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Author Chris Neill was formerly director of the MBL Ecosystems Center.

In the 1970s, four scientists from the Woods Hole Oceanographic Institution—John Ryther, Joel Goldman, Ken Tenore and William Dunstan—began to publish convincing evidence that nitrogen controlled the growth of phytoplankton in the coastal waters of Long Island and Woods Hole.

Ivan Valiela and Robert Howarth at the Marine Biological Laboratory—and others up and down the East Coast—soon followed with more evidence that nitrogen loading to estuaries from land caused the loss of submersed aquatic vegetation. Mounds of supporting evidence have since piled up.

We also know where this nitrogen comes from. The largest single source is wastewater. Unlike in many other parts of the United States where suburban homes built largely after the 1960s were connected to municipal sewers, Falmouth and Cape Cod chose to rely on septic systems to treat wastewater. While properly functioning septic systems effectively remove bacteria and pathogens, they remove very little nitrogen.

Cape Cod’s decisions on how to build its wastewater infrastructure resembled many of society’s environmental management decisions—it didn’t account for the full cost of reducing environmental harm. It pushed these costs out to the future.