"If the area hadn't been covered by a glacier all these thousands of years, these tree remnants would never have made it. The finds yield information indicating that the 20th century was probably the warmest century in 7,000 years. The fact that the climate is so unique during the last century means that we must question whether this could be 100 percent the result of natural mechanisms," says Leif Kullman, professor of physical geography, who is directing the project.
Pines and birches grew on the site of the glacier during parts of or perhaps the entire period between 11,800 and 7,000 years ago. This is shown by carbon 14 dating of the remains of trees that have now been uncovered. During that period, the glacier did not continuously exist, and the climate was warmer than at any time afterward.
All in all, there are four finds, parts of birch and pine trunks, that have been uncovered under the shrinking glacier in the Lapland mountains. In most cases they are well preserved, but they are degrading rapidly as they come in contact with air and water. As early as 2003, tree remnants of a similar age were found in Sylarna, in Jämtland province. They have completely crumbled into dust at this point. The warmer climate during the last century, which is the reason the tree remnants have now seen the light of day, may therefore be unique in the perspective of many millennia.
The oldest tree, a pine, lived and died on the site of the Kårsa glacier around 12,000 years ago. The area is 400-450 meters above today's timberline. This discovery places the thawing of ice at the end of the latest ice age in an entirely new perspective.
"Previous research indicated that Lapland was covered with ice at this time. These finds show that the ice melted and life returned much earlier than we previously thought," says Leif Kullman.
The researchers are now continuing their examination of glaciers in northern Lapland and Västerbotten (West Bothnia). This ongoing research is part of a larger project that comprises glaciers throughout the entire range of mountains in Sweden. The project is funded by the Swedish Research Council and is directed by Professor Leif Kullman, Umeå University.
In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy