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

Monday, June 19, 2023

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.”

Wednesday, June 14, 2023

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. 

Monday, June 12, 2023

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.

Thursday, June 8, 2023

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. 

Wednesday, June 7, 2023

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.

Tuesday, May 16, 2023

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.

Monday, May 15, 2023

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.

Thursday, May 11, 2023

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.

Wednesday, May 10, 2023

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. 

Monday, May 1, 2023

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.”

Wednesday, April 19, 2023

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.

Thursday, March 30, 2023

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.

Wednesday, March 29, 2023

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.”

Monday, March 27, 2023

With fewer salmon to eat, Southern Resident killer whales spend less time in the San Juan Islands

killer whales
Photo Credit: Michelle Klampe

As a key food supply declines, the endangered population of Southern Resident killer whales, known to frequent the Salish Sea off the coasts of Washington and British Columbia, is spending far less time in that region, a new study shows.

The Salish Sea around the San Juan Islands has traditionally been a hotspot for the whales. The Southern Residents would spend the summer months feeding on Chinook salmon, much of which belonged to the Fraser River stock that passes through the islands on its way to spawning grounds upriver.

But 17 years of whale sighting data shows that as the Fraser River Chinook salmon population dropped, the time spent by the Southern Residents around the San Juan Islands also declined ­– by more than 75%, said Joshua Stewart, an assistant professor with Oregon State University’s Marine Mammal Institute and the study’s lead author.

The findings were just published in the journal Marine Mammal Science. Co-authors of the paper are Jane Cogan, an independent researcher in Friday Harbor, Washington; John Durban, a professor with MMI who is also affiliated with the nonprofit SeaLife Response, Rehabilitation and Research (SR3); Holly Fearnback of SR3; David Ellifrit, Mark Malleson and Ken Balcomb of the nonprofit Center for Whale Research; and Melisa Pinnow of San Juan Orcas, a website dedicated to identification of individual orcas.

Tuesday, March 21, 2023

Recovery of endangered sunflower sea stars may play key role in restoring devastated submarine forests

Sunflower sea stars, such as the one that appears in the foreground, could help keep purple sea urchins in check, according to new research from Florida State University Assistant Professor Daniel Okamoto and colleagues published in Proceedings of the Royal Society B.
Photo Credit: Lynn Lee

Scientists working to understand the decimation of kelp forests on the Pacific Coast have found that the endangered sunflower sea star plays a vital role in maintaining the region’s ecological balance and that sea star recovery efforts could potentially help restore kelp forests as well.

The multi-institution team, which includes Florida State University Assistant Professor of Biological Science Daniel Okamoto, has published a new study showing that a healthy sea star population could keep purple sea urchins — which have contributed to the destruction of kelp forests — in check.

Their work is published in the Proceedings of the Royal Society B.

“Our work is focused on understanding what factors maintain healthy kelp forests as well as healthy urchin populations,” Okamoto said. “That is, what scenarios lead to collapse versus coexistence of these important species.”

Friday, March 17, 2023

New Study Provides First Comprehensive Look at Oxygen Loss on Coral Reefs

Coral reefs at a study site off Taiping Island, South China Sea.
Photo Credit: Yi Bei Liang

Scripps Oceanography scientists and collaborators provide first-of-its-kind assessment of hypoxia, or low oxygen levels, across 32 coral reef sites around the world

A new study is providing an unprecedented examination of oxygen loss on coral reefs around the globe under ocean warming. Led by researchers at UC San Diego’s Scripps Institution of Oceanography and a large team of national and international colleagues, the study captures the current state of hypoxia—or low oxygen levels—at 32 different sites, and reveals that hypoxia is already pervasive on many reefs.

The overall decline of oxygen content across the world’s oceans and coastal waters—a process known as ocean deoxygenation—has been well documented, but hypoxia on coral reefs has been relatively underexplored. Oxygen loss in the ocean is predicted to threaten marine ecosystems globally, though more research is needed to better understand the biological impacts on tropical corals and coral reefs.

The study, published March 16 in the journal Nature Climate Change, is the first to document oxygen conditions on coral reef ecosystems at this scale.

Wednesday, March 15, 2023

“Denoising” a Noisy Ocean

Study lead author Ella Kim (pink helmet) helps deploy a HARP instrument package.
Photo Credit: Ana Širović

Come mating season, fishes off the California coast sing songs of love in the evenings and before sunrise. They vocalize not so much as lone crooners but in choruses, in some cases loud enough to be heard from land. It’s a technique of romance shared by frogs, insects, whales, and other animals when the time is right.

For most of these vocal arrangements, the choruses are low-frequency. They’re hard to distinguish from the sounds of ships passing in the night among others.

Biologists, however, have long been interested in listening in on them in the name of understanding fish behavior toward an ultimate goal: They can help preserve fish populations and ocean health by identifying spawning seasons to inform fisheries management.

Now scientists at Scripps Institution of Oceanography at UC San Diego and colleagues have developed a way for computers to sift through sounds collected by field acoustic recording packages known as HARPs and process them faster than even the most trained human analysts. The method represents a major advance in the field of signal processing with uses beyond marine environments.

Monday, March 13, 2023

Stanford study reveals why the world's largest whales needed to be so big

Minke whales in Antarctica were studied by researchers using instrumented tags that can measure various aspects of their feeding activity.
Image Credit: Duke Marine Robotics and Remote Sensing.
This research was conducted under National Marine Fisheries Service permit #23095

Scientists studied a unique group of Antarctic minke whales and found that these gigantic mammals actually represent the smallest possible body size required for their style of feeding. The findings could inform which whale species are more vulnerable to future climate change impacts, like shifting food sources.

The largest animals to ever live owe their enormous size to feeding on the tiniest creatures in the sea, but their survival requires a minimum body size, Stanford-led research has found.

Published March 13 in Nature Ecology & Evolution, the study focuses on the “rorqual whales,” a lineage of filter feeders that includes the blue whale, the largest animal of all time. The group is characterized by a lunging maneuver where individuals engulf an enormous amount of water along with their prey, which they then strain through fringed structures at the roof of their mouth.

By examining the smallest living species in this group – the Antarctic minke whale – the authors found that individuals need to grow to at least 4.5 meters (approximately 15 feet, or weighing 1-2 tons), the length of weaned minke juveniles, in order to eat enough food to survive.

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