Two years of investigations into phytoplankton and ecosystem dynamics in Lake Fulmor, CA using the N
Parameters: Active Fluorescence
Phytoplankton communities in lake ecosystems
Communities may be diverse or dominated by one or few species
The environment that phytoplankton experience is highly dependent on water stratification and flow
These parameters are highly variable on both spatial & temporal scales
Blooms of potentially toxic cyanobacteria & overall eutrophication an important issue for lake ecosystems
Light extremes & nutrient stress may alter the photosynthetic efficiency of phytoplankton, which is still poorly understood.
Lake Fulmor, San Jacinto Mountains, CA
Subalpine lake, altitude ~5000ft. Maximum depth: 6m Low flow but relatively strong discrete wind events Observed surface scum formation during wind events
Problem Description: Networked Aquatic Microbial Observing System (NAMOS)
Combined mobile & static components for estimating phytoplankton biomass & water structure
Temperature sensors provide information on water column stratification
surface - 2.5 meters
Chlorophyll fluorometers estimate phytoplankton biomass near the surface
Meteorological instrumentation, including wind speed & direction which influence surface water currents & temperature.
Active fluorometer & NIMS RD provided additional sensor information (pH, DO)
Discrete samples for nutrients, microscopical analysis, toxin & molecular analyses.
Proposed Solution: Diverse Sensors and Techniques to Characterize a Dynamic Community
Fluorometer data (blue line) and Phytoflash yield (green line) from August 2006.
Phytoflash fluorometer (Turner Designs) uses ‘active fluorescence’ to estimate efficiency of light absorption in photosynthesis.
Data shows lower efficiency:
during night hours, when there is no light for photosynthesis
at mid-day, when light is supra-optimal & can cause cellular damage
Thermal Stratification increases throughout the 2006 season, with implications for the mixing regime & phytoplankton distribution.
We observed a large chlorophyll peak at 3m depth in August 2006. • Isolated small green flagellate from samples