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Spatial Heterogeneity of Cyanobacteria and Diatoms in a Thermally Stratified Canyon‐Shaped Reservoir
Author(s) -
MorenoOstos Enrique,
CruzPizarro Luis,
Basanta Ana,
George D. Glen
Publication year - 2009
Publication title -
international review of hydrobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 1434-2944
DOI - 10.1002/iroh.200811123
Subject(s) - phytoplankton , water column , spatial distribution , canyon , stratification (seeds) , environmental science , advection , oceanography , diel vertical migration , geology , cyanobacteria , buoyancy , current (fluid) , plankton , hydrology (agriculture) , ecology , geomorphology , nutrient , biology , paleontology , seed dormancy , botany , remote sensing , germination , physics , geotechnical engineering , quantum mechanics , dormancy , bacteria , thermodynamics
Phytoplankton communities in lakes and reservoirs are seldom homogeneously distributed but usually aggregate in patches and gradients. In this study we have combined the use of in vivo spectrofluorometry and acoustic Doppler current profiling to investigate the effect of water movements on the spatial distribution of cyanobacteria and diatoms in a thermally stratified reservoir in SW Spain. The distinctive canyon‐shaped morphometry of the reservoir (El Gergal) favoured the development of a “conveyor belt” pattern of circulation aligned with the long axis of the reservoir. Under non‐regulated conditions, the spatial distribution of phytoplankton was almost entirely dependent on the interactions between advective transport and the buoyancy properties of the different functional groups of phytoplankton. The positively‐buoyant cyanobacteria accumulated near the surface and were then transported downwind by the surface drift currents. In contrast, the negatively‐buoyant diatoms sank in the water column and were transported upwind by the sub‐surface return currents. When deep water was abstracted from the reservoir, these distribution patterns were modified. The results are discussed in relation to the problem of acquiring representative water samples from the reservoir and the application of a simple empirical model to optimize the location of the station used for routine cyanobacteria sampling on the reservoir. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)