Brendan Talwar

A crowdfunded ecology project byBrendan Talwar

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Equipment: "Lanternfish"

Lab Note #5
Apr 04, 2014

Hi!

Big thanks to everyone who has contributed and shared the campaign thus far. We're doing great!

Today I'll be describing the deep sea lights that Blue Turtle Engineering can build for us. They are pretty much amazing.


The Challenge

In the ocean, light penetration is limited. Check out the diagram from the NASA website below and you'll notice that most wavelengths of light are absorbed in seawater at <100 m down. Bluish wavelengths can penetrate deeper, potentially reaching 300 m in absolutely clear water, but at very very small quantities. In reality, light gets both absorbed and scattered as it hits particles in the water column. Because of this, even the blue wavelengths will not reach beyond 200 m down in any sort of practical sense.

You might recognize this phenomenon if you've used a digital camera underwater. Even on a 60 ft dive, photos appear almost colorless and washed out by the blues that dominate. Through the use of a strong flash, you pick up on all the reds and yellows that are otherwise invisible. Again, the NASA website provides a great visual. Here is the difference between a photo taken without flash, and then with a flash:

The Solution: Lanternfish

Now imagine taking a video at 500 meters down. It would be pitch-black and colorless. Because of this, we need lights that can withstand the pressure, cold temperatures, and harsh environment associated with such great depths. Thankfully, we have some designs for lights that can go the distance. On top of that, they can be programmed to turn on and off on a timer over the course of many hours. This saves battery life and will allow us to synch the lights with the video cameras, giving us stunning images of the post-release behavior of uniquely identifiable sharks.

These lights have adjustable brightness to manipulate operating time, an extremely wide beam angle, and are rated to 1000 meters. They are also small, portable, and light weight for easy deployment. Can't beat that.

The beauty of this equipment is that it is reusable. We could use the lights for future projects ranging from deep water baited video to ROV exploration, making them a great investment for our lab here at Florida State.

I hope you've enjoyed the most recent lab note. Thanks again for your help and have a great weekend!

Best,

Brendan

P.S. This evening, a group of us at FSU are hosting the Wild and Scenic Film Festival. If you're near Tallahassee, come out and support us! We'll have a reception, 9 film screenings, and a panel discussion at the end. It should be a great time, and all proceeds go towards a local program that brings middle school children to the Gulf Coast. Here is the website for our event.

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