Periphytic algae in a floodplain lake and river under low water conditions

Abstract

Drought events will become more frequent due the climate change. In floodplains, periphytic algae are responsible for part of the primary production, are the principal source of organic carbon deposition, play an important role in mineralization and nutrient cycling, and are the base of the food web for many organisms. As algae distribution in aquatic environments is a strong indicator of physical and chemical conditions of the sites, we aimed to determine the structure of periphytic algae in lentic and lotic environments during drought conditions and to uncover the main local abiotic factors in community structuring. We hypothesized diatoms would be more frequent than green algae and desmids at both sites, due to their resistance characteristics, and that higher periphyton algal richness, density and diversity would occur in the lake due to the greater availability of nutrients and the absence of flow. The study was carried out in the Finado Raimundo lake and the Ivinhema river in the Upper Paraná river floodplain during the low water period of 2011. Petioles of the aquatic macrophyte Eichhornia azurea (Sw.) Kunth were used as a substrate for periphytic algae. We found a total of 171 species, 104 species in the lake and 80 in the river. Diatoms were predominant at both sites due to their strategic traits, and between sites, there were different patterns in the periphytic algal community structure, owing to the distinctive physical and chemical characteristics of the lake and the river. Achnanthidium minutissimum (Kützing) Czarnecki and Nitzschia palea (Kützing) W. Smith were the most abundant species in both environments. Our results showed patterns of periphytic algae in a floodplain during drought conditions, which will assist in understanding their structuring during future drought scenarios.

Periphytic algal community in lentic environments of the Upper Paraná River floodplain: seasonal and spatial variation

“…High values of species richness were registered in May and February 2015, coinciding with high water level, and the lowest number of algal species was found in August 2014, which presented the lowest water levels of the Paraná River. Other studies performed in lentic and semi-lotic environments of the Upper Paraná River floodplain also registered higher species richness of periphytic algae during high-water periods (Rodrigues & Bicudo, 2004;Fonseca & Rodrigues, 2005;Algarte et al, 2009Algarte et al, , 2017Carapunarla et al, 2014;Biolo et al, 2015;Bichoff et al, 2016), in agreement with our results.…”

“…Compared to other periphytic algae, diatoms show higher tolerance to seasonal changes in the hydrological regime, and adapt more easily to different environmental conditions (Round, 1991;Rodrigues & Bicudo, 2001b;Algarte et al, 2009). Besides colonizing all types of environments and being r-strategists (Biggs, 1996), diatoms have morphological adaptations to produce mucilage (such as in peduncles), which favour adhesion to the substrate (Biggs, 1996;Azim & Asaeda, 2005;Schneck et al, 2008;Bichoff et al, 2016).…”

“…Two stands of the aquatic macrophyte Eichhornia azurea (Sw.) Kunth were sampled in each lake. In each stand, at each of the five sampling periods, one petiole in adult stage was sampled (Schwarzbold, 1990;Algarte et al 2016;Bichoff et al, 2016;Algarte et al, 2017). We thus collected two petioles (n = 2) per site, totalling 30 samples.…”

Abundance of Diadesmis confervacea Kützing and Eunotia camelus Ehrenberg indicates the historical water level variation in a marsh

“…Periphytic algae are present in the periphytic matrix, mainly adhered to the substrate or entangled (Wetzel 1983;Stevenson 1996;Tuji 2000). These species as D. confervacea possess adaptations and strategies that allow them to explore the shallow lakes and marginal regions of aquatic environments, where there is more substrate and light (Stevenson 1996;Vadeboncoeur and Staineman 2002;Bichoff et al 2016). Therefore, the increase in D. confervacea abundance during the transition period-in which the environment begins to isolate itself from the main channel of the Paraná River-suggests an environment with low water levels, such as a swamp.…”

Periphytic Cosmarium (Zygnematophyceae, Desmidiaceae) in lentic environments of the Upper Paraná River floodplain: Taxonomy and ecological aspects

“…Figures 16a-c Material examined: HNUP-16499, 16500, 16501, 16502. O c c u r re n c e : A l g a r t e e t a l . ( 2 0 0 6 ) ; Bichoff et al (2016); Dunck et al (2016);Train et al (2004).…”