Terrestrial eco 2nd exam

Sensible heat flux (H)

Movement of energy between atmosphere and ground surface by temp gradient NO STATE CHANGE

^ = H+ (surface warmer)

Latent heat flux (LE)

movement of energy between atmosphere and ground surface involving EVAPORATION. 

^ LE + = h20 gain energy and evaporate

Ground Heat Flux (G)

Movement of energy between surface and subsurface

^ G- = substrate warmer than surface

• Via conduction

Factors of Influence on heat flux

• soil thermal gradient

• soil thermal conductivity (moisture, bulk density)

• time of day (sunlight warming)

Bowen ratio

tells moisture content of a system

• SH : LH

• Higher moisture = lower value

Factors that influence BR

• species characteristics

• moisture content

• structural configuration (mechanical turbulence)

Transpiration

From leaves alone

evapotranspiration

All things in ecosystem

Interception loss of precipitation

stays on canopy and evaporates (10-20%)

Precipitation throughfall

Precip that falls through canopy gaps

• Influence: Layers of canopy

Precipitation stem flow

Precip that comes down branches, bark, stems.

• Influence: crown shape, bark type 

Net water balance formula

Net precip = Total precip - interception loss

Osmosis

movement of water from high to low water potential area.

facilitated force

helps water not use energy

• Gravity

Resistance force

makes water spend energy

• organisms

• solute concentrations

• surface binding forces

True potential energy

Energy after facilitated and resistance forces.

Pressure potential (water)

energy left after gravity and organism activity. 

Osmotic potential (water)

Energy left after account for solutes concentration.

Matric potential (water)

Energy left after account for soil surface binding sources

Abscisic acid

Plant hormone that controls plant response to stress.

• too much induces dormance

Plants water gradiant

• Taking in water because leaves have less than soil, going down the gradiant to the leaves. 

• Transpiration is key

Soil Plant Atmosphere continuum (SPAC)

• soil solution - root interface

  • root (shape and openings)

  • soil matrix

• Leaf surface - atmosphere interface

  • canopy architecture (boundary layer)

  • leaf resistance (stomata)

Photosynthesis

• Redox process

• compound is reduced and oxidated

Where photosynthesis happens

Organelles

• Chloroplasts (stomata and thylacoids)

• Pigments (organic compounds absorb/reflect light)

• visible light 400-700

Chlorophyll (a,b)

• C and N compounds

• free electron movement (can share)

• absorb most in BLUE AND RED

carotenoid

• Accessory pigment

  • expand light absorption range

  • transfer captured energy to chlorophyll

    • Absorb most in BLUE SOME GREEN

  • reduce tissue overheating

Anthocyanin

• water soluble pigment in flower, fruits, veggies

• expand range in light absoprtion

• reduce tissue overheating

• Aid in pollination, seed dispersal

Season leaf color change because

change in temp/ light intensity

• Chlorophyll dies first

RuBP

Carbon skeletal structure in cell

• cannot participate in PSN until carbon is brought in.

ATP

Made when light strikes on chloroplasts

• resevoir of potential chemical energy

• Ribose sugar, N cpd, 2 high energy p bonds

ADP

P bond released and energy released. 

• q low energy p bond, c cpd, ribose sugar

NADP

• Electron carrier for ATP

• NADPH OR NADP+

Rubisco

Catalyzes photosynthesis

• Dual fixation compound

  • Oxygen

  • Co2

Rubisco determination

• Concentration of Co2 to O2

• High temp, easier to fix O2

Photorespiration

Plants begin to break down chem. energy before they use it.

• limits production of new energy

C3 Photosynthesis (1 enzyme)

1. Light dependent stage

• captures light, recharges ADP to ATP

  • Inputs: water and light

  • Outputs: ATP, NADPH, O2

1. Calvin cycle

• Creates sugar

  • Inputs: CO2, NADPH, ATP

  • outputs: Sugar, ADP, NADP+

Main cells in photosynthesis

Mesophyll and Bundle Sheath

C4 Photosynthesis (2 cells)

1. CO2 fixed into mesphyll by PEP Carboxylate

2. Intermediate 4-C cpd is formed

3. Malate moved mesothyll to bundle sheath

4. CO2 extracted from intermediate 4-C cpd

5. Rubisco fixes CO2 into Calvin Cycle

C4 areas

• Hot/sunny enviroments

• 3% global flora but 23% GPP

CAM Photosynthesis

1. Night time stomata opens

2. CO2 fixed into mesophyll by PEP Carboxylase

3. 4-C intermediate cpd formed 

4. 4-c cpd stored in cell till morning

5. Daylight stomata closes

6. CO2 extracted from 4-C cpd

7. CO2 fixed into carbon cycle by Rubisco 

Regulate Photosynthesis:

• Reactants (light, CO2, water)

• Nitrogen

• Temperature

Major C Pools

• GPP (Gross Primary Production)

• Npp (Net Primary Production)

• NEP (Net eco production)

• NECB (Net eco. C production)

GPP

Total C gained by ecosystem before use

NPP

Balance between GPP and C used by pants

• Growth, maintenance, obsoption)

NEP

Balance between GPP C and C lost from plant and heterotrophic respiration. 

• Microbes, animal consumption, disturbance

NECB

Balance between GPP C gained and C loss via all avenues of loss.

Influence of Temp/Moisture on NPP

• Moisture is stronger driver

  • temp affects moisture.

Liebig’s law of the minumum

Grwth is most limited by single resource at a time. Another resource becomes most limiting when supply of first is increased.

Response to limitations

Ability to alter max capture or min loss

• Storage and transpiration cacti (xerophytes)

• Consistently shooting deep roots to get to water table. (Phreatophytes)