January 1, 2010.
Thin layers of plankton are commonly found in coastal environments, with a vertical scale ranging from centimeters to a few meters, but extending horizontally over kilometers. These layers are highly productive and can contain 50-75% of the total biomass of the water column2-4. A two-week study was conducted in San Luis Obispo Bay comparing a traditional sampling method, Niskin bottles, with a recent advancement, autonomous profilers. Diversity Indexes were calculated for all species sampled in both methods. T Tests were conducted to compare the diversity indexes between methods and were not statistically significant (P(T<=t) one-tail=0.15). The abundance of a bioluminescent species, Noctiluca was compared at three different depths (shallow, within a spike in bioluminescence, and deep) and was found to be statistically significant (P(T<=t) one-tail=0.0177 for the shallow depth vs. spike and P(T<=t) one-tail=0.048 for the deep depth vs. spike). Future work could examine the vertical migration of phytoplankton and zooplankton throughout the night as opposed to one nightly sampling. This would allow interpretation of thin layers based on the behavior of the organisms comprising the layer, as opposed to the physical processes forming thin layers (as examined in this study).
California Polytechnic State University (Cal Poly SLO)