Unihedron
General Category => General Discussion => Topic started by: admin on October 24, 2012, 07:42:21 pm
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Some researchers have used the SQM light meters for studying the effects of artificial lighting on sea turtle habits.
A few points about such studies would be:
- The Field of View (FOV) may be critical in your tests, see this chart (http://unihedron.com/projects/darksky/images/fovcurves.jpg). If you are using the meter as a directional light meter then the SQM-L model would be the best suited to pointing at specific bright spots.
- If you are taking sample readings over a period of time for comparison, make sure that the meter is located at the same spot and facing the same direction each time. It may be a good idea to have a registration stand (peg in the ground with a holder for the meter) to ensure that the meter is always facing the same direction for each successive sample.
- Also be aware that the FOV will capture obstructions like your body, so be sure to always hold the meter in the exact same direction above your head (to avoid and shading or reflection from your body into the meter sensor).
- You may want to gather readings from both Zenith (straight up) and various angles towards and away from the shore vertically and horizontally to get an idea of what the Turtles would see in their travels.
- Make sure you record the time and date as the Moon will heavily influence sky brightness. Even if the night is very overcast, a moonlit night will provide a wide range if readings. You will get the most consistent readings on moonless nights.
- If you have the funds, and access to a secure site on the beach, you may want to consider the SQM-LU-DL (http://unihedron.com/projects/sqm-lu-dl/) which can sit unattended for months collecting readings for later retrieval.
- The meter will likely not saturate at all in the night, even if you point it directly at distant condominium or hotel lighting.
- Please see this report (http://unihedron.com/projects/darksky/sqmreport_v1p4.pdf) (by Pierantonio Cinzano) for spectral response of the meter and other scientific details.
- A longterm exposure photo of the beach-line may be a good base image to obtain relative brightnesses so that light readings can be noted on there.
Here are some resources:- Cloud Coverage Acts as an Amplifier for Ecological Light Pollution in Urban Ecosystems (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0017307) by Christopher C. M. Kyba, Thomas Ruhtz, Jürgen Fischer, Franz Hölker, March 2, 2011
- http://www.conserveturtles.org/seaturtleinformation.php?page=lighting
- Broken link: http://www.fpl.com/environment/endangered/sea_turtles_and_lights.shtml
- Broken link: http://www.co.palm-beach.fl.us/erm/permitting/sea-turtles/seaturtlelighting.htm
- Broken link: http://myfwc.com/wildlifehabitats/managed/sea-turtles/turtles-lights/
- Broken link: Long Term Monitoring of the Marine Turtles of Scott Reef (http://www.woodside.com.au/Our-Business/Browse/publications/Reports/21%20Guinea%202010-%20Long-term%20monitoring%20of%20the%20marine%20turtles%20of%20Scott%20Reef%20-%20February%202010%20field%20survey%20report.PDF), February 2010 Field Survey Report, Michael L. Guinea, Charles Darwin University, Darwin 0909, Northern Territory, September 2010
Please reply with your comments regarding details about your own studies or questions.
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Here is an entertaining and educational podcast about Sea Turtles and light pollution By Molly Bloom – December 30, 2016:
http://www.brainson.org/lighting-the-way-for-sea-turtles-at-gulf-islands-national-seashore/
"We don’t know much about the long life of a sea turtle, since it’s
mostly spent in the ocean. When they do come ashore to lay their eggs,
we know the babies use the moon and stars to guide them back to sea.
But what happens when hotels and houses and streetlights compete for
their attention?
A citizen science group at Gulf Islands National Seashore in Pensacola,
Florida helps map the night sky in order to keep these mysterious
creatures on the right path."