Очередная любопытная статья (ангельский) - Coral growth under Light Emitting Diode and Light Emitting Plasma: a cross-family comparison

[Dann 49]

Coral growth under Light Emitting Diode and Light Emitting Plasma: a cross-family comparison

 

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The measured spectra differed significantly between LEP and LED. The LED fixture, consisting of three different LED types (white, blue and royal blue), emitted a spectrum with a strong blue peak around 458 nm. The LEP fixtures showed a balanced irradiance over the entire visible spectrum, with an exception of two dips around 412 and 452 nm. Irradiance of UV-A (315-400 nm) and infrared (>750-780 nm) was also measured. A spectral analysis was conducted for each of the three irradiance intervals applied, which demonstrated that spectrum was not affected by irradiance level. A 12:12h light:dark regime was used for all treatments. All treatments lasted 70 days.

 

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Interestingly, a positive effect of irradiance on the growth of Stylophora pistillata was only found for the blue-dominant LED spectrum. Under a more balanced LEP spectrum, containing more red and less blue light, S. pistillata already maximized its growth at the lowest irradiance.

 

Pocillopora damicornis showed negative growth rates under all LED treatments, which was a result of tissue necrosis. It is unclear why this occurred, but it may have been due to limiting water flow rate.

 

Montipora aequituberculata exhibited highest growth rates under LED at low irradiance, which contrasts with the results of other species. In a similar way to S. pistillata and A. millepora, this species may be chromatically adapted to a high blue spectrum, which is found in the wild at depths below approximately 10 meters.

 

All other species investigated in this study showed no clear preference for one particular spectrum, which may be a reflection of the plasticity of their zooxanthellae, in terms of chromatic adaptation.

 

the results reveal that the effect of irradiance on coral growth is less prominent than often believed. For only three out of the ten species investigated (S. pistillata, Seriatopora hystrix and A. millepora), a positive effect of irradiance was found. In addition, the effect of irradiance was saturating, i.e. a higher irradiance did not result in a proportional increase in specific growth rates.