Featured Research

from universities, journals, and other organizations

How diving leatherback turtles regulate buoyancy

Date:
November 15, 2010
Source:
Journal of Experimental Biology
Summary:
Virtually nothing has been known about leatherback turtle diving strategies, but now scientists have discovered that leatherbacks regulate their buoyancy by varying the amount of air they inhale before they dive. Fitting nesting leatherbacks with triaxial accelerometers, temperature and pressure gauges, the team was able to make the first detailed recordings of leatherback turtle diving behavior.

Large leatherback turtle swimming.
Credit: NOAA Ship DAVID STARR JORDAN Collection; Commander John Herring, NOAA Corps / via NOAA Photo Library

Leatherback turtles are remarkably versatile divers. Routinely diving to depths of several hundred meters, leatherbacks are occasionally known to plunge as deep as 1250 meters. The animals probably plumb the depths to avoid predators, search for prey and avoid heat in the tropics. However it wasn't clear how these mammoth reptiles regulate their buoyancy as they plunge down.

Sabrina Fossette from Swansea University explains that no one knew how the turtles descended so far: do they swim down or become negatively buoyant and plummet like a stone? Curious to find out how nesting leatherbacks plumb the depths, Rory Wilson and his long time collaborator, Molly Lutcavage, decided to deploy data loggers containing triaxial accelerometers on leatherback females as they nested on beaches on St Croix in the US Virgin Islands. They found that leatherbacks probably regulate their buoyancy by varying the amount of air they inhale just before submersion.

Their finding was published Nov. 12, 2010 in the Journal of Experimental Biology.

"When you first see a leatherback turtle coming out of the water it's like a dinosaur it's really impressive," says Fossette, having just returned from collecting data in the Indian Ocean. According to Fossette, Andy Myers, Nikolai Liebsch and Steve Garner attached accelerometers to five females as they laid their eggs, and then waited 8-12 days for the reptiles to return to the beach to lay more eggs having headed out to sea. Retrieving the accelerometers, the team found that only two of the five had collected usable data, but the data loggers that functioned showed 81 dives that the team could analyze ranging from 64 meters down to 462 meters.

Back in Swansea, Fossette, Adrian Gleiss, Graeme Hays and Rory Wilson analysed the temperature, pressure and acceleration data collected by the loggers. Describing the accelerometer data Fossette says, "You can almost see the animal swimming. It's the first time we could see the locomotor activity during those deep dives."

Extracting the acceleration data that showed the leatherbacks' movements, the team could see that the turtles dived deeply at an average angle of 41 degrees as they began their descent. Initially the turtles swam with each flipper stroke lasting 3 seconds, but as they descended further they swam less hard until they stopped swimming all together, became negatively buoyant and began gliding down. At the bottom of the dive, the turtles began swimming as they heading to the surface and continued swimming until they regained buoyancy near the surface and began gliding again.

Fossette explains that many diving animals exhale before they leave the surface to minimise the risk of decompression sickness, however, leatherbacks do not. They dive carrying a lung full of air. Curious to find whether leatherbacks vary the amount of air that they inhale to regulate their buoyancy, Fossette and Gleiss compared the depths at which the turtles became negatively buoyant with the maximum depth that they reached. The team found that the deepest divers remained buoyant the longest and started gliding at deeper depths. So the turtles probably regulate their buoyancy before diving by varying the amount of air they inhale. Fossette also says, "The nesting turtles may glide for 80 percent of the dive's descent to optimize their energetic reserves, which is crucial for the production of eggs."

The team is now keen to look at the diving patterns of leatherbacks in their foraging grounds in the North Atlantic. Fossette explains that nesting turtles lose weight while foraging turtles are gaining weight and this could affect their buoyancy and diving behaviour. However, tagging a 400-kilogram turtle in the ocean is a much bigger problem than tagging them on a beach.


Story Source:

The above story is based on materials provided by Journal of Experimental Biology. The original article was written by Kathryn Knight. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Fossette, A. C. Gleiss, A. E. Myers, S. Garner, N. Liebsch, N. M. Whitney, G. C. Hays, R. P. Wilson, M. E. Lutcavage. Behaviour and buoyancy regulation in the deepest-diving reptile: the leatherback turtle. Journal of Experimental Biology, 2010; 213 (23): 4074 DOI: 10.1242/jeb.048207

Cite This Page:

Journal of Experimental Biology. "How diving leatherback turtles regulate buoyancy." ScienceDaily. ScienceDaily, 15 November 2010. <www.sciencedaily.com/releases/2010/11/101112075954.htm>.
Journal of Experimental Biology. (2010, November 15). How diving leatherback turtles regulate buoyancy. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2010/11/101112075954.htm
Journal of Experimental Biology. "How diving leatherback turtles regulate buoyancy." ScienceDaily. www.sciencedaily.com/releases/2010/11/101112075954.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins