INTRODUCTION
In aquatic
biology, the paradox of the plankton describes the situation in which a limited
range of resources supports an unexpectedly wide range of plankton species,
apparently flouting the competitive exclusion principle which holds that when
two species compete for the same resource, one will be driven to extinction.
ECOLOGICAL
PARADOX
The paradox of
the plankton results from the clash between the observed diversity of plankton
and the competitive exclusion principle,[1] also known as Gause's
law,[2] which states that, when two species compete for the same
resource, ultimately only one will persist and the other will be driven to
extinction. Phytoplankton life is diverse at all phylogenetic levels despite
the limited range of resources (e.g. light, nitrate, phosphate, silicic acid,
iron) for which they compete amongst themselves. The paradox of the plankton
was originally described in 1961 by G. Evelyn Hutchinson, who proposed that the
paradox could be resolved by factors such as vertical gradients of light or
turbulence, symbiosis or commensalism, differential predation, or constantly
changing environmental conditions.[3] More recent work has proposed
that the paradox can be resolved by factors such as: chaotic fluid motion;[4]
size-selective grazing;[5] spatio-temporal heterogeneity;[6]
and environmental fluctuations.[7] More generally, some
researchers suggest that ecological and environmental factors continually
interact such that the planktonic habitat never reaches an equilibrium for
which a single species is favoured.[8] In Mitchell et al. (2008),
researchers found that small-scale analysis of plankton distribution exhibited
patches of aggregation, on the order of 10 cm, that had sufficient lifetimes
(> 10 minutes) to enable plankton grazing, competition, and infection.[9]
REFERENCES
1. Hardin, G. (1960).
"The Competitive Exclusion Principle". Science. 131 (3409):
1292–1297. Bibcode:1960Sci...131.1292H. doi:10.1126/science.131.3409.1292. PMID
14399717.
2. Gause, G. F. (1932). "Experimental
Studies on the Struggle for Existence - I. Mixed Population of Two Species of
Yeast". Journal of Experimental Biology. 9: 389–402.
3. Hutchinson, G. E. (1961)
The paradox of the plankton. American Naturalist 95, 137-145.
4. Károlyi, G., Péntek, Á.,
Scheuring, I., Tél, T., Toroczkai, Z. (2000) Chaotic flow: the physics of
species coexistence. Proceedings of the National Academy of Sciences 97,
13661-13665.
5. Wiggert, J.D., Haskell,
A.G.E., Paffenhofer, G.A., Hofmann, E.E. and Klinck, J.M. (2005) The role of
feeding behavior in sustaining copepod populations in the tropical ocean
Archived 2008-09-05 at the Wayback Machine. Journal of Plankton Research 27,
1013-1031.
6. Miyazaki, T., Tainaka, K.,
Togashi, T., Suzuki, T. and Yoshimura, J. (2006) Spatial coexistence of
phytoplankton species in ecological timescale "Archived copy".
Archived from the original on 2007-09-27. Retrieved 2007-06-06.. Population
Ecology 48(2), 107-112.
7. Descamps-Julien, B.;
Gonzalez, A. (2005). "Stable coexistence in a fluctuating environment: An
experimental demonstration" (PDF). Ecology. 86 (10): 2815–2824.
doi:10.1890/04-1700. Archived from the original (PDF) on 17 November 2006.
Retrieved 18 October 2014.
8. Scheffer, M., Rinaldi, S.,
Huisman, J. and Weissing, F.J. (2003) Why plankton communities have no
equilibrium: solutions to the paradox. Hydrobiologia 491, 9-18.
9. Mitchell, J.G., Yamazaki,
H., Seuront, L., Wolk, F., Li, H. (2008) Phytoplankton patch patterns: Seascape
anatomy in a turbulent ocean. Journal of Marine Systems 69, 247-253.
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