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 Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>