Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Encrustation provides clues about ancient seas

25.03.2003


David L. Rodland, a Ph.D. student in Virginia Tech’s Department of Geological Sciences, has been studying encrustation, or the colonization of seashells by other marine organisms that live permanently attached to hard surfaces.



Examples of encrusting organisms (or epibionts) include serpulid and spirorbid worms, bryozoans, barnacles, and algae. Many epibionts produce their own calcareous tubes, shells, or skeletons, which are attached to that surface and may become fossilized along with it. "The encrustation of seashells by epibionts provides a great deal of ecological data or, for fossils, paleoecological, data," Rodland said. "You can count the number and diversity of epibionts on a shell, for example, and see how it changes as a function of shell size. Or you can examine how encrustation varies between different kinds of shells or between the shells collected at different places and under different environmental conditions. Some workers have even suggested that they could be used to estimate the amount of nutrients and plankton available in ancient seas."

At the meeting of the Southeastern Sections of the Geological Society of America (GSA) in Memphis March 12-14, Rodland presented a comparison of the encrustation of a bivalve mollusk (Macoma) with the encrustation of an articulate brachiopod (Bouchardia) from the coast of Brazil. "This is the only tropical / subtropical site where both bivalves and brachiopods occur in abundance in the present day, or at least, the only one we know," Rodland said. "Brachiopods were a common element in Paleozoic fossil beds (>250 million years ago) and so this is the first opportunity we really have to compare brachiopods and bivalves in the modern world."


"As it turns out," he said, "epibionts appear to preferentially colonize the brachiopod Bouchardia, and occur less frequently on the bivalve Macoma. There are a large number of different measures one can use to evaluate the degree of encrustation on a shell, but Bouchardia is always preferred. This may be in part because Macoma lives in the sand, while Bouchardia sits on the surface; but because storms periodically rework everything, some shells get brought back to the surface while others get buried, so they both get encrusted eventually. The composition of the shells may also make a difference to the organisms colonizing them; Macoma is aragonitic while Bouchardia is calcitic."

What does this mean? Bivalves are very common today, while brachiopods were much more common hundreds of millions of years ago, Rodland said. Therefore, differences in the encrustation of each may have implications for the evolution of the organisms that encrust them. "But no one really knows," he said, "because there has been next to no study of brachiopod encrustation, and no one has really compared brachiopods and bivalves in this way before. If you’re trying to measure changes in ocean nutrients through the fossil record of epibionts, this means you have to account for differences between the shells that are getting encrusted in the first place."

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

More articles from Earth Sciences:

nachricht NASA finds newly formed tropical storm lan over open waters
17.10.2017 | NASA/Goddard Space Flight Center

nachricht The melting ice makes the sea around Greenland less saline
16.10.2017 | Aarhus University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>