The Non-linearity of Environmental Change: A coral reef model part of Cutting Edge:Environmental Geology:Activities
This is an exercise that is used in an undergraduate, non-major course titled "Coral Reefs: Biology, Geology & Policy". The course uses this popular environment as a proxy for environmental decline in general and has two broad goals beyond the course content: 1) to encourage science majors to think about complex environmental problems outside the context of their individual major, and 2) to help non-majors understand the scientific thought process in the context of their own personal interests and opinions.The computer model described here was built to provide a user-friendly interface that is visually stimulating but non-"threatening" to math-phobic students. It runs on FREE software that can be run on any computer. It can be run and modified by an instructor or student with no modeling skills.For this exercise, it demonstrates how losses of grazing fish and/or the addition of nutrients to the reef system will reduce the relative abundance of corals and algae on the reef - leading to eventual decline. The main lessons for the students are:1) If you increase a particular stress, there is often little or no change until suddenly the system rapidly declines.2) If multiple stresses are added, the pattern is more complicated but basically the same. 3) Once the system collapses, simply returning to the "safe" side of the collapse threshold has no result.The Big Picture: All of this is referred to as "non-linearity" and demonstrates that on the reef (as in most natural systems), it's a LOT easier (and cheaper) to not "break it" in the first place than it is to "fit it" once it crashes. Coral Reefs Computer Model Modeling Environmental change Diversity Reef Decline Anthropogenic Stress
Sequence Stratigraphy Model (for Macintosh) part of Cutting Edge:Sedimentary Geology:Activities
This is an interactive model that generates facies parasequences based on user defined sea-level curves, initial profile and other easily defined input conditions.