By analyzing the fossilized sea lily fossils, researchers tried to determine how long and how far they would have traveled in the Jurassic period, and discovered that ancient marine creatures spent decades crossing the ocean on giant rafts that carried entire ecosystems around the world.
Their study, published in the British Royal Society Open Science on July 22, reported that these creatures clung to tree trunks, creating floating rafts that likely supported a host of other creatures and allowed them to be transported long distances across the Jurassic seas. .
Live fossils
The sea lily is one of the oldest living things on Earth, and it appeared in the Ordovician era about 485 million years ago in shallow seas in central Europe, and it spread in abundance, fossilized and formed fossils.
The sea lily belongs to the sea urchin and sea stars from the animal kingdom, and it lives at great depths south of the equator, and most of its species have a stem that clings to the sea floor and bears a thin, funnel-shaped body.
Life during the Jurassic period was negatively affected by the lack of oxygen. Only free-range sea lilies were able to survive in the depths of the sea, and lived either alone or in colonies to form "living fossils."
In the 1830s, William Buckland, known for the discovery of the first dinosaur, collected fossils with the pioneering British paleontologist Mary Anning from Lyme Regis in the southwest of England, which is now part of the World Heritage Site of the Jurassic Coast.
Anning is known worldwide for her important discoveries in the Jurassic fossil strata. Her discoveries included the first ichthyosaur skeleton and the first pterosaur skeleton.
One of their important discoveries was the remains of fossil sea lilies, dating back to the Jurassic period, which look like polished copper because they were petrified with pyrite, a mineral known as false gold for its similarity to gold in shape and color.
Diffusion model
Buckland notes that these fossils were associated with small pieces of driftwood that had turned into charcoal, and he hypothesized that these organisms would have associated with the driftwood while alive.
His idea was initially thought of as fanciful until an amazing group of fossils was discovered in the 1960s in the village of Holtsmaden, between Stuttgart and Ulm, Germany.
In the Jurassic period, seabeds were uninhabitable due to low oxygen levels, and organisms cling to wood all their lives.
One of the main questions asked was whether these wooden rafts could survive long enough for organisms to grow to maturity, so a team of scientists from the United Kingdom and Japan decided to answer these questions.
Scientists led by Aaron Hunter, a visiting postdoctoral researcher in the Department of Geosciences at the University of Cambridge in the United Kingdom, and colleagues have shown that such rafts can last for at least 15 years and possibly even 20 years before they begin to sink.
Their research revealed that sea lilies are extremely lightweight, even in large, mature colonies, and they came up with a way to calculate the time required to saturate tree trunks with water and then drown them into the sea.
In his article published on The Conversation, Hunter stated that they had succeeded in calculating how long a colony could last after developing the "diffusion model," and they used information on trees that were present in the Jurassic period such as conifers and cycads.
Sea Lilies and Their Ancestors
The researchers also used a new technique known as "spatial point analysis" to plot distances between fossils. This technique enabled them to reveal that sea lilies were actually hanging under the driftwood, but gathering at the edges.
These exciting techniques are now being used by another research team to compare the populations of sea lilies that currently live on the sea floor with their ancestors from the Jurassic period.
The research could reveal how past changes in climate shaped ancient marine societies, and their findings will help to understand how these societies respond to future challenges in an ever-changing world.