MonthDayTopic Nov.27Ecosystem services 29Global change biology Dec.1MM’s research 4Review for exam 6Final 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 LevelSource of energy Primary producersSolar energy HerbivoresPrimary producers Primary carnivoresHerbivores Secondary carnivoresPrimary carnivores OmnivoresEverything! DecomposersDead 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) CO 2, 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 N 2 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 services 1.Purify air and water water 2.Pollination of crops 3.Detoxify and decompose wastes 4.Stabilize climate 5.Ozone protection from UV 6.Maintain biodiversity 7.Control agricultural pests 8.Generate and preserve soil fertility 9.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?

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

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 services 1.Purify air and water water 2.Pollination of crops 3.Detoxify and decompose wastes 4.Stabilize climate 5.Ozone protection from UV 6.Maintain biodiversity 7.Control agricultural pests 8.Generate and preserve soil fertility 9.Maintain recreational areas Which would you pay for?

Ecosystem services 1.Purify air and water water 2.Pollination of crops 3.Detoxify and decompose wastes 4.Stabilize climate 5.Ozone protection from UV 6.Maintain biodiversity 7.Control agricultural pests 8.Generate and preserve soil fertility 9.Maintain recreational areas How much would you pay?