CICEET Progress Report for the period 08/01/01 through 01/31/02
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 3 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.
Work Plan to Accomplish Tasks
Nitrate, temperature, salinity and dissolved oxygen were continuously monitored at the mouth YSI deployment sites in Elkhorn Slough through September 17, 2001. Digi-Scanners were also deployed at either Weeks Bay Reserve and Apalachicola Bay Reserve through November 27, 2001.
Dr Chapin with collaboration from Drs. Jannasch and Caffrey has prepared one of several manuscripts describing the nitrate Digi-Scanners and the results from the Outfall and 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.
Difficulties Encountered
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.
Preliminary Results
Hourly measurements of nitrate concentrations were made with an in-situ nitrate analyzer at Weeks Bay between January - March 2001 and between July - September 2001. Analyzers were also deployed at Apalachicola Bay in April 2000 and between September - November 2001. A strong negative relationship between nitrate concentration and salinity was evident during all deployments at both locations demonstrating a tight linkage between river flow and nutrient input to these estuaries. Nitrate concentrations were high throughout the year in the main tributary to Weeks Bay. Following rainfall events, nitrate concentrations at the head of Weeks Bay ranged between 1 µM and 50 µM over a tidal cycle as high salinity, low nitrate water entered the Bay on flood tides and low salinity, high nitrate water entered the Bay on ebb tides. The spring deployment in Apalachicola Bay coincided with a declining river discharge (from 2120 to 425 m3/s). There was a significant negative relationship between nitrate and salinity in Apalachicola Bay, with salinity explaining about 70% of the variation in nitrate concentrations.
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. We will continue processing and analyzing data in a timely fashion. Further results will be presented at the AGU/ASLO Ocean Sciences meeting in February 2002. We will continue preparing of manuscripts for publication describing both the technology of the NO3- Digi-Scanners and the monitoring results from Azevedo Pond and the outfall. 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 Limnology and Oceanography for publication. Two additional manuscripts will be prepared for publication. Analysis of Weeks Bay and Apalachicola Bay data will cont.
Concerns or difficulties
We have no concerns or difficulties at this time.
Expenditures
Expenditures were within the expected range.