Biological traits of diatoms in the characterization of a reservoir and a stream in a subtropical region

Abstract

The structure of epiphytic diatom communities in a reservoir and a stream were studied with regard to different taxonomic levels (species, genera, and families) and biological traits (strategies of attachment to the substrate). We expected that strongly attached diatoms would abound in the stream, and those employing a loosely attached strategy should predominate in the reservoir due to the lentic flow condition. The congruence of high taxonomic levels and biological traits of the species was assessed and tested against an equal pattern of distribution. Our hypothesis was that taxonomic levels and biological traits have high congruence with species community. As periphytic diatoms have specialized structures to colonize substrates, we believed biological trait groups would show greater congruence with the species than groups formed by taxonomic levels. In fact, we observed the prevalence of strongly attached strategies in the lotic environment and stalked, prostrate, motile, and planktonic strategies predominated in the reservoir. The congruence between species and biological traits was stronger in both environments than that with different taxonomic levels. These results suggest that the strategies of attachment represent a key factor to the occurrence and distribution of species. The attached strategy showed greater competitive advantages under unstable environmental conditions than the loosely attached strategy, which predominated under stable conditions. Our results demonstrated a strong association of the diatom community with environmental conditions and suggest that biological traits may be an additional alternative for characterizing environments.

Expanding the trait-based concept of benthic diatoms: Development of trait- and species-based indices for conductivity as the master variable of ecological status in continental saline lakes

“…The use of trait-based measures in ecological status assessments might potentially be favoured since they are related to functional properties of the biological elements of ecosystems directly (Larras et al, 2017). Initially, trait-based approaches have been suggested complementary (Bayona et al, 2014, Algarte et al, 2017 since they are relatively rapid and simple (Algarte et al, 2017). Functional approaches may also enhance our ability in predicting the community composition from the environment (Mc Gill et al, 2006; also in context of ecological indication.…”

“…Motility of diatoms represents an important function in habitats with fine sediments, and an applicable indicator of siltation and land use of running waters (Stevenson et al, 2010;Smucker and Vis, 2010). They are characteristic in lakes under stable hydrodynamic conditions (Algarte et al, 2017); and in parallel with water abstraction, their relative abundance increases at high farm intensity (Lange et al, 2011). Therefore, besides the high salinity, all characteristic features of the soda pans such as high nutrient content, turbidity, the decreasing water level, or the temporary drying phases support the dominance of diatoms with characteristic functional traits in this guild.…”

Local environment and connectivity are the main drivers of diatom species composition and trait variation in a set of tropical reservoirs

“…Some studies have been successful in using traits to evaluate various processes. Growth morphology, for example, has been used to evaluate the influence of environmental conditions, especially hydrodynamics, on diatom community structure (Algarte, Pavan, Ferrari, & Ludwig, 2016;Passy, 2007).…”

Diatom Biogeography From the Labrador Sea Revealed Through a Trait-Based Approach

“…However, they have only recently been applied to freshwaters systems (Weithoff, 2003;Kruk et al, 2010;Schwaderer et al, 2011;Edwards et al, 2013b;Jamil et al, 2014;Zwart et al, 2015) and, far less frequently, to marine ecosystems (Barton et al, 2013a,b;Edwards et al, 2013a), to understand the distributional patterns and re-organisation of phytoplankton communities under climate change scenarios. Examples of functional traits associated with diatom species and morphotypes, which link to their seasonal and/or spatial occurrence, include: cell size (Alves- de-Souza et al, 2008), shape (Pahlow et al, 1997;Leonilde et al, 2017), morphological characteristics (Ligowski et al, 2012;Assmy et al, 2013b;Allen, 2014), chain formation (Pahlow et al, 1997), colony shape (Passy, 2002), attachment mechanisms to a hard substrate (Algarte et al, 2016), nutritional strategies (Edwards et al, 2015), and the level of cell wall silicification, some of which may confer resistance to grazing (Assmy et al, 2013b) or contribute to carbon export (Tréguer et al, 2018).…”