ENKI (Czechia)

Destabilization of the water cycle threatens human lives and livelihoods. Meanwhile our understanding of whether and how changes in vegetation cover could trigger transitions in moisture availability remains incomplete. This challenge calls for better evidence as well as for the theoretical concepts to describe it. Here we briefly summarize the theoretical questions surrounding the role of vegetation cover in the dynamics of a moist atmosphere. We discuss the previously unrecognized sensitivity of local wind power to condensation rate as revealed by our analysis of the continuity equation for a gas mixture. Using the framework of condensation-induced atmospheric dynamics, we then show that with the temperature contrast between land and ocean increasing up to a critical threshold, ocean-to-land moisture transport reaches a tipping point where it can stop or even reverse. Land-ocean temperature contrasts are affected by both global and regional processes, in particular, by the surface fluxes of sensible and latent heat that are strongly influenced by vegetation. Our results clarify how a disturbance of natural vegetation cover, e.g., by deforestation, can disrupt large-scale atmospheric circulation and moisture transport: an increase of sensible heat flux upon deforestation raises land surface temperature and this can elevate the temperature difference between land and ocean beyond the threshold. In view of the increasing pressure on natural ecosystems, successful strategies of mitigating climate change require taking into account the impact of vegetation on moist atmospheric dynamics. Our analysis provides a theoretical framework to assess this impact. The available data for the Northern Hemisphere indicate that the observed climatological land-ocean temperature contrasts are close to the threshold. This can explain the increasing fluctuations in the continental water cycle including droughts and floods and signifies a yet greater potential importance for large-scale forest conservation.

Man-made shallow fishponds in the Czech Republic have been facing high eutrophication since the 1950s. Anthropogenic eutrophication and feeding of fish have strongly affected the physicochemical properties of water and its aquatic community composition, leading to harmful algal bloom formation. In our current study, we characterized the phytoplankton community across three eutrophic ponds to assess the phytoplankton dynamics during the vegetation season. We microscopically identified and quantified 29 cyanobacterial taxa comprising non-toxigenic and toxigenic species. Further, a detailed cyanopeptides (CNPs) profiling was performed using molecular networking analysis of liquid chromatography-tandem mass spectrometry (LC-MS/MS) data coupled with a dereplication strategy. This MS networking approach, coupled with dereplication, on the online global natural product social networking (GNPS) web platform led us to putatively identify forty CNPs: fourteen anabaenopeptins, ten microcystins, five cyanopeptolins, six microginins, two cyanobactins, a dipeptide radiosumin, a cyclooctapeptide planktocyclin, and epidolastatin 12. We applied the binary logistic regression to estimate the CNPs producers by correlating the GNPS data with the species abundance. The usage of the GNPS web platform proved a valuable approach for the rapid and simultaneous detection of a large number of peptides and rapid risk assessments for harmful blooms.

This chapter deals with a largely unrecognised service of wetlands – their role in regulating air temperature through evapotranspiration. We explain quantitatively how solar energy striking the earth’s surface is dissipated by water (expressed in energy units (W m−2)) in three processes: dissolution-precipitation of salts, disintegration-recombination of the water molecule in biological processes and evapotranspiration-condensation. The direct effect of wetlands on regional climate, through reduction of temperature gradients and the role of water vapour and clouds in lowering the passage of solar radiation are then described. We quantify the huge upsurge of sensible heat (warm air) that must have occurred after the drainage of wetlands in the northern hemisphere over the past 260 years. The radiative forcing that was caused by the increase in greenhouse gases in the atmosphere over the same period (from 1 to 3 W m−2 from 1750 to the present day) is markedly lower than radiative forcing caused by wetland drainage and indeed, is too small to measure. The amounts of carbon dioxide, methane and water vapour in atmosphere and their dynamics are compared. We question the meaning of ‘average temperature’ as the criterion of climate change in terms of thermodynamics. We show temperature differences in the present-day cultural landscape, on a clear sunny day, in thermovision pictures: wetlands and forests are upto 20 °C cooler than drained surfaces. We argue that persisting with the dogma of climate change caused by the greenhouse effect alone results in society ignoring the most important functions of natural vegetation, manifest through their direct effect on climate and water cycling. This facilitates further wetland drainage and deforestation. We believe that it is now essential to support and restore natural vegetation structures, like wetlands and forests, in order to make any serious reduction in climate warming.

Many hydrologic models and agricultural management applications require evapotranspiration estimates. The intensity of evapotranspiration is mainly determined by mathematical models rather than by direct measurement. In addition to its own estimate of evapotranspiration it is necessary to determine the uncertainty of this estimate. This uncertainty is not usually mentioned. In this paper these formulas are derived for the uncertainty estimate of evapotranspiration under simplifying assumptions. These assumptions enabled one to derive an expression of evapotranspiration estimation uncertainty suitable for practical applications. The paper focuses on both the absolute and the relative uncertainty of evapotranspiration estimation. The derived formulas can be used for determining the uncertainty in evapotranspiration estimation, but as well as for the accuracy estimate which is necessary for the measuring of input variables. The derived relationship shows that the net radiation should be more accurately measured than the other energy fluxes that have an influence on evapotranspiration. It follows that the relative uncertainty of evapotranspiration is primarily influenced by the relative uncertainty of net radiation. The uncertainty in the measurement of net radiation was derived from data obtained by using a radiometer which was equipped with a pair of pyranometers and with a pair of pyrgeometers. Planck’s Law was used for spectral analysis. The possible presence of systematic errors in the measuring of net radiation was evaluated for its potential impact on the errors of the evapotranspiration estimate. This paper is accompanied by measurement records and graphs documenting the achieved results.

The present area of European wetlands is only a fraction of their area before the start of large-scale human colonization of Europe. Many European wetlands have been exploited and managed for various purposes. Large wetland areas have been drained and reclaimed mainly for agriculture and establishment of human settlements. These threats to European wetlands persist. The main responses of European wetlands to ongoing climate change will vary according to wetland type and geographical location. Sea level rise will probably be the decisive factor affecting coastal wetlands, especially along the Atlantic coast. In the boreal part of Europe, increased temperatures will probably lead to increased annual evapotranspiration and lower organic matter accumulation in soil. The role of vast boreal wetlands as carbon sinks may thus be suppressed. In central and western Europe, the risk of floods may support the political will for ecosystem-unfriendly flood defence measures, which may threaten the hydrology of existing wetlands. Southern Europe will probably suffer most from water shortage, which may strengthen the competition for water resources between agriculture, industry and settlements on the one hand and nature conservancy, including wetland conservation, on the other.

Constructed wetlands with horizontal subsurface horizontal flow are commonly used for treatment of municipal sewage and are well monitored for removal of organics, suspended solids, nutrients and bacteria. However, the information on removal of heavy metals and their sequestration in plants growing there is very limited. The present study deals with sequestration of six heavy metals in Phalaris arundinacea growing in a constructed wetland treating municipal sewage in the Czech Republic during the period 2004–2008. The aboveground biomass of Phalaris arundinacea is higher that the average Phalaris biomass in other Czech constructed wetlands and also as compared to natural stands. Contrary to natural stands, the root to shoot (R/S) ratio is lower than 1.0 and varied between 0.34 and 0.68 with a mean value of 0.49. For all studied heavy metals the concentrations are the highest in the roots while in other parts, i.e. leaves, stems, rhizomes and flowers, the concentrations usually do not differ significantly. Because of low belowground biomass, the standings stocks are higher aboveground for Zn, Cd, Pb and Cu with copper standing stock being significantly higher than belowground. On the other hand, for Cr and Ni the belowground standing stocks were significantly higher than aboveground because of very high Cr and Ni concentrations in the roots. In most cases the concentrations found in our study are within the order of magnitude as compared to results from other constructed wetlands and natural stands. Heavy metal aboveground standing stocks represented between 1.6% (Cr) and 15.1% (Cd) of the annual metals inflow with an average value of 6.5%. The amount of heavy metals sequestered in the aboveground biomass accounted for between 3.7% (Zn) and 38.4% (Cd) of the heavy metal removal in the filtration beds with an average value of 13.2%.