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 New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>