The Earliest Earth Ecosystem Icon Tribrachidium heraldicum Is Complex

Summary: The earliest Earth ecosystem and its icon, Tribrachidium heraldicum, are more complex than ever imagined possible.

computer simulation of water flow around 3-D model of Tribrachidium: Dr Imran A. Rahman/University of Bristol, usage restrictions: credit required; single use to illustrate articles on Dr. Imgran Rahman's Dec. 1, 2015, Science Advances article, via EurekAlert!

The earliest Earth ecosystem and its icon, Tribrachidium heraldicum, of 575 million to 541 million years ago appear complex in a study published online Dec. 1, 2015, in the journal Science Advances.

The five co-researchers in Canada, England and the United States base their findings upon simulations of the iconic late Ediacaran fossil animal’s feeding modes. Rachel Racicot, postdoctoral researcher at Los Angeles County’s Natural History Museum, considers: “Methods for digitally analyzing fossils in 3D have become increasingly widespread and accessible over the last 20 years. We can now use these data to address any number of questions about the biology and ecology of ancient and modern organisms.”

Computer simulations draw upon computational fluid dynamics.

Application of the common method for simulating fluid flows in aircraft design engineering to paleontology (study of ancient creatures) emerges as a novel use of CFD.

CFD furnishes the five co-researchers with unique opportunities to test alternative feeding modes of absorbing organic particles through osmotrophy or of collecting them through suspension feeding. The combination of CFD modeling and CT scanning gives patterns of water flowing toward the top of Tribrachidium heraldicum and generating low-velocity eddies above localized areas. That pattern has nothing in common with the current-oriented flow over the entire surface of a particle-absorber to maximize the surface area available for nutrient uptake.

If fluids flow slowly, turbulently enough for particle-capturing, then it is suspension feeding.

Paleontologists judge Ediacaran shallow marine settings more hospitable to particle-absorbing than to particle-gathering because of seafloor microbial mats preventing horizontal and vertical burrowing for frond-bearing sediment-dwellers.

Marc Laflamme, co-author and assistant professor at the University of Toronto Mississauga in Ontario, Canada, knows that despite obstacles to finding modern counterparts and reconstructing prehistoric ecosystems “Tribrachidium doesn’t look like any modern species, and so it has been really hard to work out what it was like when it was alive. The application of cutting-edge techniques, such as CT scanning and computational fluid dynamics, allowed us to determine, for the first time, how this long-extinct organism fed.”

The results lead to other conclusions regarding both the icon and its ecosystem.

Simon Darroch, co-author and assistant professor at Vanderbilt University in Nashville, Tennessee, mentions: “For many years, scientists have assumed the Earth’s oldest complex organisms, which lived over half a billion years ago, fed in only one or two different ways [by filter-feeding or particle-absorbing]. Our study has shown this to be untrue, Tribrachidium and perhaps other species were capable of suspension feeding.”

Scientists need to re-think both the early Earth ecosystem and its iconic Tribrachidium.

Dr. Imran Rahman, research fellow at the University of Bristol in England, notes: “This demonstrates that, contrary to our expectations, some of the first ecosystems were actually quite complex. This approach has great potential for improving our understanding of many extinct organisms.”

fossil of extinct organism Tribrachidium, 555-million-year-old organism with no known modern relatives: M. Laflamme, usage restrictions: credit required; single use to illustrate articles on Dr. Imgran Rahman's Dec. 1, 2015, Science Advances article, via EurekAlert!

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

3D Tribrachidium: Dr Imran A. Rahman/University of Bristol, usage restrictions: credit required; single use to illustrate articles on Dr. Imgran Rahman's Dec. 1, 2015, Science Advances article, via EurekAlert! @ http://www.eurekalert.org/multimedia/pub/103808.php?from=312379

Tribrachidium fossil: M. Laflamme, usage restrictions: credit required; single use to illustrate articles on Dr. Imgran Rahman's Dec. 1, 2015, Science Advances article, via EurekAlert! @ http://www.eurekalert.org/multimedia/pub/103807.php?from=312379

For further information:

Hays, Brooks. 30 November 2015. “Study: Earth’s Earliest Ecosystems More Complex Than Previously Thought.” United Press International > Science News.
Available @ http://www.upi.com/Science_News/2015/11/30/Study-Earths-earliest-ecosystems-more-complex-than-previously-thought/8031448904991/

Rahman, Imran A.; Darroch, Simon A. F.; Racicot, Rachel A.; Laflamme, Marc. 1 December 2015. “Suspension Feeding in the Enigmatic Ediacaran Organism Tribrachidium Demonstrates Complexity of Neoproterozoic Ecosystems.” Science Advances 1 (10): 1–8. DOI: 10.1126/sciadv.1500800
Available @ http://advances.sciencemag.org/content/1/10/e1500800