The Laguna Salada Ecosystem Study: Targeted Data Collection from a Vital Tributary of Baffin Bay

The once pristine water quality of Baffin Bay that supported a vibrant fishery has deteriorated in recent decades due to excessive nutrient loads and persistent "brown tide” algal blooms. Efforts are now underway to implement watershed restoration and protection activities to reduce pollutant loadings to the bay. However, data is lacking from the Los Olmos Creek-Laguna Salada tributary, which was recently found to be an incubator for brown tide. In other words, the nutrient and physical conditions of the tributary support a continuous population of brown tide that eventually can spread into the larger Baffin Bay system. Because of a lack of data, the tributary was not included in a newly approved Watershed Protection Plan. Furthermore, pollution sources to the Laguna Salada remain largely uncharacterized. The goal of this study is to characterize water quality in the data-poor Los Olmos Creek-Laguna Salada tributary of Baffin Bay, thereby informing stakeholder-led pollutant load reduction efforts that are taking place for Baffin Bay.

To address this data deficiency, a targeted study of the tributary will be conducted. Given that the Laguna Salada may hold the key to controlling brown tide blooms in the larger Baffin Bay system because of its role as an incubator, more work is clearly needed to determine pollutant sources (natural or human-derived) to it, the algal response to nutrient inputs from the different sources, and overall water quality conditions in it. Project results will lead to more informed decision making on nutrient load reduction needs and watershed protection plan efforts (see attached letters of support).

Specific tasks within this project include:

1. Conduct biweekly water quality sampling at three sites along the fresh-saltwater gradient in Los Olmos Creek-Laguna Salada. Nutrient measurements and nitrogen isotope data will be used to assess sources under different hydrologic conditions, while these and algal-related indicators will also be used to assess the conditions that fuel brown tide blooms.

2. Deploy a water quality sonde at a strategic location in the tributary for continuous water quality measurements. This data will support the aforementioned assessments and will also be available for future modeling efforts aimed at characterizing e.g., water exchange between the tributary and Baffin Bay, and influence of hydrologic variability on water quality conditions.

3. Disseminate project findings to entities that need this data to achieve their goals within the context of Baffin Bay pollution management, and watershed and bay protection/restoration. This will be accomplished through regular engagement of the Baffin Bay Stakeholder Group and partners in the natural resource management sector.

4. Production of a final report. The final report will describe potential nutrient sources to algae in Laguna Salada, spatial-temporal variability in nutrients-algae and drivers of the variability, potential ecological/water quality impacts of exchange between Laguna Salada and the Baffin Bay complex, and nutrient management recommendations