ISSN:
1365-2427
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Biologie
Notizen:
1. A phytoplankton community model [Phytoplankton RespOnses To Environmental CHange (PROTECH)] was used to examine the effect of a wide range of varied light intensities and mixed depths upon simulated phytoplankton populations. Two different column lengths of the simulated water body were examined (the upper 5 m and the whole 14.5 m water column) for each scenario.2. The hypotheses tested were that: (i) under low light intensity and/or deep mixing the simulated community will be dominated by a phytoplankter with a low critical light intensity; (ii) at high light intensity and shallow mixing the simulated community will be dominated by small, fast-growing phytoplankters; (iii) under all conditions, except deep mixing, the largest proportion of phytoplankton biomass will be found near the surface.3. It was found under most conditions that, although there was a bloom in the upper column (dominated by algae such as Chlorella, Ceratium or Rhodomonas), the largest phytoplankton biomass in the water column was located 9 m below the surface and consisted of solely Asterionella. This bloom was missed by the 5-m samples. Thus, using the whole column sample lengths, hypothesis (i) was not rejected but hypotheses (ii) and (iii) were refuted.4. The inclusion of specific movement characteristics of phytoplankton in the model allowed the possibility of the dominance of multiple spaces within the water column and should be included in any model-based investigation of this topic. Further, the results from the model suggest that a reduced depth of mixing creates greater environmental heterogeneity, allowing more species to persist.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1046/j.1365-2427.2002.00813.x
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