Environmental Change and its impact on biological organisms

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Environmental Change and its impact on biological
organisms

• Pete Wyckoff
• Ecosystem and Community Ecology
• U of M Morris

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Environmental Change

• Changes in the past
• How do we study past changes?
• Current changes
• How do we study current changes?

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A. A really big change THERE IS OXYGEN IN THE
AIR!!!
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Why? Photosynthesis

• Carbon Dioxide Water energy-gt Carbs
  Oxygen
• (CO2) (H2O) (C6H12O6) (O2)

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What is in the air you breathe?

• Nitrogen as N2 (inert) 78
• Oxygen as O2 21
• Argon (inert) almost 1
• Carbon dioxide 370 ppm
• (0.037)

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B. Bad day to be a dinosaur
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Note to the Grants and their Finch
FriendsThere are worse things in life than a
bad EL NIÑO
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Tunguska River, Russia1908
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C. Ice Ages It was darn cold in Morris 16,000
years ago
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Environmental Change

• Changes in the past
• How do we study past changes?
• Current changes
• How do we study current changes?

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A. Ice cores reveal past climates
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Temperature and atmospheric carbon dioxide from
Vostok Core
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Indirect impacts of increasing Carbon Dioxide
the Greenhouse Effect
Image source DOE website
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B. Diatoms used to reconstruct climate
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Example diatoms reveal past salinity
Red Dots Dolphin Sightings www.vims.edu/cbnerr/te
ach/ dolphin/bay.html
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C. Pollen record reveals past vegetation
Arabidopsis pollen
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How do we obtain diatom and pollen data? Dig in
the mud.
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D. Tree rings from tree cores
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Bristlecone pine records reveal past droughts
Age of trees- up to 5000 years
Source Multi-Millennial Dendroclimatic Studies
from the Western United States. Hughes, Malcolm
K. and Graumlich, Lisa J. (2001)
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Environmental Change

• Changes in the past
• How do we study past changes?
• Current changes FOCUS ON CARBON
• How do we study current changes?

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A. More people living large
Source World Almanac and Book of Facts, 1994
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B. Changing land use
Imperial Valley, CA (source CA EPA website)
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Morris past prairieMorris now a mosaic of
urban? agriculture, forest and prairie
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C. Rising atmospheric carbon dioxide
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Combustion and respiration

• O2 Snickers Bar ? CO2 H20 Energy
• O2 Gasoline ? CO2 H20 Energy
• O2 Coal ? CO2 H20 Energy
• O2 Decaying Tree ? CO2 H20 Energy
• Reverse photosynthesis
• CO2 H20 Solar Energy? Glucose O2

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Sources of carbon dioxide released by US
Image source DOE website
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Global Sources of Carbon Dioxide

• 85 from fossil fuels
• 15 from loss of vegetation
• (Source Schlesinger 1997)

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Relative importance of greenhouse gases
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Future Temperature in Minnesota

• Temp increase- global average
• 2.5-3.8 C (4.5-6.8 F) IPCC 2001
• Mean 5.7 F with double CO2
• Temp increase in MN
• Much greater than 5.7 in winter
• Slightly greater than 5.7 during summer

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Environmental Change

• Changes in the past
• How do we study past changes?
• Current changes
• How do we study current changes? Focus on direct
  impacts of Carbon Dioxide

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Direct impacts of rising Carbon Dioxide
Photosynthesis Carbon Dioxide Water -gt Plants
Oxygen (CO2) (H2O) (C6H12O6)
(O2)
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Potential direct impacts of rising Carbon Dioxide

• Hypothesis 1 ? CO2 ? ? Plant growth
• Hypothesis 1a ? CO2 ? No change in growth (other
  limiting factors)
• Hypothesis 2 ? CO2 ? Changed relative abundances
  of plants in natural communities
• Hypothesis 3 ? CO2 ? Decreased nutritional value
  of plants (? carbohydrateprotein ratio)

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Initial CO2 studies done in growth chambers
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Initial results

• Increased seedling growth with increased carbon
  dioxide (Supports Hypothesis 1)
• Transient increase only? (Supports 1a)
• Increase a function of pot size? (Supports
  confusion) (Thomas and Strain 1991)
• Changes in the competitive relationships among
  plant species? (Supports Hypoth 2) (Tolley and
  Strain 1984, Bazzaz et al. 1990)

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High Carbon Dioxide Tips Competitive
Balance(Tolley and Strain 1984)
Low CO2 High CO2
DRY WET
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Some plants benefit more than others (changes
competitive hierarchy)(Bazzaz et al. 1990)
Low CO2 High CO2
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Open top growth chambers
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Results from open tops

• NASA finds trees leaves with increased
  carbohydrate protein
• Insects suffer from malnutrition
• Owensby et al. 1996 cows fed high CO2 grass
  dont grow as fast
• SUPPORTS HYPOTH 3 The Potato Chip Effect

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Elevated CO2 in a forest
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Duke FACE results (through 2001)

• CO2 driven increase in photosynthesis sustained
  through 3 years-- Supports Hypoth 1. (Herrick and
  Thomas 2001)
• Less time to maturity and increased seed
  production-- New finding. (Ladeau and Clark 2001)
• Poison ivy everywhere- Supports Hypoth 2

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CO2 growth fertilization only transient?

• Oren et al. 2002 Growth slows down after 3 year
  surge. Picks back up again with added Nitrogen
• No increased growth at a 2nd, nitrogen poor
  site.
• Supports Hypothesis 1a Other factors besides CO2
  limit growth.

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