On the Active Role of Plants on Land Atmosphere Processes Amilcare - - PowerPoint PPT Presentation

On the Active Role of Plants on Land‐Atmosphere Processes

Amilcare Porporato Duke University

From stochastic rainfall to soil moisture dynamics and plant water stress

0.05 0.15 0.25 150 200 250 300 350 Julian D ay q (%) interspace canopy

5 10 15 20

Precipitation (mm day )

Sevilleta, NM Courtesy of Eric Small

Runoff

INPUT: RAINFALL (intermittent- stochastic)

t h

Evapo- transpiration Troughfall Zr Effective porosity, n Zr Effective porosity, n Leakage Runoff

          



s

u du s Exp s c s p ) ( ) ( ) (    

Soil Moisture PDF: climate soil and vegetation

Rodriguez-Iturbe et al., Proc. Royal Soc. A, 455, 3789, 1999 Laio et al. AWR 2001; Porporato et al. Am. Nat., 2004

Salvucci G. (2001) Water Resour. Res. 37(5), 1357-1365.

Experimental verification

Soil moisture control on C-N cycling

Denitrif.

NH4

+

NO3

• Adsorption

(desorption) Leaching

SOM PLANTS

Litter

Immobilization Ammonification Nitrification Plant Uptake

Microbes Humus

Biological fixation Wet and dry deposition Ammonia volatilization Litter

Porporato et al. AWR 2003; Manzoni et al., Science 2008

Calhoun Critical Zone Observatory

Critical Zone Observatories

Calhoun, 1950 circa

NSF‐FESD – frontiers in earth system dynamics Geo‐genomics – geology, eco‐hydrology and evolution of biodiversity in the Amazon

Weathering

• Ecohydrological mediation of weathering – soil

alternate states: two brief examples

– bistability and – rapid change in weathering and carbon sequestration during carboniferous.

stomatal control CAM photosynthesis

Devoninan (400‐360 Ma) and Carboniferous (360‐300 Ma)

Plants, Leaching & Soil formation

Physical weathering PS, photosynthesis Soil depth, h Respiration, R Chemical weathering Infiltration Mineral soil Organic mat’l Atmosphere Soil moisture ET Rainfall L, percolation & export of dissolved carbonates

• J

2

Q Morel and Hering, Aquatic chem.

Simplified model

,

• ⋅

CO2 proxy data from: DL Royer, Geochimica et Cosmochimica Acta 70 (2006)

Quasi‐steady state assumptions in the soil solution

we know that L decreases with h …  Increased convective precipitation?  increased infiltration?

10

site of light reactions site of Calvin cycle site of Calvin cycle

Chloroplasts in the mesophyll

Ecohydrology and photosynthetic pathways

H2O here for photolysis Water stress (l) Water stress function on Farquhar’s model of photosynthesis only in 2004: Daly et al. JHM (2004) Tuzet et al. PCE (2004)

11

Triose 3C sugar G3P 3C compound

Carboxylase/Oxygenase …

C3 photosynthesis – Calvin cycle: a chemical engine to produce sugar

Weathering

• Ecohydrological mediation of weathering – soil

alternate states: two brief examples

– bistability and – rapid change in weathering and carbon sequestration during carboniferous.

13

bundle sheath cell mesophyll cell

C4 photosynthesis: Krantz anatomy

CO2 pump

greater WUE

very productive crops with water and energy availability

• a

200 400 2 4

ETseas mm Yton ha1

• b

200 400 600 4 8 12

ETseas mm Yton ha1

Wheat Corn

Vico and Porporato, AWR (2012) Kramers and Boyer 1995

A curious analogy…

CO2 pump

16

But C4 is more sensitive to water stress

C3 C4 C3 C4 C3 C4 C4 C4

Weibull-type vulnerability curve

                

c l l

d Exp a f   ) (

Vico and Porporato, C3 and C4 photosynthesis under‐water stressed conditions, Plant and soil (2008)

0.5 1 0.5 1 soil moisture E/EpC3 C3 C4

Sugarcane

Largescale land‐atmosphere feedback?

18

ABL development and convective precipitation

as the ABL grows, the conditions for convective precipitation: 1) LCL crossing 2) CAPE>400

Slab or mixed‐layer models of the ABL

• Idealized ABL

– Hydrostatic atmosphere – Homogeneous horizontal conditions – Well‐mixed vertically (instantaneous) – Zero‐order “jump” at capping inversion – No latent heat release

• Simplified profiles/geometry

– Constant in mixed layer – Linear in free atmosphere

It is a good approximation : e.g., Large Eddy Simulation of ABL

after Stevens – J. Atm. Sci. (2007)

21

– Surface energy balance: – Conservation equations in the mixed layer:

           c h d dt H c dh dt h dq dt E q q dh dt dh dt H c h

p p f f p

       

( ) ( ) ( ) 1 2

e.g., Garrett 1994 Porporato BLM 2009

E H Q q q g g g g E g c H

w w n a i a s a s w a a p

              ) ( ) ( dt dh c H dt d h c

f p p

) (         h c H dt dh

p 

  ) 2 1 (   dt dh q q E dt dq h

f w

) (      

2 4 6 8 2 4 8 time (hr) s=0.25 Altitude (km) 2 4 6 8 2 4 8 time (hr) s=0.32 Altitude (km) 2 4 6 8 2 4 8 time (hr) s=0.38 Altitude (km) 2 4 6 8 2 4 8 time (hr) s=0.45 Altitude (km) 2 4 6 8 100 200 300 400 time (hr) s=0.25 J/kg 2 4 6 8 100 200 300 400 time (hr) s=0.32 J/kg 2 4 6 8 100 200 300 400 time (hr) s=0.38 J/kg 2 4 6 8 100 200 300 400 time (hr) s=0.45 J/kg

Huang et al. WRR (2007)

Yin et al. (in preparation)

smax soil moisture that likely triggers strongest convection for the given atmospheric conditions (A) Dry soil advantage regime (B) Transitional regime (C) Wet soil advantage regime unstable wet (E) No crossing (D & F) LCL crosses at certain soil conditions but CAPE<400J/Kg

Yin et al. (in preparation)

C3 vs C4

2 4 6 8 0.5 1 1.5 2 time (hr) s=0.3 Altitude (km) 2 4 6 8 0.5 1 1.5 2 time (hr) s=0.8 Altitude (km) 2 4 6 8 200 400 600 800 time (hr) s=0.3 (J/kg)

2 4 6 8 200 400 600 800 time (hr) s=0.8 (J/kg)

Weathering

• Ecohydrological mediation of weathering – soil

alternate states: two brief examples

– bistability and – rapid change in weathering and carbon sequestration during carboniferous.

CAM pathway

CAM = Crassulacean Acid Metabolism

27 Thick-leaved orchid: Phalaenopsis amabilis

Storage of malic acid in cell vacuoles + control system (circadian rhythm)

Bartlett, Vico and Porporato, Plant and Soil (2014) Hartzell et al. JTB in revision

Pursuing the analogy a bit further…

• Similar evolutionary sequence
• C4: low CO2  turbocharger: low oxygen (more power/works

well at high elevations)

• CAM  hybrid: storage limits and costs: variability is essential

Porporato et al. in preparation 2014

NOBEL, P.S. Biologia ambiental. In: Agroecologia, cultivo e uso da palma forrageira. FAO, 1995. SEBRAE‐PB. p.36‐48. 216p. 2001.

• K. Orkun and J. Michalek, Influence of driving patterns on

life cycle cost and emissions of hybrid and plug‐in electric vehicle powertrains. Energy Policy 60 (2013): 445‐461.

Model for CAM photosynthesis

Ac(ci,Tl,)

classic Farquhar et

• al. (1981) model

Circadian rhythm z

          M T z M dt dz A R A dt dM

l E vc dv sv

) , ( 

Plant capacitance Demand‐driven stomatal conductance

Bartlett, Vico and Porporato, Plant and Soil (2014) Hatzell et al. JTB in revision

Agave tequiliana Clusia minor

results

Comparison of C3, C4 and CAM plants

Decreasing rainfall frequency

Back to our analogy

C4 C3 CAM

Conclusions

• Work in progress…
• Fascinating interactions between plant and their

environment which are impacted by and in turn control the water cycle

• Important for long term dynamics of soils,

biogeochemical cycles and landscape formation

• Optimizing our management of soil and water

resources (quantitative answers to the problem

• f sustainability)

Opunthia ficus indica, growing on an obelisk in Ethiopia

Photo: courtesy of Paolo Inglese,

• Univ. of Palermo, Italy

Thank you!

sorghum

• Improve rate of carboxylation (reduce
• xygenase)  CO2 pump (Krantz anatomy)
• Improve comburent concentration 

turbocharger