Exploring the use of nuclear alterations, motility and ecological guilds in epipelic diatoms as biomonitoring tools for water quality improvement in urban impacted lowland streams

Looking back, looking forward: a review of the new literature on diatom teratological forms (2010–2020)

“…The mechanisms involved in the teratological form development are, nowadays, still unknown, but they likely involve both cytoskeleton alterations and/or the impairment of the silicon metabolic pathway. As already discussed in our previous paper, abnormal frustule formations could be the result of nuclear alterations (such as dislocation, micronucleus formation, nucleus fragmentation and nucleus membrane breakage) which can be induced through the exposition to toxic compounds and can present significantly higher percentage of occurrence in strongly impacted urban sites (Nicolosi Gelis et al, 2020). Based on the hypotheses of Debenest et al (2008), nucleus alterations would disrupt part of the diatom cytoskeleton involved in the migration of important components for cell wall formation, leading to the development of teratological forms.…”

“…Pandey & Bergey (2016) observed lower motility rate in species colonizing severely polluted sites (contaminated by Cu and Zn) than less polluted ones; in addition, diatoms in the less contaminated site followed straight curved or sigmoid paths, while erratic and random under higher pollution. However, as evidenced in a recent paper, parameters related to motility are difficult to be interpreted since highly variable even within the same genus (Nicolosi Gelis et al, 2020). Even though, culture conditions offer a less harsh environment than natural rivers and streams, where flow plays a key selective role, these studies recently suggested the evolutionary success of the teratological forms.…”

“…Teratology type 6 is excluded from the figure since none of the examined genera presented an unusual arrangement of the individuals forming a colony (i.e. exploring the response of several metrics, such as diatom cell size, growth forms and ecological guilds) for the evaluation of the ecological status of water bodies Falasco et al, 2018b;Nicolosi Gelis et al, 2020). The evidence, herein, led us to take into consideration the approach in the framework of contamination assessment and the consequent production of teratological forms.…”

Las diatomeas del biofilm fluvial como indicadores ambientales a corto plazo en el seguimiento de la recuperación de la calidad del agua de sistemas acuáticos pampeanos

“…En las últimas décadas se han incorporado nuevos parámetros de diatomeas vinculados al campo de la ecotoxicología. Entre éstos se encuentran las anomalías nucleares (Debenest et al, 2008;Licursi y Gómez, 2013); la clasificación de las diatomeas utilizando rasgos ecológicos (Passy et al, 2007;Rimet y Bouchez, 2011;B-Béres et al 2016) y la movilidad (Coquillé et al 2015;Pandey et al 2016;Nicolosi Gelis et al 2020a). Estas variables cuentan con varias ventajas, como ser rápidas, fáciles de aplicar y requieren generalmente menor experiencia en taxonomía (Pandey et al 2017).…”

“…Existen en la literatura cuatro tipos de anormalidad nucleares en las diatomeas: localización anormal del núcleo, presencia de micronúcleos, ruptura de la membrana nuclear y fragmentación del núcleo (Debenest et al 2008;Licursi y Gómez 2013). Estas variables ha demostrado ser indicadores sensibles de los efectos de los herbicidas (Debenest et al 2008), de Cr (VI) (Licursi y Gómez 2013), y de la contaminación urbana (Nicolosi Gelis et al, 2020a) El estudio de las alteraciones nucleares en diatomeas revela los efectos de los contaminantes (metales y herbicidas) en los microproductores que forman el nivel trófico 14 Capítulo 1: Introducción basal de los ecosistemas fluviales, lo que ayuda a comprender los mecanismos de cambio en la composición de especies en los biofilms, la dominancia de las especies de diatomeas más tolerantes, así como factores que pueden conducir a anomalías morfológicas en las frústulos de diatomeas (Pandey et al 2017).…”