Antarctic krill form the largest biomass population on Earth. “You can even see them from space,” says behavioral biologist Alicia Burns of the Taronga Conservation Society in Australia.Krill swarm Play an important role Carbon in the food chain and circulating atmosphere enters the deep Southern Ocean. How these tiny shrimp-like creatures form and maintain giant colonies is unclear.But Burns and her colleagues describe inside Proceedings of the Royal Society B Unique and mathematically predictable social rules govern the seemingly chaotic crustacean group.
To observe herd behavior, the researchers collaborated with the Australian Antarctic Division’s aquarium in Tasmania, one of only two facilities in the world capable of rearing krill. There, the researchers photographed the krill from different angles, tracked the individuals in 3D, and then statistically determined each animal’s movement patterns in relation to its neighbors. “Matching math with biology is the new part,” Burns said.
Geraint Tarling, a biological oceanographer at the British Antarctic Survey, who was not involved in the study, agrees: “This is the first time we theoretically expected – what we expected – to achieve. One leap. [krill] Do – Absolutely observe the identification of what the rules of conduct are. “
Swarming helps animals avoid predators, find mates and food, and travel more efficiently. New research shows that when forming these clusters, krill (like many flock species) adjust their speed according to the speed of their neighbors in front — similar to drivers in traffic. But unlike other species, krill most often change direction based on their neighbors on the vertical plane, swimming toward their peers ahead and below, but away from those ahead and above. Ryan Lukeman, a mathematician at St. Francis Xavier University who studies bee colonies but was not involved in the study, says it’s fundamentally different from what’s seen in fish and birds: For them, “very little information is often transmitted vertically.”
Researchers are still analysing why this is the case. Tarling says the krill’s eyes are upward, and when they’re startled, their undersides flash bioluminescence. These features may help explain their vertical focus when swarming. With their many predators attacking vertically, the krill may watch each other for signs of impending danger. They may also avoid the vortex created by their neighbor’s paddle, which pushes the water down and back, unlike the way fish swim.
Burns said the next goal is to confirm that the newly discovered swarming rules apply in the wild, using “krill cams” suspended from buoys. Scientists could one day use these rules to simulate how changing ocean temperatures and currents affect the ability of these important crustaceans to stick together, Lukeman said.