Month Day Topic

Nov. 27 Ecosystem services

29 Global change biology

Dec. 1 MM’s research

4 Review for exam

6 Final exam—ecology

Energy flow through ecosystems

Only 5% of the solar energy that arrives on earth is captured by photosynthesis.

The energy captured powers life.

Trophic levels

Level Source of energy

Primary producers Solar energy

Herbivores Primary producers

Primary carnivores Herbivores

Secondary carnivores Primary carnivores

Omnivores Everything!

Decomposers Dead things

Energy flow

versus

Biogeochemical cycles

Consumers

Producers

Abiotic reservoir

Geological processes

Decomposers

A generalized biogeochemical cycle

Carbon cycle

Carbon is the conduit for energy flow!

Carbon cycle

Carbon is the conduit for energy flow!

Carbon cycles through the atmosphere, organisms, soils, and oceans

(and rocks at very long time scales)

Carbon cycle

Carbon is the conduit for energy flow!

Carbon cycles through the atmosphere, organisms, soils, and oceans

(and rocks at very long time scales)

Gaseous, mineral, organic

Carbon cycle

Ecosystem carbon balance

C in = storage + C out

NPP

Soil, plant growth (wood)

CO2, C leaching, erosion

C in > storage + C out: accumulating C

C in = storage + C out: balanced C

C in < storage + C out: loosing C

Carbon stocks

Sedimentary rocks > deep oceans >

atmosphere = organisms and soils

Nitrogen cycle

• N cycles through the atmosphere, organisms, soils and sediments

Nitrogen cycle

• N cycles through the atmosphere, organisms, soils and sediments

• Organically bound N is one of the main constituents of organisms (after C and H)– enzymes for photosynthesis, metabolism

– proteins

– building blocks of DNA...

Nitrogen cycle

• N cycles through the atmosphere, organisms, soils and sediments

• Organically bound N is one of the main constituents of organisms– enzymes for photosynthesis, metabolism

– proteins

– building blocks of DNA...

• Gaseous, mineral, organic

Nitrogen cycle

• Although N2 gas makes up 72% of the

atmosphere, few organisms can use it.

• N is the element that is most likely to

limit plant growth

Nitrogen cycle

• N enters system through biological

fixation

Nitrogen accumulates over primary succession

Nitrogen cycle

• N enters system through biological

fixation

• If organisms can fix N, why don’t they

take over and fix enough N so that it is

no longer limiting to plant growth?

Why is N in short supply?

• Only a few types of organisms can do it

Why is N in short supply?

• Only a few types of organisms can do it

• Energetically expensive to fix N

Why is N in short supply?

• Only a few types of organisms can do it

• Energetically expensive to fix N

• Chemically expensive to fix N

Why is N in short supply?

• Only a few types of organisms can do it

• Energetically expensive to fix N

• Chemically expensive to fix N

• N can be lost from the system– Leaching– Fire– Erosion

Hydrological cycle

Water cycles through the oceans, fresh waters, atmosphere, and land

Hydrological cycle

Water cycles through the oceans, fresh

waters, atmosphere, and land

Gaseous phase and liquid phase

Hydrological cycle

Evaporation: liquid to gas

Transpiration: plant transport of water from the soil to the atmosphere

Precipitation: gas to liquid

Water inputs to ecosystems

• Precipitation– THE major water input to ecosystems

• Groundwater (in some ecosystems)

• Fog deposition (in some ecosystems)

Water balance in ecosystems

Inputs = storage + outputs

Water balance in ecosystems

Soil is like a bucket

Water balance in ecosystems

Soil is like a bucket

• Inputs– Mainly precipitation

Water balance in ecosystems

Soil is like a bucket

• Inputs– Mainly precipitation

• Storage– Plants, soil and water bodies

Water balance in ecosystems

Soil is like a bucket• Inputs

– Mainly precipitation

• Storage– Plants, soil and water bodies

• Outputs– Evaporation– Transpiration– Drainage

Hydrological cycle

• Over oceans, evaporation >> precipitation

• On land, evaporation << precipitation and transpiration– Lakes, rivers, streams, groundwater

Ecosystem services

Processes by which the environment produces fundamental life-support

services enjoyed by humans

Ecosystem services

Key ingredients of our agricultural, pharmaceutical, and industrial

enterprises

Ecosystem services1. Purify air and water water2. Pollination of crops3. Detoxify and decompose wastes4. Stabilize climate5. Ozone protection from UV6. Maintain biodiversity7. Control agricultural pests8. Generate and preserve soil fertility9. Maintain recreational areas

Ecosystem services

We know that they are:

• Essential to civilization

Ecosystem services

We know that they are:

• Essential to civilization

• So complex that they can’t be replaced by technology (???)

Ecosystem services

We know that they are:

• Essential to civilization

• So complex that they can’t be replaced by technology (???)

• Impaired by human activities

Ecosystem services

We know that they are:

• Essential to civilization

• So complex that they can’t be replaced by technology (???)

• Impaired by human activities

• Altered at an unprecedented rate

What are ecosystem services worth?

What are ecosystem services worth?

Examples:

• 1993 floods on the Mississippi due to land use change cost $12 billion.

What are ecosystem services worth?

Examples:

• 1993 floods on the Mississippi due to land use change cost $12 billion.

• Top 118 prescription drugs in the US are from natural sources (US: $40 billion/year).

What are ecosystem services worth?

Examples:• 1993 floods on the Mississippi due to land use

change cost $12 billion.

• Top 118 prescription drugs in the US are from natural sources (US: $40 billion/year).

• 1/3 of human food comes from plants that are naturally pollinated (US: $4-6 billion/year).

Valuing ecosystem services

Valuing ecosystem services

• NYC water quality decreases due to – Suburban sprawl– Bad septic systems– Loss of forested areas

Valuing ecosystem services

• NYC water quality decreases due to – Suburban sprawl– Bad septic systems– Loss of forested areas

• Estimated cost of $6-8 billion for new treatment plant

Valuing ecosystem services

• NYC water quality decreases due to – Suburban sprawl– Bad septic systems– Loss of forested areas

• Estimated cost of $6-8 billion for new treatment plant

• Estimated cost of $6 million for conservation and restoration of ecosystem services

Ecosystem services1. Purify air and water water2. Pollination of crops3. Detoxify and decompose wastes4. Stabilize climate5. Ozone protection from UV6. Maintain biodiversity7. Control agricultural pests8. Generate and preserve soil fertility9. Maintain recreational areas

Which would you pay for?

Ecosystem services1. Purify air and water water2. Pollination of crops3. Detoxify and decompose wastes4. Stabilize climate5. Ozone protection from UV6. Maintain biodiversity7. Control agricultural pests8. Generate and preserve soil fertility9. Maintain recreational areas

How much would you pay?