Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brazilian shellfish may improve understanding of ancient world

25.10.2002


Brachiopods, the most common shellfish in Paleozoic times, now live primarily in the chilly waters of northern fjords and the Antarctic shelf, except for an abundant population in the tropic waters of the continental shelf off southeast Brazil.


Argyrotheca


Platidia



The Brazilian brachiopods are the best modern analogy for the life and times of the critter that was so pervasive over 250 million years ago, says David Rodland, Ph.D. student in geological sciences at Virginia Tech. He has been studying the population since July 2000.

Rodland is studying the encrustation, or colonization, of the modern brachiopods by oysters, bryozoans -- or "moss animals," and, in particular, worm tubes. There has been no large-scale study of modern brachiopod encrustation, he says. The study results might allow scientists to estimate such things as the water depth at which Paleozoic brachiopods lived and the productivity of plankton populations, of the earth’s waters at that time.


He will present his findings at the Geological Society of America’s 114th annual meeting in Denver October 27-30.

Rodland is looking at "every scale, from shell to shelf," he says. Factors affecting encrustation are water depth, nutrients in the water, and shell surface.

Some findings are that encrustation is highest in shallower water and in deep water where upwelling delivers nutrients." The brachiopods appear to be concentrated in nutrient rich water and the variations in the abundance of encrusters suggest a link to productivity," Rodland says.

Below 100 meters, encrustation drops to about 2 percent for all brachiopods combined, although it varies by species. About 9 percent of the grooved Argyrotheca are encrusted at depths of 100 to 500 meters, while fewer than 1 percent of the spiny Platidia are still colonized."Similar patterns are found on Paleozoic brachiopods," Rodland says. "Shell ornamentation affects colonization by encrusters. Grooves seem to encourage colonization, while spines discourage it."

However, looking at the variability in encrustation at a range of depths along the approximately 300 miles of the shelf, Rodland has determined that the amount of plankton in the water is more likely a driving factor than depth alone in whether or not worms and oysters set up housekeeping on the brachiopods. "Depth influences the amount of encrustation we see, but it’s clearly not depth alone. In one transect, encrustation decreases with depth but in another bay, encrustation is high regardless of depth," Rodland says.

He is also looking at the numbers and different kinds of organisms that colonize brachiopods. "I’m looking at the diversity of each shell as the function of the shell size," he says. His findings appear to parallel studies of islands. "The larger the island, the more species are present. On a shell, diversity increases logarithmically with valve area," he says.

Worms and bryozoans are some of the most common encrusters. "The fauna has changed since the Paleozoic, but the ecological principles are similar in terms of the pattern and frequency of encrustation," Rodland says. "A difference from Paleozoic times is that then most of the encrustation was on the outside of the shell. Now, there is more encrustation on the inside of the shell, after the death of the brachiopod. But it is still too early to say whether this is a major difference -- whether the colonizing organisms are looking for living or dead brachiopods. Modern outer-shelf brachiopods are mostly encrusted on the outside, probably because most of them were collected alive. That is another reason encrustation is less common in deeper water," he says.

The paper, "Colonists of a ’Lost World’: Quantitative analysis of brachiopod encrustation on the subtropical shelf of the southeast Brazilian bight," will be presented at 8:45 a.m. on Sunday, Oct. 27 in room A112 of the Colorado Convention Center. Co-authors are Michal Kowalewski, professor of geological sciences at Virginia Tech; Monica Carroll of the University of Georgia, and Marcello Simoes of the Universidade Estadual Paulista, Botucatu, Brazil.

Rodland, who grew up in Portland, Ore., received his undergraduate degree from Colorado College in 1996 and his master’s degree from the University of Southern California in 1999.


Contact Information: David L. Rodland, drodland@vt.edu, 540-231-8828

PR Contact: Susan Trulove, 540-231-5646, strulove@vt.edu

David Rodland’s major professor is Michal Kowalewski

David Rodland | EurekAlert!
Further information:
http://www.technews.vt.edu/

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>