Sherlock Solves Sea Snot Mystery

[MrRING]

Giant Balls of 'Snot' Explain Ocean Mystery Bjorn Carey
LiveScience Staff

Scientists have discovered giant sinking mucus "houses" that double the amount of food on the sea floor.

The mucus houses, or "sinkers," are produced by tadpole-like animals not much bigger than your index finger. As sinkers drop to the sea floor, small sea critters and other food particles get stuck to the mucus and end up on the bottom of the ocean. For years scientists have observed loads of life at the bottom of the ocean. But they weren't able to find enough food - carbon - to support all that life. Sinkers, previously overlooked, may help fill that gap.

"We have 10 years of data on sinkers, and using average figures from those years, we can account for twice as much carbon than sediment traps can measure below 1,000 meters," Rob Sherlock of the Monterey Bay Aquarium Research Institute told LiveScience. The animals responsible for making sinkers are called giant larvaceans. They spin a mucus web, about a yard in diameter. They sit in the middle of the house and use it to filter food that is small enough for them to eat.

"Larger particles get stuck to the outside of these filters, and after some amount of time the filters get plugged and the animal moves out," Sherlock said. "The house deflates and begins to sink, picking up more particles. It's a fast-sinking carbon bomb." Sherlock usually sees twice as many sinkers as active houses, and sometimes four to five times that amount. So how did they evade scientists for so long?

"A sinker is basically snot," Sherlock said. "It's very fragile. We have very skilled ROV (Remotely Operated Vehicle) pilots and special containers to collect these things. We were only able to adequately collect one out of four."

They're so fragile that sometimes just touching one causes it to rapidly break apart. Sinkers are particularly good at staying out of sediment traps - the most common way of testing the amount of carbon food on the sea floor.

"Sometimes the sinker wouldn't pass through the trap's filter, or would be broken up by it. Or people checking the traps would find this weird goop in the trap, and consider it to be contamination and throw it out," Sherlock said. "Plus, the odds of a sinker landing straight down into trap are fairly slim."

Sherlock and his colleagues have tried to observe larvaceans building the houses in a laboratory tank, but so far it has been difficult because the houses are so fragile. "We just don't have a tank that's been designed well enough to observe the process," Sherlock said. "We do know that they build very rapidly for a short while, and they probably go through about one house a day."

These findings are published in June 9 issue of Science.

http://news.yahoo.com/s/space/20050610/sc_space/giantballsofsnotexplainoceanmystery

 

[EnolaGaia]

Giant larvaceans are back in the scientific news ...

Scientists learn how tiny critters make ocean ‘snot palaces’

Master builders of the sea construct the equivalent of a complex five-story house that protects them from predators and funnels and filters food for them — all from snot coming out of their heads.

And when these delicate mucus homes get clogged, the tadpole-looking critters — called giant larvaceans — build a new one. Usually every day or so.

These so-called “snot palaces” could possibly help human construction if scientists manage to crack the mucus architectural code, said Kakani Katija, a bioengineer at Monterey Bay Aquarium Research Institute.

Her team took a step toward solving the mystery of the snot houses and maybe someday even replicating them, according to a study in Wednesday’s journal Nature.

The creatures inside these houses may be small — the biggest are around 4 inches (10 centimeters) — but they are smart and crucial to Earth’s environment. Found globally, they are the closest relatives to humans without a backbone, Katija and other scientists said.

Together with their houses “they are like an alien life form, made almost entirely out of water, yet crafted with complexity and purpose,” said Dalhousie University marine biologist Boris Worm, who wasn’t part of the study. “They remind me of a cross between a living veil and a high tech filter pump.”

Also, when they abandon their clogged homes about every day, the creatures collectively drop millions of tons of carbon to the seafloor, where it stays, preventing further global warming, Worm said. They also take microplastics out of the water column and dump it on the sea floor. And if that’s not enough, the other waste in their abandoned houses is eaten by the ocean’s bottom dwellers.

But it’s what they build that fascinates and mystifies scientists. Because the snot houses are so delicate, researchers haven’t often been able to take them to the lab to study them. So Katija and team used a remote submarine, cameras and lasers to watch these creatures in water about 650 to 1300 feet (200 to 400 meters) deep off Monterey Bay in Northern California.

These mucus structures aren’t simple. They include two heart-like chambers that act as a maze for the food that drifts in, except there’s only one way for it to go: into the larvacean’s mouth. The snot houses often are nearly transparent and flow all around the critter that looks like a tadpole, but isn’t.

“It could be the most kind of complex structure that an animal makes,” Katija said. “It’s pretty astonishing that a single animal is able to do it.” ...

FULL STORY (With Illustrations): https://apnews.com/4240b38444a7752d70a358c1e50be1a9

 

[EnolaGaia]

Here are the bibliographic details and abstract of the Nature article.

Katija, K., Troni, G., Daniels, J. et al.
Revealing enigmatic mucus structures in the deep sea using DeepPIV.
Nature (2020).
https://doi.org/10.1038/s41586-020-2345-2

Abstract
Many animals build complex structures to aid in their survival, but very few are built exclusively from materials that animals create 1,2. In the midwaters of the ocean, mucoid structures are readily secreted by numerous animals, and serve many vital functions3,4. However, little is known about these mucoid structures owing to the challenges of observing them in the deep sea. Among these mucoid forms, the ‘houses’ of larvaceans are marvels of nature5, and in the ocean twilight zone giant larvaceans secrete and build mucus filtering structures that can reach diameters of more than 1 m6. Here we describe in situ laser-imaging technology7 that reconstructs three-dimensional models of mucus forms. The models provide high-resolution views of giant larvacean houses and elucidate the role that house structure has in food capture and predator avoidance. Now that tools exist to study mucus structures found throughout the ocean, we can shed light on some of nature’s most complex forms.

SOURCE: https://www.nature.com/articles/s41586-020-2345-2