Analysing

Analysing a Virtual Ecosystem

A Virtual Ecosystem comprises several data sets, including:

1. Water column track and external forcing (megabyte/year)
2. Environmental fields (gigabytes per year)
3. Audit trails (megabyte/year for each particle)
4. Demography (megabyte/year per population).

You use VEW Analyser to extract emergent properties from this data set, and to explain them in terms of the external forcing and the model equations.

You have all the required information at your disposal to achieve an unambiguous test of your hypotheses about emergent phenomena in the virtual ecosystem. If the selected VE does not contain all that is needed, you can easily use VEW Controller to create a new virtual ecosystem that does. That is the power of the workbench.

The first step is to select a virtual ecosystem from those stored in the VEW Archive.
VEW Analyser automatically confifigures its GUIs and menus to match the variables contained in the chosen Virtual Ecosystem.

Analysis usually starts with the environmental fields, which contain time series of the vertical profiles of physical, chemical and demographic variables.

Any variable can be selected from the environmental menu, and windowed in depth and time. The resulting data selection is then plotted in one of three forms: (1) a profile at one instant in time, (2) a timeseries at one depth, (3) a contour plot in depth and time. The data used to create these plots can also be exported for further analysis in any statistics package (such as Microsoft Excel).
Using these tools you identify some emergent feature of the environment for detailed investigation.

The next step is to devise a hypothesis to explain the chosen feature.
You test your hypothesis initially by checking whether related environmental variables are consistent with it. Then you examine audit trails for individual plankton sub-populations. They reveal how the plankton influence the emergent feature. This stage is critical because it brings you closest to the biological primitive equations.

Audit trail

1. Depth of the mixed layer (red line)
2. Trajectory of a diatom sub-population. Depth at noon each day (black line).
3. Number of diatoms in the sub-population (blue line).

Environment

The annual cycle in partial pressure of carbon dioxide.

Demography

Zooplankton per cubic metre at noon each day of the year. This shows the maximum depth of diel migration