Vanishing world: alkaline, saline lakes in Central Europe and their diatom assemblages

Abstract

European shallow, alkaline, saline lakes are potential indicators of climate change. Diatoms have often been reported as valuable proxies for different kinds of anthropogenic activities. Diatom assemblages and 14 environmental variables from shallow, alkaline lakes from 2 different regions of the Carpathian basin (Europe) were investigated for 3 years to (1) elucidate the physical and chemical parameters and diatom assemblages of these lakes, (2) select the principle variables affecting the diatom communities, and (3) , and Cl − ), platinum (Pt) units (colour), and oxygen saturation. Dominance by the stress-tolerant, motile diatom ecological guild, represented mainly by Nitzschia and Navicula species, was characteristic in these saline, turbid environments. Indicator species of the 2 regions were found to be different. Diatom assemblage composition was chiefly determined by conductivity and HCO 3 − and SO 4 2− concentrations. Nutrient loads, extreme weather events, and consequences of habitat maintenance management were unequivocally identifiable by variations in the benthic diatom assemblage composition. Diatoms are valuable indicators for assessment of ecological status of these saline, alkaline lakes. Including these organisms in ecological status assessments of inland saline lakes may improve the effectiveness of directives for conservation management and might be useful in preserving these pristine habitats that depend on natural hydrological processes.

Trait‐based diatom functional diversity as an appropriate tool for understanding the effects of environmental changes in soda pans

“…On the basis of the optical categorization of the pans, various cyclic patterns were determined: filling and concentrated phases for the colored types and filling, diluted, drying and concentrated for the turbid types (Lengyel, Pálmai, Padisák, & Stenger‐Kovács, ). The sampling times and their frequency depended on the water supply of these intermittent lakes (Stenger‐Kovács et al, , ). The sampling date was matched to the four seasons of the temperate climate.…”

“…The sampling date was matched to the four seasons of the temperate climate. (Detailed maps of and information concerning these lakes may be found in the studies by Stenger‐Kovács et al (, ), Stenger‐Kovács et al () and Lengyel et al ()).…”

“…In contrast to typical saline waters, which are often permanent and characterized mainly by chloride ions, astatic soda pans are mostly dominated by bicarbonate (Boros & Kolpakova, ) and are to be found across Africa, Europe, Asia, Australia, and America. The various aquatic communities (such as benthic and planktic algae, zooplankton and macroinvertebrates) of these ecosystems are exposed to extreme physical and chemical stress (strongly alkaline pans with high conductivity, nutrient concentration, turbidity, and diurnal temperature variation) (Boros, ; Stenger‐Kovács et al, ), all of which may play a decisive role in selection of a given species (Horváth et al, ) able to survive under such circumstances (Pálffy et al, ). This strong environmental filter causes a low degree of α‐diversity in alkaline lakes, not only in the case of benthic communities (Stenger‐Kovács, Hajnal, Lengyel, Buczkó, & Padisák, ), but also in planktic communities (Nkambo et al, ; Vidaković et al, ; Vignatti, Paggi, Cabrera, & Echaniz, ).…”

Taxonomical and distribution guide of diatoms in soda pans of Central Europe

“…During 2012-2013, other 90 samples were collected, especially from the Fertő-Hanság region from three lakes: Borsodi-dűlő, Lake Legény and Nyéki-szállás. Th e physical and chemical features of the lakes were published in Stenger- Kovács et al (2014b).…”

“…46(Suppl. ), 2015 , Stenger-Kovács and Padisák 2012, Stenger-Kovács et al 2014a, Körmendi et al 2015 and explained physical and chemical characteristics of the lakes (Stenger-Kovács et al 2014b, Abonyi et al unpubl.). Diff erent diversity metrics were also tested (Stenger-Kovács et al unpubl.…”