Vegetation-environment relationships in peatlands dominated by Sphagnum fallax (Klinggr.) Klinggr. in Western Poland

We investigated species composition and relative abundance of Sphagnum fallax dominated peatlands in relation to measured environmental variables on the basis of 26 sites in the Wielkopolska region. Most of studied plots were characterised with soft waters, poor in Ca+ but rich in nutrients, especially N-NH4+ and P-PO43-, with high electrolytic conductivity and high DOC (dissolved organic carbon) concentration. Six out of 19 measured variables of surface water chemistry (DOC, pH, SO42-, P-PO43-, Na+ and Ca2+) explained significantly 23% of the variation in floristic composition. 107 species were observed in 65 vegetation plots. Cluster analysis revealed 4 types of vegetation in studied mires. Sphagnum fallax was the most abundant species and formed plant communities in the wide range of habitats: in the floating mats, with the plants usually adjoining the mineral basin edge (e.g. E. vaginatum, Andromeda polifolia and Ledum palustre) as well as it occupied central parts of Sphagnum lawn (e.g Eriophorum angustifolium) and rich fen habitats (e. g Carex rostrata or Phragmites australis). In Wielkopolska terrestrializating peatlands poor-rich gradient is developed mainly by four variables: conductivity, DOC, SiO2 dissolved, Ca and alkalinity. This study provides a new data on the ecology and typology of Sphagnum peatlands in western Poland

Anchor Groups Effect on Spectroscopic and Electrochemical Properties of Quaternary Nanocrystals Cu–In–Zn–S Capped with Arylamine Derivatives

A two-step procedure is reported enabling preparation of quaternary Cu–In–Zn–S nanocrystals with electrochemically active ligands consisting of 4-dodecylphenylaminobenzene and amine, thiol, or carboxylic anchor groups. Detailed ¹H NMR and IR studies of nanocrystals dispersion as well as free ligands recovered via nanocrystals dissolution indicate that in the organic shell of initial ligands weakly (1-octadecene (ODE)) and more strongly (1-dodecanethiol (DDT) and oleylamine (OLA)) bound ligands coexist. Treating the nanocrystals with pyridine removes weakly bound ligands; however, DDT and OLA molecules remain present as coligands with pyridine. Labile pyridine ligands can then be exchanged for the target 4-dodecylphenylaminobenzene derivatives with different anchor groups. ¹H NMR lines of these ligands are broadened due to their restricted rotation; this broadening is especially pronounced for the lines corresponding to the anchor group protons. Electrochemical activity of the ligands is significantly altered after their binding to the nanocrystal surface. Strongly interacting anchor groups such as −Ph–SH or −Ph–CH₂NH₂ lose their electrochemical activity upon coordination to nanocrystals, and weakly interacting groups (−PhNH₂) retain it. Secondary amine −Ph–NH–Ph– remains electrochemically active in all nanocrystals capped with the studied ligands; however, the potential of its oxidation depends on the conjugation with the anchor group

Synthesis and surface chemistry of high quality wurtzite and kesterite Cu2ZnSnS4 nanocrystals using tin(II) 2-ethylhexanoate as a new tin source

International audienceA novel synthesis method for the preparation of Cu2ZnSnS4 nanocrystals is presented using a liquid precursor of tin, namely tin(II) 2-ethylhexanoate, which yields small and nearly monodisperse NCs either in the kesterite or in the wurtzite phase depending on the sulfur source (elemental sulfur in oleylamine vs. dodecanethiol)

Experimental warming and precipitation reduction affect the biomass of microbial communities in a Sphagnum peatland

Due to their unique flora, hydrology and environmental characteristics, peatlands are precious and specific habitats for microorganisms and microscopic animals. Their microbial network structure and their biomass are crucial for peatland carbon cycling, through primary production, as well as decomposition and mineralization of organic matter. Wetlands are one of the ecosystems most at risk from anthropogenic activities and climate change. Most recent scenarios of climate change for Central Europe predict an increase in air temperature and a decrease in annual precipitation. These changes may disturb the biodiversity of aquatic organisms, and the peat carbon sink. Considering the above climatic scenarios, we aimed to: i) assess the response of microbial community biomass to warming and reduced precipitation through the lens of a manipulative experiment in a peatland ecosystem ii) predict how global warming might affect microbial biodiversity on peatlands exposed to warmer temperatures and decreased precipitation conditions. Additionally, we wanted to identify ecological indicators of warming among microorganisms living in Sphagnum peatland. The result of a manipulative experiment carried out at Rzecin peatland (W Poland) suggested that the strongest reduction in microbial biomass was observed in heated plots and plots where heating was combined with a reduction of precipitation. The most pronounced changes were observed in the case of the very abundant mixotrophic testate amoeba Hyalosphenia papilio and cyanobacteria. Shifts in the Sphagnum microbial network can be used as an early warning indicator of peatland warming, especially a decrease in the biomass of important phototrophic microbes living on the Sphagnum capitula, e.g. Hyalosphenia papilio.publishedVersio

Hyplant-derived sun-induced fluorescence—a new opportunity to disentangle complex vegetation signals from diverse vegetation types

Hyperspectral remote sensing (RS) provides unique possibilities to monitor peatland vegetation traits and their temporal dynamics at a fine spatial scale. Peatlands provide a vital contribution to ecosystem services by their massive carbon storage and wide heterogeneity. However, monitoring, understanding, and disentangling the diverse vegetation traits from a heterogeneous landscape using complex RS signal is challenging, due to its wide biodiversity and distinctive plant species composition. In this work, we aim to demonstrate, for the first time, the large heterogeneity of peatland vegetation traits using well-established vegetation indices (VIs) and Sun-Induced Fluorescence (SIF) for describing the spatial heterogeneity of the signals which may correspond to spatial diversity of biochemical and structural traits. SIF originates from the initial reactions in photosystems and is emitted at wavelengths between 650–780 nm, with the first peak at around 687 nm and the second peak around 760 nm. We used the first HyPlant airborne data set recorded over a heterogeneous peatland area and its surrounding ecosystems (i.e., forest, grassland) in Poland. We deployed a comparative analysis of SIF and VIs obtained from differently managed and natural vegetation ecosystems, as well as from diverse small-scale peatland plant communities. Furthermore, spatial relationships between SIF and VIs from large-scale vegetation ecosystems to small-scale peatland plant communities were examined. Apart from signal variations, we observed a positive correlation between SIF and greenness-sensitive VIs, whereas a negative correlation between SIF and a VI sensitive to photosynthesis was observed for large-scale vegetation ecosystems. In general, higher values of SIF were associated with higher biomass of vascular plants (associated with higher Leaf Area Index (LAI)). SIF signals, especially SIF760, were strongly associated with the functional diversity of the peatland vegetation. At the peatland area, higher values of SIF760 were associated with plant communities of high perennials, whereas, lower values of SIF760 indicated peatland patches dominated by Sphagnum. In general, SIF760 reflected the productivity gradient on the fen peatland, from Sphagnum-dominated patches with the lowest SIF and fAPAR values indicating lowest productivity to the Carex-dominated patches with the highest SIF and fAPAR values indicating highest productivity

Experimental warming and precipitation reduction affect the biomass of microbial communities in a Sphagnum peatland

Due to their unique flora, hydrology and environmental characteristics, peatlands are precious and specific habitats for microorganisms and microscopic animals. Their microbial network structure and their biomass are crucial for peatland carbon cycling, through primary production, as well as decomposition and mineralization of organic matter. Wetlands are one of the ecosystems most at risk from anthropogenic activities and climate change. Most recent scenarios of climate change for Central Europe predict an increase in air temperature and a decrease in annual precipitation. These changes may disturb the biodiversity of aquatic organisms, and the peat carbon sink. Considering the above climatic scenarios, we aimed to: i) assess the response of microbial community biomass to warming and reduced precipitation through the lens of a manipulative experiment in a peatland ecosystem ii) predict how global warming might affect microbial biodiversity on peatlands exposed to warmer temperatures and decreased precipitation conditions. Additionally, we wanted to identify ecological indicators of warming among microorganisms living in Sphagnum peatland. The result of a manipulative experiment carried out at Rzecin peatland (W Poland) suggested that the strongest reduction in microbial biomass was observed in heated plots and plots where heating was combined with a reduction of precipitation. The most pronounced changes were observed in the case of the very abundant mixotrophic testate amoeba Hyalosphenia papilio and cyanobacteria. Shifts in the Sphagnum microbial network can be used as an early warning indicator of peatland warming, especially a decrease in the biomass of important phototrophic microbes living on the Sphagnum capitula, e.g. Hyalosphenia papilio