Since its publication, the article ‘Towards\ud
a functional classification of the freshwater phytoplankton’ (Reynolds et al., J Plankton Res 24: 417–428, 2002), has attracted the attention of dozens of phytoplankton ecologists worldwide. These numerous applications of the functional classification to describe phytoplankton patterns in various aquatic ecosystems allowed the recognition of some uncertain features of this concept originating from various reasons. In this article, we attempt to facilitate the application of the functional classification, by providing a detailed description of the typical misplacements and by modifying some of the original habitat templates and species allocations. Furthermore, we discuss in this review those coda that were additionally described after the publication of the original article, and attempt giving an overview, as complete as possible, of the state of art
1. Based on a comprehensive data set collected monthly during 8 years (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004), we evaluated the effects of mechanical removal of Eichhornia crassipes on the limnological characteristics and algal biomass of a polymictic shallow tropical reservoir. 2. Interrupted time series analyses indicated that the limnological responses to macrophyte removal can be classified as an 'abrupt permanent impact' implying that the overall mean of the time-series shifted promptly after intervention. These analyses indicated a significant increase for pH, total phosphorus, total phytoplankton and cyanobacterial biomass, and a decrease in water transparency and CO 2 concentrations in the surface water; also, the increase in water stability, increase of bottom soluble reactive phosphorus (SRP) and decrease in bottom oxygen levels. 3. Cyclic anoxic periods previously observed during springs and summers were replaced by a persistent period of anoxic conditions in the sediment overlying water. Anoxic conditions were suitable for SRP release from sediments. Heavy cyanobacterial blooms became more persistent, maximum biomass (4229 mm 3 L )1 ) was 30 times larger, the blooms frequently reached 2 m and sometimes the bottom of the reservoir, contrasting to the preremoval period in which it reached at most 1 m deep. 4. The long-term P dynamics in the system, initially driven by allochthonous nutrient loadings were replaced by internal ecological processes. Water hyacinth removal markedly accelerated the process of eutrophication due to internal feedback mechanisms, leading to a switch to a more turbid state. Biological feedback mechanisms were driven by cyanobacterial blooms by enhancing water stability, oxygen anoxia at the bottom and by increasing suitable conditions for P internal loading. These data support the hypothesis of the role of cyanobacterial blooms as an important factor impairing water quality and driving the ecosystem towards a stable degraded state. 5. These findings have important implications for the restoration of shallow stratifying eutrophic lakes, as the alternative degraded state is most likely to occur when compared with their non-stratifying counterparts. Moreover, feedback mechanisms in tropical and subtropical shallow lakes seem to be stronger than in temperate ones, as stratification events are more likely to occur over the year, intensifying system resilience to restorative strategies.
The present study was carried out in Faxinal Reservoir, a warm monomictic, meso-eutrophic reservoir in subtropical southern Brazil, with a long-standing, well-stratified condition, low epilimnetic nutrient concentrations, and a relatively clear epilimnion. In this study, we analyzed the dynamics of the phytoplankton functional groups, recognizing their driving forces in Faxinal Reservoir. Samples were taken at monthly intervals from
This study aimed at evaluating phytoplankton as a monitoring tool for water quality assessment in an urban shallow eutrophic reservoir considering temporal and vertical scales. Garças Reservoir is located in the Parque Estadual das Fontes do Ipiranga Biological Reserve (23°38 0 08 00 S and 23°40 0 18 00 S; 46°36 0 48 00 W and 46°38 0 00 00 W) that lies in the southeastern part of the Municipality of São Paulo, southeast Brazil. Samplings were carried out monthly during 8 consecutive years (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004) following the water column vertical profile (5 depths: subsurface, 1, 2, 3 m and *20 cm from the bottom). Abiotic variables analyzed were: water temperature, electric conductivity, DO, pH, total alkalinity, free CO 2 , dissolved inorganic carbon, N series, P series and SiO 4 H 4 . Biological variables studied were: total density, total biomass and chlorophyll a, which were integrated arithmetically. At the beginning of the 8 year series, Garças Reservoir was an eutrophic ecosystem with 20% of its surface covered by Eichhornia crassipes (phase I
European shallow, alkaline, saline lakes are potential indicators of climate change. Diatoms have often been reported as valuable proxies for different kinds of anthropogenic activities. Diatom assemblages and 14 environmental variables from shallow, alkaline lakes from 2 different regions of the Carpathian basin (Europe) were investigated for 3 years to (1) elucidate the physical and chemical parameters and diatom assemblages of these lakes, (2) select the principle variables affecting the diatom communities, and (3) , and Cl − ), platinum (Pt) units (colour), and oxygen saturation. Dominance by the stress-tolerant, motile diatom ecological guild, represented mainly by Nitzschia and Navicula species, was characteristic in these saline, turbid environments. Indicator species of the 2 regions were found to be different. Diatom assemblage composition was chiefly determined by conductivity and HCO 3 − and SO 4 2− concentrations. Nutrient loads, extreme weather events, and consequences of habitat maintenance management were unequivocally identifiable by variations in the benthic diatom assemblage composition. Diatoms are valuable indicators for assessment of ecological status of these saline, alkaline lakes. Including these organisms in ecological status assessments of inland saline lakes may improve the effectiveness of directives for conservation management and might be useful in preserving these pristine habitats that depend on natural hydrological processes.
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