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c'est bien une ampoule pour les plantes car les pics de jaune et rouge étaient super important les plantes adorant ça.. mais cette ampoule mise en récifal avec son super bleu trompeur transformerai vite nos bac en marais a algues nuisibles,

 

Bonsoir,

 

L' as tu testée cette ampoule pour avancer ca?

 

Je l' utilise depuis trois ans en 400w sur mon bac et je ne suis pas d' accord avec ce que tu dis car je n' ai pas d' algues nuisibles, enfin ca n' a pas l' air .... ;)

 

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l'échange dans les commentaires sur Advanced Aquarist indique en plus qu'il y avait apparemment un gros problème au niveau de l'eau utilisée pendant les expériences.
Donc c'est quand même un cumul de circonstances qui a mené ces nécroses et pas seulement la lumière rouge…
 

Tim Wijgerde  Karl Krzyminski  13 hours ago

 

Leonard, thanks for "illuminating" our research on Advanced Aquarist. I have to note here that the image above was taken before we introduced PVC boards to completely prevent the different spectra from overlapping, which would of course confound the results. The flow pumps were positioned just below these boards, to maintain sufficient water flow.

Having some red light in your spectra is no problem at all. I suspect red irradiance can be quite high for corals that are acclimated to a shallow environment-where high red irradiance persists-without negative effects. What is important is that at least some blue light is present in the spectrum, to maintain growth of the zooxanthellae. If no blue light is present at all, the cell cycle of zooxanthellae is disrupted. In addition, red light in the 100's of micromols can lead to bleaching events, i.e. a dramatic loss of chlorophyll. I think that most, if not all currently used light spectra are balanced enough to prevent this, as long as corals are slowly acclimated to higher irradiances.

In addition, Jason makes the fair point that we used only one genotype of coral, with one complement of zooxanthellae. Thus, we should be careful with extrapolating our results to all corals. Nevertheless, our study seems to be nicely in line with previous studies, including the one by Dana Riddle (2003) published in AA. The reason we conducted this study was that we wanted to answer the following question: are the negative effects of red light on corals caused by the presence of red light, or the absence of blue light? It seems that both are true, where blue and red light are co-dominant in terms of regulating zoox density in Stylophora pistillata, and red dominant over blue light regarding chl a synthesis.

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    Ted_C  Tim Wijgerde  8 hours ago

    I read the full study and found it fascinating. Good job in your analytical
    techniques and outlines. 
    From your discussion section - it appeared that all of the coral fragments in your
    study were "on their way out" - i.e. dying (from Zinc concentrations
    or something else) and your conclusions were leaning more towards blue light
    was giving them something they needed (anti-oxidants) to live in the
    environment while the red and white light was giving them nothing they needed
    to counteract the high concentrations of Zinc or whatever may have been
    bothering them. So the title "red light negatively affects coral health"
    seems a little misleading to me.

    If we take that premise that there was an issue within the experiment with high
    zinc concentrations negatively affecting the coral - then that issue would also
    affect your quantum measurements and the NVDI. So you would see the effects downstream in all of your samples (which I think was demonstrated).
    I would be more apt to compare wavelengths of light for corals to required vitamins for humans. Without certain vitamins (like citric acid) - we have a hard time processing food into energy. We can still do it - but it's not optimum. If we are sick or have some other problem - then the lack of citric acid becomes critical. We can't substitue citric acid with anything else to complete our energy cycle.
    Same with corals - They have all developed their own methods of survival where light spectrums are equivalent to our citric acid. Change the spectrum by moving them up or down the water column and yes - they may survive but they wont thrive. If they are already "stressed" from some other issue - then they may not be able to tolerate the change.

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      Tim Wijgerde  Ted_C  4 hours ago

      Hi Ted, the title "red light negatively affects coral health" was not conceived by me, nor was it the title of our paper. You are indeed right that zinc or other issues may have been responsible for the necrosis we observed. I myself am more interested in the effects of red light on zoox densities and chl a, rather than the survival rates. Of course, we only took healthy tissue for our analysis.

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        Leonard Ho Mod  Tim Wijgerde  2 hours ago

        Sorry if the title was misleading. It was derived from the abstract's final concluding sentence: "Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata"

 

 

il faudra que je trouve le temps de lire l'article en entier, mais il me semble qu'il y a quelques raccourcis rapides qui sont pris entre observations et conclusions.

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Au fait est ce qu'on s'ai posé la question pourquoi du rouge est rajouté dans les rampes.

 

En effet la quantité de rouge necessaire est minime vu l'absorbtion de ces longueurs d'onde mais n'est pas nul.

 

Par contre le rajout de cian qui est bénéfique donne un aspect visuel pour notre oeil vert jaune ce qui ne plait pas a bon nombre d'entre nous.

 

Le fait de rajouter du rouge au cian avec le bleu déjà omniprésent nous donne du Blanc et contrebalance cette aspect visuel vert jaune.

 

Après c'est comme tout une question de dosage. C'est un peu comme si nous nous amusion a boire que de l'eau osmosé( TDS à zéro).

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  • 1 moi plus tard...

Un nouvel article intéressant vient de voir le jour sur le sujet des différents spectres et intensités lumineuse des LED vis à vis de leur efficacité photosynthétique et de leur action sur le cycle des Xanthophyll des coraux à court thermes : http://www.advancedaquarist.com/2014/5/aafeature

 

Comme quoi les rouges (631 à 657 nm) ne seraient pas si inutiles que ça, selon leur intensité.
 
Une étude sur le long thermes est en cours de réalisation.

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