plankton

Size

The earliest convention for binning plankton by size appears to be that agreed upon at a symposium in Bergen, Norway in 1957.

Megaloplankton > 1 cm
Macroplankton 1 mm - 1 cm.
(Mesoplankton) 0.5 - 1 mm.
Microplankton > 60 μ.
Nanno [sic] > 5 μ.
Ultra < 5 μ.

D. H. Cushing, George F. Humphrey, K. Banse and Taivo Laevastu.
Report of the committee on terms and equivalents.
Table 3, page 16.
in
Conseil Permanent International pour l'Exploration de la Mer.
Measurements of Primary Production in the Sea.
Rapport et Procès-Verbaux des Réunions, vol 144. (April 1958).

In 1965 Dussart proposed the following classification:

netplankton megaloplankton > 2000 micrometers
mesoplankton 200 - 2000 micrometers
microplankton 20 - 200 micrometers
nanoplankton nanoplankton 2 - 20 micrometer
ultraplankton < 2 micrometer

B. M. Dussart
Les différentes catégories de plancton.
Hydrobiologia, vol. 26, pages 72-74 (1965)

Omori and Ikeda in 1984:

megaloplankton > 20 millimeters  
micronekton 20 - 200 millimetersnet
plankton
macroplankton 2 - 20 millimeters
mesoplankton 200 micrometers - 2 millimeters
microplankton 20 - 200 micrometers water bottle
plankton
nanoplankton 2 - 20 micrometers
ultrananoplankton < 2 micrometers

Makoto Omori and Tsutomu Ikeda.
Methods in marine zooplankton ecology.
New York: Wiley, c1984.

Summary

Designation Comment Size in micrometers,
by groups of authors
1 2 3
macroplankton visible to the naked eye 200 – 2000
netplankton older term based on plankton net with 80 micrometer mesh greater than 22
microplankton 20 – 200 50 – 500
nanoplankton 2 – 20 10 – 50 5 - 22
ultraplankton 0.5 – 10 0.2 – 5*,

or, less than 5

picoplankton less than 2,
or, 0.2 – 2
less than 1
femtoplankton Viruses and small bacteria less than 0.2

*Thus in the abstract, but the introduction defines ultraphytoplankters as less than 3 micrometers.

 

1. Based on 2 × 10n

David C. Sigee.
Freshwater Microbiology. Biodiversity and Dynamic Interactions of Microorganisms in the Aquatic Environment.
Hoboken (NJ): J. Wiley and Sons, 2005(?).

Pages 6-7.

Makoto Omori and Tsutomu Ikeda.
Methods in marine zooplankton ecology.
New York: Wiley, c1984.

David Moreira and Purificación López-Garcia.
The molecular ecology of microbial eukaryotes unveils a hidden world.
Trends in Microbiology, vol. 10, no. 1, pages 31-38 (1 January 2002).

Jed A. Fuhrman.
Marine Viruses and their biogeochemical and ecological effects.
Nature, vol. 399, no. 6736, pages 541-548 (10 June 1999).

Christine M. Happey-Wood.
Diurnal and seasonal variation in the contributions of autotrophic pico-, nano- and microplankton to the primary production of an upland lake.
Journal of Plankton Research, vol 15, no. 2, pages 125-159 (1993).

 

2. Based on 1 × 10n and 5 × 10n

 

3. Idiosyncratic

Hilary E. Glover et al.
Pico- and ultraplankton Sargasso Sea communities: Variability and comparative distributions of Synechococcis spp. and algae.
Marine Ecology- Progress Series, vol 49, pages 127-139 (1988).

 

 

The history of the sizing systems for plankton is a good example of the evolution of a system of sizes from one based on technologies of collection and sorting to one based purely on numerical values.

Plankton nets

Early plankton nets were made of silk bolting cloth, and on occasion, mesh sizes are still referred to by their old “silk size” designations such as #10 or #12. Today's nylon mesh nets have the mesh specified in micrometers (microns or μm) or in millimeters (mm).

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