Project Title: In-Situ Nutrient Monitoring in Estuaries
Principal Investigator(s): Jane M. Caffrey, Hans Jannasch, Mark Silberstein

Accomplishments
Scheduled Tasks:
The tasks scheduled for completion in year 2 include: Continuously monitor nitrate, temperature, salinity, dissolved oxygen, etc. at two locations in Elkhorn Slough. Process and analyze data in a timely fashion. Adapt phosphate chemistry to analyzer. Make necessary changes to manifold (e.g., add heater) and electronics/software. Purchase parts and assemble four more analyzers. Test phosphate analyzers in Elkhorn slough. Begin deployments at other NERR sites. Present preliminary results at National meeting.

Progress on Tasks
Nitrate, temperature, salinity and dissolved oxygen have been continuously monitored at the Azevedo Pond and the mouth YSI deployment sites in Elkhorn Slough. Digi-Scanners have also been deployed at Weeks Bay Reserve and Apalachicola Bay Reserve.

Dr Thomas Chapin has increased the duration of the instruments by using lithium batteries. This means the Digi-Scanners could be deployed for as long as the regeants, standards and blanks are stable. Dr Chapin with collaboration from Drs. Jannasch and Caffrey has prepared two of several manuscripts describing the nitrate Digi-Scanners and the results from the Azevedo Pond deployments.

Additional parts have been purchased for the construction of in-situ ultraviolet spectrophotometric sensors (ISUS) for the analysis of nitrate. This technology may prove to be the most robust way to detect nitrate in the marine environment. After laboratory testing, sensors will be deployed in Elkhorn Slough and other sites as time permits.

Concerns or Difficulties We have no concerns or difficulties at this time

Anticipated Success in Meeting Project Objectives in Scheduled Project Period
With our one-year no cost extension and the third year of funding, we anticipate meeting the project objectives. E. Preliminary data

Deployments in Weeks Bay between January and March were successful. Preliminary data from these deployments showed enhanced nitrate concentrations up to 60 µM following rainfall events (See Figure 1). Two Digi-Scanners were deployed in Apalachicola Bay 4 weeks in April. One deployment was successful, and the other was not due to a pinched reagent line. Summer deployments in Weeks Bay were mixed. The June deployment was unsuccessful due to an electrical short in the system. The July deployment again showed the influence of rainfall events on nitrate concentrations (data not shown). Deployments in Azevedo Pond and the mouth of Elkhorn Slough have been successful.

Tasks and activities for next reporting period

Tasks for the next reporting period
The tasks for the next report period include testing of the phosphate Digi-Scanners and ISUS sensors in Elkhorn Slough. Deployments in Weeks Bay and Apalachicola Bay will end in the fall. We will continue processing and analyzing data in a timely fashion. Further results will be presented at the Estuarine Research Federation meeting in November 2001. We will continue preparing of manuscripts for publication describing both the technology of the NO3- Digi-Scanners and the monitoring results from Azevedo Pond. We will begin preparing manuscripts on the results from Weeks Bay and Apalachicola Bay deployments.

Work plan to accomplish tasks
The current manuscript will be submitted to the journal Estuaries for publication. Two additional manuscripts will be prepared for publication. Testing at other NERRs sites will continue in the fall with deployments at Weeks Bay and Apalachicola Bay. Analysis of Weeks Bay and Apalachicola Bay data will continue.

Concerns or difficulties
We have no concerns or difficulties at this time.

Expenditures
Expenditures were within the expected range.