A climate counterbalance?
In high-temperature-only and high-acidity-only conditions, Varma expects to see more frequent bouts of activity, since animals naturally seek more suitable environments when under duress. He also expects these two conditions will increase squids’ metabolic demands for food, but simultaneously make them sluggish and unable to meet those demands in prey capture experiments.
But, Varma predicts increasing temperature and acidity at the same time will result in behaviors similar to normal conditions. It’s possible the effects of higher temperature and higher acidity could actually counterbalance one another, he said, and animals faced with both effects will do better than animals faced with only one or the other.
Coleoid cephalopods can adapt to stressful environments in part because they can edit their RNA, Varma said. RNA, like DNA, is a form of genetic instructions; by tweaking it, an organism can adjust which proteins it produces in its body and better suit itself to its environment. Coleoid cephalopods make about 100 times more edits to their RNA than most other animals, Varma said.
“The key enzyme for RNA editing, ADAR2, appears to be less active at high temperatures, but more active at lower pH's,” he explained. “So, I argue that the net balance of RNA edits needed by an animal [to adapt to environmental change] can be achieved when both temperature and pH are altered.”
That line of thinking is speculation for now, he cautioned, pending further research. No matter what he finds, Varma hopes people don’t draw the wrong conclusions from his research.
“I hope it does not suggest to the public that climate change is not a crisis,” he said. “It is very much a crisis, and just because the occasional animal is doing well doesn't mean that we should always relax.”
Despite the harsh realities of climate change, cephalopods provide a glimpse at what success can look like. Varma’s research could open the door for a better understanding of how organisms adapt to a changing world.