Lower Light Par With Longer Duration Vs High Light Par Shorter Duration

[reeftankdude]

Example 100 par light with a duration of 12 hours vs 200 par light with a duration of 6 hours. Would corals do just as well with 100 par and 12 hours? Thanks all

 

[blaxsun]

I run my lights for 12 hours, and the PAR ranges from 100-125 at the start/end of the day to 250-175 at the peak.

 

[oreo54]

Example 100 par light with a duration of 12 hours vs 200 par light with a duration of 6 hours. Would corals do just as well with 100 par and 12 hours? Thanks all

Theoretically probably close.

In the general photosynthesis world that is termed dli. Daily light integral

Using the same dli but going from say 10 to 12 hours of light may not increase nor decrease photosynthesis.

There seem to be a few gotcha like 1200 par for an hour is probably not like 100 par for 12 hours. Metabolic systems have ramp up times.
Or if you exceed photosaturation levels.


I don't t know of any studies done on the effects of equal dli but varied time frames on corals though.

There are regarding different dli' s though

Effects of variability in daily light integrals on the photophysiology of the corals Pachyseris speciosa and Acropora millepora

Phototrophic sessile organisms, such as reef corals, adjust their photosynthetic apparatus to optimize the balance of light capture versus protection in response to variable light availability (photoacclimation). In shallow marine environments, daily light integrals (DLI) can vary several-fold...

journals.plos.org

But it's all complicated as you will see by this:
https://www.mdpi.com/2073-4395/9/12/857/htm

Oddly the equal dli but using varied intensity ( low/ high/ low) had some of the the more pronounced differences.

Some people swear by split ( or see saw) photo periods.

Just more experiments.

 

[Nano sapiens]

Example 100 par light with a duration of 12 hours vs 200 par light with a duration of 6 hours. Would corals do just as well with 100 par and 12 hours? Thanks all

The effects of two such drastically different lighting regimes is a very difficult question to answer since the different corals/false corals can have very different lighting needs/wants. If I were to be restricted to one or the other, I would ensure that the coral communities selected would be amenable to the respective lighting conditions.