CICEET Progress Report for the period 8/1/02 through 2/1/03

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 include: 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. Publish results in peer reviewed literature.

Progress on Tasks
Dr Chapin with collaboration from Drs. Jannasch, Caffrey and others is submitting the first of several manuscripts describing the nitrate Digi-Scanners and the results from the Outfall and Azevedo Pond deployments to Estuaries. A second manuscript is in preparation.

The phosphate DigiScanner has been successfully deployed off the MBARI dock several times, operating two to three weeks continuously. It can run at sample rates up to 4 per hour without any heating of the sample and reagents.

Several ISUS systems have been built. One has been deployed off the MBARI dock. With a newly designed passive copper covered screen protecting the probe, data has been collected for over a month without significant fouling. The first side-by-side comparison of the NO3- DigiScanner (with a 2 mm glass flowcell) and NO3- ISUS shows excellent agreement between the two instruments. Over an 11 day period, nitrate concentrations varied tidally from <20 to >400 uM, and the correlation of hourly samples had a slope of 0.96 and an R² of 0.83.

Difficulties Encountered
We have no concerns or difficulties at this time

Anticipated Success in Meeting Project Objectives in Scheduled Project Period
We anticipate meeting the project objectives.

Preliminary results
The ISUS performed remarkably well over a 3 month period in the Moss Landing Harbor, which was made possible by incorporating an anti-fouling filter onto the ISUS. The filter was designed last year as part of an effort to make ISUS available for turbid water deployments, like Elkhorn. In addition, the filter has proven useful in highly productive oceanic waters, as the external copper screen has been shown to eliminate growth on the adjacent side of the Nitex filter cloth. Figure 1 shows peak NO3- concentrations exceeding 500 µM on low tide as agricultural runoff in the Old Salinas River channels drains into Moss Landing Harbor.

Tasks and activities for next reporting period

Tasks for the next reporting period
Preparation of final report.

Work plan to accomplish tasks
The second paper describing statistical methods of analyzing this kind of data will be prepared for submission to Estuarine Coastal and Shelf Science. 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. As of October 2002 there were no remaining funds in the MBARI subcontract.