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 X-ray scattering shines light on protein folding
10.07.2020 | The Korea Advanced Institute of Science and Technology (KAIST)

nachricht Surprisingly many peculiar long introns found in brain genes
10.07.2020 | Moscow Institute of Physics and Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

X-ray scattering shines light on protein folding

10.07.2020 | Life Sciences

Looking at linkers helps to join the dots

10.07.2020 | Materials Sciences

Surprisingly many peculiar long introns found in brain genes

10.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>