Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs.      Cr...
Responses to Climate Change:     Where to sample?
Lakes as Sentinels & Integrators       of Climate Change     Williamson et al. 2009 Limnol. Oceanogr. 54:2273
Treeline is advancing to higher elevations (black dots)      in 52% of 166 systems sampled worldwide. Receding treelines o...
DOM Source is Largely Terrestrial               Terrestrial               Vegetation                    Low – Medium - Hig...
DOM as an Ecosystem Regulator    Low DOM                                  High DOMHigh transparency                       ...
DOM Has Doubled in 15-20 yr in Many Lakes & Rivers             Evans et al. 2006. Global Change Biology 12:2044(See also F...
Beartooth Mountains, MT-WY, USA  Saros et al. 2005  CJFAS 62:1681
Ganguly et al. 2009. Proc. Nat. Acad. Sci. U.S. 106:15555
Central Rocky Mountains, Western USA:  Changing Snowfall in Red Lodge, MTRose et al. 2009 Photochem. Photobiol. Sci. 8:1244
Changes in Diatoms in the Central RockyMtns. Associated with Climate Change                       Saros et al. 2003. AAAR ...
Central Question: How will climate-driven increases in DOMinfluence consumer:producer relationships             in mountai...
Climate Change in Montane Ecosystemstemperature, precipitation, treeline --> more DOM                           ?        H...
Epilimnion       (H)Warm, High Light                   (A)   ? Hypolimnion       (H)   Cold, Dark                   (A)   ?
Epilimnion       (H)Warm, High Light                   (A)   ? Hypolimnion       (H)   Cold, Dark                   (A)   ...
Experimental Design  With DOM              No DOMResource Subsidy     Resource Subsidy      (H)                 (H)       ...
Experimental Design• 3 week field microcosms• 3.8 L transparent bags• Natural phytoplankton• Treatments (3 replicates):   ...
Phytoplankton Biomass                  300                        Initial                Epilimnion                       ...
Phytoplankton Biomass                  300                        Initial                Epilimnion                       ...
Total Zooplankton Biomass                  800                        Initial                   Epilimnion                ...
Zooplankton:Phytoplankton (H:A) RatioZooplankton Biomass:Phytoplankton Biomass                                            ...
No Terrestrial               With TerrestrialResource Subsidy              Resource Subsidy     (-DOM)                    ...
DOM & Transparency: Vertical overlap of   Consumers and their Resources• Do we see variations in DOM and transparency in a...
Lake Oesa, Canadian Rocky MountainsUV Transparency July 28, 2008-2009                                        380 nm UV (% ...
380 nm UV (% of subsurface)                          CDOM fluorescence                  10                           100  ...
Lake Oesa Hesperodiaptomus July 28                     Copepods per Liter              0.00     1.00     2.00      3.00   ...
Oesa Zooplankton & Chlorophyll July 28                     Copepods per Liter                                             ...
Lake Oesa Transparency vs. Precipitation         (PRELIMINARY: N= 4 only!!!)
Indirect Effects on Terrestrial DOM?                Terrestrial                Vegetation                     Low – Medium...
Indirect Effects of Climate Change: Wildfire
Bark Beetle Damage
Lakes are Good Sentinels & Integrators ofClimate Change: Direct & Indirect Effects         Williamson et al. 2009 Limnol. ...
Specific Conclusions Higher DOM will stimulate producer biomass more than  consumer biomass, reducing consumer regulation...
AcknowledgementsField and Laboratory Assistance:    – Jeremy Mack, Kevin Rose, E. Overholt, R. Moeller, S. Lee, A. Nurse, ...
Extra Slides Follow
Net Zooplankton Grazing EffectNet Grazing Effect (ml cleared/ug zooplankton/week)                                         ...
Changes in DOC (% yr-1)(up to 100% in past 15-20 yr in some areas)         Monteith et al. 2007         Nature 450:537
Template
Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs [Craig W...
Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs [Craig W...
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Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs [Craig Williamson]

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Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs. Presented by Craig Williamson at the "Perth II: Global Change and the World's Mountains" conference in Perth, Scotland in September 2010.

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Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs [Craig Williamson]

  1. 1. Water transparency to UV radiation in montane lakes: consequences of climate-driven changes in terrestrial inputs. Craig Williamson, Carrie Kissman, Kevin Rose Miami University Global Change Limnology Lab Jasmine Saros University of Maine Climate Change Institute Janet Fischer & Jennifer Everhart Franklin & Marshall College
  2. 2. Responses to Climate Change: Where to sample?
  3. 3. Lakes as Sentinels & Integrators of Climate Change Williamson et al. 2009 Limnol. Oceanogr. 54:2273
  4. 4. Treeline is advancing to higher elevations (black dots) in 52% of 166 systems sampled worldwide. Receding treelines observed in only 1% of systems. Harsch et al. 2009. Ecology Letters 12:1040.
  5. 5. DOM Source is Largely Terrestrial Terrestrial Vegetation Low – Medium - High DOM in water
  6. 6. DOM as an Ecosystem Regulator Low DOM High DOMHigh transparency Low transparency DOM Regulates UV transparency Compensation depth Mixing depth Nutrient cycling Anoxia Metal toxicity Pesticide toxicity Other …
  7. 7. DOM Has Doubled in 15-20 yr in Many Lakes & Rivers Evans et al. 2006. Global Change Biology 12:2044(See also Findlay 2005. FEE 3:133; Monteith et al. 2007. Nature 450:537)
  8. 8. Beartooth Mountains, MT-WY, USA Saros et al. 2005 CJFAS 62:1681
  9. 9. Ganguly et al. 2009. Proc. Nat. Acad. Sci. U.S. 106:15555
  10. 10. Central Rocky Mountains, Western USA: Changing Snowfall in Red Lodge, MTRose et al. 2009 Photochem. Photobiol. Sci. 8:1244
  11. 11. Changes in Diatoms in the Central RockyMtns. Associated with Climate Change Saros et al. 2003. AAAR 35:18
  12. 12. Central Question: How will climate-driven increases in DOMinfluence consumer:producer relationships in mountain lakes?
  13. 13. Climate Change in Montane Ecosystemstemperature, precipitation, treeline --> more DOM ? Heterotrophic Consumers Zooplankton (H) HB:AB = 3 Autotrophic Phyto. (A)
  14. 14. Epilimnion (H)Warm, High Light (A) ? Hypolimnion (H) Cold, Dark (A) ?
  15. 15. Epilimnion (H)Warm, High Light (A) ? Hypolimnion (H) Cold, Dark (A) ? ? Epilimnion (H) Warm, High Light (A) ? Hypolimnion (H) Cold, Dark Anoxic (A) ?
  16. 16. Experimental Design With DOM No DOMResource Subsidy Resource Subsidy (H) (H) 1.5 m (A) ? (A) ? +/- Zooplankton (H) (H) 8.0 m (A) ? (A) ?
  17. 17. Experimental Design• 3 week field microcosms• 3.8 L transparent bags• Natural phytoplankton• Treatments (3 replicates):  +/- Zooplankton grazers  +/- DOM  2 depths to give different light & temperature: – 1.5 m (epilimnion) – 8 m (hypolimnion)
  18. 18. Phytoplankton Biomass 300 Initial Epilimnion Hypolimnion 250Biomass (µg L ) 200 -1 DOM p < 0.001 ZP p < 0.001 150 Depth p = 0.090 DOM*ZP p = 0.187 100 DOM*Depth p = 0.077 ZP*Depth p = 0.009 DOM*ZP*Depth = 0.65 50 0 l tia M M M M M M M M Ini -D O DO DO DO O DO O DO + - + -D + -D + + Zoop + Zoop Treatment
  19. 19. Phytoplankton Biomass 300 Initial Epilimnion Hypolimnion 250Biomass (µg L ) 200 -1 DOM p < 0.001 ZP p < 0.001 150 Depth p = 0.090 DOM*ZP p = 0.187 100 + DOM*Depth p = 0.077 ZP*Depth p = 0.009 DOM*ZP*Depth = 0.65 50 - 0 l tia O M M O M M M M M M Ini -D DO -D DO O DO O DO + + -D + -D + + Zoop + Zoop Treatment
  20. 20. Total Zooplankton Biomass 800 Initial Epilimnion Hypolimnion 600Biomass (µg L ) -1 DOM p = 0.010 400 Depth p = 0.003 DOM*Depth = 0.21 200 0 al M M M M n iti DO DO DO DO I - + - + Treatment
  21. 21. Zooplankton:Phytoplankton (H:A) RatioZooplankton Biomass:Phytoplankton Biomass 30 Initial Epilimnion Hypolimnion 25 DOM p = 0.002 Depth p =0.216 20 DOM*Depth = 0.585 15 10 5 0 al - + - + iti M M M M In DO DO DO DO Treatment
  22. 22. No Terrestrial With TerrestrialResource Subsidy Resource Subsidy (-DOM) (+DOM) (H) (H) (A) Initial (H) (A) (H) (H) (A)
  23. 23. DOM & Transparency: Vertical overlap of Consumers and their Resources• Do we see variations in DOM and transparency in alpine lakes among years?• What are the implications of these transparency changes for vertical overlap of consumers and their resources?
  24. 24. Lake Oesa, Canadian Rocky MountainsUV Transparency July 28, 2008-2009 380 nm UV (% of subsurface) 10 100 0 2 4 Depth (m) 6 8 10 12 2008 14 2009 16
  25. 25. 380 nm UV (% of subsurface) CDOM fluorescence 10 100 0 10 20 30 0 0 5 5 10 10 Depth (m) Depth (m) 15 15 20 20 25 25 2008 2008 30 30 2009 2009 35 35 Chlorophyll Fluorescence Turbidity 0 200 400 0 10 20 30 40 50 60 0 0 2008 2008 5 5 2009 2009 10 10 Depth (m)Depth (m) 15 15 20 20 25 25 30 30 35 35
  26. 26. Lake Oesa Hesperodiaptomus July 28 Copepods per Liter 0.00 1.00 2.00 3.00 0 5 10Depth (m) 15 20 25 2008 30 2009 35
  27. 27. Oesa Zooplankton & Chlorophyll July 28 Copepods per Liter Chlorophyll Fluorescence 0.00 1.00 2.00 3.00 0 200 400 0 0 5 2008 5 2009 10 10Depth (m) Depth (m) 15 15 20 20 25 2008 25 30 2009 30 35 10% UV380 35
  28. 28. Lake Oesa Transparency vs. Precipitation (PRELIMINARY: N= 4 only!!!)
  29. 29. Indirect Effects on Terrestrial DOM? Terrestrial Vegetation Low – Medium - High DOM in water
  30. 30. Indirect Effects of Climate Change: Wildfire
  31. 31. Bark Beetle Damage
  32. 32. Lakes are Good Sentinels & Integrators ofClimate Change: Direct & Indirect Effects Williamson et al. 2009 Limnol. Oceanogr. 54:2273
  33. 33. Specific Conclusions Higher DOM will stimulate producer biomass more than consumer biomass, reducing consumer regulation of autotrophic production and fate of fixed carbon. Shorter, interannual climate-induced variations in DOM and other variables can alter transparency and consumer-resource interactions.
  34. 34. AcknowledgementsField and Laboratory Assistance: – Jeremy Mack, Kevin Rose, E. Overholt, R. Moeller, S. Lee, A. Nurse, N. McCulligh, M. Collado, A. Tucker and M. CohenFunding: – USA National Science Foundation, Miami University
  35. 35. Extra Slides Follow
  36. 36. Net Zooplankton Grazing EffectNet Grazing Effect (ml cleared/ug zooplankton/week) 2.0 Epilimnion Hypolimnion 1.8 1.6 1.4 1.2 DOM < 0.001 Depth = 0.992 1.0 DOM*Depth = 0.839 0.8 0.6 0.4 0.2 0.0 - + - + D OM OM OM OM D D D Treatment
  37. 37. Changes in DOC (% yr-1)(up to 100% in past 15-20 yr in some areas) Monteith et al. 2007 Nature 450:537
  38. 38. Template

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