The size structure and functional composition of ultraplankton and nanoplankton at a frontal station in the Alboran Sea. Working groups 2 and 3 report
Garcia, C.M.; Jimenez-Gomez, F.; Rodriguez, J.; Bautista, B.; Estrada, M.; Garcia-Braun, J.; Gasol, J.M.; Figueiras, F.G.; Guerrero, F.
Scientia Marina 58(1-2): 43-52
1994
ISSN/ISBN: 0214-8358 Accession: 009626251
Plankton samples from the water column at an offshore station in the Alboran Sea (Western Mediterranean) were analyzed to describe the size structure of the community in the size range including pico- and nanoplankton. Three complementary techniques (Utermohl-inverted microscopy, epifluorescence and flow cytometry) were employed in a way that allowed a large size-range overlap. We discuss the particular artifacts and methodological errors linked to these methods and particular size ranges, and illustrate how these artifacts affect the process of modelling the size-abundance spectrum. Variability associated with the frontal character of the sampling station is mainly reflected by the secondary (ecological) scaling of body size: the invasion of large cells determined a clear decrease in the negative value of the nanoplankton size-abundance slope, whereas the picoplankton spectrum remains close to the primary (physiological) scaling values. From an operative point of view, it seems more interesting to extend the size range studied through epifluorescence towards larger cell sizes than to push the Utermohl technique down to enumerating and measuring very small cells.