Deep and extreme: Microbes thrive in transition

KING ABDULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY (KAUST)

Research News

 

IMAGE: A RICH COMMUNITY OF PREVIOUSLY UNDESCRIBED MICROBES EXISTS IN THE TRANSITION LAYER BETWEEN THE DEEP WATER OF THE RED SEA AND THE SURFACE OF BRINE POOLS, SUCH AS THAT PICTURED... view more 

CREDIT: © CALADAN OCEANIC LLC

A diverse microbial community has adapted to an extremely salty environment deep in the Red Sea. The microbes, many unknown to science, occupy a one-meter-thick area overlying the Suakin Deep, an expansive 80-meter-deep brine lake, 2,771 meters below the central Red Sea. The chemical properties of this thin "brine-seawater interface," along with the composition of microbial communities, change surprisingly rapidly across a sharp gradient.

"Our study sheds light on how microorganisms in the Suakin Deep's brine-seawater interface make an oasis of life in the desert of the deep Red Sea," says microbial ecologist Daniele Daffonchio, who led the study. Daffonchio and his colleagues at KAUST, with collaborators in Germany and Spain, found that microbial cell densities are more than double in this interface than in normal deep Red Sea water and the brine below.

The Suakin Deep is one of around 25 deep brine lakes in the Red Sea. Few studies have analyzed the thin brine-seawater interface above it, and none have taken into account how its properties change from top to bottom.

Daffonchio's team used a sampler called a Niskin Rosette to analyze water every nine centimeters within this interface. This cylindrical apparatus holds 23 identical 90-centimeter-long 10-liter bottles, along with a detector that measures salinity, temperature and depth.

The sampler was deployed by KAUST's research vessel with the bottles open until the detector signaled that the apparatus had reached the Suakin Deep's brine-seawater interface. The bottles were then filled with interface water and remotely shut, and the apparatus then returned to the ship. This way, the water column in the bottles represented most of the water column in the interface. One-liter fractions of water, each corresponding to a different depth in the actual interface, were analyzed for their chemical and microbial contents.

The team found many types of microbial communities, which changed with variations in oxygen and salinity within the water column.

"Many of the microbes were new, with their closest relatives coming from hydrothermal vents at the bottom of the sea and from subsurface sediments," says environmental microbiologist Grégoire Michoud, the study's first author.

The team sequenced the genome of a microbe they called Candidatus Scalindua arabica, which was concentrated within a 20-centimeter-layer in the middle of the brine-seawater interface. The metabolic processes conducted by this and other microbes suggest this transition zone is a critical niche for nitrogen cycling.

Oceanic brine pools could be similar to extraterrestrial environments like the saline ocean that is expected to exist under the surface of Jupiter's satellite Europa. "Knowledge of the microbial networks in extreme Earth environments could help us hypothesize how lifeforms on extraterrestrial bodies thrive and function," explains Daffonchio. "These microbes could also harbor enzymes and other properties that could be useful in medical and biotechnology applications."

The team plans to continue analyzing other Red Sea brine pools and their brine-seawater interfaces to examine how different conditions affect microbial content.

Plasma jets reveal magnetic fields far, far away

Radio telescope images enable a new way to study magnetic fields in galaxy clusters millions of light years away

NAGOYA UNIVERSITY

Research News

 

IMAGE: A BLACK HOLE (MARKED BY THE RED X) AT THE CENTRE OF GALAXY MRC 0600-399 EMITS A JET OF PARTICLES THAT BENDS INTO A "DOUBLE-SCYTHE " T-SHAPE THAT FOLLOWS THE MAGNETIC... view more 

CREDIT: MODIFIED FROM CHIBUEZE, SAKEMI, OHMURA ET AL. (2021) NATURE FIG. 1(B)

For the first time, researchers have observed plasma jets interacting with magnetic fields in a massive galaxy cluster 600 million light years away, thanks to the help of radio telescopes and supercomputer simulations. The findings, published in the journal Nature, can help clarify how such galaxy clusters evolve.

Galaxy clusters can contain up to thousands of galaxies bound together by gravity. Abell 3376 is a huge cluster forming as a result of a violent collision between two sub-clusters of galaxies. Very little is known about the magnetic fields that exist within this and similar galaxy clusters.

"It is generally difficult to directly examine the structure of intracluster magnetic fields," says Nagoya University astrophysicist Tsutomu Takeuchi, who was involved in the research. "Our results clearly demonstrate how long-wavelength radio observations can help explore this interaction."

An international team of scientists have been using the MeerKAT radio telescope in the Northern Cape of South Africa to learn more about Abell 3376's huge magnetic fields. One of the telescope's very high-resolution images revealed something unexpected: plasma jets emitted by a supermassive black hole in the cluster bend to form a unique T-shape as they extend outwards for distances as far as 326,156 light years away. The black hole is in galaxy MRC 0600-399, which is near the centre of Abell 3376.

The team combined their MeerKAT radio telescope data with X-ray data from the European Space Agency's space telescope XXM-Newton to find that the plasma jet bend occurs at the boundary of the subcluster in which MRC 0600-399 exists.

"This told us that the plasma jets from MRC 0600-399 were interacting with something in the heated gas, called the intracluster medium, that exists between the galaxies within Abell 3376," explains Takeuchi.

To figure out what was happening, the team conducted 3D 'magnetohydrodynamic' simulations using the world's most powerful supercomputer in the field of astronomical calculations, ATERUI II, located at the National Astronomical Observatory of Japan.

The simulations showed that the jet streams emitted by MRC 0600-399's black hole eventually reach and interact with magnetic fields at the border of the galaxy subcluster. The jet stream compresses the magnetic field lines and moves along them, forming the characteristic T-shape.

"This is the first discovery of an interaction between cluster galaxy plasma jets and intracluster magnetic fields," says Takeuchi.

An international team has just begun construction of what is planned to be the world's largest radio telescope, called the Square Kilometre Array (SKA).

"New facilities like the SKA are expected to reveal the roles and origins of cosmic magnetism and even to help us understand how the universe evolved," says Takeuchi. "Our study is a good example of the power of radio observation, one of the last frontiers in astronomy."

###

The study, "Jets from MRC 0600-399 bent by magnetic fields in the cluster Abell 3376," was published in the journal Nature on May 5, 2021, at https://www.nature.com/articles/s41586-021-03434-1.

About Nagoya University, Japan

Nagoya University has a history of about 150 years, with its roots in a temporary medical school and hospital established in 1871, and was formally instituted as the last Imperial University of Japan in 1939. Although modest in size compared to the largest universities in Japan, Nagoya University has been pursuing excellence since its founding. Six of the 18 Japanese Nobel Prize-winners since 2000 did all or part of their Nobel Prize-winning work at Nagoya University: four in Physics - Toshihide Maskawa and Makoto Kobayashi in 2008, and Isamu Akasaki and Hiroshi Amano in 2014; and two in Chemistry - Ryoji Noyori in 2001 and Osamu Shimomura in 2008. In mathematics, Shigefumi Mori did his Fields Medal-winning work at the University. A number of other important discoveries have also been made at the University, including the Okazaki DNA Fragments by Reiji and Tsuneko Okazaki in the 1960s; and depletion forces by Sho Asakura and Fumio Oosawa in 1954.

Website: http://en.nagoya-u.ac.jp/

AUSTRALIA

Endangered wallaby population bounces back after ferals fenced out

UNIVERSITY OF NEW SOUTH WALES

Research News

 

IMAGE: A BRIDLED NAILTAIL WALLABY JOEY IN ITS MOTHER'S POUCH. view more 

CREDIT: ALEXANDRA ROSS/UNSW SYDNEY

A population of bridled nailtail wallabies in Queensland has been brought back from the brink of extinction after conservation scientists led by UNSW Sydney successfully trialled an intervention technique never before used on land-based mammals.

Using a method known as 'headstarting', the researchers rounded up bridled nailtail wallabies under a certain size and placed them within a protected area where they could live until adulthood without the threat of their main predators - feral cats - before being released back into the wild.

In an article published today in Current Biology, the scientists describe how they decided on the strategy to protect only the juvenile wallabies from feral cats in Avocet Nature Refuge, south of Emerald in central Queensland, where they numbered just 16 in 2015.

Article lead author Alexandra Ross says juvenile wallabies under 3kg - or smaller than a rugby football - are easy prey for feral cats.

"Previous studies have shown that more than half of these young bridled nailtail wallabies were killed by feral cats before they could reach adulthood," Ms Ross says.

"But when you look at the numbers of adults, the survival rate goes up to 80 per cent - which shows that size is a good predictor of survival.

"So we figured if we can just get them through that tough period - when they're still little and an easy size for a cat to prey on - by putting them in feral-free protected areas, then we could make a positive difference to the population numbers."

The results more than confirmed the scientists' hunches. Of the 56 bridled nailtail wallabies that were raised within the headstart enclosure between 2015 and 2018, 89 per cent survived to be large enough to be let back into the wild. The 11 per cent that didn't make it included one that needed to be euthanised due to injury, two found dead from accidents or unknown causes and four killed by birds of prey.

LESS EXPENSIVE, MORE EFFECTIVE

Professor Mike Letnic, a co-author on the article, says headstarting is a cost-effective intervention when compared to other more complex strategies involving the creation of large nature reserves after complete eradication of feral animals, like the one created in Sturt National Park in 2019.

"Aly's [Ms Ross's] headstarting project involved fencing off an area about 10 hectares which was big enough to hold about 30 or 40 wallabies at a time," Prof. Letnic says.

"We're basically growing them from football size to medicine ball size before releasing them back into the wild, which can take anywhere from a few months to a year.

"For the most part they're fending for themselves in the headstart exclosure just like they do in the wild, except without the threat of feral animals. But they're not completely protected - they can still get eaten by eagles which means there is still some predator recognition."

Double the size

Ms Ross says the population of the bridled nailtail wallabies more than doubled following the three years of headstarting in Avocet Nature Refuge, which is the largest increase that had been observed in this particular population since monitoring began in 2011.

"Before we started the headstarting strategy, we estimated the core Avocet population at 16 individuals. When we did a recount in 2018 after three years of gradually releasing headstarted wallabies that had reached the right size, the estimate of the total population of bridled nailtail wallabies - both inside and outside the headstarting exclosure - was 47.

"This clearly demonstrates the effectiveness of the headstart exclosure as a conservation strategy."

Worryingly, when Ms Ross and her fellow researchers crunched the numbers on how the population would fare without, or with varying lengths of headstarting scenarios - none, five years, 10 years, 20 years and 50 years - the projections found that extinction resulted once headstarting ceased - within a timeframe of two to 52 years.

"What this tells us is that until we find a way to eliminate feral cats in the wild, headstarting may be the only way to keep this population at a sustainable level."

But the team's implementation of the first headstarting project for a land-based mammal raises new hope for other potential endangered species in Australia - and potentially around the globe - where size of young may be factor in population survival.

"One of the great things about headstarting is it's relatively cheap, doesn't interfere too much with animals' awareness of predators, and can get good results in a short time," Ms Ross says.

"And there are plenty of other mammal species around the world that could benefit. Any species that is particularly vulnerable in the early life stage could potentially thrive under a headstarting strategy."

Up until now, headstarting has been used with some success with birds, fish, reptiles, and seals, and there's no reason why it shouldn't also be implemented for terrestrial mammals, Ms Ross and Prof. Letnic argue.

PREDATOR AWARENESS

Prof Letnic says one of the drawbacks with separating animals for longer periods in feral-free enclosures is that they unlearn their fear of predators on the outside. "After only a few years of being in a protected zone, evolution kicks in and animals start developing new ways to compete with one another. They tend to become bolder in an attempt to be first to the food. If they were then to be released back into the wild among feral animals, the bold ones end up getting eaten because they've lost that cautious awareness of predators."

However, Ms Ross believes that headstarting could avoid this problem, as animals are only separated from predators for a few months or a year at the most. There is also minimal human interaction and the animals are still preyed upon by their natural predators, like eagles and snakes, ensuring they retain some predator awareness.

Her next study will examine the behaviour of the bridled nailtail wallabies once released from the headstarting exclosure and the length of time it took for them to fully integrate back into the wild.

BRIDLED NAILTAIL WALLABY - VITAL STATS

The bridled nailtail wallaby is a small macropod that grows up to a metre in length, half of which is the tail. It takes its name from the white 'bridle' line that runs down the back of the neck and shoulders and a tail spur about 3 to 6mm in length.

Bridled nailtail wallabies live mostly on succulent grasses, can grow to a weight of 8kg, with an average life-span of around six years in the wild.

Once the most common macropods at the time of European settlement, these nocturnal animals are now in critically low numbers in the wild after being hunted extensively for their fur in the early 1900s, and more recently, preyed upon by feral cats and foxes.

The species was even believed extinct from 1937 until 1973. It was only when a fencing contractor reported he'd seen a population of the wallabies living on a property near Dingo, Queensland - after reading about it in an article published in Woman's Day - that the species was rediscovered.

After the Queensland Parks and Wildlife Service confirmed its existence, the property near Dingo eventually became a nature reserve to ensure its ongoing survival.

There are believed to be only 500 of the animals living in the wild, and more than 2000 in captivity.

###

UH OH

Oregon State University research shows two invasive beachgrasses are hybridizing

OREGON STATE UNIVERSITY

Research News

 

IMAGE: ALL THREE AMMOPHILA BEACHGRASSES, BOTH PARENT SPECIES AND A RECENTLY IDENTIFIED HYBRID, OCCUR AT SUNSET BEACH, OREGON. view more 

CREDIT: OREGON STATE UNIVERSITY

CORVALLIS, Ore. - Two species of sand-stabilizing beachgrasses introduced to the Pacific Northwest starting in the early 1900s are hybridizing, raising new questions about impacts to the coastal ecosystems the non-native plants have been engineering for more than a century.

Researchers in the Oregon State University College of Science identified the hybrid in a paper published in Ecosphere.

In addition to their ecological implications, the findings are important in the context of coastal vulnerability to the effects of climate change, including increasing danger from flooding and erosion from storms and rising water.

An OSU collaboration led by integrative biology Ph.D. candidate Rebecca Mostow and professor Sally Hacker employed multiple analytical techniques to show that the beachgrasses that dominate the Northwest's dunes, Ammophila arenaria and A. breviligulata, have hybridized.

A. arenaria is a European species and A. breviligulata an American species. Scientists say the hybrid's traits fall between its parent species in many ways, but the hybrid is taller, which is particularly important because shoot height is an indicator of dune-building potential.

"Understanding the ecological and population genetic consequences of the hybridization is critical in a system where any change in dominant beachgrass species can have large effects on both biodiversity management and coastal protection," Hacker said.

Dunes comprise nearly half of the combined coastline of Oregon and Washington and a quarter of California's. Starting in the early 20th century, the intentional planting of Ammophila beachgrasses has been used as a tool to stabilize an otherwise shifting sand environment.

Beachgrasses grow in stiff, rugged clumps capable of reaching 4 feet tall. Their strong rhizome mat - the mass of underground stems - helps stabilize the sand and allows for fast colonization. These clumps are able to capture sand and build dunes at rates of up to 3 feet per year.

"By the 1950s, Ammophila arenaria had spread from Mexico to Canada while building tall, continuous coastal foredunes," Mostow said. "Midway through that spread, in the 1930s, Ammophila breviligulata was planted in dunes near the Columbia River. Over the next 50 years, it moved north and dominated the sandy Washington coast. And there's no doubt the spread of these beachgrasses has had a positive impact on development by stabilizing the ground and building dunes that protect the coastline."

As with many introduced species, though, the beachgrasses come with ecological costs to the native flora and fauna. Resistant to pests and grazing, the hardy, densely growing plants have changed the ecology of dunes by displacing native plants and animals, including pink sand verbena and the endangered western snowy plover.

The OSU researchers say the hybrid of A. arenaria and A. breviligulata has been found at a total of 12 locations in Washington and Oregon. Plant morphology - what they look like and how they are put together - are consistent with hybridization, and genotyping and genome-size comparisons show the hybrid is a first-generation blend of the two introduced beachgrasses whose ranges overlap.

"Novel hybrid zones are an ecologically important upshot of species introductions and invasions," Mostow said. "Hybridization between different species can lead to gene flow between parent species or produce novel taxa that can alter invasion dynamics or ecosystem services. As far as we know, the Pacific Northwest is the only place in the world where the two Ammophila species have had the opportunity to hybridize."

A. breviligulata, Hacker notes, is better than A. arenaria at establishing its place in an ecosystem - it competes better - but A. arenaria builds taller dunes. The strengths and weaknesses trace to differences in grass density, morphology and growth form and their effects on sand capture.

"If the hybrid exceeds its parents in traits associated with dune-building, which it very possibly could, then its spread could affect dune shape and size and have huge, ecosystem-scale consequences," she said. "Hybridization could end up resulting in a really invasive taxon or increasing the invasive potential of either parent species."

###

Also collaborating on this research was Felipe Barreto, assistant professor in the OSU College of Science.

The study was supported by Oregon Sea Grant, the National Science Foundation and the Washington Native Plant Society.

Ongoing research includes a citizen science component in which beachgoers are invited to look for and photograph specimens of the hybrid. Details are available at iNaturalist.

 

Surge in nitrogen has turned sargassum into the world's largest harmful algal bloom

FAU Harbor Branch unique historical baseline (1983-2019) reveals dramatic changes in composition of sargassum

FLORIDA ATLANTIC UNIVERSITY

Research News

VIDEO: SARGASSUM, FLOATING BROWN SEAWEED, HAVE GROWN IN LOW NUTRIENT WATERS OF THE NORTH ATLANTIC OCEAN FOR CENTURIES. SCIENTISTS HAVE DISCOVERED DRAMATIC CHANGES IN THE CHEMISTRY AND COMPOSITION OF SARGASSUM, TRANSFORMING... view more 

CREDIT: BRIAN LAPOINTE, PH.D.

For centuries, pelagic Sargassum, floating brown seaweed, have grown in low nutrient waters of the North Atlantic Ocean, supported by natural nutrient sources like excretions from fishes and invertebrates, upwelling and nitrogen fixation. Using a unique historical baseline from the 1980s and comparing it to samples collected since 2010, researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute and collaborators have discovered dramatic changes in the chemistry and composition of Sargassum, transforming this vibrant living organism into a toxic "dead zone."

Their findings, published in Nature Communications, suggest that increased nitrogen availability from natural and anthropogenic sources, including sewage, is supporting blooms of Sargassum and turning a critical nursery habitat into harmful algal blooms with catastrophic impacts on coastal ecosystems, economies, and human health. Globally, harmful algal blooms are related to increased nutrient pollution.

The study, led by FAU Harbor Branch, in collaboration with the University of South Florida, Woods Hole Oceanographic Institution, the University of Southern Mississippi, and Florida State University, was designed to better understand the effects of nitrogen and phosphorus supply on Sargassum. Researchers used a baseline tissue data set of carbon (C), nitrogen (N) and phosphorus (P) and molar C:N:P ratios from the 1980s and compared them with more recent samples collected since 2010.

Results show that the percentage of tissue N increased significantly (35 percent) concurrent with a decrease in the percentage of phosphorus (42 percent) in Sargassum tissue from the 1980s to the 2010s. Elemental composition varied significantly over the long-term study, as did the C:N:P ratios. Notably, the biggest change was the nitrogen:phosphorus ratio (N:P), which increased significantly (111 percent). Carbon:phosphorus ratios (C:P) also increased similarly (78 percent).

"Data from our study supports not only a primary role for phosphorus limitation of productivity, but also suggests that the role of phosphorus as a limiting nutrient is being strengthened by the relatively large increases in environmental nitrogen supply from terrestrial runoff, atmospheric inputs, and possibly other natural sources such as nitrogen fixation," said Brian Lapointe, Ph.D., senior author, a leading expert on Sargassum and a research professor at FAU Harbor Branch.

A total of 488 tissue samples of Sargassum were collected during various research projects and cruises in the North Atlantic basin between 1983-1989 and more recently between 2010-2019, and included seasonal sampling offshore Looe Key reef in the lower Florida Keys (1983 and 1984) and a broader geographic sampling (1986 and 1987) offshore the Florida Keys, Gulf Stream (Miami, Charleston and Cape Fear), and Belize, Central America. Oceanic stations included the northern, central and southern Sargasso Sea.

The highest percentage of tissue N occurred in coastal waters influenced by nitrogen-rich terrestrial runoff, while lower C:N and C:P ratios occurred in winter and spring during peak river discharges. The overall range for N:P ratios was 4.7 to 99.2 with the highest mean value in western Florida Bay (89.4) followed by locations in the Gulf of Mexico and Caribbean. The lowest N:P ratios were observed in the eastern Caribbean at St. Thomas (20.9) and Barbados (13.0).

Because of anthropogenic emissions of oxides of nitrogen (NOx), the NOx deposition rate is about five-fold greater than that of pre-industrial times largely due to energy production and biomass burning. Production of synthetic fertilizer nitrogen has increased nine-fold, while that of phosphate has increased three-fold since the 1980s contributing to a global increase in N:P ratios. Notably, 85 percent of all synthetic nitrogen fertilizers have been created since 1985, which was shortly after the baseline Sargassum sampling began at Looe Key in 1983.

"Over its broad distribution, the newly-formed Great Atlantic Sargassum Belt can be supported by nitrogen and phosphorus inputs from a variety of sources including discharges from the Congo, Amazon and Mississippi rivers, upwelling off the coast of Africa, vertical mixing, equatorial upwelling, atmospheric deposition from Saharan dust, and biomass burning of vegetation in central and South Africa," said Lapointe.

Long-term satellite data, numerical particle-tracking models, and field measurements indicate that the Great Atlantic Sargassum Belt has recurred annually since 2011 and extended up to 8,850 kilometers from the west coast of Africa to the Gulf of Mexico, peaking in July 2018.

"Considering the negative effects that the Great Atlantic Sargassum Belt is having on the coastal communities of Africa, the Caribbean, Gulf of Mexico and South Florida, more research is urgently needed to better inform societal decision-making regarding mitigation and adaptation of the various terrestrial, oceanic, and atmospheric drivers of the Sargassum blooms," said Lapointe.

Sargassum removal from Texas beaches during earlier, less severe inundations was estimated at $2.9 million per year and Florida's Miami-Dade County alone estimated recent removal expenses of $45 million per year. The Caribbean-wide clean-up in 2018 cost $120 million, which does not include decreased revenues from lost tourism. Sargassum strandings also impact marine life and cause respiratory issues from the decaying process and other human health concerns, such as increased fecal bacteria.

"Human activities have greatly altered global carbon, nitrogen, and phosphorus cycles, and nitrogen inputs are considered now 'high risk' and above a safe planetary boundary," said Lapointe. "Based on scientific research, population growth and land-use changes have increased nitrogen pollution and degradation of estuaries and coastal waters since at least the 1950s. Despite decreases in nitrogen loading in some coastal watersheds, N:P ratios remain elevated in many rivers compared to historic values. The trend toward higher N:P ratios in the major rivers in the Atlantic basin parallel the increased N:P ratios we now see in Sargasum."

CAPTION

A photo taken this week shows Sargassum piled up on a beach in Palm Beach County, Florida.

CREDIT

Brian Lapointe, Ph.D.

Study co-authors are Rachel Brewton, a research coordinator, and Laura Herren, a research biologist, both at FAU Harbor Branch; Chuanmin Hu, Ph.D., a professor of optical oceanography, University of South Florida; Mengqui Wang, Ph.D., a post-doctoral researcher in the College of Marine Science, University of South Florida; Dennis McGillicuddy, Jr., Ph.D., senior scientist and department chair of applied ocean physics and engineering, Woods Hole Oceanographic Institution; Scott Lindell, a research specialist, Woods Hole Oceanographic Institution; Frank J. Hernandez, Ph.D., an assistant professor, Division of Coastal Sciences, University of Southern Mississippi; and Peter Morton, Ph.D., Department of Earth, Ocean and Atmospheric Science, Florida State University.

This research was funded by the U.S. NASA Ocean Biology and Biogeochemistry Program (NNX14AL98G, NNX16AR74G) and Ecological Forecast Program (NNX17AE57G), NOAA RESTORE Science Program (NA17NOS4510099), National Science Foundation (NSF-OCE 85-701 15492 and OCE 88-12055) and a Red Wright Fellowship from the Bermuda Biological Station.

CAPTION

Brian Lapointe, Ph.D., senior author, a leading expert on Sargassum and a research professor at FAU Harbor Branch, emerges from Sargassum at Little Palm Island in the Florida Keys in 2014.

CREDIT

Tanju Mishara

- FAU -

About Harbor Branch Oceanographic Institute:

Founded in 1971, Harbor Branch Oceanographic Institute at Florida Atlantic University is a research community of marine scientists, engineers, educators and other professionals focused on Ocean Science for a Better World. The institute drives innovation in ocean engineering, at-sea operations, drug discovery and biotechnology from the oceans, coastal ecology and conservation, marine mammal research and conservation, aquaculture, ocean observing systems and marine education. For more information, visit http://www.fau.edu/hboi.

About Florida Atlantic University:

Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 30,000 undergraduate and graduate students across six campuses located along the southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, FAU embodies an innovative model where traditional achievement gaps vanish. FAU is designated a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report and a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. For more information, visit http://www.fau.edu.

Dental crowding: Ancient baleen whales had a mouthful

CT scans of a 25 million year-old fossil skull show the Aetiocetus weltoni had both teeth and baleen, unlike modern whales

SAN DIEGO STATE UNIVERSITY

3D digital reconstruction of Aetiocetus weltoni skull.

CREDIT: ERIC EKDALE, SAN DIEGO STATE UNIVERSITY

A strange phenomenon happens with modern blue whales, humpback whales and gray whales: they have teeth in the womb but are born toothless. Replacing the teeth is baleen, a series of plates composed of thin, hair- and fingernail-like structures growing from the roof of their mouths that act as a sieve for filter feeding small fish and tiny shrimp-like krill.

The disappearing embryonic teeth are testament to an evolutionary history from ancient whales that had teeth and consumed larger prey. Modern baleen whales on the other hand use their fringed baleen to strain their miniscule prey from water, hence the term filter feeding.

A new study that utilized high-resolution computed tomography (CT) to scan a 25 million year-old fossil whale skull found neurovascular evidence that Aetiocetus weltoni, an evolutionary "cousin" of today's baleen whales (Mysticeti), had both teeth and baleen simultaneously in adulthood, making for a very crowded mouth.

The Oligocene age mysticete fossil was discovered along the coast of Oregon by graduate students with the Museum of Paleontology at the University of California, Berkeley, and loaned to biologist and lead author Eric Ekdale with San Diego State University and paleontologist Thomas Deméré with the San Diego Natural History Museum for the study.

Since baleen decomposes and is rarely preserved intact in fossils, the scientists relied on digital reconstructions with CT imaging to search for evidence of baleen in Aetiocetus. The study revealed grooves and holes on the roof of the mouth that connect internally with a vascular canal in a fashion consistent with the pattern of blood vessels that lead to baleen in modern mysticetes.

What that demonstrates is that the blood supply for the teeth was co-opted for a new function, to support the growth of baleen in living baleen whales, the authors said.

The study also revealed separate connections between the major internal canal and smaller canals that would have delivered blood to the upper teeth, which is consistent with the pattern of blood supply to teeth in living toothed whales such as sperm whales and killer whales, porpoises, dolphins, and terrestrial mammals.

"We have found evidence that supports a co-occurrence of teeth and baleen, indicating the tooth-to-baleen transition occurred in a stepwise manner from just teeth, to teeth and baleen, to only baleen," Ekdale said.

Shift in food habits

"Our study provides tangible fossil evidence of a major shift in feeding behavior from a raptorial carnivorous feeding mode to a bulk filter-feeding mode for obtaining food, among the largest animals that have ever lived in earth's oceans," Ekdale said. "Krill are around 1/600th the size of blue whales. That's like us humans eating nothing larger than sesame seeds floating in a pool."

The four main living groups of baleen whales each pursue different diets and use their baleen filter in different ways, so they divide up ocean resources rather than compete with each other for the same prey.

The study will be published with open access May 24 in the Zoological Journal of the Linnean Society, part of the Oxford University Press family of journals.

Anatomical distinction

In the case of Aetiocetus, which was less than half the size of a living gray whale, what puzzles some researchers in the field is how the whale managed to process its food, if it had both baleen and teeth, since the baleen might get in the way of teeth in the mastication process. However, the position of the holes observed in Aetiocetus suggests that the baleen was not in the "line of fire" and unlikely to result in interference between the teeth and baleen.

The study establishes that "while the tiny holes on the palate of Aetiocetus may look similar at a superficial level to other mammals, we can clearly demonstrate that this anatomy is related to baleen in baleen whales," Deméré said.

Ancestors of whales evolved for hundreds of millions of years, first on land as terrestrial mammals, and began their invasion of the sea around 53 million years ago. It's this transition and the subsequent diversification of fully aquatic whales that fascinates Ekdale and Deméré, and discoveries such as theirs indicate how remarkable is the history of life on our planet.

CAPTION

Artist's reconstruction of Aetiocetus weltoni, a 25 million year old baleen whale, with teeth and baleen. Co-occurrence of teeth and baleen side-by-side allow the animal to eat single prey, such as small fish, with their teeth, as well as large accumulations of small crustaceans with their baleen.

CREDIT

Art by C. Buell, used with permission from J. Gatesy.

Impact of school nutrition policies in California varies by children's ethnicity

US SCHOOLS DELIVER SOCIAL WELFARE

EDUCATION NOT SO MUCH

PLOS

Research News

 

California state school nutrition policies and federal policies for school meals have mixed impacts on childhood obesity in children of Pacific Islander (PI), Filipino (FI) and American Indian/Alaska native (AIAN) origins, according to a new study published this week in the open access journal PLOS Medicine by Mika Matsuzaki of Johns Hopkins Bloomberg School of Public Health, USA, and colleagues.

Children of PI, FI and AIAN origin are some of the most understudied subgroups experiencing high rates of overweight/obesity. California has enacted policies on foods and beverages available in schools through a series of standards beginning in 2004, and federal policies in 2010 also sought to improve school nutrition standards. In the new study, researchers used data on demographics, body composition and fitness that were collected by the California Department of Education on students in 5th and 7th grade each year between 2002 and 2016 as part of the state Physical Fitness Testing program.

Overall, the prevalence of overweight/obesity was higher among PI (39.5-52.5%), FI (32.9-36.7%), and AIAN (37.7-45.6%) children in comparison to White (26.8-30.2%) students. During the baseline period of the study, the overweight/obesity prevalence increased among nearly all students, with the steepest increases for PI and AIAN students. After California state policies went into effect, from 2002 to 2004, the overweight/obesity rates decreased for almost all groups, with the largest fall seen among PI girls in 5th grade (before: log odds ratio = 0.149 (95%CI 0.108 to 0.189; p<0.001); after: 0.010 (-0.005 to 0.025; 0.178)). When both the California and federal nutrition policies were in effect, after 2010, additional declines in the overweight/obesity prevalence were seen among White and FI students but not for PI or AIAN students. As the study was only conducted in California, without a comparison group unaffected by the policies, the researchers could not establish that all changes in prevalence of overweight/obesity were solely attributable to the policies.

"There remain wide racial/ethnic disparities between these racial/ethnic minority subgroups and their White peers," the authors say. "Additional strategies are needed to reduce childhood obesity and related disparities among these understudied racial/ethnic populations."

###

Research Article

Peer reviewed; Observational study; Humans

In your coverage please use this URL to provide access to the freely available paper:

http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003596

Funding: The study was supported by the Robert Wood Johnson Foundation (https://www.rwjf.org/ 74375, ESV), the National Heart, Lung, and Blood Institute of the National Institutes of Health (https://www.nhlbi.nih.gov/ K01HL115471 and 1R01HL136718, ESV; and R01-HL131610 and P01ES022844 BNS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

Citation: Matsuzaki M, Sánchez BN, Rebanal RD, Gittelsohn J, Sanchez-Vaznaugh EV (2021) California and federal school nutrition policies and obesity among children of Pacific Islander, American Indian/Alaska Native, and Filipino origins: Interrupted time series analysis. PLoS Med 18(5): e1003596. https://doi.org/10.1371/journal.pmed.1003596

PRIVATIZED HEALTHCARE

Study finds health insurance disruptions associated with worse healthcare access

AMERICAN CANCER SOCIETY

Research News

 

ATLANTA - MAY 24, 2021 - A new study underscores the importance of health insurance coverage continuity in access to and receipt of care and care affordability in the United States. Researchers found that health insurance coverage disruptions were consistently associated with worse healthcare access and problems with care affordability. The study appears in the American Journal of Preventive Medicine.

Decades of research has demonstrated that health insurance coverage is associated with better access to care and health outcomes in the U.S. However, less research has addressed coverage disruptions (i.e., periods without insurance) among adults with current coverage and the relationship of disruptions with care access, receipt of recommended preventive services, and affordability. To learn more, investigators led by Robin Yabroff, PhD, MBA of the American Cancer Society conducted a comprehensive examination of insurance coverage disruptions among adults aged 18 to 64 years from the 2011-2018 National Health Interview Survey using multiple measures of access and affordability, and evaluated the effects of the duration of coverage disruption among currently insured and uninsured.

The study found that prior disruptions in insurance coverage were relatively common among adults aged 18-64 years in the U.S. Among currently insured adults, 5.0% with private insurance and 10.7% with public insurance reported a coverage disruption in the prior year, representing nearly 9.1 million adults in 2018. Among currently uninsured adults, 24.9% reported coverage loss within the prior year, representing nearly 8.1 million adults in 2018. Compared to adults with continuous health insurance coverage, adults with coverage disruptions were less likely to receive recommended preventive services and more likely to forgo any needed care because of cost and report medication non-adherence because of cost.

Longer coverage disruptions were associated with worse care access and affordability. The magnitude of associations between coverage disruptions and care access and affordability was similar among adults with either current private or current public coverage. Currently uninsured adults, especially with longer uninsured periods, reported significantly worse care access, receipt, and affordability than currently insured adults with coverage disruptions or continuous coverage.

"Our findings highlight the importance of health insurance coverage continuity related to access to care and affordability. This is especially relevant with recent increases in unemployment due to the COVID-19 pandemic and widespread loss of employer-based private coverage, the primary source of private coverage in the working-age population," said the authors.

###

Article: Yabroff R, Zhao, J, Halpern M, Fedewa S, Han X, Nogueira L, Zheng Z, Jemal A. Health insurance disruptions and care access and affordability in the US. AJPM: American Journal of Preventive Medicine, 2021. doi: 10.1016/j.amepre.2021.02.014.

URL upon embargo: https://www.ajpmonline.org/article/S0749-3797(21)00178-1/fulltext

Babies with seizures may be overmedicated

Study suggests that keeping newborns on longer term antiseizure medication may not prevent continued seizures or epilepsy or change development.

MICHIGAN MEDICINE - UNIVERSITY OF MICHIGAN

Research News

 

ANN ARBOR, Mich. - Newborns who experience seizures after birth are at risk of developing long term chronic conditions, such as developmental delays, cerebral palsy or epilepsy.

Which is why all of these babies receive medication to treat the electrical brain disturbances right away.

While some babies only receive antiseizure medicine for a few days at the hospital, others are sent home with antiseizure medicine for months longer out of concern that seizures may reoccur.

But according to a new multicenter study, continuing this treatment after the neonatal seizures stop may not be necessary.

Babies who stayed on antiseizure medications after going home weren't any less likely to develop epilepsy or to have developmental delays than those who discontinued the medicines before leaving hospital, suggest findings in JAMA Neurology.

"There is wide variability in how different hospitals and physicians manage care for newborns with seizures," says senior author Renée Shellhaas, M.D., M.S., pediatric neurologist at University of Michigan C.S. Mott Children's Hospital.

Although neonatal seizures usually resolve within 72 hours, longer term medication is often prescribed out of caution, according to co-principal investigator and lead author for the study, Hannah C. Glass, MDCM, MAS.

"Our findings suggest that staying on antiseizure medication after leaving the hospital doesn't protect babies from continued seizures or prevent epilepsy and it does not change developmental outcomes," says Glass, a pediatric neurologist at the University of California, San Francisco Benioff Children's Hospital.

The study involved about 300 babies born at nine different centers over a three-year period who all developed seizures in their first days to weeks after birth. Two-thirds of babies stayed on medication after discharge from the hospital - averaging four months of treatment. But a third had antiseizure medicine discontinued before they went home - after just a few days of treatment.

Thirteen percent of babies developed epilepsy but there were no associations with medication duration.

Overmedication risks

Among the biggest concerns for longer term use of antiseizure medicine is that it may expose babies to potentially neurotoxic effects, which research indicates may be associated with lower cognitive scores.

The most commonly used medication for neonatal seizures is phenobarbital, which slows down brain activity but causes sedation.

Newborns who are prescribed this kind of medication for seizures may also have more trouble waking up to feed and engaging in other types of activities important to growth and development.

"We really need to balance the risks of continued medication with benefits to babies' health," Shellhaas says. "If it's not necessary, then keeping them on medicine could do more harm than good."

"Most of the babies in this study went home on antiseizure medications, which suggests we need to re-think standard practice," adds Glass. "We've never had such robust data from multiple centers to support this type of change for newborns with seizures."

Previous small, single-center studies have also suggested that early discontinuation of antiseizure medication isn't harmful.

More than 16,000 newborns in the U.S. experience neonatal seizures each year, with nearly half developing long-term health problems, according to nonprofit organization PCORI, which supported the new study.

Shellhaas, Glass and their colleagues will continue to follow this cohort of infants up to school age to assess development, including sensory processing, IQ and potential learning disabilities through research supported by the National Institutes of Health.

"We want to continue to track these children to watch for any subtle differences that may emerge over time," Shellhaas says.

"We hope this research will help drive decisions about caring for newborns with seizures and help us improve their outcomes over the course of their lives."

###

Study Cited: "'Safety of Early Discontinuation of Antiseizure Medication After Acute Symptomatic Neonatal Seizures," JAMA Neurology, Doi:10.1001/jamaneurol.2021.1437.