Team Ecology Biogeochemical cycling: Global water cycle Kasey Barton Carolyn Bergstrom Fenny Cox Don Drake Oceana Francis David Tallmon Chris Tubbs

Goals: For students to understand the water cycle, including: 1. Understand relative sizes of pools and fluxes of H 2 0 cycle. 2. Understand how human activities affect pools and fluxes of H 2 0 cycle. 3. Appreciate ethical consequences of human effects on H 2 O cycle. Biogeochemical cycling: Global water cycle

Outcomes: 1. Predict how several human activities will alter the H 2 0 cycle (qualitative/quantitative). 2. Assess the global ethical implications of human impacts on H 2 0 cycle. Biogeochemical cycling: Global water cycle

pools = 1000’s km 3, fluxes 1000’s km 3 /yr Global water cycle

Rain falling on a tropical rain forest can be lost via three paths: 1. evaporation 2. transpiration (water from soil → atmosphere via plants) 3. runoff & groundwater Rank the paths in order of magnitude from greatest → least amount of water lost. A. 1 > 2 > 3 B. 1 > 3 > 2 C. 2 > 3 > 1 D. 2 > 1 > 3 E. 3 > 2 > 1 Figure not to scale

Rain falling on a tropical rain forest can be lost via three paths: 1. evaporation 2. transpiration (water from soil → atmosphere via plants) 3. runoff & groundwater Rank the paths in order of magnitude from greatest → least amount of water lost. C. 2 > 3 > 1 48% transpiration 36% runoff & groundwater 16% evaporation Globally, 2/3 of water flux from land → atmosphere is via transpiration.

pools = 1000’s km 3, fluxes 1000’s km 3 /yr Global water cycle

What human activities might affect the water cycle?

With your group, discuss the main effects that either deforestation or global warming will have on the global water cycle. Include changes in fluxes and pools. ‘Modify’ your large handout template with colored post-its: blue for increase, red for decrease. Tape your template to wall. + -

pools = 1000’s km 3, fluxes 1000’s km 3 /yr Global water cycle

1.What could we do to make this scenario more realistic? 2.What is the scale of deforestation? 3.What is the scale of global warming? 4.Model how these two activities simultaneously affect the water cycle 5.What are the ethical implications of human effects on the water cycle? Where do these activities occur, and who is affected? Summative assessment: take-home exam