Reed stands during different water level periods: physico-chemical properties of the sediment and growth of Phragmites australis of Lake Balaton

Abstract

This manuscript is contextually identical with the following published paper: 26During the transition from average to low water levels, the sediment shifted from severely anoxic to poorly 27 oxidised levels, with more favourable nutrient content while the amount of ammonia and sulphides decreased, too. 28It was shown that lowering water levels could act on plants via increased redox potential of the sediment and could 29 counteract the die-back of Phragmites, suggesting the effectiveness of water level decrease as a management 30 practice to counter reed die-back. 31Keywords: redox potential, morphology, growth dynamics, carbohydrates, water level changes 32 2 Introduction 33Water depth is one of the crucial factors that controls zonation, distribution and progression of Phragmites 34 australis within lakes (Coops et al., 1996; Vretare et al., 2001;Engloner & Papp, 2006;Tóth & Szabó, 2012). 35Numerous studies have shown that, due to specific cytological and biophysical features, common reed is able to 36 tolerate high and prolonged inundation (Armstrong et al., 1994; Crawford & Braendle, 1996; Vartapetian & 37 Jackson, 1997). A continuous gas space within the plant tissue called aerenchyma runs down from the aerial to the 38 underground parts of the plant, channelling air from leaves to rhizomes and roots. This flux of atmospheric gases 39 is driven by humidity-induced partial pressure differences between the air and the substomatal space (Armstrong & Armstrong, 1991). Without it, the reed could suffer complete or partial oxygen deprivation due to high microbial 41 oxygen consumption within the sediment (Brinson et al., 1981; Crawford & Braendle, 1996). To survive anoxic 42 conditions of the sediment the air from the aerenchyma is pressurised into the sediment surrounding reed roots via 43 radial diffusion creating an oxygenated rhizosphere (Armstrong et al., 1991; Beckett et al., 2001). This mechanism 44 cannot however compensate for effects of a severe or prolonged anoxia, which causes the temporary or permanent 45 die-back of plants. 40 46Reed die-back in Europe is a thoroughly discussed topic and several causes have been proposed (Den Hartog 47 et al., 1989;Ostendorp, 1989; Crawford & Braendle, 1996;Fürtig et al., 1996;Kubín & Melzer, 1996;Brix, 1999; 48 Armstrong & Armstrong, 2001). The simultaneous and general nature of this phenomenon (many sites) indicates 49 that it could be caused by a widespread disturbance. In Lake Balaton, the process started in the 1970s (Kovács et 50 al., 1989; Virág, 1997). The die-back was similar in many cases: the stands lost their homogeneity and the 51 clumping of reed progressed with time, eventually leading to bands of clustered Phragmites at the affected sites. 52This phenomenon occurred predominantly at the maximal depth of reed penetration (i.e., at the lakeward side of 53 the stands), suggesting the importance of water depth and thus the water level fluctuation. In all cases, plant density 54 gradually decreased outside the clumps and eventually discret...

Physiological Responses to Hypoxia and Manganese in Eucalyptus Clones with Differential Tolerance to Vale do Rio Doce Shoot Dieback

“…This is partially explained by a decrease in water absorption, which reduces transport. Another contributing factor is a decrease in active uptake by the roots, caused by the limitation of available energy after glycolysis reduction (Parent et al, 2008;Marschner, 2011;Tóth, 2016). A quiescent root tissue should reduce energy expenditure to a minimum, as well as the active uptake of nutrients.…”

Photophysiology and Spectroscopy of Sun and Shade Leaves of Phragmites australis and the Effect on Patches of Different Densities

“…Due to its high adaptability, high growth rate and predominantly clonal vegetative reproduction, Phragmites monopolized littoral zones of most freshwater lakes and became the dominant species [40,[67][68][69]. As seed dispersal in Phragmites stands is impossible in water covered areas, the spatial distribution of their shoots (ramets) is mainly determined by vegetative (clonal) spread using rhizomes.…”

“…The steep windward northern shore's sediment consists of dolomite limestone, while the shallow southern shore is dominated by sandy sediment. On the northern shore of the lake the average and maximum depth of water that reed stand can be found is 1.5 m and 2.4 m respectively, while on the southern shore the average depth on the waterward side of reed stands is 1 m [40,41] Lake Balaton has received significant scientific attention due to the reed die-back phenomenon observed (e.g., [40][41][42][43]), the macrophytic traits and species mapping (e.g., [44][45][46][47]) and the dynamic trophic gradient of the water (e.g., [48,49]). The field data for this study were collected at the Kerekedi bay, an oligo-mesotrophic bay at the easternmost basin of Lake Balaton situated at the geographic coordinates 46 • Map of the study area in Lake Balaton (inset) and field sampling points' location in the Kerekedi Bay (main).…”

“…Lake Balaton is a large (596 km 2 ) and relatively shallow (average water depth 3.5 m) freshwater lake located in Central Europe. Extended and continuous populations of helophytic perennial plants at the littoral zone of the lake form reed stands scattered along 112 km of the 240 km of the total shoreline [40,41]. The reed stands cover cumulatively an area of approximately 16 km 2 with the majority of it (73%-12 km 2 ) encountered at the northern part of the shore.…”

Effect of bottom sediments on the nutrient and metal concentration in macrophytes of river-lake systems

“…Fluctuations in the water level play a significant role in regulating the growth of macrophytes. Water depth is one of the most important factors determining the division into zones, distribution and spatial arrangement of the reed, P. australis, tolerant to long-term flooding (Tóth, 2016). In the research object, this species occurred most often in all zones of the river-lake water body covered by plants, often occupying the entire area of the examined transects (ranging from 60 to 100%).…”