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  1. #21
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    Great idea Scott. Bill has shown interest in Uroplatus and even published information in the past so his help would probably get the most accurate and scientific information. I know from experience, the right ratio of UV (no D-3) made many of my past Uroplatus as productive as a leopard geckos...

  2. #22
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    Thank you Doug!!!!

    I have not had one ounce of negative feedback from one person. This study could really turn into something way more useful than what I had origianlly thought. In a seperate follow-up email to the one posted, below Frances has graciusly offerd to help organize the results of the project in a formulated scientific manner and add the research results to the UK UV Guide website!
    The two meters below are the units we will be buying. As you will read they will fit our application, are high tech and affordable, and are used world wide by many performing reptile UV research as we speak (it is important we use universal meters!!)
    Most importantly this company also sells a meter for under $200.00 which any of us could use and afford in order to get readings in our terrariums to help simulate lighting needs.

    Frances Baines response:

    Date: Wed, 5 Mar 2008 01:23:37
    Hi, Scott.

    Thanks for contacting us.

    What an excellent project. I'm convinced that many nocturnal species receive all the UVB they need during the day, since there is published work showing that the skin of at least one species of gecko is extremely efficient at producing vitamin D3 from low levels of UV light, and there is also circumstantial evidence that many species sleep with parts of their body exposed from the entrance of the shelter/ crevice etc - especially the tail, which of course can be shed if attacked by a predator. Our skin shed samples also reveal high transparency to UVB light in nocturnal and crepuscular species studied... suggesting that if any UVB is there, it can be utilised.

    We are very excited to hear of yet another project involving the recording of UVB in the natural habitat. I have just received a report from Dr Gary Ferguson (who, you may know, researched in detail into the UVB requirements of Panther Chameleons) in which he and his team took ambient UV Index recordings and temperatures from wherever they encountered Texas Spiny Lizards (Sceloporus olivaceous) during a regular walk taken each day by a member of the team, over a year.
    A research worker from the Durrell Institute in Jersey, Matt Goetz, has been studying the UVB environment of wild Blue Iguanas (Cyclura lewisi) - this is the second year he has done this, and he will be continuing for yet a third visit - again recording the total UVB and UV Index where an iguana is found - although he follows one iguana for a whole day or series of days.
    A German author of a book on tortoise husbandry, Horst Kher, is off to follow wild tortoises in Turkey in the summer.
    In Alice Springs, in Australia, Peter Nunn, a herpetologist, is likewise planning to take matched pairs of readings for total UVB and UV Index whilst following long-nosed dragons Amphibolurus longirostris over full days during his study.
    I believe your project will be, however, the first ever to look at the UVB environment of a nocturnal species! Your results could help change the whole way we keep crepuscular and nocturnal lizards forever....
    If you want results that unequivocally show that the UVB from sunlight in the rainforest can produce vitamin D3 - where light levels are going to be pretty low and humidity is going to be very high - you are stretching to the very limit, what technology is currently available.
    I'm assuming you don't have the budget for a portable spectrometer with laptop. You would also need a fairly high quality one as the intensity of light will be low and the percentage of light in the UVB range that makes vitamin D3 is very, very small....

    You therefore need sensitive hand-held meters.
    What are available are all so-called "broadband" devices. The serious-quality ones vary in price from a few hundred dollars to thousands of dollars. Unfortunately, because they are ALL calibrated differently and have different sensors, no brand will give you exactly the same reading as a competitor's brand, for the SAME lamp or light source! Dr. Bill Gehrmann wrote a paper on this subject - he's done many years of research on reptile lighting.
    The answer is, for as many scientists and herpetologists to use the same device as possible. And fortunately for all of us, the devices that have been taken up most readily by people worldwide are some of the most inexpensive... the little Solarmeters designed by Steve Mackin in Michigan.
    Dr. Bill Gehrmann and Dr. Gary Ferguson, in Texas, as well as Matt Goetz and Peter Nunn, currently use two Solarmeters for their studies - the Solarmeter 6.2 (total UVB) Welcome to Solartech
    and the Solarmeter 6.5 (UV Index) Welcome to Solartech
    (or the earlier model, the 6.4 which has, however, rather confusing units of measurement, Units of D3 per minute, which only refer to human skin, necessitating conversion of the readings to UV Index by a simple mathematical formula.)
    I will need to explain to you, why you need two. (Yes, it is a huge initial outlay, but compared to the total cost of a trip to Madagascar, surely it cannot be too frightening a sum? And the pair are a powerful tool which, together with an infra-red non-contact thermometer, would be able to equip numerous expeditions for years to come...)
    I know you mention that you don't really understand the technical part of the ranges these meters read, but I think I can explain it. It's important, because your results are important.

    I've attached a picture of the spectrum of the sun, recorded with a spectrometer.
    If you've never looked at one before, it may look confusing... but it's ok. The numbers at the bottom are the wavelengths - the rainbow shows what colour (in the visible light range) that wavelength is; for example, reds are above 630 - 640 nanometers (nm); blues are about 400 - 465nm. Ultraviolet is at shorter wavelengths than we can see - below 400nm.
    Then above this, there is a wavy red line. This graph line shows the intensity of the light (taken in a single "snapshot" by the spectrometer) at each wavelength. So, the higher the line is, above the wavelength directly below it, the more intense was the sun's light at that wavelength.

    The sun's light begins at about 290nm in the tropics with the sun overhead; as the sun falls in the sky, the atmosphere blocks the lower wavelengths selectively so as far north as here in Wales, UK, where I live (or early morning/ late afternoon in the tropics) all light below about 300nm is blocked by the atmosphere. That's why the line goes down to zero at just below 300nm.
    You can see that only a very, very small amount of light is present below 315nm. That is the crucial "vitamin D3-producing" light. And look how much more higher-wavelength UVB and UVA there is....
    When you get into the visual light, after a bit of an up-and-down seesaw with the blues, you can see that there is more blue than red, but basically, a lot of visible light right across the spectrum. This is from a clear mid-day sun giving a strong, blue-white sunlight.....

    Now, to measure the tiny amount of light that is in the UVB range requires a very sensitive meter. Many much more expensive broadband UVB meters than the Solarmeter 6.2 don't have its sensitivity... it can register one microwatt of UVB per square centimetre (1W/cm) which is absolutely excellent.
    However, it is a BROADBAND meter so it looks at, and adds up, anything from 280nm (none in sunlight) right up to 320nm, and high levels of UVA up to even as high as 330nm will get a small reading at the edge of its sensitivity.
    What this means is that you have a very sensitive instrument that will give you a reading in very poor light. I think you need this, especially, for your study... but the reading it gives you does NOT tell you exactly how much of that light is in the crucial 290 - 315nm range. With sunlight, if you are getting high readings the light almost certainly contains some.... but with lower readings you can't be so sure. If what's causing the low readings is shade or overhead cloud in front of a noonday sun, it may still have the same fraction of low wavelength UVB than it would have had... only less of all wavelengths, if you see what I mean. But if what's causing the low readings is a sun that's low in the sky, then most of the shorter wavelengths will have been absorbed by the atmosphere.
    We have been collecting solar data with just this one meter for several years now (see the files in the Solar folder in the Files section of the Yahoo Group: UVB_Meter_Owners : UVB Meter Owners) but it is not ideal because it can't be accurately linked to vitamin D3 production. (Especially with artificial lamps, but that's another story)

    Then along came the Solarmeter 6.5. I only started using this just over a year ago and haven't got much of the website updated sufficiently, yet, to show my results... but I am very impressed. This has a different sensor, and it only responds to exactly the wavelengths we want! Its peak response is from 290 - 298nm with a much more sharply fading response up through to 315nm. It's calibrated to give the readings in terms of the UV Index, which is really easy to understand... and it "proves" whether the light has vitamin D3-producing ability.

    Soooo... why not just use a 6.5?

    Ah. Well, look at the solar graph again. Look at the difference in the amount of light below 298nm, which this meter "sees" and the amount below 320nm, which the 6.2 meter "sees"...
    This meter cannot possibly be expected to detect vanishingly small amounts of light... not even our spectrometer does that very well... so the accuracy diminishes noticeably in deep shade. To the user, it seems "less sensitive" - when the levels are very low, it often flickers between 00.0 and 00.1 and it often does so anyway, because the gain is turned up so high, or something (I don't know the technical way of explaining that) that it rarely says exactly zero. I routinely ignore the last 1 of the 00.1and subtract it automatically from every highest reading I see.
    But it does work in rainforest. What you do, is take paired readings for the patches of sunlight filtering through the canopy with the UVB and UVI meters... that gives you a ratio of total UVB:UVI .... and once you have a set of paired readings for a time and place, you can use regression analysis, knowing the total UVB, to measure the UV Index (even if it is very small)


    Here is a link to a piece showing my use of these two meters in Daintree rainforest in Queensland:Daintree Rainforest, Queensland, Australia - UVB and light recordings


    The only other difficulty with working in rainforest is.. rain. The meters, like all delicate electronics, don't like high humidity. It causes the baseline readings to go up from zero by several points if the meter is in really wet air. The secret is, according to Steve Mackin, to keep the meters in a waterproof bag with silica gel, and only poke the sensor out when you're actually taking readings.
    I have never had trouble with mine.... but it wasn't raining or more than 80% humidity while we were there, so maybe that wasn't high enough to make them malfunction. (Steve says if it does happen, they dry out just fine when you get back to an air-conditioned hotel...)

    I've recently been asked to proof-read a paper due to come out in the Chicago Herp Soc bulletin (in April I think) by Dr. Bill Gehrmann, Jukka Lindgren and others, in which they found excellent (95%) correlation between the readings taken with a 6.4 meter (same sensor as the 6.5) and Dr. Gehrmann's in vitro vitamin D3 assays, where light produces vitamin D3 in test tubes, which can be measured accurately.

    So this would be my recommendation....
    A Solarmeter 6.2 (essential for very low light) and a Solarmeter 6.5 (hopefully, for proof that there's D3-producing wavelengths down there)
    If you absolutely can't get both, get the 6.2.

    Plus a 100% waterproof tote bag for them. I'm buying one of these for my next field trip: AQUAPAC - 100% Waterproof Cases for MP3, Camera, Phone, VHF, GPS and more

    And take lots of photos of the readings being taken! This is excellent for people who need that little bit more convincing.

    I wish you every success... please keep us posted. If there's any way I can help further, just ask.
    We would love to have your material on our website. I'm planning to put up Dr. Gary Ferguson's report soon, along with some other field recordings that I have been sent.

    With best wishes,

    Frances Baines


    UV Guide UK - Ultraviolet Light for Reptiles - UVB reptile lighting on test
    Last edited by Scott F; 05-09-2008 at 09:16 AM.

  3. #23
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    This definitely sounds like it should be done. I'm behind this project along with GU and will gladly kick in a decent amount towards it. I'd ask members and vendors to do the same. PM me when you're ready to collect funds. I'm Marty, GU Admin, and I approve this message

    MistKing.com - Adjustable Reptile & Amphibian Vivarium Misting Systems

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  4. #24
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    This is the equipment being used along with actual total project cost:


    (1) Solarmeter model 6.2 -------- $179.00
    (1) Solarmeter model 6.5 -------- $179.00
    (plus shipping) ---------------$7.00

    (2) water proof cell phone bag ---$50.00
    (including shipping)
    -----------
    TOTAL COST: $415.00



    ***** $415.00 IS THE AMOUNT OF MONEY WE HAVE TO RAISE *****

  5. #25
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    Not bad at all... Count me in for $100

  6. #26
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    Thank you Marty and Geckos Unlimited for promoting the advancement of cutting edge research in herpetoculture.......this is what it is all about people!
    Last edited by Scott F; 03-06-2008 at 10:28 AM.
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  7. #27
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    Thanks for your vote of confidence on entrusting me to record UV data for the group. I hope I'm able to return and carry it out for you. Please don't hesitate to let someone else do this too in case someone gets the op to go before me, as having multiple readings from various regionss and species' ranges would be all that much better.

    The process doesn't sound too complicated to figure out as long as you send the instructions along with the one or two devices. Protecting them is nothing I'm not used to already doing with my camera gear. Taking photos of the readings being taken, and the habitat, would be no problem either.
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  8. #28
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    I would like to give Bill a "special" thanks.



    Much can be accomplished through the dedication of few.
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  9. #29
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    Bill nice to have you here. Welcome to GU!

  10. #30
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    Hello, everyone.
    Thank you for inviting me to join the group here, Scott... and for inviting me to help with what sounds like a magical combination of a very serious research project and a glorious adventure...
    I wish we were all going to Madagascar with Bill Love, don't you?

    I'll certainly help where I can, but this is your project, GU team. It's amazing what a small group of dedicated, serious amateurs - armed with enthusiasm and the internet - can achieve when they work together.

    Bill Love -hi; good to meet you! You'll find using the meters very easy and they are small enough to tuck both of them into one SLR lens pocket in a camera bag.

    Keep in touch.

    Frances
    Frances Baines
    UV Guide UK
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