Benthic diatom communities and their relationship to water chemistry in wetlands of central Italy

Abstract

Diatoms are good environmental indicators and are often the main component of phytobenthos, one of the key groups of organisms recommended by the Water Framework Directive (W.F.D.) for the assessment of ecological status of surface waters. Although diatoms are regularly used as indicators in rivers and in lakes, less is known about the benthic diatom communities in wetland systems, especially in Italy. The main aim of the project was to provide a contribution to the knowledge on distribution, composition and structure of benthic diatom communities in wetland systems in Italy. In 2005, we investigated the benthic diatom communities and their relationships to water variables of nine ponds and wetlands along the Tyrrhenian coast near Rome. Furthermore, a first application of seven European diatom-based indices on this type of water body was undertaken. A total of 225 species and varieties belonging to 54 genera were identified. The Canonical Correspondence Analysis indicated that certain species were closely associated with each wetland type and their distribution mainly depended on nutrient and chloride contents: pollution tolerant species (i. e. Luticola goeppertiana, Mayamaea atomus, Navicula subminuscula) in the wetlands connected to river mouths, halophilous species and also marine littoral species (i. e. Nitzschia elegantula, Amphora coffeaeformis, Achnanthes brevipes var. intermedia, Epithemia adnata var. porcellus) in the coastal brackish ponds and wetlands, and less eutrophic species (i. e. Achnanthidium minutissimum, A. biasolettianum) in the lowland freshwater wetland. In general, the indices classified most of the studied water bodies as bad, poor and moderate status; few sites were classified into a good class, even for at least in one sampling occasion. Eutrophication and Pollution Index (EPI-D), Trophic Diatom Index (TDI), Taxa Pollution Tolerant (%PT), Pollution Sensitivity Index (IPS) and Generic Diatom Index (IDG) were significantly correlated to nutrient contents in the studied wetlands. Our preliminary data set illustrated the potential of the use of these benthic algae as bioindicators in wetlands.

Epiphytic Diatoms along Environmental Gradients in Western European Shallow Lakes

“…For instance, Denys found that epiphytic assemblages from acid lakes are more weakly related to TP concentrations. Despite this, several large‐scale studies suggest that nutrient concentrations are the main variables determining the composition and structure of epiphytic diatom communities . Our results strongly support the conclusion that epiphytic diatom assemblages are useful bioindicators of shallow lake trophic status.…”

“…The present study aims to explore the effect of geographical, morphological and physical/chemical for epiphytic diatom communities in shallow lakes. Previous studies suggest a strong dependence of this community on water chemistry. However, the responses of epiphytic algae to trophic state could be modified by the influence of other factors such as lake altitude or latitude that determine lake characteristics and, therefore, biological community structure .…”

Eutrophication decreases distance decay of similarity in diatom communities

“…Sample sizes of 500 cells or lower have been used previously to study the distribution of diatom communities along environmental and spatial gradients (Pan et al ., ; Soininen, ; Della Bella et al ., ; Astorga et al ., ; Wetzel et al ., ). In addition, questions about how diversity changes across disturbance gradients usually require only relative diversities among sites under the different treatment regimens (Hughes et al ., ), and therefore, 500 cells is deemed sufficient to investigate diatoms in reed microhabitats of peatland ditches.…”

Taxonomic Investigation of Euplanktonic Diatom Communities as Indicator of Copper in the Bank of the Subarnarekha River, Ghatshila, Jharkhand, India

“…In our study we have observed the pH value in station 1 was 6.8, which is slightly acidic suggesting the starting point of acidification due to pollution (Petrou et al, 2019). High acidification also diminishes silica production in diatoms (Petrou et al, 2019 (Bella et al, 2007). Diatom communities play a significant role in maintaining the water quality in India.…”