of Cellular and Molecular Medicine at UC San Diego School of Medicine and Cell and Developmental Biology at UC San Diego and an Investigator of the Howard Hughes Medical Institute, describe how opalescent inshore squid (Doryteuthis opalescens) employ RNA recoding to change amino acids at the protein level, improving the function of molecular motors that carry out diverse functions within cells in colder waters.

RNA recoding allows organisms to edit genetic information from the genomic blueprint to create new proteins. The process is rare in humans but is common in soft-bodied cephalopods, such as D. opalescens, which makes seasonal spawning migrations along the coast of San Diego. 

Coral disease tripled in the last 25 years. Three-quarters will likely be diseased by next century

Warming ocean temperatures are linked to an increase in coral disease prevalence.
Photo Credit: Lisa

Research suggests warming temperatures will see nearly 80 per cent of coral in reefs diseased in the next 80 years.

Deadly coral disease is spreading as global temperatures warm, and it’s likely to become endemic to reefs the world over by the next century, according to new research.

The study, published today in Ecology Letters, shows the extent coral health will suffer from climate change, which threatens to wipe out entire reef habitats and devastate coastal communities.

For the meta-analysis, researchers from UNSW Sydney analyzed 108 studies of coral health where coral reefs were surveyed for disease symptoms. They then linked the disease surveys to ocean sea surface temperature records to understand how climate change – specifically ocean warming – has influenced coral disease prevalence worldwide and performed modelling to forecast disease under future warming scenarios.

They found coral disease increased with ocean temperatures over time, tripling over the past 25 years to 9.92 per cent globally. Their modelling also predicts disease prevalence can increase to 76.8 per cent in 2100 if temperatures continue to rise on the same trajectory – the most conservative worst-case scenario.

Sea butterfly life cycle threatened by climate change

An adult sea butterfly, a tiny free swimming sea snail.
Photo Credit: Victoria Peck – British Antarctic Survey

Shelled pteropods, commonly known as sea butterflies, are increasingly exposed to ocean changes, but some species are more vulnerable to this threat. In a new study, published this month in the journal Frontiers in Marine Science, British Antarctic Survey (BAS) scientists examining pteropod life cycles in the Southern Ocean have found that some species might be more vulnerable to this threat due to different timings of their life cycle.

Sea butterflies are tiny, free-swimming sea snails, which are an important part of the marine ecosystem. They are also vulnerable to climate change as their shells are sensitive to ocean acidification. Now, a team of researchers led by BAS has examined the life cycles of two free-swimming sea snail species. They found that one is less vulnerable to changes in the Southern Ocean than the other, which could affect the sea snails on a population level and in turn impact the marine ecosystem.

The world’s oceans absorb approximately a quarter of all carbon dioxide (CO2) emissions. During absorption, CO2 reacts with seawater and oceanic pH levels fall. This is known as ocean acidification and results in lower carbon ion concentrations. Certain ocean inhabitants use carbon ions to build and sustain their shells. Pteropods, which are important components of the marine ecosystem, are among them.

Sea anemone’s sweet efforts help reef ecosystems flourish

KAUST researchers have discovered how corals can thrive in nutrient-depleted oceans. Their study shows how sea anemones are able to recycle the essential nutrient Nitrogen.
Photo Credit: Morgan Bennett-Smith / King Abdullah University of Science and Technology

Tropical oceans are known for being low in nutrients, yet they support incredibly diverse and thriving reef ecosystems created by symbiotic cnidarians such as corals and anemones. This intriguing contradiction, referred to as the Darwin Paradox, has fascinated scientists ever since Charles Darwin first described it in 1842.

A group of researchers from KAUST conducted a study on sea anemones called Aiptasia. They found out that Aiptasia uses the sugar it gets from its partners to recycle waste in its body and survive in places where there are not many nutrients.

According to Guoxin Cui, a research scientist who worked on the project with Manuel Aranda, many studies in the past have tried to figure out where the limited nutrients in the ocean come from, especially nitrogen which is rare.

Guoxin Cui explains that some studies about coral have suggested that the partnership between coral and algae creates areas with lots of nutrients. But until now, researchers didn't fully understand how these organisms were able to create such large ecosystems.

Like ancient mariners, ancestors of Prochlorococcus microbes rode out to sea on exoskeleton particles

New research suggests the Prochlorococcus microbe’s ancient coastal ancestors colonized the ocean by rafting out on chitin particles.
Illustration Credit: Jose-Luis Olivares/MIT
(CC BY-NC-ND 3.0)

Throughout the ocean, billions upon billions of plant-like microbes make up an invisible floating forest. As they drift, the tiny organisms use sunlight to suck up carbon dioxide from the atmosphere. Collectively, these photosynthesizing plankton, or phytoplankton, absorb almost as much CO2 as the world’s terrestrial forests. A measurable fraction of their carbon-capturing muscle comes from Prochlorococcus — an emerald-tinged free-floater that is the most abundant phytoplankton in the oceans today.

But Prochlorococcus didn’t always inhabit open waters. Ancestors of the microbe likely stuck closer to the coasts, where nutrients were plentiful and organisms survived in communal microbial mats on the seafloor. How then did descendants of these coastal dwellers end up as the photosynthesizing powerhouses of the open oceans today?

MIT scientists believe that rafting was the key. In a new study they propose that ancestors of Prochlorococcus acquired an ability to latch onto chitin — the degraded particles of ancient exoskeletons. The microbes hitched a ride on passing flakes, using the particles as rafts to venture further out to sea. These chitin rafts may have also provided essential nutrients, fueling and sustaining the microbes along their journey.

Singing humpback whales respond to wind noise, but not boats

UQ researchers recorded humpback whales off the Queensland coast for the study.
Photo Credit: Mike Doherty

A University of Queensland study has found humpback whales sing louder when the wind is noisy, but don’t have the same reaction to boat engines.

Research lead Dr Elisa Girola from UQ’s Faculty of Science said this quirk of whale evolution could have consequences for breeding and behavior.

“Humpback whales evolved over millions of years with noise from natural sources but noise from man-made vessels is foreign to their instincts,” Dr Girola said.

“It’s a surprising finding given engine noise has a similar frequency range to the wind.

“It’s possible the whales are picking out other differences such as wind noise being broadband and the same over large areas, while vessel noise is generated by a single-point source with specific peaks in frequency.

“We don’t know yet if this lack of response to boat noise is making whales communicate less effectively or making breeding practices more difficult.

Researchers Track Endangered Nassau Grouper Eggs with Underwater Microscope

Nassau grouper spawning aggregation off Little Cayman, Cayman Islands. Credit: Jason Belport
 Photo Credit: Grouper Moon Project

Scripps Oceanography researchers show fertilized eggs stayed local, but in some years drifted to nearby islands.

Each winter off the western tip of the Caribbean island of Little Cayman, thousands of endangered Nassau grouper gather to spawn under the light of the full moon. The fish pack the coral reef and when the ritual begins individual females dash out of the fray straight up towards the surface with multiple males in pursuit. During these vertical bursts, females release their eggs and the males jostle to fertilize them, leaving milky plumes drifting in the moonlit sea.  

These precious fertilized eggs are the engine that powers the still-limited recovery of this critically endangered species that is a key reef predator and was once the target of an important fishery in the Caribbean. But where do these eggs end up after they’re cast adrift? 

Scientists at the University of California San Diego’s Scripps Institution of Oceanography, Oregon State University (OSU), and the conservation organization Reef Environmental Education Foundation (REEF) teamed up with the Cayman Islands Department of the Environment to address this question by physically tracking clouds of tiny, transparent Nassau grouper eggs through the night with an underwater microscope developed by Scripps Oceanography Marine Physical Laboratory scientist Jules Jaffe. 

Fish thought to help reefs have poop that’s deadly to corals

A coral-eating butterflyfish on a Moorea reef in July 2019.
Photo Credit: Carsten Grupstra

Feces from fish that are typically thought to promote healthy reefs can damage and, in some cases, kill corals, according to a recent study by Rice University marine biologists.

Until recently, fish that consume algae and detritus — grazers — were thought to keep reefs healthy, and fish that eat coral — corallivores — were thought to weaken reef structures. The researchers found high levels of coral pathogens in grazer feces and high levels of beneficial bacteria in corallivore feces, which they say could act like a “coral probiotic.”

“Corallivorous fish are generally regarded as harmful because they bite the corals,” said Carsten Grupstra, a former graduate student at Rice and lead author of the open-access study in Frontiers in Marine Science. “But it turns out that this doesn’t tell the whole story.”

Massive Caribbean sea urchin die-off caused by parasite

In a study led by Cornell microbiology professor Ian Hewson, scientists have discovered that a parasite is behind a severe die-off of long-spined sea urchins across the Caribbean Sea, which has had devastating consequences for coral reefs and surrounding marine ecosystems.

Video Credit: Noël Heaney/Cornell University 

Scientists have discovered that a parasite is behind a severe die-off of long-spined sea urchins across the Caribbean Sea, which has had devastating consequences for coral reefs and surrounding marine ecosystems.

The long-spined sea urchins (Diadema antillarum) serve as vital herbivores that graze on algae, which if left unchecked will outcompete corals for resources and space and blanket them, block light and kill them. By feeding on algae, the sea urchins are essential to maintaining coral health and balance in the marine ecosystem.

Diadema mortalities were first reported in St. Thomas in the U.S. Virgin Islands in late January 2022. By late March, the condition was found across the Lesser Antilles, Jamaica and the Mexican Caribbean. And by June of last year, it had been detected in most of the Greater Antilles, Florida and Curacao.

Prior to an experiment designed to verify the source of infections, a healthy sea urchin was swabbed to ensure it had never been exposed to the ciliate parasite.

Scientists have been trying to identify the cause of the mysterious illness, which has led to declines of between 85% and 95% compared to pre-mortality numbers in affected areas. When sea urchins die, they lose their spines and detach from their anchors.

Juvenile black rockfish affected by marine heat wave but not always for the worse, research shows

A juvenile black rockfish
Photo Credit: Will Fennie

Larvae produced by black rockfish, a linchpin of the West Coast commercial fishing industry for the past eight decades, fared better during two recent years of unusually high ocean temperatures than had been feared, new research by Oregon State University shows.

“The study is important for gauging the conditions and making management plans that will affect the species’ survival as the ocean experiences increasing variability because of climate change,” said Will Fennie, the study’s lead author.

Findings were published in Nature’s Scientific Reports.

Rockfish, a diverse genus with many species, are a group of ecologically as well as economically important fishes found from Baja California to British Columbia.

They are known for lifespans that can reach triple digits, an ability to produce prodigious numbers of offspring and variable survival during their early life stages, during which they are highly sensitive to environmental conditions.

Three newly discovered sea worms that glow in the dark

 Polycirrus onibi, a newly discovered marine worm that glows in the dark was named after a creature from Japanese folklore.
Photo Credit: Naoto Jimi / Nagoya University

A research group from Nagoya University in central Japan has discovered three new species of bioluminescent polycirrus worms from different parts of Japan. Usually found in shallow water, polycirrus are small worms, known for their bioluminescence. The researchers named one of their discoveries after a ghostly yokai, a creature in Japanese folklore; another after a lantern yokai; and the other after an influential Japanese marine biologist. They published their findings in the journal Royal Society Open Science. 

Scientists have studied only a small fraction of the more than 7,000 species of luminescent organisms in the world. Research remains limited to certain species because of the existence of specimens that are difficult to classify into species. Without correct identification of the species, comparisons of different results are of limited use.  

Naoto Jimi (he/him) and Special Assistant Professor Manabu Bessho-Uehara (he/him) at Nagoya University’s Graduate School of Science, led a research group with members from AIST, Olympus Corporation, and Japan Underwater Films Corporation, that organized Polycirrus according to their diversity. They discovered three new species, all of which emit blue-violet light.   

How whale shark rhodopsin evolved to see, in the deep blue sea!

Whale shark
Photo Credit: Mitsumasa Koyanagi, OMU

A new study reveals that the photoreceptor rhodopsin of whale sharks (Rhincodon typus), pictured here, evolved to improve sight for the low-light low-temperature deep-sea environment in a unique way.

A research group including Professors Mitsumasa Koyanagi and Akihisa Terakita of the Osaka Metropolitan University Graduate School of Science has investigated both the genetic information and structure of the photoreceptor rhodopsin, responsible for detecting dim light, of whale sharks to investigate how they can see in the dim light at extreme depths. The research group compared the whale sharks to zebra sharks, which are considered their closest relative, and brown-banded bamboo sharks, which are in the same group: the order orectolobiformes—commonly known as carpet sharks.

“This research used genetic information and molecular biological techniques to achieve stunning results—without harming whale sharks’ or their biology. Our research approach is to use these techniques to provide clues that reveal the mysteries of how these organisms live,” explained Professor Koyanagi. “The beautiful part is that it even works for species where information is limited, such as large or wild animals that are difficult to observe or follow in their natural habitat.”