Identification and Assessment of Anthropogenic Eutrophication in Shallow Estuaries (CICEET-UNH #99-304/NOAA NA87OR0512)

Principal Investigator (s):

Ivan Valiela

Work Accomplishments

Tasks for the Period.

• Continue work in monthly coverage of Waquoit Bay sites for complete seasonal coverage and assessment of inter-annual differences.
  We have continued the monthly sampling for Waquoit Bay (nutrients, phytoplankton chlorophyll, and production of major producers) and have scheduled to return to Great Bay this coming spring to fill in the rest of the seasonal coverage.
  
• Return to Great Bay and Apalachicola Bay in mid summer (July) and midwinter to complete seasonal coverage to our data. Our results clearly point out the need to do this.
  Dr Just Cebrian and I are working out a sampling plan to finish the seasonal coverage necessary. All field sampling should be all or nearly all finished by the next project reporting period.
  
• Start seasonal work in Weeks Bay. J. Cebrian will move to a permanent faculty position in Dauphin Is. Sea Lab in Feb., and so he will be near both Weeks Bay and Apalachicola. This will make it far less costly to cover these sites, and to do so seasonally.
  Cebrian has established his lab at DISL and is planning to sample Apalachicola Bay and Weeks Bay.
  
• Complete synthesis of data, and start manuscripts on changes in vegetation prompted by changing loading regimes, and on the response of stable isotopic signatures to the differences in watershed mosaics among the different sites.
  The next step for us is to test the applicability of the Waquoit Bay Nitrogen Loading model to these other systems (Great Bay, Apalachicola Bay, and Weeks Bay). In addition we have just received the second half of our isotope data for both Great Bay and Apalachicola Bay. We this new isotope data we intend to test the isotope approach as a detector of incipient eutrophication. We have planned that this part of the project will take us into the end of this third year of funding.
  

Work Plan to Accomplish Tasks.

We will finish the field sampling component of this project by the next reporting period or soon there after (by April of 2001). In the mean time we will continue to synthesize the data for the nitrogen loading model applicability and the isotope approach.

Concerns or Difficulties.

We have a slow return of the stable isotope data from the mass spec facility due to great demand, and limited manpower. For future samples we will use a new laboratory at UC Davis with a faster turn-around time.

Anticipated Success in Meeting Project Objectives in Scheduled Project Period.

Since we are switching isotope laboratories and finishing the field component of this project we anticipate meeting project objectives and deadlines.

Preliminary data

Table 1. New isotope data for Great Bay and Apalachicola Bay. This data encompases a broad range of isotopic values that should make interpretation on N loads and incipient eutrophication possible.

Tasks and Activities for the Next Report Period.

Tasks for the Next Report Period.

We anticipate completing the field component of this project and making significant headway with the synthesis component.

Work Plan to Accomplish Tasks.

Scope of work for Valiela
We will continue to sample Waquoit Bay in the same manner as we have been, monthly sampling of primary producers (production and biomass) as well as collect nutrient samples with in these estuaries. In addition we will return to Great Bay NH, once this winter and again in the following spring. This should complete the field sampling component of this project.

Scope of work for J. Cebrian
We will visit Apalachicola and Weeks Bay seasonally throughout a year. The first visit will be on the fall of 2000. The other visits will be in the winter, spring and summer of 2001. On each sampling visit, we will:

• Determine the diversity and abundance of submerged aquatic vegetation (SAV) across a grid of stations across two enclosed embayments within each of the two bays studied. The embayments have already been indentified in Apalachicola Bay during previous visits (Nick's Hole and Yent's Bayou), but the remain to be decided in Weeks Bay. We will do this based on preliminary surveys where well-defined subparcels within the Bay (such as the mouths of Magnolia and Fish Rivers) will be identified.
  
• Quantify chlorophyll, nitrate and ammonium concentrations in the water column in number of stations within each embayment
  
• Assess phytoplankton and SAV (seagrasses and macroalgae) production
  
• Collect water, phytoplankton and SAV samples for isotopic analyses
  

Concerns or Difficulties

We do not anticipate any concerns of difficulties in the work plan discussed. We do however have concerns regarding the applicability of the WBNLM to these other systems that are mainly dominated by river inputs. We are going ahead and making the model calculations and will have to assess the applicability at the time when we have model results.

Expenditures

We are on track as far as budgeting in concerned. We are supporting 2 graduate students (6 mo, 12 mo)and part of Valiela’s salary (1.5 mo). We are about to transfer funds to DISL for Cebrian to continue work in the southern sites.