30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems?
Scientific Question: What effect do higher
CO2 levels have on plant growth?
To study this question, researchers have set up several
sites in forests in the US and Europe called Free-Air
Carbon dioxide Enrichment (FACE). FACE devices are
made up of tall vertical pipes placed in a circle around a
plot up to 30 meters in diameter. They emit either
ambient air (control plots) or CO2-enriched air
(experimental plots)
30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems?
Scientific Question: What effect do higher
CO2 levels have on plant growth?
550 ppm
Richard Norby and colleagues assessed how
increased levels of CO2 affect plant net primary
production (NPP). (NPP = assimilation – respiration)
376 ppm
They estimated NPP by measuring the biomass of
trees growing in the experimental and control plots.
NPP is expressed as grams of carbon fixed per
square meter of land per year (g C × m-2 × yr-1)
Norby and his colleagues also measured absorbed
photosynthetically active radiation (APAR, or the
light energy absorbed by the canopy) by taking the
difference of the amount of light energy at the top of
the canopy and that striking the forest floor.
APAR is a measure of how much light energy is
used by the trees.
Ecological events that disrupt homeostasis:
1. A “catastrophe” removes local life (fire, volcano, deforestation), or new
uninhabited ground is exposed
2. Pollution/Exposure to a contaminant
3. Change in atmospheric CO2
1. change in CO2
2. change in temperature
3. change in rainfall
30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems?
Tropical cloud forests, or high elevation moist forest with persistent
clouds in the tree canopy, contain species adapted to live in
conditions where clouds persistently form in tree canopies
Theoretical models predict that even a slight rise in greenhouse
gas concentrations will increase the altitude at which clouds form in
tropical mountains, up to 200 meters higher.
Scientific Question: How
does a change in the
altitude of cloud formation
affect tropical forest
ecology?
30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems?
Nalini Nadkarni and Rodrigo Solano studied the responses of
epiphytes to the predicted drier conditions under global climate
change. Their study took place in the Monteverde Cloud Forest
Reserve (MCFR) in Costa Rica.
The researchers transplanted mats of
epiphytes from high elevations to
mid- and low-elevation sites that have
cloud formation more like what is
predicted for high elevations under
future climate change.
The transplant experiment was
performed twice; once starting in the
dry season (January) and once
starting in the wet season (June).
30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems?
1. What control experiment would you do to ensure that effects in the
mid- and low-elevation transplants are not due to the
transplantation procedure itself?
•
transplant mats from high elevation to high elevation
2. Which elevation had the most amount of moisture in the epiphyte
mats? Which one had the least?
•
•
most: high elevation
least: low elevation
3. What is the effect of elevation
(moisture content) on epiphyte
growth?
•
less moisture means fewer
leaves are produced and more
epiphytes die
3. What will happen to epiphytic
cloud forest ecological systems if
moisture levels continue to drop?
•
many epiphyte species will go
extinct, eliminating an
important habitat that many
other species depend on
30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems?
Scientific Question: How does a change in the altitude of cloud formation
affect tropical forest ecology?
1. Living systems have multiple
mechanisms to store, retrieve, and
transmit information.
2. The diversity and unity of life
can be explained by the process of
evolution.
3. Cells are a fundamental
structural and functional unit of life.
4. Interdependent relationships
characterize biological systems,
and these interactions give rise to
emergent properties.
5. Biological systems maintain
homeostasis.
1. Living systems have multiple
mechanisms to store, retrieve, and
transmit information.
2. The diversity and unity of life
can be explained by the process of
evolution.
3. Cells are a fundamental
structural and functional unit of life.
4. Interdependent relationships
characterize biological systems,
and these interactions give rise to
emergent properties.
5. Biological systems maintain
homeostasis.
Categorize the data we
learned about on Friday
and today as examples of
these 3 Big Ideas of
Biology.
Ecological events that disrupt homeostasis:
1. A “catastrophe” removes local life (fire, volcano, deforestation), or new
uninhabited ground is exposed
Tree growth in Glacier Bay
2. Pollution/Exposure to a contaminant
3. Change in atmospheric CO2
1. change in CO2
2. change in temperature
3. change in rainfall
S. acuminata growth
in nickel-rich soil
brake fern growth in arsenic-rich soil
Tree growth in high CO2 “FACE” plots
Spring events in WI occur earlier
Reduced epiphyte growth with less rain
Instructor: Jayme Dyer
Course Title: Biology I with Lab
Course Location: Uhall 2-142
Course No.: CBIOL-1101-02
For Course Evaluation Supplement Question #5:
• muddiest point (getting to express them and having them addressed later)
• data worksheets
• Powerpoint lectures
• whiteboard lectures
• simulation activities (e.g. evolution with marshmallows; genetics with
marshmallows; sorting DNA pieces by size; role-playing adrenaline signaling
pathway components; building DNA with marshmallows)
• ethics discussions (who owns your DNA? how should human population be
regulated? which diseases should be researched for potential precision medicine
applications? should top predator be reintroduced to ecosystems?)
• “wet” labs (DNA extraction; microscopy; agar diffusion; microbiology)
• watching videos/listening to radio pieces in class
• collecting data online with team (climate change; microbiology)
• reading & interpreting abstracts