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Thesis defense

Master's Thesis Defense

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Thesis defense

  1. 1. SEASONAL PATTERNS OF NUTRIENT RETENTION IN A RESTORED TIDAL FRESHWATER STREAM OF THE MID-ATLANTIC COASTAL PLAIN Joe Wood, Virginia Commonwealth University, Department of Biology
  2. 2. Outline• Nutrient transport and associated problems• Description of Tidal Freshwater Systems• Site Description & Project Goals• Methods• Results• Conclusions and implications
  3. 3. What are Nutrients? •Elements whose environmental supply is low in relation to biological demand (N, P) •Small amounts of nutrients can result in large responses from biotic systems.
  4. 4. ExponentialIncrease inNutrientTransportBy watershedsStimulatedAlgaeProductionDecompositionof AlgaeDepletesDissolvedOxygen,Eutrophication
  5. 5. Watershed-scale budgets Basic Terminology •Sources vs. Sinks •Inorganic (NH4,NO3) vs. Organic forms •Assimilation vs. mineralization •De-nitrification
  6. 6. Tidal Freshwater Systems “Along the hydrologic continuum between streams and ocean lies a unique ecotone where river meets estuary” Ensign et al 2008•These systems areecologically distinct fromboth non-tidal streams andsalt marshes but havebeen understudied. Gravity Tides Fresh Water Salt Headwaters Tidal Freshwater Oceans
  7. 7. Why are Tidal Freshwater Streams “biogeochemical hotspots”?1. Increased exposure to active surfaces (benthic layer)2. Diverse chemical and physical habitats (anaerobic zones, floodplains)3. Higher Organic Matter availability (Neubauer et al 2009)
  8. 8. Ecosystem MetabolismPhotosynthesis:CO2 + H2O + Light  CxH2xOx + O2Respiration: Gross Primary Production =CxH2xOx + O2  CO2 + H2O total amount of energy (or C) fixed via photosynthesis per unit of time. How do these parameters influence Ecosystem Respiration= Nutrient Retention? total amount of energy (or C) used via respiration per unit time.
  9. 9. .Seasonal Variation Primary Production Respiration Exchange Volume Ambient Nutrient levels Mass Nutrient Retention
  10. 10. Project Goals• Characterize Annual nutrient Budgets for a recently restored tidal freshwater stream.• Estimate seasonal variation in Ecosystem Metabolism (using diel dissolved oxygen patterns).• Determine controlling factors of nutrient retention.
  11. 11. Methods• Site Description• Tidal exchange sampling method• Characterizing Hydrology with rhodamine• Nutrient additions• Estimating Ecosystem Metabolism
  12. 12. Until September 2006 When a breach occurred in the dam in Kimages Creek Was dammed causing to formDrawdown, and 1927 Lake lake Charles reconnecting tidal inputs to Kimages creek.This narrow breach provides the ability tomeasure all exchange between KimagesCreek and the James River.
  13. 13. Sampling Regime Q = Discharge (L/s) X = Solute Concentration (mg/L) QntXnt Qtidal , Xtidal Qout, Xout X = Cl, NO3, NH4, TN, PO4, TP and DOCHead of tide
  14. 14. Non-tidal input Stream Cl input River Cl inputChloride shouldbehaveconservatively, thusproducing un-alteredoutflows. A Conservative Tracer (Chloride) Tidal Exchange
  15. 15. Stream input Non-tidal input chemistry River input chemistry Retained NitrogenA Non-ConservativeTracer (Nutrients) Tidal Exchange
  16. 16. Characterizing HydrologyRhodamineAdditions (2) on aRising Tide.
  17. 17. Nutrient Additions (3) Raised ambient NH4 and PO4 nutrient levels by roughly 20%
  18. 18. Measuring Ecosystems Metabolism 16 DARK LIGHT 15 (R) (PS + R) 14DO eq (mg/L) 13 12 11 10 9 8 0:00 9:30 19:00 4:30 14:00 23:30 9:00 18:30 4:00 13:30 23:00 Photosynthesis: CO2 + H2O + Light  CxH2xOx + O2 Respiration: CxH2xOx + O2  CO2 + H2O We Must also account for Atmospheric Exchange…
  19. 19. Atmospheric Exchange OxygenTo estimate Atmospheric Exchange (AE) we useda method which assumes a constant boundarylayer thickness. Thus AE is only influenced byDepth and Difference in Saturation.
  20. 20. Advective influences 12 0.08 DO 10 Depth 0.06 8O2 (mg/L) Depth (m) 6 0.04 4 0.02 2 0 0.00 During certain times of the year when oxygen concentrations were drastically different between sources, Kimages displayed advective influences of Oxygen.
  21. 21. Results• Water• Nutrient• Annualized Budgets• Metabolism Estimates• High Flow events• Controlling factors of nutrient retention
  22. 22. Rhodamine Additions indicate this is a macro-tidal system Inflow Outflow Inflow 2.5 Rhodamine Flux (g/min) I 2 n j 1.5 e c 1 t i 0.5 o n 96,80% 0 0 2 4 6 8 10 12 14 16 18 Time since rhodamine injection (hours)
  23. 23. Average Water Fluxes 8000 1500 3500 (Storage) 13000All Units in M3/ Tidal Cycle
  24. 24. 40000 Water Fluxes 0.4 35000 Gloucester Point James River 0.2Volume of Exchange (m3) 30000 0 Water Stage (m) 25000 20000 -0.2 15000 -0.4 10000 -0.6 5000 0 -0.8 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Storage Tidal output Tidal Input Non-tidal input 60000 50000 Exchange volume (m3) R² = 0.78 40000 30000 20000 10000 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 River depth (m)
  25. 25. Predicted Outflow - Actual outflow Predicted Outflow - Actual outflow (NH3 mg/L) NH4 (mg/L) NO3 (mg/L) (NOx mg/L) (mg/L) Cl Outflow (mg/L) Measured Cl -0.10 -0.05 -0.25 -0.20 -0.15 0.00 0.05 0.10 0.02 0.00 0.04 -0.06 -0.02 -0.12 -0.10 -0.08 -0.04 0 10 20 30 60 70 40 50 0S 9/24/2008 10O 10/24/2008 20 P = 0.0000D R² = 0.9909 12/9/2008 30J 1/18/2009 40F 2/21/2009 Predicted Cl (mg/L) 50 60M 3/21/2009 Cl Inflow (mg/L) 1:1 70A 4/25/2009M 5/19/2009J 6/19/2009J 7/31/2009A 8/19/2009 Predicted Outflow - Actual outflow Predicted Outflow - Actual outflow TN (mg/L) (TN mg/L) TON (mg/L) (TON mg/L) -0.150 -0.100 -0.050 -0.250 -0.200 0.000 0.050 0.100 -0.10 -0.05 -0.20 -0.15 0.00 0.05 0.10S 9/24/2008O 10/24/2008D 12/9/2008J 1/18/2009F 2/21/2009 RELEASEM differences 3/21/2009A 4/25/2009M 5/19/2009J 6/19/2009J RETENTION 7/31/2009 Nutrient ConcentrationA 8/19/2009
  26. 26. Chloride Fluxes 1,600,000 1,400,000 Delta Storage 1,200,000 Total output 1,000,000 Tidalg cl Flux/Tidal Cycle 800,000 Non-tidal 600,000 400,000 200,000 0 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Dec Jan Feb Mar Apr May Jun July Aug
  27. 27. Inorganic Nitrogen Fluxes 7,000 "Change in Storage" 6,000 Total output g NOx Flux/Tidal Cycle 5,000 "Change in Storage" g NO3 4,000 Tidal Total output Tidal 3,000 Non-tidal Non-tidal 2,000 1,000 0 2,500 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Dec Jan Feb Mar Apr May Jun July Aug 2,000In Out In Out In Out In Out In Out In Out In Out In Out In Out g NH4 Flux/Tidal Cycle g NH4 1,500 Dec Jan Feb Mar Apr May Jun July Aug 1,000 500 0 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Dec Jan Feb Mar Apr May Jun July Aug
  28. 28. 30,000 25,000 "Change in Storage" g DIN Flux/Tidal Cycle 20,000 Total output g DIN 15,000 10,000 Tidal Non-tidal 5,000 0 30,000 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out 25,000 Sep Oct Dec Jan Feb Mar Apr May Jun July Aug g TON Flux/Tidal Cycle 20,000 g TON 15,000n Out In Out In Out In Out In Out In Out In Out In Out In Out 10,000 Dec Jan 5,000 Feb Mar Apr May Jun July Aug 0 30,000 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Dec Jan Feb Mar Apr May Jun July Aug 25,000 g TN Flux/Tidal Cycle 20,000 g TN 15,000 10,000 5,000 0 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Dec Jan Feb Mar Apr May Jun July Aug
  29. 29. 1,800 1,600 "Change in Storage" 1,400 Total "Change in Storage" output g PO4 Flux/Tidal Cycle 1,200 g PO4 Total output 1,000 Tidal Tidal Non-tidal 800 Non-tidal 600 400 200 0 5,000 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out 4,500 Sep Oct Dec Jan Feb Mar Apr May Jun Jul Aug 4,000n Out In Out 3,500In Out In Out In Out In Out In Out In Out g TP Flux/Tidal Cycle 3,000 g TP Jan Feb 2,500 Mar Apr May Jun July Aug 2,000 1,500 1,000 500 0 300,000 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out 250,000 Sep Oct Dec Jan Feb Mar Apr May Jun Jul Aug g DOC 200,000 g DOC Flux/Tidal Cycle 150,000 100,000 50,000 0 In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out Sep Oct Dec Jan Feb Mar Apr May Jun July Aug
  30. 30. Tracer 1600 Experiments ∆ Storage 1400g NH4 /Tidal Cycle Injection 1200 1000 Output 800 Tidal 600 Non-tidal 400 200 0 2500 Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflowg PO4 /Tidal Cycle 2000 Ambient Injection Ambient Injection Ambient Injection May June August 1500 1000 500 0 Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Ambient Injection Ambient Injection Ambient Injection May June August
  31. 31. 3.0 a River Depth (m) 2.8 2.6 Extrapolating 2.4 River Depth (m) 2.2 between 2.0 sampling dates 1.8 1.6 Daily Modeled Values Sampling Dates 1.4 1.2 3 per. Mov. Avg. (Daily Modeled Values) 1.0 40000 7/21/2008 9/9/2008 10/29/2008 12/18/2008 2/6/2009 3/28/2009 5/17/2009 7/6/2009 8/25/2009 10/14/2009 60000 b 35000 Exchange Volume/Tidal Cycle (m3) 50000 30000Exchange volume (m3) Volume(m3) R² = 0.78 40000 25000 Exchange 30000 20000 20000 15000 10000 10000 5000 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 River depth (m) 2000 7/21/2008 9/9/2008 10/29/2008 12/18/20082/6/2009 3/28/2009 Net Release 5/17/2009 7/6/2009 8/25/2009 10/14/2009 1000 c 0 DIN FluxFlux/Tidal Cycle -1000 (g) -2000 DIN (g) -3000 -4000 Net Retention -5000 -6000 7/21/2008 9/9/2008 10/29/2008 12/18/2008 2/6/2009 3/28/2009 5/17/2009 7/6/2009 8/25/2009 10/14/2009
  32. 32. Annualized Budgets North River, MA (Bowden et al Kimages Creek, VA 1991) in (kg) out (kg) diff (kg) % %NH4 309 330 -21 -6.8% 1.2%Nox 1046 994 52 5.0% 6.8% DIN 1361 1323 38 2.8% 4.4%DON 2605 2827 -222 -8.5% TN 3966 4150 -184 -4.6% Cl 65641 68451 -2809 -4.3%DOC 32082 30820 631 4% TSS 113494 125627 -6067 -10%
  33. 33. Metabolism 20 0.60 James RIver NOx (mg/L) James River 0.50 15 [NOx] 0.40 Results 10 5 0.30 0.20 g O2/M2/d 0.10 0 0.00 -5 -10 -15 -20 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug 20 Kimages Creek 15 10 5 g O2/M2/d 0 -5 R -10 GPP AE -15 -20 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
  34. 34. Hurricane KyleIn < 1% of the year, 10%of total annual exchangevolume and 7% ofannual Nox Inflow, halfof which was retained. 1.4 4500 Residual water table height (m) Cartersville Discharge (m3/s) 1.2 4000 3500 1 3000 0.8 2500 Rice Pier 0.6 2000 Ches B.B. 1500 0.4 Cartersvill Discharge 1000 0.2 500 0 0 23-Sep-08 25-Sep-08 27-Sep-08 29-Sep-08 1-Oct-08
  35. 35. Controlling factors of NO3 Retention 3000 2500 Hur. Kyle Kyle Hur. 2000 Retention (g NO3 /tide) 1500 1000 R² = 0.49 500 R² = 0.69 "GPP" 0 -500 R² = 0.44 "R" -1000 0 10 20 30 40 0 2 4 6 8 10 Temp (C) GPP or R (g O2/M2/Day) 3000 Hur. Kyle Hur. Kyle Hur. Kyle 2500 2000 Retention (g NO3 /tide) 1500 R² = 0.55 1000 500 0 R² = 0.50 -500 -1000 0 10,000 20,000 30,000 40,000 0.0 0.2 0.4 0.6 Exchange Volume (m3) Ambient NO3 (mg/L)
  36. 36. Seasonal . .86 Variation(Temperature) .82 .57 GPP-.95 Exchange R Volume 0.62 0.86 Ambient Nutrient Concentrations -.84 .80 NOx Mass Retention Correlation.89 Coefficients
  37. 37. .47* . Seasonal Variation -.05 (Temperature) .03 GPP -.42* Exchange Volume R 0.62* 0.86** .80** Ambient Nutrient Concentrations -.84** NOx Mass Retention.62* Path * p<.05 analysis ** p<.05
  38. 38. Future Restorationof Kimages Creek,Breach expansion
  39. 39. Conclusions• DIN Retention exhibits strong 3,500 2,500 g DIN Flux/Tidal Cycle 1,500 seasonal variation that includes net 500 -500 -1,500 -2,500 -3,500 release. 3,500 Sep Oct Dec Jan Feb Mar Apr May Jun Jul Aug 2,500 g TON Flux/Tidal Cycle 1,500 500 -500 -1,500 -2,500 -3,500 Seasonal .47* 3,500 Sep Variation Dec Oct Jan Feb Mar Apr -.05 May Jun Jul Aug 2,500 (Temperature) g TN Flux/Tidal Cycle 1,500• Metabolism, Exchange Volume and -.39 Exchange 500 GPP Volume -.42* -500 R 0.62* -1,500 0.86** -2,500 .80** -3,500 Ambient Ambient Nitrate Concentration Sep Oct Nutrient Jan Dec Concentrations -.84** Feb NOx Mass Retention Mar Apr May Jun Jul Aug Path regulate nitrate retention. .62* * p < .05 analysis ** p < .01 Hurricane Kyle In < 1% of the year, 10%• High flow events can significantly of total annual exchange volume and 7% of annual Nox Inflow, half of which was retained. influence annual budgets of nutrient 1.4 4500 Residual water table height (m) Cartersville Discharge (m3/s) 1.2 4000 3500 1 3000 0.8 2500 Rice Pier retention. 0.6 2000 Ches B.B. 1500 0.4 Cartersvill Discharge 1000 0.2 500 0 0 23-Sep-08 25-Sep-08 27-Sep-08 29-Sep-08 1-Oct-08
  40. 40. Thank you!• Dr. Paul Bukaveckas • Dr. Ed Crawford• Dr. Joanna Curran • Jim Deemy• Dr. James Vonesh • Alex Fredua-Agyemang• Dr. Chris Gough • Mac Lee• Michael Brandt • Nader Shehadeh• Kristen Cannatelli • Nathan Conway• Maureen Daughtery • Doug Perron• Anne Schlegel • Brenda Nguyen• Cat Luria • Charlie Wood• Molly Sobotka • Drew Garey• Brian Hasty • Elizabeth Snider•
  41. 41. Questions?

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