Starfish on ocean floor found to have well developed eyes

February 7, 2018 by Bob Yirka, Phys.org report

A team of researchers from the University of Copenhagen and the Greenland Institute of Natural Resources has found that starfish living in the dark on the ocean floor have eyes on their arms that are similar to other starfish living near shore. In their paper published in Proceedings of the Royal Society B, the group describes their study of the unique sea creatures and what they learned about starfish vision.

Scientists have known for some time that some starfish that live near shore have compound eyes in the tips of their arms. In this new study, the researchers have found the same to be true for many types of starfish that live in the dark at the bottom of the ocean.

To learn more about starfish vision in places besides the shoreline, the researchers collected hundreds of specimens (representing 13 species) from depths ranging from shallow waters to 1,000 meters below the surface—all living in the North Atlantic near Greenland. They found that 12 of the species had compound eyes similar to those found in starfish near the shoreline—the one lone species without eyes was a burrowing starfish that lives relatively close to shore.

In all of those with compound eyes, the eyes were uncovered, the researchers report, and were located on the bottom side of the arm tip, which means the starfish bend the tips to use them, pointing the eyes at targets. Visual acuity and sensitivity to light varied among the species they studied.

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Meet Yoda, the deep-sea acorn worm

A worm from an ecosystem far, far away on the ocean floor has been named after the Star Wars character Yoda.

Yoda purpurata is one of three new species of deep-sea acorn worms discovered 1.5 miles beneath the Atlantic.

Scientists coined the name after large lips on either side of the creature's head reminded them of the Jedi master's floppy ears.

The other part of the worm's name is Latin for purple and describes its colour.

The Yoda worm, technically known as an enteropneust, is described in the latest issue of the journal Invertebrate Biology.

A remotely-operated robot submersible collected the specimen during a research mission along the Mid-Atlantic Ridge between Iceland and the Azores.

Professor Monty Priede, from the University of Aberdeen, said: "Our colleague in California, Nick Holland, the world authority on enteropneusts, chose the name Yoda for the new genus characterised by its large ear-like lips.

"There is much interest in acorn worms from the point of view of understanding the early evolution of the vertebrates. Whilst they are not strictly a missing link in our own evolution, they give an insight into what the lifestyle of our remote ancestors might have been like."

http://uk.news.yahoo.com/meet-yoda-deep-sea-acorn-worm-130200702.html

Dinosaur die out might have been second of two closely timed extinctions

The most-studied mass extinction in Earth history happened 65 million years ago and is widely thought to have wiped out the dinosaurs. New University of Washington research indicates that a separate extinction came shortly before that, triggered by volcanic eruptions that warmed the planet and killed life on the ocean floor.

The well-known second event is believed to have been triggered by an asteroid at least 6 miles in diameter slamming into Mexico's Yucatán Peninsula. But new evidence shows that by the time of the asteroid impact, life on the seafloor -- mostly species of clams and snails -- was already perishing because of the effects of huge volcanic eruptions on the Deccan Plateau in what is now India.

"The eruptions started 300,000 to 200,000 years before the impact, and they may have lasted 100,000 years," said Thomas Tobin, a UW doctoral student in Earth and space sciences.

Continued:  http://archaeologynewsnetwork.blogspot.co.uk/2012/09/dinosaur-die-out-might-have-been-second.html#.UEx9vLKPUYk

Tiny Deep-Sea Life Eats Dinosaur-Era Meals

Microbes living in the seabed below the deep ocean are taking the slow-food movement to extremes. According to new research, these microorganisms are subsisting on nutrients first laid down when dinosaurs still walked the Earth.

Nutrient-carrying sediment rarely makes it to the deep seafloor at the North Pacific Gyre far north of Hawaii. If a grain of sand falls to the seabed, it will be another 1,000 years before another grain lands on top of it, said Hans Røy, aquatic ecologist at Aarhus University in Denmark and leader of the new study, published Thursday (May 17) in the journal Science. And yet, an expedition to the North Pacific turned up populations of incredibly slow-living microbes in these depths.

"It's pretty amazing, because if you look at the deepest parts, these are layers that were laid down back when the dinosaurs were walking on this planet, and there has been no input of new organic material since that," Røy told LiveScience. "They've been chewing on the same bone for 86 million years."

Continued  http://www.livescience.com/20393-slowest-life-seafloor-microbes.html