Spatiotemporal changes in diatom ecological profiles: implications for biomonitoring

Abstract

Diatom indices developed in certain geographic regions are frequently used elsewhere, despite the strong evidence that such metrics are less useful when applied in regions other than that where species-environment relationships were originally assessed, showing that species have particular autoecological requirements in different geographic areas. In this study, we define the ecological profiles for selected environmental variables in three common epilithic diatom species in the Duero Basin (NW Spain), comparing our results with data gathered from different geographic regions. We assess differences in autoecological parameters obtained from the northern and southern subbasins, and from different years, in order to observe whether significant small-scale, spatiotemporal changes exist. Our results show that there are variations in species' autoecological parameters between different regions. Furthermore, there are significant changes comparing northern and southern Duero subbasins for certain species and physiochemical variables. Additionally, different autoecologies have been observed for certain diatoms and environmental factors comparing two different years. It can be concluded that freshwater diatom autoecologies can vary between different geographic areas. This implies that, in order to improve water-quality bioassessments, autoecology-based diatom metrics should be developed by quantifying species distributions along environmental gradients, using datasets representative of the areas or river types where the metrics will be applied.

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

“…However, although we found significant pure connectivity and land-use effects on the planktonic diatoms in winter, local spatially structured variables were the most important driver for size-group variation, showing that connectivity still plays an important role in the distribution of cell-size groups. The lack of a stronger pure spatial effect can be related to the small size and high dispersal capacity of all diatoms, compared with other taxonomic groups (Heino & Soininen, 2006 Blanco, 2011). Overall, differences in TP optima between studies can be related to local environmental variations that limit diatom species abundance differently in different regions, or to genetic variability among local populations (Charles, Acker, Hart, Reimer, & Cotter, 2006).…”

Environmental factors controlling lake diatom communities: a meta-analysis of published data

“…Rühland and Smol (2002) highlight the need to define environmental optima and tolerances of diatom taxa in new geographical regions to build robust and meaningful infer-10 ence models. In general, although diatom assemblage composition is related to climatic patterns (Weckström and Korhola, 2001), the potential influence of geographical factors has been underestimated (Enache and Prairie, 2002;Yang et al, 2003;Álvarez-Blanco et al, 2011). Climate has a profound effect on diatom dynamics, affecting diatom communities via its links with nutrient availability (Kirilova et al, 2008).…”

“…Denys, L.: Calibration of littoral diatoms to water chemistry in standing fresh waters (Flanders, Lower Belgium): inference models for historical sediment assemblages, J. Paleolimnol., 35, Freshwater Biol., 57, 2044-2056, doi:10.1111/j.1365-2427.2011.02670.x, 2012 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Hassan, G. S., Tietze, E., and Francesco, C. G. D.: Modern diatom assemblages in surface sediments from shallow lakes and streams in southern Pampas (Argentina), Aquat. Sci., 71, 487-499, doi:10.1007/s00027-009-0104-4, 2009.…”

“…Despite the widespread use of such multivariate methods, little effort has been made to determine the relative importance of different predictors over a large geographical scale. Quantitative models for a many variables are demonstrated to have limited spatial transferability (Álvarez-Blanco et al, 2011;Juggins, 2013). This study explores the 25 relative impact of key abiotic factors on diatom composition by jointly analyzing the results presented in different studies covering a broad range of limnological and climatic conditions.…”

Diatom species composition and indices for determining the ecological status of coastal Mediterranean Spanish lakes

“…Moreover, among the indices, there is a wide heterogeneity in their database and about the diatom species that they consider. Furthermore, their effectiveness varies depending on the ecosystem type and the eco-region (Cejudo-Figueiras, 2011;Álvarez-Blanco & al., 2011Álvarez-Blanco & al., , 2012. Nowadays, the information about the use of diatoms indices in Mediterranean standing waters is scarce.…”