Estuaries are some of the most diverse and productive ecosystems in the world, supporting everything from fish, birds, and otters to mussels and plants. To monitor the health of these important habitats, NOS partners with 28 state-managed National Estuarine Research Reserves, which serve as living laboratories. One NERRS program is the System-Wide Monitoring Program. As part of this program, scientists collect information such as temperature, salinity, pH, biodiversity, and population characteristics at reserves across the country. Collected information helps changing reserve conditions in both the short and long terms and provide an important baseline for evaluating similar habitats outside reserve boundaries.