Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ancient marine invasion sheds light on diversity

09.11.2004


Fossils from the sea floor illuminate the relationship between local and global diversity, and these relationships may help us understand the effects of global climate change on species diversity.



"Looking at fossils can tell you something about the controls on global diversity, but so much of the investigation of the fossil record has looked only at global compilations of fossil species," says Dr. Mark E. Patzkowsky, associate professor of geosciences. "Recently, a few studies have shown that if you look at diversity locally, it is not necessarily mimicking global diversity at that time."

Researchers look at three types of diversity: local or alpha diversity, which is diversity at a specific location; regional or gamma diversity, which is diversity in a large area up to continent size; and beta diversity which is the diversity gained as one moves from one area to another.


Patzkowsky and Steven M. Holland, professor of geology, University of Georgia, looked at fossils similar to modern corals, clams, snails and brachiopods from 450 million-year-old fossil beds in the area around Cincinnati, Ohio. These Ordovician fossils show great diversity of sea floor invertebrates.

They made 700 individual collections and counted about 41,000 individual animal fossils. A typical collection area was a half meter piece of exposed ancient sea floor. Fossils were collected from areas that were originally deep sea floor, deep subtidal sea floor, shallow subtidal sea floor and protected lagoon sea floor. The fossils represent six time slices, each of about a million years, however, for this study, they only looked at fossils from the four time slices that contained fossils from deep and shallow subtidal areas. "We already knew that there was an invasion of species during one of the time slices," says Patzkowsky. "We wanted to see how that invasion affected diversity."

The researchers found that alpha, or local, diversity changed only slightly, but on a regional or gamma diversity basis, diversity increase was much more by about 26 percent. "We realized that the large change in gamma diversity was not coming from the meager change in alpha diversity," said Patzkowsky. "If not alpha diversity than it had to come from the beta diversity, but how?"

Patzkowsky and Holland suggest two ways beta diversity could increase gamma diversity. One way to increase beta diversity is for the habitat distribution of populations to become much narrower so that populations are using smaller amounts of resources. The other way is that the habitat becomes much more diverse providing different habitat niches.

The researchers want to test if the habitat distribution narrowed or if there was greater heterogeneity of habitat. They also want to figure out which species invaded, where they came from and if they replace species or simply add to the mix. "We are fairly certain that the invasion occurred because of a climate change," says Patzkowsky. "We would like to know if the invasion caused extinctions."

Carbonate rocks created in cool waters exist before the invasion, but during the invasion, the rocks were formed in warmer waters. During the Ordovician, the central United States was situated on the equator. The rock deposits indicate that the temperatures were increasing on a regional scale, just prior to a significant interval of global cooling. "We want to see how changes in the environment and temperature can affect the distribution of species," says Patzkowsky. "We are only one of a series of studies trying to understand the factors that control global diversity."

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

More articles from Earth Sciences:

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

nachricht Drones survey African wildlife
11.07.2018 | Schweizerischer Nationalfonds SNF

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>