Sanctuary Integrated Monitoring Network
Monitoring Project

NERR System Wide Monitoring Program

Principal Investigator(s)

  • John Haskins
    Elkhorn Slough National Estuarine Research Reserve
Start Date: September 01, 1995

The National Estuarine Research Reserve System is a network of state-federal protected areas, representing diverse estuarine ecosystems. Elkhorn Slough NERR has 24 partner reserves that are located on both coasts of the US, as well as the Great Lakes and Puerto Rico. Since 1995 these 25 NERRs carry out consistent system-wide water quality and weather monitoring. Since data are collected in an identical manner at all reserves, statistical comparisons can be made between regions and over time, providing a unique estuarine time series. All reserves measure water temperature, salinity, dissolved oxygen, depth, pH, and turbidity at four water monitoring stations. This data is collected every 30 minutes. In 2002, we began collecting nutrient data monthly at these stations. (The stations in Elkhorn Slough are located at Vierra's near the mouth, in South Marsh and North Marsh on the Reserve, and at Azevedo Pond in the upper Slough). In addition, each reserve operates a weather station which collects data on air temperature, wind speed and direction, barometric pressure, rainfall, relative humidity, and photosynthetically active radiation.

Summary to Date

Our data have revealed interesting short term fluctuations in dissolved oxygen and salinity. For instance, our Azevedo Pond site, with limited tidal circulation, undergoes virtually daily alternation between hypoxia and supersaturation. In summer, all of our upper Slough sites become hypersaline due to evaporation. This salty water mass moves out the mouth of the Slough on the next receding tide, leaving a distinctive signal at our lower Slough station.

Study Parameters

  • Temperature
  • Salinity
  • Chl A
  • Nitrates
  • Nitrites
  • Ortho-phosphate
  • Turbidity
  • Conductivity
  • pH
  • Dissolved oxygen