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A CASE STUDY OF THE REFERENCE CONDITION APPROACH TO NITROGEN MANAGEMENT IN ESTUARIES
Citation:
Latimer, J S., G. L. Chmura, C Pesch, AND W S. Boothman. A CASE STUDY OF THE REFERENCE CONDITION APPROACH TO NITROGEN MANAGEMENT IN ESTUARIES. Presented at Estuarine Research Federation 16th Biennial Conference, St. Petersburg, FL, November 4-8, 2001.
Description:
One way to estimate estuarine response to changes in nitrogen loading in coastal systems is by using a reference approach. This talk details the application of paleoecological analysis and use of historical data to estimate reference loads of nitrogen to New Bedford Harbor (NBH), MA. Analysis of proxies such as biogenic silica, dinoflagellate cysts, and organic carbon magnitude and type in sediment cores record the history of estuarine response to stress. These data were used to infer when and how the system began to change in response to excess nitrogen and other stressors, while historical watershed population and land use data provides nitrogen loading estimates for the periods of change. This approach allows consideration of multiple restoration goals. For example, is it necessary to return to pre-colonial nutrient inputs or would inputs comparable to more recent periods in the developmental history of the estuary be sufficient? The proposed NBH nitrogen Total Maximum Annual Load (TMAL), determined using an empirical multiple-system load-response approach, is 92,000 kg N/yr down from current inputs of 174,000. This TMAL is compared to results from the reference approach. We will discuss the advantages and disadvantages of the reference condition methodology .