ScubaBabe22
Guest
i'm sorry. You did WHAT? in WHAT? No thanks. There's sooo much that could go wrong with those suckers! I'll leave those levels to the scary fishes like Nemo and happily cruise along at a max of 130ft. Thaaaanks for playing!
how deep before it gets dark?
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Green_Manelishi
Contributor
Several dives @ Newfound Lake in Bristol, NH and always needed a light much
below 70ft. Not there was anything for me to see, but I still needed the light.
below 70ft. Not there was anything for me to see, but I still needed the light.
H2Andy:
There is a guy in Roatan (West End) that has a home made sub he takes down to 2000 FSW. He charges people to go down in it. He has been on the Science channel and National geographic.
I was told he rolls it back so you can look up and there is still a faint deep purple glow above after your eyes adjust to the darkness.
NO, I haven't yet got up the Kahuna's to try the sub yet. It is afterall home made!
This is what I found about light penetration and water depth. It seems that it various a lot, probably has to do with clearity of the water, temperature etc. But is seems that after 900 meter it is pretty much dark.
"Water depth versus light penetration
Sunlight obviously cannot penetrate beyond a certain depth in the ocean. Some organisms have, however, evolved to cope with the absence of sunlight at great depths. Plants require sunlight to carry on photosynthesisthe process by which they convert carbon dioxide, water, and other nutrients to simple carbohydrates to produce energy, releasing oxygen as a by-product. Below a depth of about 660 feet (200 meters), not enough sunlight penetrates to allow photosynthesis to occur. The area of the ocean where photosynthesis occurs is known as the euphotic zone (meaning "good light").
From the standpoint of living organisms, the euphotic zone is probably the most important of all oceanic zones. By some estimates, about two-thirds of all the photosynthetic activity that occurs on Earth (on land and in the water) takes place within the euphotic zone.
From 660 to 3,000 feet (200 to 900 meters), only about 1 percent of sunlight penetrates. This layer is known as the dysphotic zone (meaning "bad light"). Below this layer, down to the deepest parts of the ocean, it is perpetual night. This last layer is called the aphotic zone (meaning "without light"). At one time, scientists thought that very little life existed within the aphotic zone. However, they now know that a variety of interesting organisms can be found living on the deepest parts of the ocean floor."
"Water depth versus light penetration
Sunlight obviously cannot penetrate beyond a certain depth in the ocean. Some organisms have, however, evolved to cope with the absence of sunlight at great depths. Plants require sunlight to carry on photosynthesisthe process by which they convert carbon dioxide, water, and other nutrients to simple carbohydrates to produce energy, releasing oxygen as a by-product. Below a depth of about 660 feet (200 meters), not enough sunlight penetrates to allow photosynthesis to occur. The area of the ocean where photosynthesis occurs is known as the euphotic zone (meaning "good light").
From the standpoint of living organisms, the euphotic zone is probably the most important of all oceanic zones. By some estimates, about two-thirds of all the photosynthetic activity that occurs on Earth (on land and in the water) takes place within the euphotic zone.
From 660 to 3,000 feet (200 to 900 meters), only about 1 percent of sunlight penetrates. This layer is known as the dysphotic zone (meaning "bad light"). Below this layer, down to the deepest parts of the ocean, it is perpetual night. This last layer is called the aphotic zone (meaning "without light"). At one time, scientists thought that very little life existed within the aphotic zone. However, they now know that a variety of interesting organisms can be found living on the deepest parts of the ocean floor."
It also depends on the other divers in your group. Some divers don't seem to understand the concept of your eyes adapting to low light conditions and will immediatley turn on their dive lights - and then shine them in your eyes. Very annoying in those dim depths where with even a couple minutes of partial adaptation, you'd be seeing a lot more than with your light.
Since (mostly) full adaptation where the rods on your retina are nearly fully functional and no longer heavily suppressed by the chemical activity from the cones takes 20-30 minutes, I have toyed with the idea of using red lenses above water 30 minutes prior to the dive to pre-adapt my eyes. But I would also need a removeable red lens over my dive mask as well until I got 30 ft or so under water and that has been the catch so far.
Since (mostly) full adaptation where the rods on your retina are nearly fully functional and no longer heavily suppressed by the chemical activity from the cones takes 20-30 minutes, I have toyed with the idea of using red lenses above water 30 minutes prior to the dive to pre-adapt my eyes. But I would also need a removeable red lens over my dive mask as well until I got 30 ft or so under water and that has been the catch so far.
Brewone0to
Contributor
Hey Andy,H2Andy:oh, especially when you are cavern certified only, there's this photon field that moves with you ... and the daylight zone suddenly "extends" defying all the laws
of physics ...
Is there not a secondary ruling that the cavern ceases to be and becomes a cave at some point of penetration,reguardless of light being present?I thought this number was like 170' from surface or maw 70' into an overhead?
At least I thought I read that somewhere.
If this is true, then "the sign" doesn't signify the begining of darkness.
Although I can't recall seeing too many of them all that far from what I perceive as being "dark".
Brian
OP
H2Andy
Contributor
the definition of cavern depends on the agency; NSS-CDS defines it as the zone
in a cave where you can see ambient light, maximum 100 feet depth, 200 feet
maximum linear penetration (counting from surface).
then there are additional requiremenst, such as 1.4 ATA PPo2, minimum 70 cf to start
dive, no restrictions, etc.
(it used to be 70 feet max depth, and 130 max linear penetration, but that
was changed last year or the year before)
in a cave where you can see ambient light, maximum 100 feet depth, 200 feet
maximum linear penetration (counting from surface).
then there are additional requiremenst, such as 1.4 ATA PPo2, minimum 70 cf to start
dive, no restrictions, etc.
(it used to be 70 feet max depth, and 130 max linear penetration, but that
was changed last year or the year before)
I've been to 200ft in Fla and had plenty of light, enough that I didn't need or use my light.
anyway, it basicly means that these depth are to deep for recreational divers, so for most of the times the visibility depends on the current, tubidity and the divers in front of you (if you know that I mean )
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