--Bruce Stallsmith
Huntsville, AL, US of A
>From: "Todd Crail" <farmertodd_at_buckeye-express.com>
>Reply-To: nanfa_at_aquaria.net
>To: <nanfa_at_aquaria.net>
>Subject: Re: NANFA-- 135 gal. Freshwater Tank
>Date: Tue, 3 Feb 2004 10:19:02 -0500
>
>This doesn't suprise me. Well at least now... I have a good friend who did
>his masters studying the plasticity of lupine plants in various degrees of
>shading. I was suprised to find out how much more PAR terrestrial systems
>require/receive.
>
>To make a comparison, the sun in our Northwest Ohio region, open prairie,
>in
>June recieves 1100 5Mols7m27sec. He would shade from that point down. All
>the way to 400 5Mols7m27sec, which was a point where death became an issue.
>
>The 400 watt metal halides I was using to make all my _tropical_ corals and
>macroalgaes grow and glow only registered in at 600 5Mols7m27sec in the
>open
>air!!! This is stuff that lives in 4' of water under the Fijian sun, where
>it's more accepted that the values there above the water surface are 2000+
>5Mols7m27sec !
>
>We discovered this as we were trying to conserve energy and use metal
>halide
>to light our baby lupine and New Jersey tea plants instead of running a
>bazillion flourescents. It worked out okay because we were only mimicing
>the April sun, and the discrepantcy in light worked out to be "75% shade".
>
>So much for that Tim the Tool Man Taylor "Reah rreeee grot prooower huh huh
>huh!" :)
>
>But it blew my mind that something I thought I was _scorching_ was getting
>a
>severely reduced amount of light energy due to reflection at the water
>surface, refraction in the column, minerals and any organic matter
>absorbing
>the photons.
>
>I think we can extrapolate that to create this kind of color from the
>tropics:
>http://www.farmertodd.com/images/Shawn/DSCN2201.JPG
>That these coral have evolved to receive about 20-25% of the available PAR
>intensity, even in shallow depths! Most of these corals are hermatypic
>fore
>reef, back reef animals. I think only the reef crest ones are those who
>can
>really take the beating (that 2000 number), as low tides as spring and fall
>have them actually exposed to the full sun.... They have evolved coping
>mechanisms tho (pigments, slime, etc) I'm sure there's a study
>somewhere....
>
>So, 3% of the radiation at northern latitudes, in tannic and or organic
>loaded water... Yep, that makes a ton of sense.
>
>Here's a nice site I found while poking around refreshing myself on units
>and stuff. Might be worth a looky.
>
>http://www.coralreefecosystems.com/ltg_technical_data.htm#Spectral%20Distribution
>
>Todd
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