Oceanic Remote Chemical/optical Analyzer (ORCA)

1. PRISM John Dunne; Wendi Ruef ORCA overall; Steven Emerson; Allan Devol Jan Newton; Rick Reynolds General Support Nutrient Analyzer T,S, O2 NO3, l Oceanic Remote Chemical/optical Analyzer (ORCA) An autonomous profiler monitoring water quality in south Puget Sound

2. ORCA GOALS • Develop a robust remote chemical and biological monitoring system • T, S, Light, Meteorology • NO3, O2, Chl-a, turbidity • NH4, Gas Exchange parameters • Telemeter data back to UW • Monitor the spectrum of time-scales • Hourly (tides), Daily (solar), Weekly (plankton growth), Monthly (blooms), Annual (seasons, and inter-annual, e.g., El Nino) • Describe natural variability and characterize and help evaluate potential human influence • Validate PRISM physical and biological models

3. WHAT DOES ORCA LOOK LIKE? ORCA Schematic View light weather station radar reflector superstructure 4.2 m solar panel Platform and housing For Winch, electronics, etc solar panel Atlas float (cut away view) package ballast ring anchoring (break in scale)

5. WHERE IS ORCA?

7. Seattle Tacoma Seattle Tacoma

8. http://www.ocean.washington.edu/research/orca/

9. Nutrient Analysis

10. Spring Bloom Movie Fall Bloom Movie Growing Season Movie

11. Basic data shows varibility

12. primary productivity (mg C m-3 d-1) 0 200 400 600 0 500 1000 0 500 1000 0 0 0 5 5 5 10 depth (m) 15 10 10 20 10 Jul 00 12 Oct 00 25 Sep 00 15 25 15 enhancement surface enhancement no enhancement July 12 - 28, 2000 Sept. 20- Oct. 2, 2000 October 15-21, 2000 Sigma-t Chl ug/l blue = ambient production red = spiked with NH4 and PO4 O2 mg/l enhancement no enhancement surface enhancement Effect of nutrient addition on phytoplankton productivity Carr Inlet, WA Ecology

13. What Causes varibility ?

14. What causes high frequency variability ? Tidal Advection ?

15. What causes high frequency variability ? Wind and destratification ?

16. Analysis by Kate Edwards

18. How frequently do we need to sample? • What is gross O2 production (GP)? • What is net community O2 production (NCP)? O2 flux í Photosynthesis (J) CO2 + H2O + nutrients CH2O + O2 5 m Mixed í mixing Deep C flux

19. How frequently do you need to sample? Gas Exchange = G* (O2sat-O2obs) G=f(average daily wind speed) (Liss and Merlivat, 1986)

20. Diurnal O2 Change Model So, how do we get O2 production terms? 500 450 400 O2 mmoles/m3/d 350 300 250 200 850 900 950 1000 jDay 10 Oct. 1Apr.

21. diurnal O2 change Amplitude ~ 14 mmoles m-3 1) night-time respiration, R = 14 mmoles m-3 (d/2)-1 2) Assume R~ constant, thus, R =28 mmoles m-3 d-1*5 m = 140 mmoles m-2 d-1 3) Since dO2/dt = 0 over 24 h, R = j = 140 mmoles m-2 d-1 (j = O2 production required to balance R)

22. Hourly Oxygen Averages

23. Box Model for net oxygen production h*dO2/dt = G*DO2+ Kz*dO2/dz + NCP h * dO2/dt = observed box depth & oxygen change with time G *DO2 = gas exchange: wind speed; oxygen gradient across air-water interface Kz* dO2/dz= vertical diffusion: diffusion coefficient & observed vertical oxygen gradient NCP= net biological oxygen production: determined from model G = f (average daily wind speed) (Liss and Merlivat, 1986) Kz = f (buoyancy frequency) (Denman and Gargett, 1983)

24. Simple Box Model Results • NCP = 0.011 moles m-2 d-1 • (132 mg C m-2 d-1) • G.E. = -0.012 moles m-2 d-1 • Vertical mixing = -0.0008 • h (dO2/dt) = -0.0021 Is This Reasonable ?

25. 10 Oct. 1Apr. NCP=0.011, G.E.=-0.012, mix=-0.0008, h*dO2/dt=-0.0021 regression = 380-320 mmoles m-3 (380-320)/150 = 0.4 mmoles m-3d-1 h*(dO2/dt) = 2.1 mmoles m-2d-1 (2.1mmoles m-2d-1)/(5m)=0.4mmoles m-3d-1 Conclusion: NCP ~0.011 mmoles m-2d-1

26. What, then is GP? GP = j + G.E. = 140 + 12 = 152 mmoles m-2 d-1 (1824 mg C m-2 d-1)

27. Figure 15. Seasonal levels of ambient primary production integrated over the euphotic zone. Data shown are Apr. 99, Jul. 00, Sep. 99 and Dec. 99. Newton and Reynolds, 2000

28. 0.85 Y = 1.22 X 2 r = 0.93 Chl Based Productivity Model* *Rick Reynolds

29. Productivity Model Input Data Daily-Integrated Surface Insolation Daily depth- Integrated Chl

30. Modeled* Daily Production at The Carr Inlet-ORCA Site *Rick Reynolds model

31. Production Summary

32. Wrap Up • High frequency sampling reveals high frequency features • Some of the high frequency signal is due to tidal effects • Frequent sampling required to capture the true value of certain fluxes, e.g. gas exchange • Bloom starts when water air temperature becomes equal to water temperature • Frequent summer destratification driven by wind events • Production can be derived from oxygen distribution

35. Orca Home Page

37. Longer Term Goals • Science • Study Bloom Dynamics/gas exchange/nutirent/physics coupling • Mixed layer • Aphotic zone • Add Sensors (PO4, Eddy Correlation, micro-gradient) • Publish Orca Results • Expand Network: • South Sound, Main Basin, Hood Canal, Admiralty Inlet • Continue and Expand Outreach/Education

38. Advection

39. Production

40. Goals for 2003 • Science Goals: • MIXED experiment (April 2003) • Nutrients; NO3 and NH4 • Move Orca for Brightwater • Publish Orca Results • Prism Goals: • Use Orca to Validate ABC-POM • Carr Inlet • Brighwater site • Outreach • Maintain Orca Website • Orca School

41. [O2] Box Model Gas Exchange Horizontal Advection Biological Oxygen Production Upwelling Mixing