Disappearing glaciers enhanced biodiversity

Biodiversity decreases towards the poles almost everywhere in the world, except along the South American Pacific coast. Investigating fossil clams and snails Steffen Kiel and Sven Nielsen at the Christian-Albrechts-Universität zu Kiel (CAU) could show that this unusual pattern originated at the end of the last ice age, 20.000 to 100.000 years ago.

The retreating glaciers created a mosaic landscape of countless islands, bays and fiords in which new species developed rapidly – geologically speaking. The ancestors of the species survived the ice age in the warmer Chilean north.

The exceptional biodiversity of the southern Chilean coast is known for a long time. More than 500 species of clams and snails are known from this area, twice as many as at comparable latitudes in the northern hemisphere. The reasons for this diversity were so far speculative, report Kiel and Nielsen in the current issue of the scientific journal Geology: “Opinions include that southern Chile is a museum of diversity where species survived for millions of years in addition to new arrivals; or that Antarctic species colonized this area from the south.” Their analysis of around 35.000 fossil clams and snails, belonging to about 400 species, allowed the paleontologists to draw some more precise conclusions: “Our fossils reject both hypotheses. Biodiversity in this area always decreased toward the south in the geologic past, and we didn't find any intruders from Antarctica”, explains Steffen Kiel. In addition, the researchers found that the vast majority of species and genera that lived in that area only 16 million years ago had become extinct. “This area is certainly not a museum of biodiversity”, adds Kiel.

The most species-rich groups of animals in the southern Chilean fiordlands are those inhabiting rocky shores. This is exactly the habitat that was created when the glacier retreated from their marine termini. “Molecular biologic investigations on phylogenetic relationships of these species show that they are geologically very young and descended from North Chilean ancestors. This agrees well with our results”, says Sven Nielsen, who has been working on Chilean fossils for many years. “Charles Darwin, who was the first to discover fossils in this area during his voyage on the 'Beagle', would have been fascinated.”

This research shows that for species conservation not only single, exceptional habitats need to be protected, but that a diversity of habitats needs be conserved to maintain a healthy biodiversity.

Link: http://geology.gsapubs.org/content/38/10/955.abstract

Images:

http://www.uni-kiel.de/download/pm/2010/2010-152-1.jpg
Caption: Sven Nielsen takes an inventory of early biodiversity.
Photo/Copyright: Matthias Rosenau/GFZ Potsdam
http://www.uni-kiel.de/download/pm/2010/2010-152-2.jpg
Caption: Fossil Chilean clams and snails.
Photo/Copyright: Sven Nielsen
http://www.uni-kiel.de/download/pm/2010/2010-152-3.jpg
Caption: The diversity of clams and snails had been higher in earlier times.
Photo/Copyright: Sven Nielsen
http://www.uni-kiel.de/download/pm/2010/2010-152-4.jpg
Caption: Fossils from these bluffs at Cucao in southern Chile revealed insights into the exceptional history of biodiversity in this area.

Photo/Copyright: Sven Nielsen

Contact:
Dr. Sven Nielsen
E-Mail: nielsen@gpi.uni-kiel.de
Tel. +49(0)431/880-2862
Dr. Steffen Kiel
E-Mail: steffen.kiel@gmx.de
Tel: +49(0)551/3910954

Media Contact

Dr. Sven Nielsen EurekAlert!

More Information:

http://www.uni-kiel.de

All latest news from the category: Earth Sciences

Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.

Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.

Back to home

Comments (0)

Write a comment

Newest articles

Distance learning can improve women’s access to vocational training as animal health care practitioners in Nepal. Image Credit: Heifer International

Hybrid Job Training Boosts Women’s Participation in Nepal

Globally, women’s workforce participation is about 25% lower than men’s, often due to barriers such as domestic responsibilities and cultural norms. Vocational training can increase employment opportunities, but women may…

CO2release increase under repeated drying-rewetting cycles (DWCs). Image Credit: Suzuki, Nagano et al., 2025 SOIL

Drying and Rewetting Cycles Boost Soil CO2 Emissions

Niigata, Japan – The amount of carbon dioxide (CO2) released by microbial decomposition of soil organic carbon on a global scale is approximately five times greater than the amount of…

A new drug delivery system shows promise for treating a rare, aggressive form of cancer affecting pregnant women and new mothers. Oregon State's Olena Taratula and collaborators including OSU postdoctoral researcher Babak Mamnoon and Maureen Baldwin, a physician at Oregon Health & Science University, designed a type of drug nanocarrier known as a polymersome to specifically target a protein in choriocarcinoma cells. Depicted is a polymersome with its methotrexate cargo. Illustration by Parinaz Ghanbari. Image Credit: Parinaz Ghanbari

Improved Treatment Method for Rare Pregnancy-Related Cancer

PORTLAND, Ore. – A new drug delivery system shows promise for treating a rare, aggressive form of cancer affecting pregnant women and new mothers, and it has potential with other…