the-circles-of-life: Doryteuthis pealeiiAtla…


Doryteuthis pealeii
Atlantic Longfin Squid

ft. Casey Zakroff

Compared to the bottom-dwelling slugs or sea stars, squid are peculiar invertebrates. Despite their lack of backbones, these predators swim in the open waters — behaving more like fishes. But just like everything else in nature, there’s always an exception.

“It’s built to be a visual, pelagic hunter, yet it often rests on the seafloor,” Casey says about his study subject, the peculiar Atlantic longfin squid.

It is one of the better-known species in biology, having appeared in studies like neurobiology and camouflage science. But just like its weird lifestyle, it constantly surprises scientists in so many different ways.

For his research, he photographed baby squid in water droplets under the microscope to measure their growth.

“They have this little hexagon on their head. It’s the first thing I look for to see if I need to flip them over, which can be arduous as they are sticky little buggers.”

His squid were raised in tanks that simulate an extreme condition called ocean acidification. This is a global phenomenon that happens when a large amount of CO2 dissolves into the ocean, making it more acidic.

Usually, this phenomenon happens over a long period of time due to the fluctuations in our atmosphere. These days, it’s happening faster than the natural rate because humans are dumping CO2 into the atmosphere.

It turns out, higher levels of CO2 make Casey’s squid grow slower and hatch later.

This slower growth affects their swimming speed and control, which in turn may hinder their survival. This is crucial not just to the squid, but also to the countless other species that are connected to them in the food chain, including humans.

Such a global change affects all marine inhabitants, though some places and species will be more impacted than others. Animals that rely on coastal ecosystems like the longfin squid, for example, are more vulnerable because of their proximity to human settlements.

Right now, scientists are tackling global environmental challenges from many different angles. Tiny as they may seem, Casey’s squid squad is helping us understand how nature responds to a new world sculpted by mankind.

Casey Zakroff is a PhD Candidate at MIT-WHOI. Get to know Casey and his squid squad.

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