Although traditional attempts to classify phytoplankton communities have relied on recognising the types of taxa that tend to occur together, this method has limited usefulness because even closely related species can vary widely in their habitat use. A promising non-taxonomic approach to community classification involves the use of functional traits, which include physiological and morphological features that determine how plankton species cope with different environmental conditions. An analysis based on information on 711 phytoplankton species from 211 lakes in Europe and North andSouth Americashows that easily observable visual features are good indicators of traits such as growth rates, grazing avoidance and population size. For example, large species with a low surface to volume ratio are relatively sensitive to low nutrient and light conditions, sink quickly, grow slowly and tend to occur at low abundance. Cluster analysis distinguished seven functional groups by reference to maximum size, volume, surface: volume ratio, and the presence or absence of flagellae, mucilage, gas cavities and silica skeletons. This classification is objective and easy to use, has general application, and should appeal to ecologists, modellers and water quality managers interested in understanding and predicting the responses of phytoplankton communities to local conditions.
Reference: Kruk, C., Huszar, V.L.M., Peeters, E.T.H.M., Bonilla, S., Costa, L., Lurling, M., Reynolds, C. & Scheffer, M. 2010. A morphological classification capturing functional variation in phytoplankton. Freshwater Biology 55, 614–627.
Freshwater Research News 
Posted on December 15, 2011