Research links clam behaviour to climate change

New research is linking clambehaviourto climate change. That shift inbehaviourcould be contributing to increasingly lowsoft-shellclam populations on the Bay of Fundy.

Researcher Jeff Clements at the University of New Brunswick in Saint John says clams tend to refuse to burrow into ocean sediment that hashighacidity.

"One of the things that climate change does is change the chemistry of the oceans," explainsClements."So what we've been seeing is with increasing CO2 concentrations, we see more acidic conditions in the ocean and this is altering the way clams behave and make decisions."

Under ideal conditions, clams burrow into mud and silt at the bottom of the Bay of Fundy. But Clements research indicates that environments with high acidity lead to different clambehaviour.

"When we make muds more acidic, what they do is stay on top of the sediment and let the water current take them to another area."

Clamsrolling around on top of the sedimentare easy prey for hungry predators,so they have to burrow as quickly as possible. But Clements says if they burrow into sediment where the pH is too low, shellswillstart todissolve; so they have to make a decision.

Clements saysthat if the environment changes quickly, many species simply keep up. "What we're seeingwith climate change and ocean acidificationisan abnormallyrapid shift to conditions that these animals are not adapted too," he said.

Ecosystem engineers

Clementssays the clam population isimportantto the Bay of Fundy ecosystem for a number of reasons.

"They are a big source of food and nutritionfor fish and crustaceans. They can also act as ecosystem engineers," he said.

In addition to being a link in the food web for the bay, clams also bring oxygen into the sediment that they burrow into. Thisoxygenationof their habitat makes the area much more habitable for other animal speciesliving within the sediment.

"Not quite what we would call "dead zones,"but we could see more areas of less oxygenated sediments," saidClements.

"Thiscould lead to less hospitable environmentsforotheranimals living there."