Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Regional recovery more rapid following late Ordovician extinction

08.12.2004


The length of time necessary to recover from a mass extinction may seem like a problem from the past, but a team of Penn State researchers is investigating recovery from the second largest extinction in Earth’s history at the end of the Ordovician 443 million years ago and sees some parallels to today’s Earth.



"We are currently in an undeniable biotic crisis," says Andrew Z. Krug, graduate student in geosciences. "We are not just interested in what will disappear, but what will reappear and when the recovery will take place."

During the Ordovician, the majority of life was found in the seas. Scientists consider climate change, specifically widespread glaciation, as the trigger for this mass extinction.


The researchers report in this week’s on-line version of the Proceedings of the National Academy of Sciences, that "marine benthic diversity in Laurentia recovered to pre-extinction levels within 5 million years, which is nearly 15 million years sooner than suggested by global compilations."

Laurentia eventually became North America, however, during the Ordovician, it was located in the tropics and Pennsylvania was south of the equator. The researchers looked at the fossil record from Laurentia because large amounts of information are available in the Paleobiology Database (PBDB) sponsored by the National Science Foundation and housed at the National Center for Ecological Analysis and Synthesis. "Laurentia is well studied and the fact that it was tropical suggests there should be a lot of diversity," says Dr. Mark E. Patzkowsky, associate professor of geosciences.

Previously, investigations of extinctions have been on a global scale and most used a global database developed by the late Jack Sepkoski of the University of Chicago. This database lists the first appearance of an organism and the last appearance of an organism. "There is quantitative information missing from the global database," says Krug. "PBDB includes faunal lists, species occurrences and other information useful for standardization of sampling effort."

According to the global database, recovery from the Ordovician extinction took 15 to 20 million years. "We suspected that there might be a sampling issue," says Krug. "We standardized sample size and looked at how diversity recovers."

The researchers looked at 35 million years from the Ordovician to the Silurian and divided that into seven approximately equal time periods. They assembled lists of taxa – groups of related organisms – that were then standardized to account for low fossil counts in time periods for which few fossil bearing rocks are easily accessible and high fossil counts in time periods where the fossil bearing rocks are easily accessible and frequently collected.

Comparing the raw data with the standardized data, Krug and Patzkowsky saw a large difference in the number of years necessary for recovery after the extinction. The raw data for Laurentia showed a recovery period of 10 million years while the standardized data showed only 5 million years for recovery. "Based on other work, this suggests a good possibility that the region was operating differently than the globe as a whole," says Patzkowsky. "I would argue that the way the field considered the problem in the past was heavily influenced by the Sepkoski database. We show that at least in Laurentia, recovery was quicker than was thought globally."

Krug and Patzkowsky believe that the quicker recovery was caused by immigration of organisms from other areas of the globe. While this could account for the rapid rise of diversity after an extinction on a regional level, only an evolution of new organisms could account for a global diversity increase.

To see if other regions behave the same, Krug will look at faunal lists from Baltica – now Eastern Europe, Norway and Sweden – that was further south than Laurentia, Avalonia – now the United Kingdom and Nova Scotia – that was in a temperate area, and South Central Europe, which includes the western Mediterranean countries, that was even further south.

A’ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.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

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>