Rainforest mushrooms as weather makers
With the help of HZB’s x-ray microscope, MAXYMUS, MPIC
scientists in Mainz, Germany, recently decoded the methods
used by mushrooms and plants to influence Amazon rainforest
cloud formation. Organic substances condense on mushroom and
plant derived potassium salts resulting in production of
aerosol particles. On these, fog droplets form.
© Christopher Pöhlker / MPI für Chemie
Whereas in urban areas, soot or dust particles often double as condensation nuclei, in rain-forests, it is mainly organic evaporations from plants, which periodically trigger fog or cloud formation. Now, at HZB’s BESSY II, Max Planck Institute for Chemistry scientists have shown that inorganic salts also play a role in the process. It appears that tiny potas-sium salt particles make up the core of cloud condensation nuclei in the rainforest. These kinds of salts are evaporated by mushrooms and plants as a way of influencing the number of condensation nuclei and, by extension, affecting cloud formation and precipitation over the rainforest.
Christopher Pöhlker, a Ph.D. student in Dr. Ulrich Pöschl’s and Prof. Dr. Meinrat O. Andreae’s lab at the Max Planck Institute for Chemistry, recently made the discovery using a new aerosol analytical method at HZB’s BESSY II x-ray microscope, MAXYMUS, and at the Lawrence Berkeley National Laboratory’s synchrotron radiation source in California, USA.
Pöhlker examined organic aerosol particles that were collected from air filters and small, paper-thin plates in the untouched Brazilian rainforest north of Manaus, which allowed the chemist to precisely measure the particles’ potassium content. “We identified three different kinds of or-ganic aerosol particles and they all contained potassium salts,“ Pöhlker explains. “Our initial focus was on the organic material’s carbon, oxygen, and nitrogen content. But then, to our surprise, we found its potassium content to be extremely high – almost 20 percent!“ Internal structures inside the nanometer- to micrometer-size particles point to the fact that during oxidation and condensation of organic gas molecules, multi-phase processes also play a role – which involve different chemical phases like fog or cloud water and other gel-like organic substances. The results will help with the identification and quantification of the sources and impact of organic aerosol particles under pre-industrial conditions. This in turn can help scientists understand how the rainforest’s continental and regional climate works and its role in Earth’s “climate machine.“
Publication: Science 31st August 2012 “Biogenic potassium salt particles as seeds for secondary organic aerosol in the Amazon,”
http://www.sciencemag.org/content/337/6098/1075.abstract
Contact and further information:
Christopher Pöhlker: c.pohlker@mpic.de; Tel.: 06131 305-6303
Dr. Ulrich Pöschl: u.poschl@mpic.de; Tel.: 06131 305-6201
- Did marine life in the palaeocene use a compass?Some ancient marine organisms produced mysterious magnetic particles of unusually large size, which can now be found as fossils in marine sediments. An international team has succeeded in mapping the magnetic domains on one of such ‘giant magnetofossils’ using a sophisticated method at the Diamond X-ray source. Their analysis shows that these particles could have allowed these organisms to sense tiny variations in both the direction and intensity of the Earth’s magnetic field, enabling them to geolocate themselves and navigate across the ocean. The method offers a powerful tool for magnetically testing whether putative biological iron oxide particles in Mars samples have a biogenic origin.
- What vibrating molecules might reveal about cell biologyInfrared vibrational spectroscopy at BESSY II can be used to create high-resolution maps of molecules inside live cells and cell organelles in native aqueous environment, according to a new study by a team from HZB and Humboldt University in Berlin. Nano-IR spectroscopy with s-SNOM at the IRIS beamline is now suitable for examining tiny biological samples in liquid medium in the nanometre range and generating infrared images of molecular vibrations with nanometre resolution. It is even possible to obtain 3D information. To test the method, the team grew fibroblasts on a highly transparent SiC membrane and examined them in vivo. This method will provide new insights into cell biology.
- 5000th patient treated with protons for eye tumoursFor more than 25 years, Charité – Universitätsmedizin Berlin and the Helmholtz-Zentrum Berlin (HZB) have been jointly offering proton radiation therapy for eye tumours. The HZB operates a proton accelerator in Berlin-Wannsee for this purpose, while Charité provides medical care for the patients. The 5000th patient was treated at the beginning of August.