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THE INFLUENCE OF FLUCTUATING LIGHT ON DIVERSITY AND SPECIES NUMBER OF NUTRIENT‐LIMITED PHYTOPLANKTON 1
Author(s) -
Flöder Sabine,
Burns Carolyn W.
Publication year - 2005
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2005.00124.x
Subject(s) - phytoplankton , biology , nutrient , light intensity , ecology , species diversity , physics , optics
The influence of fluctuating light on diversity and species number of a natural phytoplankton assemblage competing for nutrients was investigated for 48 days under semicontinuous culture conditions. Light conditions were either changed periodically from high (65 μmol photons·m −2 ·s −1 ) to low intensity (15 μmol photons·m −2 ·s −1 ) at intervals of 1, 3, 6, and 12 days or fixed at constant light conditions of intermediate intensity (40 μmol photons·m −2 ·s −1 ). Fluctuating light at intervals of 1–12 days significantly affected phytoplankton diversity. The development of phytoplankton communities differed in treatments with different light regimes. In treatments with long light intervals, species abundance oscillated with the light phases. Differences in the temporal development of phytoplankton communities resulted in hump‐shaped relations between the interval length of the light phases and both species number and diversity index and can be explained by the intermediate disturbance hypothesis. Fluctuating light tends to sustain phytoplankton diversity under nutrient limitation if the light regime changes in the order of several days. This indicates that temporal changes in weather regime are important in preventing competitive exclusion of phytoplankton species in nature.