Impact of Increasing Atmospheric Carbon Dioxide on Ecological Systems

1. 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)

2. 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 CO2affect plant net primary production (NPP). (NPP = assimilation – respiration) 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) 376 ppm 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.

3. Ecological events that disrupt homeostasis: • A “catastrophe” removes local life (fire, volcano, deforestation), or new uninhabited ground is exposed • Pollution/Exposure to a contaminant • Change in atmospheric CO2 • change in CO2 • change in temperature • change in rainfall

4. 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?

5. 30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems? NaliniNadkarni 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).

6. 30.3: How does increasing atmospheric carbon dioxide disrupt ecological systems? 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? Which elevation had the most amount of moisture in the epiphyte mats? Which one had the least? • transplant mats from high elevation to high elevation • most: high elevation • least: low elevation What is the effect of elevation (moisture content) on epiphyte growth? What will happen to epiphytic cloud forest ecological systems if moisture levels continue to drop? • less moisture means fewer leaves are produced and more epiphytes die • many epiphyte species will go extinct, eliminating an important habitat that many other species depend on • blooming in these flowers may be determined by day length, not temperature

7. 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? • blooming in these flowers may be determined by day length, not temperature

8. 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.

9. 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.

10. Ecological events that disrupt homeostasis: • A “catastrophe” removes local life (fire, volcano, deforestation), or new uninhabited ground is exposed • Pollution/Exposure to a contaminant • Change in atmospheric CO2 • change in CO2 • change in temperature • change in rainfall Tree growth in Glacier Bay S. acuminatagrowth 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

11. 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 • Powerpointlectures • 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