Adaptations in phytoplankton life strategies to imposed change in a shallow urban tropical eutrophic reservoir, Garças Reservoir, over 8 years

• Published in: Hydrobiologia Vol. 614; no. 1; pp. 91 - 105
• Main Authors: Crossetti, Luciane O, de M. Bicudo, Carlos E
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-11-2008; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Aquatic plants; Biological and medical sciences; Biomass; Biomedical and Life Sciences; Dissolved oxygen; Ecology; Eutrophication; Floating plants; Fresh water ecosystems; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Life Sciences; Light penetration; Limnology; Monoculture; Nutrient dynamics; Nutrient removal; Phytoplankton; Plankton; Plankton Studies; Primary production; Reservoirs; Synecology; Water column; Zoology; Phytoplankton; Long-term study; Adaptive strategies; Functional groups; Tropical shallow lake; Eutrophication; Monocotyledones; Eichhornia crassipes; Functional groups; Tropical zone; Reservoir; Urban area; Adaptive strategies; Tropical shallow lake; Shallow water; Long term; Aquatic environment; Hydrobiology; Pontederiaceae; Angiospermae; Lakes; Eichhornia crassipes; Strategy; Spermatophyta; Adaptation; Functional group
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-008-9539-1

This study aimed at evaluating the phytoplankton adaptive strategies of phytoplankton in a shallow urban eutrophic tropical reservoir, Garças Reservoir, over temporal and vertical scales. Samples were taken monthly for eight consecutive years (1997-2004) at a fixed set of depths in the water column. At the beginning, the reservoir was eutrophic with 20% of its surface covered by water hyacinth Eichhornia crassipes (phase I). Then, in phase II, water hyacinth grew to cover up to 40-70% of the surface. In phase III it was mechanically removed. After macrophyte removal the limnology changed, drastically. This removal modified nutrient dynamics, drastically reduced water transparency, and increased both primary production and phytoplankton biomass, the latter impeding light penetration. Phytoplankton life strategies during water hyacinth dominance (phase II) responded promptly to this environmental disturbance in conditions of low dissolved oxygen (DO) and soluble reactive phosphorus (SRP) and high free CO₂ values. After macrophyte removal, a permanent cyanobacterial monoculture was established. Phase I was dominated basically by Sphaerocavum brasiliense, mainly during the stratified months, represented by non-flagellate colonies, the M functional group, S-strategists, and greater biomass of species with high maximal axial linear dimension (MLD) and cell volumes. Phase II was dominated by Cryptomonas curvata, C. erosa, C. marssonii, Trachelomonas sculpta, T. volvocinopsis, T. kelloggii, T. hispida, Peridinium spp., Aphanocapsa spp., and Aphanothece spp., and was represented by unicellular flagellate species, Y, W2, K, LO functional groups, and C-strategists, greater biomass of species with intermediate MLD and cell volumes. Phase III was dominated by Microcystis aeruginosa, M. panniformis, Cylindrospermopsis raciborskii, Planktothrix agardhii, and Aphanizomenon gracile, represented by non-flagellate colonies, M, S, H1, S functional groups, and S and R-strategists, greater biomass of species with high MLD and cell volumes (>50 μm and >10⁴ μm³, respectively).