Diatom Communities and Water Quality Assessment in Mountain Rivers of the Upper Segre Basin (La Cerdanya, Oriental Pyrenees)

Abstract

Epilithic diatoms of mountain rivers from the upper Segre catchment (Oriental Pyrenees) were studied in 1998, during three different seasons: March, July and September. Four rivers, the river Segre and its three most important tributaries, Duran, Molina and Querol, were sampled in upstream and downstream stretches. The diatom communities were comparable in all upstream stretches of these mountain rivers draining siliceous substrates. Dominant taxa were Achnanthidium subatomus, Diatoma mesodon, Encyonema cf. minutum, E. silesiacum, Fragilaria arcus, F. capucina, Gomphonema calcifugum, G. pumilum, Meridion circulare and Nitzschia pura. Changes in water quality in the downstream stretches lead to the appearance of pollution tolerant taxa, such as Eolimna minima, Gomphoneis minuta, Navicula gregaria, and Nitzschia inconspicua. As a result, the values obtained with the diatom water quality indices (IPS Specific Polluosensitivity Index, CEE and IBD Biological Diatom Index) decreased. The diatom community composition and the derived water quality values did not change in the upstream stretches over the year. In contrast, significant changes were observed in the downstream stretches with best water quality in July, during high flows due to melting snow, and worst values in September, during low discharge. The diatom indices, especially the IPS, showed a good performance in these mountain rivers.

Bio-écologie des diatomées épilithiques de la rivière Mfoundi (Yaoundé, Cameroun) : diversité, distribution spatiale et influence des pollutions organiques

“…La faible diversité spécifique relevée à la station Mf1 serait due à plusieurs facteurs agissant en synergie : (1) les faibles teneurs en nutriments et en matières organiques à cette station, (2) la forte vitesse d'écoulement de l'eau qui ralentit la colonisation des substrats par les diatomées, augmentant ainsi la dérive de certains taxons (BIGGS et CLOSE, 1989;CLAUSEN et BIGGS, 1997;LELAND et PORTER, 2000), et (3) le broutage qui serait exercé par les larves de Trichoptères se développant sur les substrats. Plusieurs auteurs ont montré que les indicateurs de la diversité spécifique ne permettent pas toujours, à eux seuls, d'estimer l'impact des pollutions sur l'état de santé des cours d'eau (BELLINGER et al, 2006;GOMÀ et al, 2005;LOBO et KOBAYASI, 1990;LOBO et al, 1995). Ceux-ci doivent donc être associés à la composition spécifique des organismes étudiés et à une bonne connaissance de leur autoécologie (ARCHIBALD, 1972;COX, 1988).…”

Benthic Diatoms of the Ying River (Huaihe River Basin, China) and Their Application in Water Trophic Status Assessment

“…The dominant species were Nitzschia inconspicua, Achnanthidium minutissimum, Navicula aitchelbee, Nitzschia palea, Cyclotella meneghiniana, Navicula submuralis and Mayamaea atomus. Among these, Achnanthidium minutissimum indicated the distribution of low nutrition water in the Ying River, while Nitzschia palea, Nitzschia inconspicua and Navicula aitchelbee were indicative of eutrophication status [37][38][39]. The species number of other genera was between 1 and 14 (0.27-3.78%).…”

“…Water 2017, 9, x FOR PEER REVIEW 4 of 16 nutrition water in the Ying River, while Nitzschia palea, Nitzschia inconspicua and Navicula aitchelbee were indicative of eutrophication status [37][38][39]. The species number of other genera was between 1 and 14 (0.27-3.78%).…”

Benthic diatom communities in high altitude lakes: a large scale study in the French Alps

“…E. minutum as well as D. tenuis were also abundant in this group and are mostly found in ecosystems with low nutrients concentrations ( Van et al, 1994;Hofmann et al, 2011). The dominant and indicative taxa of this group are usually observed in calcareous environments: it is the case of E. minutum (Rimet et al, 2003;Gomà et al, 2005), D. tenuis (Sabater and Roca, 1992), Brachysira vitrea (LangeBertalot and Moser, 1994) and Cymbella subleptoceros (e.g. Bahls, 2016).…”