Dear Prachi,

please contact Prof. B. C. CHoudhary, WWI, Dehradhun India or Kartik Shanker, IISC, Bangalore. They have done enormous work for turtles along the Indian coast

all the best

Deepak

Dear Prachi,

The best way according to me would be too use Thermal bands to map heat signatures along the coast which should be simple in any software that you are dealing with. Having said that I am curious to know whether your statement holds true i.e. temperature > 85F = female turtles and < 85 F = male turtles.. To confirm this why don't you make use of Landsat data that has been there for 2 decades+ and possibly you could correlate your hypothesis with SST also (more 3 decades worth of data). Prove that the statement is either right or wrong.

Now coming back to your question. Try either EarthExplorer or Giovanni (google 'em) to get Thermal Infrared data from Landsat. To identify heat signatures, look up for something called thermal heat islands.. This is a study done to map heat signatures in a city. Your signal is similar to that. Most softwares should be able to map your thermal signatures of the temperature range you mentioned. From this select your area of interest and get your satellite data for the last n year (n~15+years) and correlate your satellite temperature to the ratio of male/female turtles. Let me know if you have further questions in your process.

I am curious about your work, because mice and humans (rather most mammals exhibit this temperature preference in gender selection) and I want to know its bio-genitical impact due on Earth due to global warming (or climate change effects) induced gender selection. Feel free to ask any questions related to remote sensing data or its processing. Having said that you might want to first go through Nelly's reference and Deepak's professor's experience to begin with.

Regards

Raghu

I am also curious about this work but wonder if the spatial resolution of Landsat's Thermal Infrared Sensor (120, 60 or 100 m depending on satellite) is appropiate for this kind of work.

cheers,

Javier

Temperature-dependent sex determination has long been studied in sea turtle and many reptiles. The pivotal temperature (temperature which produce 50:50 sex ratio of hatchlings) seems to be slightly difference from beach to beach.

If you plan to use temperature map from satellite, please keep in mind that the temperature of sand surface and the temperature at the bottom of sea turtle's nest cavity (usually around 60 cm depth), which determine the sex ratio of hatchlings, are different. 

Another way to study thermal profile is to put temperature data logger into a new found nest and monitor it until they hatch.

To obtain temperatures needed to evaluate temperature dependent sex determination, you may need to rely on data loggers in the nests or at nest depths as previously mentioned.  I've had success affixing ibuttons to turtle shells to obtain high resolution behavioral data. If you choose to go this route, I'd suggest placing an ibutton in an underground nest with the eggs (and/or at nesting depths), and waterproof by wrapping it in self adhering Miracle Wrap found at hardware stores/internet search (total cost ~$20/each). You can set logging intervals as desired, and if enough nests/locations are logged, spatial interpolation methods may help you determine potential nesting temps across your study beach. Landsat may not be useful to examine microclimates that exist in underground nests, but it may be useful when related to your underground temperatures.

Erik Meyer will you please, brief me more about ibutton?

Hellow Prachi,

The thermal imaging camera might be helpful for your study.

Though I have not tried it yet.

At the same time you have to use thermometer for the sea trueth.

Good Luck.

Prachi Hatkar-I apologize, I've been on vacation and haven't been able to respond until now. These are the temp loggers I've been using:

http://www.maximintegrated.com/en/products/analog/sensors-and-sensor-interface/DS1921K.html

You can store 2048 points before the memory is full. Multiply the number of points by time to get the total time before the device is full, so 2048 points * 1hour/point = 2048. I record in 15 min intervals, which results in 21 days of data. Maxim integrated has waterproof cases but I can suggest more cost effective waterproofing if you're interested.

Hi all,

I'm a bit late but...

Satellite or other surface temperature data won't work for this, you need a data logger inside the nest in order to get the actual temperature deep in the sand.

there are many factors influencing the nest temperature like moisture, rain, type of grains, depth, etc. So surface data is s no go.

You also need to focus only on the middle third of the incubation period as this is the period when sex determination occurs. If you search on Google scholars you'll find plenty of info published.

finally, moisture has been proven to have a big effect on sex determination besides temperature, so if you are going to get a few data loggers, get them with humidity measurement as well.

hope this helps

cheers

M

Thank you for suggestion

PLS CHECK THE SAND TEMPARATURES  THEMROCOLE CALIBRATION  YOU WILL GET  AND ALSO ITS IMPACT ON DEPTHS  AND SURROUNDING  PLANTATIONS LIKE CASURINA  OTHER SEA SAND BINDING VEGITATION 

thank you sir