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 More than 100 years of flooding and erosion in 1 event
28.03.2017 | Geological Society of America

nachricht Satellites reveal bird habitat loss in California
28.03.2017 | Duke 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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>