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ALGAE IN DARKNESS 33

The world’s oceans teem with unicellular algae that carry out photosynthesis in the sunlight. 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. 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.

For more information follow this link: http://idw-online.de/en/news413265
Wed March 16 2011 10:19:50 AM by AlgaeNova algae  |  diatom  |  research  |  marine micobiology 2798 views

Comments - 3

  • Shankar wrote:
    Fri April 01 2011 11:51:02 PM

    Good post.

    Vote Up! 0 Vote Down! 0

  • Vivek wrote:
    Wed April 06 2011 04:29:46 AM

    Hello,   Very nice and juicy post..Ya its true that Algae can survive in Darkness,we are also working on some species and the result is positive..   Life changes its form according to Nature...
    Best RegardsVivek

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  • Samson wrote:
    Thu April 07 2011 10:22:54 AM

    Hi

    I would like to build a small algae pond to grow algae cultures.

     

    Can you please take me step by step what are the pre requirement

    of an Algae pond.

    e.g the kind of water,nutrients ,light needed etc.

    or

     

     

    Is there a place where I can buy a small ready made algae pond like a small fish tanks.

     

     

    once I can get this Algae pond I would then be in a position to buy Algae Cultures .

     

     

     

     

    from

     

     

    Samson Ndou

    ndousm@eskom.co.za

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