Giant crabs are appearing in the Chesapeake Bay, which sounds like a good deal for those in favor of more crab meat. Unfortunately, it seems that carbon emissions are to blame for the growth; and to make matters worse, these supersized crabs are starting to upset the region's food chain.
The crabs newfound size make them even more capable predators, feeding off of the local oyster population. To make matters worse, the same carbon emissions that are enlarging the crabs are also stunting the development of these oysters, leading to a significant imbalance.
"Higher levels of carbon in the ocean are causing oysters to grow slower, and their predators - such as blue crabs - to grow faster," Justin Baker Ries, a marine geologist at the University of North Carolina's Aquarium Research Center, explained.
This strange growth is caused by the crabs' ability to use the carbon to molt faster, allowing them to grow bigger and stronger. This isn't great news for anyone who's hoping to make a meal of these giant crabs either. Absorbing carbon only makes for improved shells, not flesh, meaning we're not in for an excess of crab meat.
Ries and his team published a study in the journal Geology in 2009 that showed the effects of carbon emissions on shellfish. They found that crabs, lobsters, and shrimp grew much larger much quicker as carbon pollution was increased in their environment. Chesapeake blue crabs in particular grew almost four times faster in high-carbon tanks compared to low-carbon ones.
On the flip side, oysters, scallops, and similar sea life struggled to grow, with the oysters growing at only one-quarter the speed in high-carbon tanks.
"It's taking them longer to go from oyster spat to oyster adult," said Luke Dodd, a doctoral candidate at UNC and one of the researchers involved in the study. "When you're a baby, there's tons of predators that want to eat you up."
This is bad news for the region as a whole, and likewise for any carbon emissions contaminated water, with the larger predatory crabs throwing off the entire ecosystem.