mr. bojangsjang
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What type of PAR rating do most seagrass species need? Also I hardly no anything about PAR, so are there any calculators or articles that you guys have n PAR?
PAR and seagrass
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Samala
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From the Reefkeeping article:
"As photosynthetic autotrophs, seagrasses require relatively high amounts of light when compared to marine macroalga. Seagrasses use light in the photosynthetic active radiation (PAR) range of 400 - 700 nm, which encompasses light of several colors (red, orange, yellow, green, blue and violet) that humans see together as white light. The scientific literature typically reports minimum light requirements for seagrasses as the percentage of surface irradiation that reaches the plants after it travels through the water column. Most seagrasses require light levels at 10 - 30% of surface irradiation for survival, though Halophila, as a deep-water genus, can survive at just 5%.16 As aquarists we are much more familiar with the photosynthetic photon flux density (PPFD) measurements of PAR, in units of micromoles/m2/second. (See Sanjay Joshi references.) However, we can convert from surface irradiation to PPFD by using the widely noted measurement of 2000 PPFD for noon surface irradiation in the tropics during the summer. Applying this, the majority of seagrasses require 200 to 600 micromoles/m2/sec of light and the Halophila genus requires 100 micromoles/m2/sec.
I have found that these measurements of light requirements from wild seagrass beds also hold true for aquaria cultured star, shoal and manatee grass. Halophila engelmannii has grown well in aquaria with 90, 150 and 280 micromoles/m2/sec. Halodule wrightii and Syringodium filiforme did not grow in 90, only slowly in 150 and had very good growth in 280 micromoles/m2/sec. Thalassia testudinum probably fits into the higher range of required light levels as it reportedly does best under very intense illumination (Bill Chamberlain, pers comm). My Thalassia have not shown any remarkable growth in the highest light regimes I have so far attempted, though light may not be the only contributing factor. "
It might be helpful to read the section under "Lighting" in my first webpost on seagrasses.
The only caveat for that page is that I assumed a linear output of PAR from bulbs, and there is actually a logarithm function for the output, which is nicely detailed in Sanjay Joshi's "Facts of Light" articles that appeared in ReefKeeping. I definitely refer you to them for a detailed and easy to read reference on all things concerning light.
Part I: What is Light?
Part II: Photons
Part III: Making Sense of Light Measures
Part IV: Color Temperature
>Sarah
"As photosynthetic autotrophs, seagrasses require relatively high amounts of light when compared to marine macroalga. Seagrasses use light in the photosynthetic active radiation (PAR) range of 400 - 700 nm, which encompasses light of several colors (red, orange, yellow, green, blue and violet) that humans see together as white light. The scientific literature typically reports minimum light requirements for seagrasses as the percentage of surface irradiation that reaches the plants after it travels through the water column. Most seagrasses require light levels at 10 - 30% of surface irradiation for survival, though Halophila, as a deep-water genus, can survive at just 5%.16 As aquarists we are much more familiar with the photosynthetic photon flux density (PPFD) measurements of PAR, in units of micromoles/m2/second. (See Sanjay Joshi references.) However, we can convert from surface irradiation to PPFD by using the widely noted measurement of 2000 PPFD for noon surface irradiation in the tropics during the summer. Applying this, the majority of seagrasses require 200 to 600 micromoles/m2/sec of light and the Halophila genus requires 100 micromoles/m2/sec.
I have found that these measurements of light requirements from wild seagrass beds also hold true for aquaria cultured star, shoal and manatee grass. Halophila engelmannii has grown well in aquaria with 90, 150 and 280 micromoles/m2/sec. Halodule wrightii and Syringodium filiforme did not grow in 90, only slowly in 150 and had very good growth in 280 micromoles/m2/sec. Thalassia testudinum probably fits into the higher range of required light levels as it reportedly does best under very intense illumination (Bill Chamberlain, pers comm). My Thalassia have not shown any remarkable growth in the highest light regimes I have so far attempted, though light may not be the only contributing factor. "
It might be helpful to read the section under "Lighting" in my first webpost on seagrasses.
The only caveat for that page is that I assumed a linear output of PAR from bulbs, and there is actually a logarithm function for the output, which is nicely detailed in Sanjay Joshi's "Facts of Light" articles that appeared in ReefKeeping. I definitely refer you to them for a detailed and easy to read reference on all things concerning light.
Part I: What is Light?
Part II: Photons
Part III: Making Sense of Light Measures
Part IV: Color Temperature
>Sarah
mr. bojangsjang
New member
thanks sarah!
