Lobsters to Be Supersized by Climate Change?
December 10, 2009
for National Geographic News
Attention lobster lovers—climate change may supersize your favorite seafood.
So says a new study showing that more acidic oceans, a consequence of rising atmospheric carbon dioxide (CO2) levels, can produce jumbo-size shelled marine species, including lobsters, crabs, and shrimp. It’s unknown whether the animals’ body mass also gets beefier along with their shells. (Learn about greenhouse gases.)
But it’s not good news for all sea creatures. In the experiment, other species—including oysters, scallops, and clams—suffered in more acidic waters because they had more trouble building their shells.
That’s because rising CO2 levels boost the amount of carbon in the oceans, but reduce levels of the carbonate ion that marine organisms need to make their protective shells.
Study leader Justin Ries, of the University of North Carolina at Chapel Hill, and colleagues grew 18 species of shelled marine animals in conditions that mimicked the elevated CO2 levels predicted in Earth’s atmosphere over the next two centuries.
The lobsters and other animals that thrived under higher CO2 levels during the experiment are better able to convert the inorganic carbon in seawater into a form they can use to produce shells.
Acid Tipping Point
The team also found that some species, such as calcifying algae, benefited from increased CO2 up to a point—and then quickly began to experience problems building their shells.
This may illustrate a specific CO2 “tipping point,” which scientists could identify and monitor in future studies, according to the report published in December’s Geology.
But even animals that grew larger in more acidic waters may ultimately suffer if an ocean food chain evolved over hundreds of millions of years is rapidly reorganized.
For instance clams—a main prey of crabs and lobsters—have “completely different” responses to rising CO2, Ries said.
“It’s a scenario where the predator is getting stronger and the prey is getting weaker. The [clams] may not be able to sustain their populations and ultimately the predators will also be adversely impacted when the prey populations crash.”
Ecological Engineers Threatened
The scenario also poses problems for “ecological engineers” such as coral, which at first had no response to the acidic water but then began to have trouble forming their shells, Ries said.
“If corals decline, like the experiment predicts, then all the organisms that need a coral reef to survive, like crabs and lobsters, are going to suffer, even though they are predicted to do well [in more acid conditions],” he said.
Likewise, the winners in acidic oceans may also see setbacks, he added.
For instance, if species are pouring more of their hard-earned energy into shell growth, other biological functions like reproduction may decline.
Bears Go Bald at Zoo; Experts Stumped
December 7, 2009—A spectacled bear named Dolores (pictured) is sporting an unconventional look after losing almost all her hair.
Since 2007 the female spectacled bear and two of her female kin at Germany’s Zoo Leipzig have been going bald—baffling experts.
Zoo experts are working to cure the bears’ non-life-threatening condition, zoo curator Gerd Noeltzhold told the BBC.
Spectacled bears—also called Andean bears—live in the mountains of South America and are the continent’s only bear species.
Armando Castellano, leader of the Andean Bear Conservation Project in Ecuador, said that he’d seen a similar case about a decade ago in a rescued spectacled bear.
“We were very scared, because it was the first time we had seen this,” Castellano said.
Keepers in Ecuador put that bear, which had previously been fed human food—including Coca-Cola—on its natural diet of fruits and bamboo, and added enrichment items, such as toys and exotic foods, into the bear’s enclosure. Four months later the fur grew back.
Similar cases have occurred in a Bolivian zoo and in Peru, Ximena Velez-Liendo, a spectacled bear specialist, said by email.
It’s unknown whether a lack of nutrition is the culprit in the Leipzig bears’ situation.
Until a cure is found, keepers have been applying medical ointment to the bears’ skin, which becomes itchy without its protective fur.
Photo Gallery: Poison Dart Frogs
Male lions
Male lions generally leave hunting duties to the female members of the pride, helping out on occasion. Only when they are on their own do they demonstrate their hunting abilities.
Lionesses are in charge of hunting for the pride and work together to bring down fast-running herd animals like wildebeest, zebra, and antelope.
Lion cubs stay with their mothers for up to three years, after which the female cubs remain with the pride while the males venture off to form their own prides.
