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

Abstract

Water level fluctuations result in changes in available habitat, affecting communities of algae and freshwater diatoms. Paleolimnological approaches assist in understanding the effects of hydrological regimes on communities over time. Therefore, the aim of this study was to identify the variation in water level due to the abundance of two diatom species, Diadesmis confervacea Kützing and Eunotia camelus Ehrenberg. Diadesmis confervacea has a periphytic habit and occurs primarily in shallow, marshy environments with high temperatures. Eunotia camelus has a planktonic habit and is mainly found in deeper environments. We analyzed the diatom fossils from sediment collected from a marsh located on Mutum Island, in the Upper Paraná River floodplain. The sediment core of 2 m was divided into layers of 2.5 cm and was dated to 830 PB using 14 C isotope. The relative abundances of the two species were obtained through quantitative analysis. The results showed a shift in the abundance of each species to the geomorphological changes and periods. The ratio of the opposing values of abundances of the two species might have been caused by changes in water levels due to ecological preferences. Competition for light between planktonic and periphytic communities also might affect algae abundance. Thus, we observed that D. confervacea and E. camelus are good indicators of hydrological changes. Therefore, our study contributes to better understand the effects of variation in water level and hydrological regime in the diatom species.

Response of diatom communities to climate and human disturbance: A 4200-year record from Costa Rica

“…Nitzschia incognita remains dominant in Zone A with average composition of 19.3% and is closely followed by Diadesmis confervacea , an epiphytic, aerophilic α-mesosaprobe known to thrive in shallow, marshy environments (Krammer and Lange-Bertalot, 1997; Ruwer and Rodrigues, 2018; Van Dam et al, 1994), which increases to its peak average abundance of 18.5%. A sedimentation hiatus suggestive of dry conditions occurred in the middle of Zone A from ca.…”

“…300 cal yr BP–present) of the LIA. Diadesmis confervacea is an aerophilic epiphyte known to thrive in shallow, marshy environments (Krammer and Lange-Bertalot, 1997; Ruwer and Rodrigues, 2018; Van Dam et al, 1994) that is associated with macrophyte cover (Haberyan and Horn, 2023) and high levels of organic nitrogen (Kilroy et al, 2017). The increase in this species from ca.…”

Subfossil and periphytic diatoms from the upper Paraná river, Brazil: last ~1000 years of a transition period

“…After its permanent establishment, there is the formation of a lateral bar of sediment on the side of the original island. The original island and the sidebar will be separated by a channel, which due to the sediment flow will become a connected lake or backwater, consequently, in a lake, transition period and, at the end of the process will be a swamp (see figure 2 in Ruwer & Rodrigues 2018).…”

Structure and species composition of diatom community during the wet season in three floodplain lakes of Brazilian Pantanal

“…Taxonomic studies contribute to the knowledge of biodiversity and provide the basis for the advancement of other approaches such as bioindication, environmental reconstruction, research on conservation and definition of priority areas such as the Pantanal, among many others. The more relevant works in the region are on the distribution of two species of diatoms and their association with the historical variation in water levels in the Paraná River [ 44 ]; the diatom flora in the Pantanal of Mato Grosso do Sul [ 45 ]; the history of the salinity in the southern Pantanal [ 46 ] and records of flood pulse dynamics [ 47 ]. Other studies, not related to diatoms, refer to the wetland carbon storage [ 48 ] and the influence that hydroclimatic variables exert on limnogeological processes [ 49 ].…”