Has the Importance of Photoautotrophic Picoplankton Been Overestimated
Postincubation differential filtration (PIDF), preincubation differential filtration (Pre-IDF), and track autoradiography (TA) were compared for estimating cell-specific and total photo-autotrophic picoplankton production. Experiments were performed in Lakes Michigan and Huron and in the Ful of Mexico. When Synechococcus dominated the photoautotrophic picoplankton community (>70% of total picoplankton abundance), PIDF estimates of cell-specific and total picoplankton production were ~3.0 x (range, 2.0--3.8 x) higher than TA estimates. PreIDF estimates of cell-specific and total picoplankton production, however, were only slightly higher than TA estimates (mean, 1.4 x; range, 1.4--1.5 x). The higher PIDF estimates were attributable to breakage and damage of larger photoautotrophs during postincubation filtration and to retention of this labeled material on the smaller (0.2 µm) pore-size filter. Results from PIDF experiments must be viewed with caution and previous estimates of picoplankto production, cell-specific or total, based solely on PIDF may need to be re-evaluated.
Limnology and Oceanography
Fahnenstiel, G. L.,
Redalje, D. G.,
Lohrenz, S. E.
(1994). Has the Importance of Photoautotrophic Picoplankton Been Overestimated. Limnology and Oceanography, 39(2), 432-438.
Available at: http://aquila.usm.edu/fac_pubs/7238