March 17, 1998
The field work will be in collaboration with Richard Petersen. The key question is whether we can demonstrate that algae from fluctuating environments show different response pattern to light than algae from stable environments. We will compare our data on adaptation rates and responses to Richard's data on productivity. Our prediction is that algae from fluctuating light environments will be better able to respond to changes in light but will not have the same optimal efficiency.
We (meaning John Rueter and students) plan to examine four different environments:
1. Coastal lakes that have deep mixing patterns and turbidity resulting in highly variable light environment over all 4 seasons.
2. Cascade lakes that have a shallow stratified layer late in summer that is optically clear.
3. Tundra lakes that are shallow, turbid, but receive light for almost the entire 24 hr period during part of the summer.
4. Lakes in Costa Rica with a well establish and long lasting (multiple year) thermocline where some algae may be residing at low light for many seasons.
1.Productivity vs. Light intensity over short (2 hr) incubations using 14C or O2 methods
2. Chlorophyll
3. Species distribution (preserved samples)
4. light depth, temperature, wind data and mixing pattern
5. short term response to light fluctuations
Samples taken from deep and shallow water will be exposed to a standard fluctuating light regime (that we need to design based on lab work) to test the amount of time it takes for the cell to adapt to changes in light. This regime will probably be looking for changes in efficiency of handleing light on the time scale of 10 sec to several minutes. We will use samples taken from different depths and then allowed to acclimate for several hours at other light levels (for example: a sample from 20 meters tested at time 0 and after 2 hours exposure to surface irradiance.)