- V. Cordlandwehr (1)
- M. Daam (1)
- Fabiane Dorr (1)
- J.M. Groenendael van (1)
- C.R. Janssen (1)
- J. Juselius (1)
- F. Laender de (1)
- Miquel Lürling (1)
- Marcelo M. Marinho (1)
- C. Melian (1)
- R.L. Meredith (1)
- W.A. Ozinga (1)
- Ernani Pinto (1)
- H. Roussel (1)
- D.E.C.M. Verschuren (1)
Combined Effect of Light and Temperature on the Production of Saxitoxins in Cylindrospermopsis raciborskii Strains
Mesquita, Marcella C.B. ; Lürling, Miquel ; Dorr, Fabiane ; Pinto, Ernani ; Marinho, Marcelo M. - \ 2019
Toxins 11 (2019)1. - ISSN 2072-6651 - 15 p.
cyanobacteria - cyanotoxins - intraspecific variability - saxitoxins
Cylindrospermopsis raciborskii is a potentially toxic freshwater cyanobacterium that can tolerate a wide range of light and temperature. Due to climatic changes, the interaction between light and temperature is studied in aquatic systems, but no study has addressed the effect of both variables on the saxitoxins production. This study evaluated the combined effect of light and temperature on saxitoxins production and cellular quota in C. raciborskii. Experiments were performed with three C. raciborskii strains in batch cultures under six light intensities (10, 40, 60, 100, 150, and 500 μmol of photons m-2 s-1) and four temperatures (15, 20, 25, and 30 °C). The growth of C. raciborskii strains was limited at lower temperatures and the maximum growth rates were obtained under higher light combined with temperatures equal or above 20 °C, depending on the strain. In general, growth was highest at 30 °C at the lower light intensities and equally high at 25 °C and 30 °C under higher light. Highest saxitoxins concentration and cell-quota occurred at 25 °C under high light intensities, but were much lower at 30 °C. Hence, increased temperatures combined with sufficient light will lead to higher C. raciborskii biomass, but blooms could become less toxic in tropical regions.
The contribution of intra- and interspecific tolerance variability to biodiversity changes along chemical gradients
Laender, F. de; Melian, C. ; Bindler, R. ; Brink, P.J. van den; Daam, M. ; Roussel, H. ; Juselius, J. ; Verschuren, D.E.C.M. ; Janssen, C.R. - \ 2014
Ecology Letters 17 (2014)1. - ISSN 1461-023X - p. 72 - 81.
intraspecific variability - functional diversity - community ecology - neutral theory - central sweden - niche - model - individuals - sensitivity - ecosystems
The worldwide distribution of toxicants is an important yet understudied driver of biodiversity, and the mechanisms relating toxicity to diversity have not been adequately explored. Here, we present a community model integrating demography, dispersal and toxicant-induced effects on reproduction driven by intraspecific and interspecific variability in toxicity tolerance. We compare model predictions to 458 species abundance distributions (SADs) observed along concentration gradients of toxicants to show that the best predictions occur when intraspecific variability is five and ten times higher than interspecific variability. At high concentrations, lower settings of intraspecific variability resulted in predictions of community extinction that were not supported by the observed SADs. Subtle but significant species losses at low concentrations were predicted only when intraspecific variability dominated over interspecific variability. Our results propose intraspecific variability as a key driver for biodiversity sustenance in ecosystems challenged by environmental change.
Do plant traits retrieved from a database accurately predict on-site measurements?
Cordlandwehr, V. ; Meredith, R.L. ; Ozinga, W.A. ; Bekker, R.M. ; Groenendael, J.M. van; Bakker, J.P. - \ 2013
Journal of Ecology 101 (2013)3. - ISSN 0022-0477 - p. 662 - 670.
northwest european flora - life-history traits - land-use change - intraspecific variability - functional diversity - aboveground biomass - relative importance - leaf traits - communities - ecology
1. Trait-based approaches are increasingly used to obtain an insight into the functional aspects of plant communities. Since measuring traits can be time-consuming, large international databases of plant traits are being compiled to share the effort. From these databases, average trait values are often extracted per species by averaging trait values of individuals over multiple populations and habitats. However, the accuracy of such aggregated information from regional databases as a surrogate for on-site measurements has seldom been tested. 2. For the local species pool (aggregated at the habitat-level) and the plant communities on the plots (aggregated at the community-level), we quantified how accurately trait values for each species measured at the plot (plot scale) and those averaged per species and site (site scale) can be estimated from those retrieved from a North-west-European trait database. We analysed three widely used plant traits, canopy height (CH), leaf dry matter content (LDMC) and specific leaf area (SLA), of species occurring in a wet meadow and a salt marsh. 3. Database values more accurately predicted traits aggregated at the habitat-level than those aggregated at the community-level. In addition, traits with lower plasticity, such as LDMC, were more accurately predicted by database values. The performance of database values also depended upon the habitat studied, for example, habitat-level SLA values were accurately predicted by database values in the wet meadow but inaccurately predicted in the salt marsh. 4. Synthesis. This study reveals that the accuracy of traits retrieved from a database depends on the level of aggregation (lower at community-level), the trait (lower in plastic traits) and the habitat type (lower in extreme habitats). For studies focussing on processes mainly acting at the site scale (e.g. trait–environment relationships), traits retrieved from a regional database and filtered according to habitat will probably lead to good results. Whereas studying processes acting at the plot scale (e.g. niche partitioning), requires the additional effort of measuring traits on-site.