The Potential Role of Water Quality Modeling in Coastal Acidification Management

1. The Potential Role of Water Quality Modeling in Coastal Acidification Management Damian C. Brady, Ph.D. Ira C. Darling Marine Center University of Maine August 1st, 2014

2. The Potential Role of Water Quality Modeling in Coastal Acidification Management …or whatchyagonna do about it? Damian C. Brady, Ph.D. Ira C. Darling Marine Center University of Maine August 1st, 2014

3. First of all… • After we determine if acidification is a problem • Now what?...what do we do societally to ‘fix’ the problem • I know of no model of pH/aragonite saturation/alkalinity/DIC that is currently used to make management decisions

4. But…there are interesting analogs to consider • We know that degradation of organic matter (and all respiration) can contribute to lowered dissolved oxygen and pH…increased CO2 • We know that freshwater flow can bring in acidified water (Salisbury et al 2011) • We know that eutrophication and reduce the buffering capacity of estuaries (Cai et al 2011) • The relevant knob to turn becomes land derived nutrient and ‘pH’ loading…we’ve essentially been doing this for decades

5. NOAA

6. MODELS • All models are wrong, some models are useful • Models come ins all sort of flavors and colors • But broadly speaking many of the management models we talk about are either empirical/deterministic or process based • There are advantages and disadvantages of both

7. Eutrophication and Hypoxia as Convenient ‘Models’

8. This is where your ecology/fisheries/resource management is added Empirical Model • Develop a relationship between loading and hypoxic area (or “acidic” area • Then show this relationship to farmers and kindly ask them to reduce May nitrate+nitrite loading

9. Empirical Models • They assume your time series contains all possible scenarios • Without process level understanding, you don’t know why your relationships work…some argue that without this understanding, predictions are doomed to fail…

10. Chesapeake Bay Program Decision Support System: “The Cadillac”? Land Use Change Model Criteria Assessment Procedures Bay Model Watershed Model Management Actions Scenario Builder Airshed Model Sparrow Effects Allocations

11. Process Level Models are Complex and Data Intensive Our challenge will be to fold in the calculation of aragonite saturation, DIC, pH, alkalinity into thes models

12. Then determine the size, severity, and duration of non-livable zones

13. But they give you more power to explore hypotheticals

14. Scales: Airshed to Watershed to Water Column to Sediments

15. Watershed Models

16. What do we have in Maine? • An amazing hydrodynamic modeling infrastructure • http://www.norwich.edu/about/news/2008/050208-cascoBayDyeMovie.html • An large monitoring network from DMR’s Division of Public Health, Citizen Monitoring Groups, NGO’s, Universities, DEP, etc • WHAT WE DO NOT HAVE? • Biogeochemical modeling • Watershed modeling • Ecosystem based approaches to dealing with abiotic management issues

17. Existing Cobscook Bay Model 20 m in the outer Cobscook Bay

18. Existing Saco-Casco Bay Model > 8 m in Saco > 20 m in Casco

19. Working on Downeast Model 100 m nearshore