Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Improving paleotemperature reconstruction: Swiss lakes as a model system

09.10.2018

For years, scientists have been trying to determine the climate of the past in order to make better predictions about future climate conditions. Now, there has been a breakthrough in the methodology of climate reconstruction based on microbial molecular fossils. Researchers under the direction of the University of Basel analyzed sediment samples collected from more than 30 Swiss lakes. Their findings can be applied to lakes worldwide, as the scientists report in PNAS.

The remains of bacteria found in lake sediments are important for the reconstruction of past environmental conditions. Particularly, cell fragments known as membrane lipids allow climate geologists to infer historic temperatures. A team led by Professor Moritz Lehmann and Dr. Helge Niemann from the Department of Environmental Sciences at the University of Basel have now investigated a very specific class of climate-sensitive lipids in 36 alpine lakes.


The researchers filtered hundreds of liters of water from Lake Lugano at depths of up to 275 m using a battery-operated in-situ pump

University of Basel, Department of Environmental Sciences

Their application in climate reconstruction has long been known, but the biological sources of the lipids remained unclear. This severely complicated their application as a temperature indicator.

“We initially assumed that these compounds were primarily produced by bacteria in soil and were washed into the lakes by rivers. But increasing evidence suggested that they are also formed within lake water itself,” explains Lehmann. Therefore, the aim of the research project was to characterize the ecology of the unknown bacteria that produce these lipids.

Link to methane

At the heart of the investigations was Lake Lugano in Switzerland, which offers an outstanding model system due to its strong stratification and great depth.

“Using stable isotope analysis, we were able to show that these bacterial lipids are dominantly formed in the cold, deep waters of the lake – where oxygen is depleted and large amounts of the greenhouse gas methane are present,” says Dr. Yuki Weber, lead author of the study. The scientists were then able to confirm their findings from Lake Lugano by similar measurements from 35 other alpine lakes.

In addition to lipid analysis, the researchers also applied molecular biological methods, which allowed them to capture the bacterial diversity at various water depths in Lake Lugano. For the first time, the research team was able to show that these climate-sensitive lipids are produced under widely different environmental conditions, by distinct groups of microbes that reside at different water depths.

Refining the paleothermometer

Despite the numerous environmental factors that may influence the composition of these lipids, the researchers were able to determine the conditions under which the lipid thermometer still yields reliable temperature estimates. “By means of stable carbon isotope analysis, we can now determine whether the lipids were formed in soil or lake water. We are therefore confident that our study will make an important contribution to the improvement of paleoclimate data worldwide,” concludes Weber.

The study was carried out in cooperation with the Royal Netherlands Institute for Sea Research, ETH Zurich, University of Applied Sciences and Arts of Southern Switzerland, and Eawag.

Wissenschaftliche Ansprechpartner:

Professor Moritz Lehmann, University of Basel, Department of Environmental Sciences, Tel. +41 61 207 36 16, email: moritz.lehmann@unibas.ch

Originalpublikation:

Yuki Weber, Jaap S. Sinninghe Damsté, Jakob Zopfi, Cindy De Jonge, Adrian Gili, Carsten J. Schubert, Fabio Lepori, Moritz F. Lehmann, Helge Niemann
Redox-dependent niche differentiation provides evidence for multiple bacterial sources of glycerol tetraether lipids in lakes
PNAS (2018), doi: 10.1073/pnas.1805186115

Iris Mickein | Universität Basel
Further information:
http://www.unibas.ch

More articles from Life Sciences:

nachricht Molecular motors run in unison in a metal-organic framework
20.03.2019 | University of Groningen

nachricht Active substance from plant slows down aggressive eye cancer
20.03.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Molecular motors run in unison in a metal-organic framework

20.03.2019 | Life Sciences

Active substance from plant slows down aggressive eye cancer

20.03.2019 | Life Sciences

Novel sensor system improves reliability of high-temperature humidity measurements

20.03.2019 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>