Thursday, November 7, 2024

SpaceX tells FCC it has a plan to make Starlink about 10 times faster

Starlink satellites before deployment.
(Image credit: SpaceX)

From Ars Tecnica by Jon Brodkin

SpaceX: "Small-but-meaningful updates" can boost speed from about 100Mbps to 1Gbps.

SpaceX is seeking approval for changes to Starlink that the company says will enable gigabit-per-second broadband service.
In an application submitted to the Federal Communications Commission on October 11, SpaceX claims the requested "modification and its companion amendment will enable the Gen2 system to deliver gigabit-speed, truly low-latency broadband and ubiquitous mobile connectivity to all Americans and the billions of people globally who still lack access to adequate broadband."

SpaceX said it is seeking "several small-but-meaningful updates to the orbital configuration and operational parameters for its Gen2 space station authorization to improve space sustainability, better respond to evolving demand, and more efficiently share spectrum with other spectrum users."

SpaceX wants to lower the altitudes of satellites "at 525 km, 530 km, and 535 km to 480 km, 485 km, and 475 km altitude, respectively." The reconfiguration will increase the "potential maximum number of orbital planes and satellites per plane" while keeping the planned total number of second-generation satellites at 29,988 or less.
The FCC has so far approved 7,500 Gen2 satellites.

The world knows Elon Musk as a visionary entrepreneur, the man behind Tesla, SpaceX, and so many cutting-edge technologies that have reshaped industries and even our future on Earth and beyond.
Yet, one area where we haven’t seen Musk’s influence as prominently is the luxury market—until now. It’s finally happening.
Elon Musk's superyacht, priced at a jaw-dropping $700 million, is hitting the market, and the world is buzzing with excitement.
 
SpaceX CEO Elon Musk wrote yesterday that "next generation Starlink satellites, which are so big that only Starship can launch them, will allow for a 10X increase in bandwidth and, with the reduced altitude, faster latency."

SpaceX promised gigabit speeds in 2016, when the satellite system was just in the planning stages and didn't even have a name yet.
"Once fully optimized through the Final Deployment, the system will be able to provide high bandwidth (up to 1Gbps per user), low-latency broadband services for consumers and businesses in the US and globally," SpaceX told the FCC in November 2016.

As for actual speeds in 2024, Starlink's website says "users typically experience download speeds between 25 and 220Mbps, with a majority of users experiencing speeds over 100Mbps.
Upload speeds are typically between 5 and 20Mbps.
Latency ranges between 25 and 60 ms on land, and 100+ ms in certain remote locations." 

Changing satellite elevation angles

Another request would change the elevation angles of satellites to improve network performance, SpaceX said.
"SpaceX seeks to lower its minimum elevation angle from 25 degrees to 20 degrees for satellites operating between 400 and 500 km altitude," SpaceX told the FCC.
"Reducing the minimum elevation angle in this way will enhance customer connectivity by allowing satellites to connect to more earth stations directly and to maintain connections with earth stations for a longer period of time while flying overhead."

Meanwhile, upgrades to Starlink's Gen2 satellites "will feature enhanced hardware that can use higher gain and more advanced beamforming and digital processing technologies and provide more targeted and robust coverage for American consumers," SpaceX said.

SpaceX is also seeking more flexible use of spectrum licenses to support its planned mobile service and the current home Internet service.
The company asked for permission "to use Ka-, V-, and E-band frequencies for either mobile- or fixed-satellite use cases where the US or International Table of Frequency Allocations permits such dual use and where the antenna parameters would be indistinguishable."

"These small modifications, which align with Commission precedent, do not involve any changes to the technical parameters of SpaceX's authorization, but would permit significant additional flexibility to meet the diverse connectivity and capacity needs of consumer, enterprise, industrial, and government users," the application said.

SpaceX said it also submitted "an amendment to the pending part of the Gen2 application requesting additional upgrades to its Gen2 system that the Commission has not yet addressed, including SpaceX's orbital shells below 400 km and frequencies beyond those requested in the original application."
 
FCC doubted earlier speed claims

There's no guarantee the FCC will approve the requests.
Other satellite operators and mobile carriers have objected to previous Starlink plans, and the FCC has been skeptical of some of the company's claims.

AT&T and Verizon recently asked the FCC to reject a key part of SpaceX's plan to offer cellular service with T-Mobile.
The mobile carriers say a SpaceX-requested waiver of FCC rules on out-of-band emission limits would interfere with and degrade service for terrestrial mobile broadband networks.

In March, the FCC denied a SpaceX application to use certain spectrum bands for mobile service.
The decision forces SpaceX to seek changes in a rulemaking process in which the FCC would evaluate whether the spectrum bands can handle the system without affecting existing users.

The FCC questioned Starlink's capabilities in 2022 when the agency denied an application for $886 million in federal funding that is supposed to be used to expand broadband access.
The FCC decided that Starlink may not be able to consistently provide low-latency service with the grant program's required download speeds of 100Mbps and upload speeds of 20Mbps.

At the time, The FCC called Starlink a "nascent" technology with "recognized capacity constraints" while pointing to falling speeds and a $600 up-front cost (which has since been lowered).
SpaceX and CEO Elon Musk have continued to criticize the FCC for denying the grant.

The application for satellite-system changes is a very different matter than the grant.
SpaceX's proposed changes might solve some of the capacity and speed problems the FCC previously identified.

Other companies will have time to file objections.
To obtain approval, SpaceX will have to demonstrate that the changes won't negatively affect other spectrum users and satellite operators. 
 
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Wednesday, November 6, 2024

Where in the world are the busiest shipping lanes?

Image: Shutterstock
 
From Geographical by Charlotte Lock

Take a deep dive into the world’s busiest shipping lanes according to the number of vessels passing through them each day

Even with a huge increase in air freight within the last few decades, ocean freight shipping remains the most popular method of transporting goods worldwide, with over 80 per cent of the world’s trade carried by sea.

Connecting manufacturers, producers and consumers all across the globe, natural and manmade shipping lanes are the backbone of maritime trade, and operating them smoothly can be difficult.
Some shipping lanes are far busier than others, particularly if their strategic placement offers a significant reduction in shipping time by offering a shortcut.

But which shipping lanes are the busiest? Find out the top five busiest shipping lanes in the world – according to their number of daily vessels – below, in reverse order.

5. Panama Canal- 32 per day
 
Image: Shutterstock

The Panama Canal connects the Pacific and Atlantic Oceans, via an 82km long artificial waterway, cutting across the Isthmus of Panama.

The canal has become a primary route for trade, enabling ships to travel between the east and west coasts of the American continents and is also crucial for container ships travelling from the US’s east coast to Asia as it provides a much shorter alternative to sailing around the southern tip of South America.

The canal’s design means that the number of ships passing each day is monitored very carefully. Around 32 vessels are permitted to transverse the waterway each day, taking a whopping 10 hours to complete. This figure used to be closer to 39, but consistent drought conditions have led to the government putting limits on daily crossings.

Similar to the canal network that still operates across England, the Panama Canal is fitted with a series of locks, allowing vessels to change their elevation, operating as a kind of lift system. The 12 locks within the Panama Canal act to raise the ships 26m from sea level to the level of Gatan Lake, and vice versa.

Using the locks, vessels are raised when moving from the Pacific to the Atlantic and lowered when moving from the Atlantic to the Pacific.

4. Suez Canal – 50 per day
 
 Image: Shutterstock

The Suez Canal connects the Mediterranean and the Red Sea via the Isthmus of Suez, making it a vital shipping lane for goods travelling between Europe and Asia. Without the use of the canal, vessels would have to travel down and around the Cape of Good Hope (the most southern tip of Africa), taking several weeks to complete.

It is also a popular route for oil tankers transporting crude oil between the Middle East and Europe.

When it was first constructed, the canal was 164km in length and was only 8m deep. But after a series of improvements and enlargements, the canal is now 193km long and 24m deep. 
Approximately 50 ships pass through the Suez Canal every day, with an average journey time of 12-16 hours.

There are very strict rules on what type of ships can pass through the canal to stop them from becoming stranded due to the shallow water or getting stuck in narrow sections.

In 2021, a ship running aground in the Suez Canal caused global trade chaos.
The Ever Given, one of the world’s largest container ships, got stuck in the canal due to a combination of factors including a sandstorm which reduced visibility, the ship’s enormous size and travelling through a narrow single-lane section. 
The container ship was stuck for 6 days before it was finally refloated by 14 tugboats. The incident held up as much as $10 billion of trade per day.
 
3. Strait of Hormuz – 103 per day
 


The Strait of Hormuz is the third busiest shipping lane in the world, acting as one of the world’s most important oil chokepoints. Located between the Persian Gulf in Iran and the Gulf of Oman. It is the only shipping lane that offers access to the open ocean from the Persian Gulf.

Around 20 per cent of the world’s sea-faring natural gas travels through the Strait of Hormuz every day, causing politics to have a heavy influence on its operation. Tensions between Iran and Western powers, particularly the United States, mean Iran has threatened to block the strait in response to sanctions or military pressure in the past, and there is currently added pressure in the region due to the ongoing Israeli-Hamas conflict.

In March this year, an average of 103 vessels travelled through the 167km-long Strait of Hormuz each day.

2. Strait of Malacca – 300 per day
 
Image: Shutterstock

The Strait of Malacca is located between Indonesia, Malaysia and Singapore, making it a primary route for the transport of goods between Asia and Europe.

Manufacturing companies in China, Japan, South Korea and lots of other Asian countries, use this shipping lane to pass goods to the Middle East and Europe – one of their biggest consumer markets. The Strait of Malacca also acts as a key route for transporting oil from the Middle East to Asia and Australia.

It is estimated that over 200 ships pass through the strait each day, even though their conditions are dangerous. At its narrowest, the water channel is as thin as a single sea lane, at around 600m and can be just 25m deep. Running aground in the strait is a very real possibility, but that doesn’t stop huge crude and cargo carriers from passing through side by side.

Japan is particularly dependent on the smooth operation of this shipping lane, with more than 80% of its oil imports passing through the water body every day.

1. The English Channel – 500 per day
 
Image: Shutterstock

While it may seem hard to believe, the English Channel is the busiest shipping lane in the world, with over 500 vessels passing through it every day.
The English Channel connects the North Sea with the Atlantic Ocean and also provides a key link between the UK and continental Europe.

The English Channel measures around 560km in length, with a width that varies between just 34km at the Dover Strait and 240km at its widest section.

Food, fuel and manufactured goods all cross the Channel, supplying the UK with much of its total imports, but goods also often travel through on their way to the Americas or Europe.

The English Channel isn’t only good for cargo however with a range of passenger ferries, cruise ships, fishing boats, military boats and oil tankers passing through every day, adding to the traffic.

The unique Channel Tunnel rail link which runs beneath the shipping lane also transports nearly 21 million passengers between the UK and Europe every year.

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Tuesday, November 5, 2024

Scientists are becoming ocean hitchhikers to fill data gaps


Scientists descend from French research vessel the Marion Dufresne in the Indian Ocean.
The high cost of research ships has prompted some scientists to work with cargo ships, fishing boats and private yachts (Image: Benoit Stichelbaut / Hemis / Alamy)

From Dialogue Earth by Daniel Cressey

Research cruises can be prohibitively expensive, so cargo ships, fishing vessels and yachts are being enlisted to help understand the ocean

Doing science at sea is expensive.

A billion dollars might not be enough to buy a state-of-the-art vessel.
Actually running a research ship can easily cost tens of thousands of dollars a day or more, before factoring in submersible trips to the depths or helicopter flights to remote ice floes.

These costs limit the number of hours researchers can spend at sea, and where they can go to gather data on fisheries, climate change, weather and a host of other issues with trillion-dollar consequences.
This leaves data on much of the ocean patchy, especially in less wealthy parts of the world.

So scientists are increasingly looking at cheaper options for getting essential and fundamental information including temperature, salinity and depth: so-called “vessels of opportunity”.
By piggybacking their work on ships that are already plying the ocean, they can fill some of the huge existing gaps in marine data at a fraction of the cost of hiring a research vessel.
 
Cold, far away and very, very expensive

One of the most difficult places to work is Antarctica.

Research vessels must first navigate the Southern Ocean’s complex politics and permit systems before they can even hope to navigate its icy waters.

So when one team wanted to hunt for colossal squid in the far south, they found a cheaper option: cruise ships that carry tourists to Antarctica in increasing numbers.

“Research vessels are about USD 100,000 a day, sometimes it can be like USD 22 a second to operate.
And it takes so much coordination to just get all the partners involved … to grant this vessel permission,” says Myrah Graham, a marine scientist at Memorial University of Newfoundland in Canada.

“But the tourism boats already have permission, and they’re already going there.” As well as saving on costs, boarding cruise ships can be greener – Graham’s team estimate that avoiding using their own vessel saved about 417kg of CO2 per researcher involved per day.


A passenger ship moored off Cuverville Island, Antarctica, near a colony of Gentoo penguins.
Marine scientists estimate that piggybacking on cruise ships can result in significantly lower greenhouse gas emissions than running dedicated research vessels (Image: David Rowland / One Image / Alamy)

Cruise ships are not without their difficulties.
Researchers have no control over where they go, what times they can drop equipment into the sea, and they must shift equipment around guests getting on and off.
While those hunting huge squid may want to target little-studied dark ocean areas, tourists are understandably keener on shores that teem with penguins.

But Graham says her trip was “definitely a success” – the team made 36 camera deployments in a little-studied region and even captured footage of what may be a colossal squid.
If true, this would be the first footage of the animal in its natural habitat.

“But also we’re just seeing these areas of the seafloor for the first time,” she says.

“Especially with climate change changing things at the poles four times faster [than in other regions], having this baseline knowledge of what’s there right now will allow us to potentially in the future monitor and see what changes are occurring on the seafloor.”
On the highways of the sea

While there are only around 100 ocean-going research vessels and a few hundred cruise ships, there are over 50,000 commercial vessels at sea.

One is the CMV Oleander.
Every week the freighter travels between New Jersey on the east coast of the United States and Bermuda.
Since 1992 it has collected data on the Gulf Stream with every journey.

Ships have been gathering weather data – what happens above the surface – for many years, but Oleander does something far rarer.
It was built with a sensor called an ‘Acoustic Doppler Current Profiler’ fitted to it, allowing it to measure currents – what is happening below the surface.


Since 1992, the freighter Oleander has collected data on the Gulf Stream every week as it travels between New Jersey and Bermuda.
Commercial ships make repeat visits to the same ocean locations – a luxury research vessels often cannot afford 
(Image: Oceanography Magazine, CC BY)

Research vessel time is so precious that repeat visits to locations may be rare.
The Oleander project offers something different and valuable: the ability to gather data on the same patch of sea over and over.

“These ships go back and forth and back and forth and back and forth on the same line.
They revisit the same ocean over and over and over again.
So you start to build up a database and inventory catalogue of the various states that the ocean can take along that line,” says Tom Rossby, a retired University of Rhode Island professor who was instrumental in instrumenting the Oleander.

Some of those involved in the Oleander work are now steering Science Research on Commercial Ships (Science RoCS), one of several programmes around the world looking to increase the opportunistic use of ships by researchers.
Science RoCS wants to build links between the shipping industry and science communities, linking up scientists with instruments and people with ships, enabling repeated measurements on a vast scale in areas rarely visited by research ships.

“There are so many other instruments now that could go on these vessels, including instruments that measure the partial pressure of carbon dioxide.
[That’s] really important for understanding what’s happening with the carbon system and the ocean and the atmosphere,” says Alison Macdonald, an oceanographer at the Woods Hole Oceanographic Institution in the US.
 
Go fish (for science)

While there are tens of thousands of merchant vessels plying the ocean, there are millions of fishing boats.

As well as data gathered in the course of fishing – such as details of what is caught and where – these boats are increasingly being enlisted to measure things specifically for scientists.
In the United States, more than 100 boats that work off the coast of New England have been rigged to measure temperature and oxygen levels via sensors attached to lobster pots.
New Zealand has gone even further.
The Te Tiro Moana (Eyes on the Ocean in Māori) programme now involves 200 vessels, over a third of the country’s fishing fleet.

Cooper Van Vranken is founder and CEO of Ocean Data Network which leads the Fishing Vessel Ocean Observing Network (FVON).
He works to match existing sensors with fishing boats, managing and distributing the data generated.
“What’s unique about fishing vessels is the opportunity to collect that subsurface data because the traps are already going down.
It turns out we have way more subsurface data out in the open ocean than we do in close to shore … where the fishing takes place,” he says.


A fisher attaching a temperature and depth sensor to his fishing net in Ghana.
Fishing boats around the globe are increasingly being enlisted to gather subsurface data for scientists (Image: Ocean Data Network, Environmental Defense Fund, Partnership for Observation of the Global Ocean, and the University of Ghana)

Cooper’s dream is to create a vastly bigger, globe-spanning network measuring temperature, salinity and other important ocean information, under the banner of the FVON.
In a recent research paper, he and others wrote that “the global fishing industry represents a vast opportunity to create a paradigm shift in how ocean data are collected.”

The past year has been a busy one.
FVON joined the umbrella body for ocean data gathering, the Global Ocean Observing System, and earned a mention in a white paper for the UN on the need to expand ocean observing.

Cooper told Dialogue Earth that there were probably 2 million fishing vessels around the world that could be harnessed and currently nearing 1,000 were already being utilised for data collection.

“Where we want to be is 10,000 vessels.
That would fundamentally change ocean observing and oceanography and coastal resilience,” he says.
 
Setting sail for science

Fishing boats and freighters travel routes determined by what pays.
But some vessels sail where their owners please: private yachts.

Several programmes are now attempting to harness yachts to gather a dizzying variety of ocean information.
Yachts for Science is one of them.
It has previously put a manta ray researcher on a cruise in the Maldives and helped a scientist studying black coral to work off a super yacht in Indonesian waters.

“If we are to collect all of the data that are needed across the ocean, then we just can’t do that off the fleet of current research vessels,” says Lucy Woodall, who oversees the scientific work of the programme.

The key thing for her organisation is matchmaking between researchers with projects they want to do, and yacht owners who will be in the right place to help them.

I’ve personally done research off everything from paddle boards to the most amazing, really kitted-out research ship.
Any platform that floats is usefulLucy Woodall, marine biologist

Acknowledging the privilege of being able to be on a ship, any ship, is something that is important to Woodall, a marine conservation and policy researcher at the University of Exeter in the United Kingdom and principal scientist at Nekton, the not-for-profit research foundation behind Yachts for Science.

“That’s a privilege that most scientists who are interested in the marine space don’t have, because either their country doesn’t have a vessel or a platform appropriate, or they are not in an institution where they can easily access it,” she says.

A lot of ocean data is biased towards the waters of Global North countries, or areas they are interested in.
Vessels of opportunity could help fill many of these gaps for areas governed by countries that lack well-funded national research ships and universities.

“I’ve personally done research off everything from paddle boards to the most amazing, really kitted-out research ship.
Any platform that floats is useful,” says Woodall.

If the hopes of those behind these and other vessels of opportunity programmes are realised, one day research at sea will not be so expensive, because nearly every ship will have the ability to do research.

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Monday, November 4, 2024

How cells resist the pressure of the deep sea


Photo: Jacob Winnikoff

From Wired by Yasemin Saplakoglu 
The original version of this story appeared in Quanta Magazine.

Cell membranes from comb jellies reveal a new kind of adaptation to the deep sea: curvy lipids that conform to an ideal shape under pressure.

The bottom of the ocean is cold, dark, and under extreme pressure.
It is not a place suited to the physiology of us surface dwellers: At the deepest point, the pressure of 36,200 feet of seawater is greater than the weight of an elephant on every square inch of your body.
Yet Earth’s deepest places are home to life uniquely suited to these challenging conditions.
Scientists have studied how the bodies of some large animals, such as anglerfish and blobfish, have adapted to withstand the pressure.
But far less is known about how cells and molecules stand up to the squeezing, crushing weight of thousands of feet of seawater.

“The animals that live down in the deep sea are not ones that live in surface waters,” said Itay Budin, who studies the biochemistry of cell membranes at the University of California, San Diego.
“They’re clearly biologically specialized.
But we know very little, at the molecular level, about what is actually determining that specialization.”

In a recent study published in Science, researchers took the deepest look yet at how cells have adapted to life in the abyss.
In 2018, Budin met Steve Haddock, a deep-sea biologist, and they combined forces to investigate whether cell membranes—specifically, the lipid molecules that membranes are made of—could help explain how animals have come to thrive in such a high-pressure environment.

To find out, they turned to comb jellies, the simple, diaphanous animals that Haddock studies at California’s Monterey Bay Aquarium Research Institute (MBARI).
Led by his student Jacob Winnikoff, the interdisciplinary team discovered that the membranes of comb jellies that reside in the depths are made of lipid molecules with completely different shapes than those of their shallow-water counterparts.
Three-quarters of the lipids in the deep-sea comb jellies were plasmalogens, a type of curved lipid that is rarer in surface animals.
In the pressure of the deep sea, the curvy molecule conforms to the exact shape needed to support a sturdy yet dynamic cell membrane.

“It’s an amazing paper … with quite profound implications,” said Douglas Bartlett, who studies how microbes sustain life at depth and pressure at the University of California, San Diego and was not involved in the new study.
“They provide another explanation for how the lipids of deep-sea animals, and likely deep-sea microbes and a range of organisms, are adapted in a way that’s pressure-specific.”


To study the cell membranes of deep-sea animals, the biochemist Itay Budin (center) joined forces with marine biologists Steve Haddock (right) and Jacob Winnikoff (left).
Photographs: From Left: Tamrynn Clegg; Geoffroy Tobe; John Lee

“They are looking into an area that, to a large degree, has not been explored,” said Sol Gruner, who researches molecular biophysics at Cornell University; he was consulted for the study but was not a co-author.

Plasmalogen lipids are also found in the human brain, and their role in deep-sea membranes could help explain aspects of cell signaling.
More immediately, the research unveils a new way that life has adapted to the most extreme conditions of the deep ocean.

Insane in the Membrane

The cells of all life on Earth are encircled by fatty molecules known as lipids.
If you put some lipids in a test tube and add water, they automatically line themselves up back to back: The lipids’ greasy, water-hating tails commingle to form an inner layer, and their water-loving heads arrange together to form the outer portions of a thin membrane.
“It’s just like oil and water separating in a dish,” Winnikoff said.
“It’s universal to lipids, and it’s what makes them work.”

For a cell, an outer lipid membrane serves as a physical barrier that, like the external wall of a house, provides structure and keeps a cell’s insides in.
But the barrier can’t be too solid: It’s studded with proteins, which need some wiggle room to carry out their various cellular jobs, such as ferrying molecules across the membrane.
And sometimes a cell membrane pinches off to release chemicals into the environment and then fuses back together again.

“The membranes are balancing right on the edge of stability … It’s actually a liquid crystal.”
JACOB WINNIKOFF, HARVARD UNIVERSITY

For a membrane to be healthy and functional, it must therefore be sturdy, fluid, and dynamic at the same time.
“The membranes are balancing right on the edge of stability,” Winnikoff said.
“Even though it has this really well-defined structure, all the individual molecules that make up the sheets on either side—they’re flowing around each other all the time.
It’s actually a liquid crystal.”

One of the emergent properties of this structure, he said, is that the middle of the membrane is highly sensitive to both temperature and pressure—much more so than other biological molecules such as proteins, DNA or RNA.
If you cool down a lipid membrane, for example, the molecules move more slowly, “and then eventually they’ll just lock together,” Winnikoff said, as when you put olive oil in the fridge.
“Biologically, that’s generally a bad thing.” Metabolic processes halt; the membrane can even crack and leak its contents.

To avoid this, many cold-adapted animals have membranes composed of a blend of lipid molecules with slightly different structures to keep the liquid crystal flowing, even at low temperatures.
Because high pressure also slows a membrane’s flow, many biologists assumed that deep-sea membranes were built the same way.

But it turns out these researchers weren’t getting the full picture.
It would take an unexpected collaboration between biochemists and marine biologists, and more advanced technology, to see that deep-sea membranes had evolved a different way of going with the flow.
 
Going Deep

Comb jellies, or ctenophores, are voracious predators in fragile bodies.
They are the largest animals that swim with cilia, which are lined up in rows known as combs, and they feed on a wide range of prey.
Genetic evidence suggests that they were the first organisms to branch off the animal tree on their own evolutionary path.
Though they resemble jellyfish in some ways, humans are actually more closely related to jellyfish than ctenophores are.
And they have successfully colonized all kinds of ocean habitats, from surface waters to ocean trenches, and from the tropics to the poles.


The researchers collected comb jellies by robot arm when exploring the deep ocean with ROV Ventana (left) and by hand when scuba diving in surface waters (right).
PHOTOGRAPHS: JACOB WINNIKOFF

You would expect such a wide-ranging group to be adaptable, and indeed comb jellies from the deep are built differently than those that live near the ocean’s surface.
“You collect the deep guys, and you bring them up to the surface, and they just fall apart,” Bartlett said.
“They just melt away.
It’s really quite dramatic.” Similarly, if the ones adapted to shallow water end up at depth, they beat their cilia faster and faster, and eventually die.
But no one really knew the molecular differences that separated them.

In 2018, Haddock, an expert on comb jellies, attended a conference on the origin of eukaryotes.
After watching Budin present research on cell membranes’ response to temperature, he approached the lipid expert.
Haddock had a graduate student, Winnikoff, who wanted to study adaptations to extreme pressure.
It was known that lipids are sensitive to pressure, so cell membranes were a prime target for investigation.
They decided to collaborate.

Haddock, Budin, and Winnikoff started by collecting comb jellies from different parts of the ocean.
In scuba gear, Winnikoff carefully coaxed comb jellies from Monterey Bay’s surface waters into jars.
From one of MBARI’s oceanographic vessels, he helped operate a deep-sea robot to collect comb jellies from depths of 12,000 feet.
To control for the effects of the cold temperatures in the deep sea, he and Budin asked friends who were on their own expedition to gather surface comb jellies from frigid Arctic waters.
In total, the team collected 66 animals from 17 related species.


Comb jellies have adapted to ocean habitats from the surface to the deep sea and from the cold poles to the warm tropics.
Four of the 17 study species, clockwise from upper left: Beroe cucumis, common in shallow Arctic waters; the shallow-water Leucothea pulchra; Beroe abyssicola, a deep-water relative of B.
cucumis; and an undescribed shallow-water mertensiid.
PHOTOGRAPH: JACOB WINNIKOFF

By the time the molecular part of the project was set to begin, the pandemic had hit.
So Winnikoff set up an experiment in his garage.
Using a fluorescence spectrometer, he sent rays of ultraviolet light into test tubes filled with small globs of membrane material from the creatures they’d collected.
The results puzzled him.
The deep-sea membranes didn’t become more fluid as he raised the temperature—a response considered universal among lipid membranes.

So he and Budin consulted Gruner, the former director of Cornell’s particle accelerator.
If they really wanted to know what was happening in the membranes, Gruner said, they would need powerful, high-energy X-rays.
And he knew the perfect source.
 
Under Pressure

Buried 50 feet beneath the main athletic fields at Cornell is a synchrotron: a particle accelerator that uses a high-frequency electric field and a low-frequency magnetic field to speed up charged particles.
Part of the facility, which Gruner fought to establish, may as well have been designed for studying deep-sea cell membranes.
Its small-angle X-ray scattering operation, which opened in 2020, can not only distinguish the finer details and shapes of molecules such as lipids, but also increase and decrease the pressure they’re under.

The team experienced some pressure, too, as they had to endure late nights to make the most of their limited time at the facility.
The powerful X-rays they shot at their lipid samples revealed the clearest picture yet of cell membranes from the abyss.
The deep-sea comb jellies had membrane lipids that, at our standard atmospheric pressure, have a curvier shape than those in surface cell membranes.
The animals had especially increased production of the group of lipids known as plasmalogens.

“In these deep-sea comb jellies, [plasmalogens] can make up three-quarters of all the lipids, and we’re talking about all the membrane lipids in the entire body of the animal, which is kind of crazy,” Winnikoff said.
“We did a lot of checks to make sure that wasn’t a mistake.”

At the surface, a plasmalogen has a small phosphate head and a pair of wide, flaring tails, resembling a badminton shuttlecock, he said.
But at high pressure, the tails squeeze together to form the necessary sturdy yet dynamic structure.

“They start their lipids at a different shape,” Budin said.
“So when you compress them, they still maintain the right Goldilocks shape that you see in our own cells, but at these extreme pressures.” Budin and Winnikoff named this novel modification “homeocurvature adaptation.”


ILLUSTRATION: MARK BELAN FOR QUANTA MAGAZINE

Taking a plasmalogen membrane to the deep sea is like pushing down on a spring, Bartlett said.
At the surface, when the spring’s tension is released, it extends dramatically.
“That’s when you can imagine the cells, their membranes, falling apart.” Meanwhile, if a surface membrane with straighter lipids is brought down to the deep, it compresses too much and becomes too rigid to function properly.

Notably, curvy plasmalogens were not present in comb jellies from the cold, shallow waters of the Arctic.
“The composition of the membrane almost restricts the organisms to a particular pressure range,” said Peter Meikle, a lipid biologist who works on plasmalogens at the Baker Heart and Diabetes Institute in Australia and was not involved in the study.

But Budin wanted to see these lipids in action, and something occurred to him during a late session at the synchrotron.
“In the middle of the night when you’re deliriously tired,” he said, sometimes you have a good idea.
He stumbled on a paper with an intriguing approach to studying lipids.
The authors had engineered Escherichia colibacteria to produce plasmalogens in their membranes instead of their normal lipids.
Budin realized that his team could similarly coax the bacteria to produce more plasmalogens and pressurize them to see how the membranes held up in living cells.

Following the paper’s methods, they showed that the bacteria with plasmalogen membranes could indeed better tolerate pressure than typical ones.
These experimental membranes were made up of only 20 percent plasmalogens, but it was “enough to make a difference,” Winnikoff said.

Bartlett was impressed that the effect of the curved lipid shapes occurred in such unrelated species.
“What is likely to come out of this is that we’ll find that this principle of homeocurvature adaptation will become a universal property of life,” he said.
 
Curvy Flexibility

Plasmalogens aren’t limited to the deep sea.
They’re also found to varying degrees in other organisms, including humans.
The percentage of plasmalogens within humans depends on the cell type.
In the liver, plasmalogens make up 5 percent of phospholipids.
In muscles, they can range between 20 percent and 40 percent.
And in the brain, they make up about 60 percent.

In fact, the deterioration of plasmalogens has been linked to neurodegenerative disorders such as Alzheimer’s disease.
“The evidence suggests that the plasmalogens are more protective,” said Meikle, who studies plasmalogens because of their links to mammalian health.

Winnikoff speculates that plasmalogens might give nerve cells the right flexibility for their communication needs.
To send signals, neurons fill cellular sacs with neurotransmitters; then those sacs fuse with the cell membrane to release the signaling compounds on to the next neuron.
Maybe plasmalogens’ curvy structure makes that possible, Winnikoff suggested.

Meikle likes the idea.
“Certainly, they’re the primary sort of cone shape that allows membranes to form those types of curvatures,” he said.
As studies better understand the role of lipids in membrane function, the findings could be relevant for a broader range of membranes.

“They’ve opened up more questions than they’ve answered,” Gruner said.
“But hopefully it will catalyze people to start thinking about and doing more experiments going deeper into the subject.”

Indeed Winnikoff, who is now a postdoctoral fellow at Harvard University, is looking into how universal this lipid adaptation mechanism is across different organisms.
He’s started experiments to figure out whether organisms found at hydrothermal vents—deep ocean areas where magma and seawater meet—have similar adaptations.

What would be really interesting, he added, would be to look at archaea, the third branch of life.
Archaea lipids behave differently than those found in bacteria and eukaryotes: They follow different chemistry, Winnikoff said.
“Do they follow the same physics?”
 
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Sunday, November 3, 2024

Time-lapse of Northern Lights from space


An aurora was spectacularly captured from the International Space Station
by NASA astronaut Matthew Dominick.
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