Skip to main content

Acidifying oceans could spell squid doomsday

Acidifying oceans could spell squid doomsday

Share this story

Earth's oceans are growing increasingly acidic, and the phenomenon is expected to produce both environmental and economic problems over the next century, according to a new study. At the center of all this is a key player in the oceanic food chain — the squid. As the acidity of seawater rises, squid will have a harder time growing and developing, according to a study from the Woods Hole Oceanographic Institution (WHOI). Such stunted growth would dramatically impact their crucial role as both predator and prey to other underwater life, and in the process be a detriment to the fishing and food industries.

"Squid are at the center of the ocean ecosystem — nearly all animals are eating or eaten by squid," T. Aran Mooney, a biologist who co-authored the study, said in a statement. "If anything happens to these guys, it has repercussions down the food chain and up the food chain." The problem started around 150 years ago, when carbon dioxide levels in Stunted growth and deformities the atmosphere started to ramp up, the study said. Since then, as seawater has absorbed carbon dioxide, carbonic acid and other byproducts have shown up in ocean water. Over the next century, this trend is expected to continue and, in the process, squid and other sea life will feel the effects. The full breadth of these changes is something researchers at this point don't fully understand, but this latest study — which focused on how squid will handle the acidity levels of the ocean 100 years from now — is a step in understanding what's coming.

In their research, Mooney and his colleague and co-author, Max Kaplan, observed how Atlantic longfin squid developed by monitoring more than 200 fertilized squid eggs spread across two tanks in WHOI's Environmental Systems Laboratory in Massachusetts. One tank was set up to reproduce current ocean water, and the other to match ocean acidity that researchers anticipate in 100 years — about three times the acid levels of today's seawater. Mooney and Kaplan then watched as the eggs hatched and the squid began to develop in the two tanks. How long it took each squid to hatch, how large the squid were at birth, how they looked, how they swam and how they grew were all recorded. In every parameter, the duo observed problems among squid living in the water with higher acidity. "The fact that we found an impact in everything we measured was pretty astounding," Mooney said. "That means that squid, this keystone species, might be really impacted by the environment that we're changing, and that's going to have ramifications down the line."

Consequences for sea life and humanity

The squid raised in higher carbon dioxide levels took longer to develop, and when they did grow up, they were about 5 percent smaller than their counterparts living in today's water, the study said. The squid in the more acidic water also had deformities that resulted in diminished swimming ability. In the wild, these side effects would leave squid more vulnerable to predators, WHOI said. If squid have a harder time hunting other sea life to eat, or if they're easier for predators to pick off, the domino effect on the aquatic food chain would greatly alter the commercial fishing industry. From here, WHOI plans to conduct more research on squid living in varying levels of water acidity as well as temperatures, given that oceans are expected to warm up in the next 100 years as well.