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plankton

Size

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

Designation	Range of sizes
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 Rèunions, 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
nanoplankton	ultraplankton	< 2 micrometer

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

Omori and Ikeda in 1984:

megaloplankton	> 20 millimeters
micronekton	20 - 200 millimeters	net 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
Designation	Comment	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).