Jellyfish Uses Supercomputing Strategy to Find Food
The barrel jellyfish uses a complex search strategy to locate food, a new study finds.
A once rare butterfly living in the United Kingdom is the latest unexpected beneficiary of the rising temperatures brought about by global climate change. Over the last 25 years, the brown Argus butterfly can now exist over a larger range thanks to a warmer environment and a new plant host to raise its young. And these fortunate insects aren't the only ones who stand to benefit from a warmer world. Yes, over the coming decades, there are certainly many other species, including humans, that will feel increasingly pressured by environmental changes brought about by climate change. But there will be some balance of winners and losers among the different species on this planet. Here's a look at some of those who will likely come out ahead.
Change in wind patterns as a result of climate change has helped albatrosses in the Southern Ocean find food more rapidly, according to a study published in a January 2012 issue of Science. The faster and more intense winds reduce the amount of energy albatrosses need to expend to fly, particularly useful given that these birds can fly distances spanning thousands of miles. By using less energy and finding more food, the albatrosses are healthier and often have better breeding outcomes, according to the study's authors.
Gray Nurse Shark
Worldwide, around one third of oceanic shark species are at risk of extinction, according to the International Union for the Conservation of Nature (IUCN). These animals are primarily at risk as a result of human intervention, particularly the overfishing of sharks for their fins. But there is one species of shark that may stand to benefit from man-made climate change, the Australian gray nurse shark. Like many shark species, gray nurse shark populations have been under pressure. This species could disappear entirely by 2050. However, thanks for warmer waters surrounding Australia, two separate populations of this nurse shark on each side of the continent may reunite for the first time in 100,000 years.
Sharks aren't the only sea life that might benefit from warmer waters. Killer whales, too, appear poised to take advantage of rising ocean temperatures, exploiting new feeding areas as Arctic snow ice melts that were once off limits. The orca's gain, however, could be detrimental to other species. Killer whales prey on two species, the beluga and the narwhale, considered "near threatened" by the IUCN. With their chances to escape to safety from the predatory killer whales dwindling as ice melts, these species could face further pressure to their populations.
This tiny insect has made major inroads into the North American continent thanks to warmer temperatures. Mountain pine beetles can decimate entire forests. During cold snaps, they are killed off. But with shorter, warmer winters, more of these bugs are surviving through the cold season and expanding their ranges even further.
Acidifying oceans and warmer waters might be encouraging swells in populations of jellyfish around the world. Although the notion that jellyfish are benefiting from climate change has been subject to debate, studies have shown that coastal jellyfish populations are generally on the rise. More jellyfish would be bad news for any species that relied on the oceans for its food supply, including humans. Jellyfish can essentially reorder the food web by eating the same plankton that would otherwise be consumed by fish, restricting the transfer of energy on the food chain since predators tend to avoid them. The increase in jellyfish populations could also lead to an ecological disaster by resulting in an increase in carbon beyond what oceans can cope with, according to a report from The Guardian. When jellyfish die, they break down into biomass with considerably higher levels of carbon than their vertebrate counterparts. Bacteria that thrive on decaying organisms cannot absorb carbon as well and instead breathe it out into the atmosphere as carbon dioxide.
U.S. Fish and Wildlife Service
Once standing on the brink of extinction due to over-hunting for their meat and feathers in the 19th century, trumpeter swans have made a comeback in Alaska, thanks not only to restrictions on hunting these birds but also to global warming. Warmer temperatures have allowed the swans to expanding their ranges, and longer summers have allowed to greater opportunities for breeding and raising young, according to Scientific American.
Americans spend some $40 billion a year caring for their lawn, according to Bloomberg News. And that industry could get even more lucrative with the spread of a pest that has its sites set on your home turf: fire ants. According to a report from the National Wildfire Foundation, the range of red imported fire ants could expand some 21 percent in the United States, more than 80 miles northward, within the lifetime of a child born today.
If there's one creature who's climate change gain is our loss, it's mosquitoes. No longer restricted to strictly tropical environments, mosquitoes have spread as warmer temperatures have crept into environments they had never previously been. More mosquitoes means higher potential to spread diseases, including malaria, West Nile virus and dengue fever. This greater risk of disease is not only bad news for humans, but also some animals, including certain bird species, who had previously been unexposed to these pests. In fact, even some of the world's largest creatures are not immune to the disease transmitted by these tiny insects. Last month, the Whale and Dolphin Conservation Society revealed that two whales kept in captivity died as a result of diseases carried by mosquitoes.
Yellow Bellied Marmot
Although most mammals won't be able to flee climate change quickly enough, some are taking full advantage of the changing conditions. The yellow-bellied marmot, which calls Colorado's Rocky Mountains home, fattens up ahead of winter before its long hibernation into spring. With a shorter season though, the marmots are emerging larger than they otherwise would. As a result, they've also been breeding more and passing their larger size onto their offspring.
The barrel jellyfish, isn't just the largest jelly found in the waters around the United Kingdom, it's also one of the animal kingdom's most strategic searchers, according to a new study.
To locate the best possible meal in the vast waters of its marine habitat, the barrel jellyfish (Rhizostoma octopus) uses a strategy most commonly associated with the world's fastest supercomputers — an approach known as fast simulated annealing.
For mathematicians, fast simulated annealing is an algorithm, implemented by a supercomputer, which can find optimal solutions to complex problems in a relatively short amount of time. For jellyfish, fast simulated annealing is a highly evolved search strategy categorized by a series of predictable movements that bring the jelly closer and closer to large numbers of plankton, its preferred prey. [Album: Amazing Photos of Jellyfish Swarms]
This complex search strategy has never been observed before in nature, according to study lead author Andy Reynolds, a scientist at Rothamsted Research, an agricultural research center in the U.K.
Yet, other mathematical patterns of movement have been widely observed in the natural world, Reynolds said. The most common of these patterns, the "Lévy walk," is a less complex version of the barrel jelly's approach.
"A Lévy walk is random walk in which frequently occurring small steps are interspersed with more rarely occurring longer steps, which in turn are interspersed with even rarer, even longer steps and so on," Reynolds told Live Science in an email. (The Lévy walk was named after French mathematician Paul Lévy, who was noted for his work in the theory of probability.)
While this may sound like a fairly complex way of searching for something, Reynolds said it's similar to the way you might search for your lost car keys in the living room sofa and then, not finding them there, head over to the closet to check your coat pocket.
"This hierarchical nested pattern is highly effective when searching because once an area has been intensively surveyed, the searcher is relocated to another area and then begins a new bout of intensive searching," Reynolds said. [Marine Marvels: Spectacular Photos of Sea Creatures]
Some of the species that have been observed using Lévy walks to locate their meals include sharks, penguins, honeybees, ants, turtles and even human hunter-gatherers.
But among these many species, the barrel jelly stands out because, in addition to exhibiting this Lévy walk pattern, it also engages several search methods that others species don't seem to use.
The barrel jellyfish uses a complex search strategy to locate food, a new study finds.Graeme Hays
One of the barrel jelly's search-optimizing behaviors, often referred to as a "bounce," occurs when the jellyfish starts out in one depth of water and then makes a long glide either upwards or downwards to a different depth of water. If it doesn't find a meal in the new location, the jellyfish will "bounce" again to return to its original position.
Some scientists believe that the jelly's tendency to bounce around in the water may actually hinder its ability to search for food, but according to Reynolds, these unusual animals have had it right all along.
The jellyfish, which will sometimes repeat its pattern of bounces dozens of times a day, uses this strategy to slowly home in on the highest concentrations of plankton, Reynolds explained.
The behavior therefore makes the barrel jelly even more efficient than other marine animals, such as penguins and sharks, that only use Lévy walks to search for prey, Reynolds said.
If the barrel jelly's unusual way of searching for food really is the best way to do it, then why aren't other marine species using the same strategy?
The answer has to do with diet, Reynolds said. The barrel jellyfish benefits from spending long periods of time searching for concentrations of prey because it needs to eat a lot of plankton before it is satisfied, Reynolds said. This is different from sharks and penguins, which Reynolds said can survive by eating the occasional fish.
"A Lévy search is highly effective in finding the next meal, when any meal will do. Fast simulated annealing, on the other hand, takes the forager to the best possible meal," Reynolds said. "This is what makes jellyfish special — they are very discerning diners, unlike bony fish, penguins, turtles and sharks, which are just looking for any meal."
This high level of discernment is also what draws certain mathematicians and engineers to the strategy of fast simulated annealing for supercomputing, Reynolds said.
Based on mathematical and computer models, Reynolds' study found that like barrel jellyfish, mathematicians tend to implement this strategy only when they're looking for the best possible solution to a problem, not a variety of potential solutions.
The new study was published online today (Aug. 5) in the Journal of the Royal Society Interface.
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