PI:              Walker Smith
 of:              Virginia Institute of Marine Science
 dataset:         Nano- and microplankton abundance and carbon biomass
 project/cruise:  AESOPS/NBP-96-4A, Ross Sea Process Cruise 1 and
 		  AESOPS/NBP-97-1, Ross Sea Process Cruise 2
 ship:            Nathaniel B. Palmer

Methods for nano- and microplankton counts

Samples for nano- and microplankton enumeration were obtained by taking 1-liter aliquots from standard hydrographic or trace metal casts. Auto- and heterotrophic flagellates, dinoflagellates and nanoplanktonic non-loricate ciliates were examined by epifluorescence microscopy on samples preserved with 0.5% glutaraldehyde, concentrated on 0.8 micron black Poretics filters and stained with DAPI (Coleman, 1980) following the protocol outlined by Booth (1993).

Whole water samples were preserved with acidic Lugol's iodine solution and/or glutaraldehyde-Lugol's solution (35 o/oo, v/v) at a final concentration of 1% (Rousseau et al., 1990). Diatoms and plankton bigger than 20 micron (including larger dinoflagellates of known trophic mode and most of the ciliates) were enumerated from 50 or 100 ml of these samples that were settled and counted with an inverted microscope (Utermöhl, 1958). Phaeocystis antarctica colonies were enumerated and measured in these samples, and colonial cell abundance was calculated from colony volume according to Mathot et al. (subm.).

Biomass was estimated by converting cell volumes (calculated from measurements of cell dimensions and using volume equations for appropriate geometric shapes) using the relationships [log10 C = 0.94 (log10 V) - 0. 60] and [log10 C = 0.76 (log10 V) - 0. 352] for flagellates and diatoms respectively (with C representing carbon as picograms per cell and V representing cell volume in cubic microns; Eppley et al., 1970). For ciliates, conversion factors outlined by Stoecker et al. (1994) were used.


Booth, B.C. 1993. Estimating cell concentration and biomass of autotrophic plankton using microscopy. In: Handbook of Methods in Aquatic Microbial Ecology. P.F. Kemp, B.F. Sherr, E.B. Sherr, and J.J. Cole (eds.), Lewis Publ., Boca Raton. Pp. 199-205.

Coleman, A.W. 1980. Enhanced staining of bacteria in natural environments by fluorochrome staining of DNA. Limnol. Oceanogr. 25: 948-951.

Eppley, R.W., F.M.H. Reid and J.D.H. Strickland. 1970. The ecology of the plankton off La Jolla, California, in the period April through September 1967; Part III. Estimates of phytoplankton crop size, growth rate and primary production. Bull. Scripps Inst. Oceanogr. 17: 33-42.

Mathot S., W.O. Smith, Jr., C.A. Carlson, D.L. Garrison & M.M. Gowing Estimation of Phaeocystis antarctica (Prymnesiophyceae) carbon biomass in the Ross Sea, Antarctica. J. Phycol. (subm.)

Rousseau, V., S. Mathot and C. Lancelot. 1990. Calculating carbon biomass of Phaeocystis sp. from microscopic observations. Mar. Biol. 107: 305-314.

Stoecker, D.K., D.J. Gifford and M. Putt. 1994. Preservation of marine planktonic ciliates: losses and cell shrinkage during fixation. Mar. Ecol. Prog. Ser. 110: 293-299.

Utermöhl, H. 1958. Zur Vervollkommnung der quantitativen Phytoplankton-Methodik. Mitt. int. Verein. theor. angew. Limnol. 9: 1-38.