How much light is too much?

Discussion in 'Lighting' started by 459b, 16 Feb 2015.

  1. 459b

    459b Moderator MASA Contributor

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    Came across this slightly old article today:

    Photobiology and growth of leather coral Sarcophyton cf. glaucum fragments stocked under low light in a recirculated system
    Rui J.M. Rochaa, b, , , Ricardo Caladoa, b, Paulo Cartaxanac, Joana Furtadoa, b, João Serôdio
    Aquaculture; Volumes 414–415, 15 November 2013, Pages 235–242

    Highlights:

    •Low PAR intensities do not negatively affect S. cf. glaucum growth and survival.
    •Low PAR intensities do not negatively affect S. cf. glaucum photobiology.
    •Low PAR intensities increase the concentration of coral endosymbionts.
    •Using low PAR intensities in ex situ coral culture can reduce production costs.


    Abstract:
    Corals are considered promising sources of new natural products and their culture, under controlled conditions, may be the solution for a sustainable and continuous supply of their biomass. Light is of utmost importance for ex situ production of corals harboring zooxanthellae, as their photosynthetic performance can significantly affect coral physiology and growth. The present study aimed to evaluate the effect of three light Photosynthetically Active Radiation (PAR) treatments (50, 80 and 120 μmol quanta m− 2 s− 1) promoted by 150 W (10,000 K) Hydrargyrum Quartz Iodide (HQI) lamps on the photobiology, survival and growth of the soft coral Sarcophyton cf. glaucum produced ex situ in recirculated systems. After 60 days of experiment coral fragments exposed to 50 μmol quanta m− 2 s− 1presented significantly higher values of Fv/Fm and Normalized Difference Vegetation Index, zooxanthellae density and most photosynthetic pigment concentrations, when compared with corals under higher PAR values. No significant differences were found on coral fragment survival and growth. S. cf. glaucum production under low PAR intensities can effectively reduce the production costs with electrical power, and simultaneously maximize the production of photosynthetic pigments or bioactive compounds mediated by the zooxanthellae.


    The PAR units tested were 50, 80 and 120!! If you remember this thread: Par readings on a deep tank - Marine Aquariums South Africa , values on tested lights reached over 300.....

    So are we wasting money on our super bright fancy lights?
     
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  3. dallasg

    dallasg Moderator MASA Contributor

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    yes they dont know GEN 3 has been realeased, hell they dont even know we dont use T8 anymore :p
     
  4. 459b

    459b Thread Starter Moderator MASA Contributor

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    Id like to see just how dull a par of 50 really is. Any chance you can get a par meter?
     
  5. RiaanP

    RiaanP Moderator

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    well, I'm not paying US $39.95 for an article where they used obsolete light units in the first place. Plus its on a leather softy, that can easily survive with lower PAR readings, after all, being a softy they are not normally found within the wave break zone.
     
    Last edited: 17 Feb 2015
  6. NO3

    NO3

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    Id agree 100% i run my PS unit on 30% ATM:lol:
     
  7. 459b

    459b Thread Starter Moderator MASA Contributor

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    Why is the light obsolete? PAR is PAR no matter where it comes from. True its on a softy, ill see if i can find any info on more light demanding corals, but how many people here keep leathers under radions?
     
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  8. RiaanP

    RiaanP Moderator

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    ME!!!

    [​IMG]
     
  9. NO3

    NO3

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    LOL....... that awkward moment
     
  10. Lord_Blackadder

    Lord_Blackadder

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    Different species, different requirements. S. trocheliophorum (the most common one) is usually in less than 10m, often as shallow as 1-2 and in fairly exposed conditions. I've even seen them in rockpools.
     
  11. Monti

    Monti

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    Damn @RiaanP- you could make a couch out of each of those leathers
     
    Last edited by a moderator: 26 Nov 2015
  12. NO3

    NO3

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    agreed in indo they come right out the water @ high tide.
     
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