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/

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

Im Focus: Graphene enables clock rates in the terahertz range

Graphene is considered a promising candidate for the nanoelectronics of the future. In theory, it should allow clock rates up to a thousand times faster than today’s silicon-based electronics. Scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) and the University of Duisburg-Essen (UDE), in cooperation with the Max Planck Institute for Polymer Research (MPI-P), have now shown for the first time that graphene can actually convert electronic signals with frequencies in the gigahertz range – which correspond to today’s clock rates – extremely efficiently into signals with several times higher frequency. The researchers present their results in the scientific journal “Nature”.

Graphene – an ultrathin material consisting of a single layer of interlinked carbon atoms – is considered a promising candidate for the nanoelectronics of the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

 
Latest News

Making better use of enzymes: a new research project at Jacobs University

19.09.2018 | Life Sciences

Light provides spin

19.09.2018 | Physics and Astronomy

Enjoying virtual-reality-entertainment without headache or motion sickness

19.09.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>