|The Great Bay National Estuarine Research Reserve is working with the University of New Hampshire and other partners to better understand how nitrogen pollution flows into New Hampshire's Great Bay. |
They are locating nonpoint nitrogen hot spots within its watershed, identifying the sources of that nitrogen, and characterizing how streams, rivers, and riparian buffers can mitigate the impact of this nitrogen on the Bay.
Ultimately, they aim to provide local managers with a clear understanding of which sources of nitrogen, under which land use conditions, pose the greatest threat to Great Bay’s water quality.
Why this project?
Nitrogen levels in Great Bay have increased significantly in recent years. Local managers need better information about where the nitrogen pollution is coming from so that they can implement cost effective strategies to reduce nitrogen pollution’s impact on important coastal resources.
In 2009, a report noted that the total nitrogen load to Great Bay had jumped 42 percent in only five years. Water clarity was declining and nitrogen-fed algae populations were on the rise. Eelgrass meadows were shrinking, taking with them their capacity to stabilize sediment and support marine life ranging from oysters and lobsters to flounder and cod. Oxygen levels were dipping, and dead zones were likely in the cards.
Seventy percent of this nitrogen comes from nonpoint sources like septic systems and lawn fertilizer. Historically, tributary rivers and streams have been able to treat much of the nitrogen they receive before it reaches the Bay. Yet as the amount of nitrogen flowing into these tributaries increases, their ability to cope with this pollution diminishes.
How much of what kind of nitrogen would cause this sensitive dynamic to fail completely is not well understood. Until it is, local communities face a ticking time bomb that they lack the science to defuse.
Maintaining local water quality has long been a priority of the Great Bay Reserve. This project is building on the Reserve's System-Wide Monitoring Program (SWMP) data, habitat maps used to benchmark the impacts of land use change, and partnerships with local decision makers focused on managing and improving water quality.