Plankton defenseless as water chemistry changes

Toronto, ON — A recent study has shown that changes in Canadian lake water chemistry has left plankton vulnerable to their predators.

York biology Professor Norman Yan, the study’s senior author, says this may pose a serious environmental threat since these tiny creatures are critical to our survival. “Without plankton, humans would be quite hungry and perhaps even dead. Much of the world’s photosynthesis, the basis of all of our food, comes from the ocean’s plankton. The oxygen in every other breath we take is a product of phytoplankton photosynthesis,” says Yan.

Together with the study’s lead author, Howard Riessen, a professor of biology at SUNY College at Buffalo, studied the effect of changes in water chemistry on plankton prey defenses. Specifically, they examined how lower calcium concentrations affect Daphnia (water flea) exoskeleton development. These low calcium levels are caused by loss of calcium from forest soils, a consequence of decades of acid rain and multiple cycles of logging and forest growth. This phenomenon of reduced calcium is also playing out on a much larger scale in the world’s oceans, notes Yan. “Increases in ocean acidity are complicating calcium acquisition by marine life, which is an under-reported effect of global carbon dioxide emissions. Thus marine plankton may also find themselves more vulnerable to predators,” he says.

The results are published this week in the Proceedings of the National Academy of Sciences. The abstract can be accessed here.