It has been known for a while that the particularly abundant diatoms (unicellular algae with a silicate frustule) are also able to survive in the dark bottom of the ocean, where neither photosynthesis nor respiration with oxygen is possible. Scientists of the Max Planck Institute for Marine Microbiology now disclose this artifice of the algae in the journal Proceedings of the National Academy of Sciences: In darkness, the diatoms breathe with nitrate in place of oxygen.
Laser-scanning-fluorescence image of the marine diatom Amphora coffeaeformis. Red: auto-fluorescing chloroplasts, green: lipid membranes (stained with MDY-64). Martin Beutler, bionsys GmbH, Bremen, Germany (www.bionsys.de).
Microalgae often measure only a few hundredths of a millimeter, but due to their vast abundance in the world’s oceans they are responsible for about 40% of the marine primary production, i.e., the biomass production via carbon dioxide fixation in the sunlight. They often appear as massive blooms near the sea surface or as greenish-brownish meadows on the sea floor, if still reached by sunlight. However, diatoms (unicellular algae with a silicate frustule) are also able to survive in the absence of sunlight and oxygen, for instance, buried in the sea floor.
Anja Kamp, Dirk de Beer, Jana L. Nitsch, Gaute Lavik, and Peter Stief, scientists at the Max Planck Institute for Marine Microbiology in Bremen cultivated several diatom species in the laboratory to explore the metabolic process that allows the tiny algae to survive in darkness. A correlation was found between the nitrate that is stored by a diatom cell and its ability to survive in the absence of sunlight and oxygen. The more nitrate the cell contained, the longer it could survive in darkness where the cell does not have the possibility to produce oxygen via photosynthesis for its own respiration. In experiments with the coffee-bean-shaped diatom Amphora coffeaeformis, the scientists proved that diatoms use the nitrate stored in their cells for respiration in the absence of oxygen. Within just one day, most of the stored nitrate is used up, converted to ammonium, and excreted by the cell.
A key finding of the Max-Planck scientists was that diatoms use nitrate just for respiration rather than for biomass production, as would be the case in sunlight. Anja Kamp says: “The rapid consumption of nitrate and the absence of biomass production tell us that nitrate respiration in diatoms is a metabolic process that only serves to prepare the cell for a resting stage and therefore nitrate respiration is not sustained for longer time periods.”
In bacteria, nitrate respiration in the absence of oxygen is nothing exceptional, as many of the bacteria studied at the Max-Planck-Institute are able to breathe with nitrate, sulfate, or even iron compounds. It is more spectacular to discover that algae, i.e., organisms with a cell nucleus, are able carry out both photosynthesis and nitrate respiration, each under different environmental conditions. These results have just been published in the renowned interdisciplinary journal Proceedings of the National Academy of Sciences.Further inquiries to:
Dr. Manfred Schloesser | Max-Planck-Institut
UK chemistry researchers develop catalyst that mimics the z-scheme of photosynthesis
26.06.2017 | University of Kentucky
New research reveals impact of seismic surveys on zooplankton
26.06.2017 | University of Tasmania - Institute for Marine and Antarctic Studies
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Ecology, The Environment and Conservation
26.06.2017 | Life Sciences
23.06.2017 | Physics and Astronomy