The turbulence in oceans forms a complex network of structures that range in size from the microscopic to thousands of kilometres across. The eddies that form on the scale of between 1 and 100 kilometres seem particularly important for ocean life with all kinds of predator/prey activity concentrated on the boundaries between these eddies. It’s likely that here, the warm upwelling of nutrient rich water seeds the entire food chain and so provides rich pickings for predators.
One puzzle though is whether land-based sea birds such as the Great Frigatebird, are able to find these rich feeding grounds and return to them. And if so, how they do it. After all, these eddies are constantly moving, the birds are unable to sit on the water and so must return to land regularly.
Now Emilie Tew Kai at the Centre de Recherche Halieutique in France and colleagues have answered at least half this question. By attaching satellite trackers to Great Frigatebirds, the team was able to “watch” the birds visit their feeding grounds in the Mozambique Channel in the Indian Ocean over a two month period in 2003. It turns out that these feedings grounds exactly match the distribution of eddies in the Channel.
” By comparing seabirds’ satellite positions with LCSs locations, we demonstrate that frigatebirds track precisely these structures in the Mozambique Channel,” they say.
But that still leaves the question: how do they do it?
Tew kai and co offer a couple of ideas: “The birds might use visual and/or olfactory cues and/or atmospheric current changes over the
structures to move along these biological corridors.”
Of course, these biological corridors are fascinating structures in themselves. Perhaps the most useful result of this work is the discovery of a way of pinpointing these structures quickly and easily whenever you want to study them: just follow the Great Frigatebirds.
Ref: arxiv.org/abs/0904.1959: Top Marine Predators Track Lagrangian Coherent Structures
The big new idea for making self-driving cars that can go anywhere
The mainstream approach to driverless cars is slow and difficult. These startups think going all-in on AI will get there faster.
Inside Charm Industrial’s big bet on corn stalks for carbon removal
The startup used plant matter and bio-oil to sequester thousands of tons of carbon. The question now is how reliable, scalable, and economical this approach will prove.
The dark secret behind those cute AI-generated animal images
Google Brain has revealed its own image-making AI, called Imagen. But don't expect to see anything that isn't wholesome.
The hype around DeepMind’s new AI model misses what’s actually cool about it
Some worry that the chatter about these tools is doing the whole field a disservice.
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.