Pitcher plants provide tipping point
Most of us want to swim in a lake where we can see our toes. Clear, oxygen-rich water supports not only human swimmers, but also intricate webs of animal and microbial life. That life can be disrupted when too many nutrients — from fertilizers, pollution, and other factors — overload the system. In those cases, aquatic ecosystems can cross a tipping point: the nutrients cause algae to bloom, and the extra bacteria eating the extra algae use up all the oxygen in the water. The end result is a murky, green lake that is difficult to restore, despite herculean interventions. Promising new research out of the Harvard Forest, funded by the National Science Foundation and published today in the Proceedings of the National Academy of Sciences (PNAS), offers insights on how and why these tipping points occur. “The first step to preventing tipping points is to understand what causes them in...