Browsing by Author "Poniecka, Ewa"
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Item Cryoconite – From minerals and organic matter to bioengineered sediments on glacier's surfaces(Elsevier, 2022) Rozwalak, Piotr; Podkowa, Paweł; Buda, Jakub; Niedzielski, Przemysław; Kawecki, Szymon; Ambrosini, Roberto; Azzoni, Roberto S.; Baccolo, Giovanni; Ceballos, Jorge L.; Cook, Joseph; Di Mauro, Biagio; Ficetola, Gentile Francesco; Franzetti, Andrea; Ignatiuk, Dariusz; Klimaszyk, Piotr; Łokas, Edyta; Ono, Masato; Parnikoza, Ivan; Pietryka, Mirosława; Pittino, Francesca; Poniecka, Ewa; Porazinska, Dorota L.; Richter, Dorota; Schmidt, Steven K.; Sommers, Pacifica; Souza-Kasprzyk, Juliana; Stibal, Marek; Szczuciński, Witold; Uetake, Jun; Wejnerowski, Łukasz; Yde, Jacob C.; Takeuchi, Nozomu; Zawierucha, KrzysztofCryoconite is a mixture of mineral and organic material covering glacial ice, playing important roles in biogeochemical cycles and lowering the albedo of a glacier surface. Understanding the differences in structure of cryoconite across the globe can be important in recognizing past and future changes in supraglacial environments and ice-organisms-minerals interactions. Despite the worldwide distribution and over a century of studies, the basic characteristics of cryoconite, including its forms and geochemistry, remain poorly studied. The major purpose of our study is the presentation and description of morphological diversity, chemical and photoautotrophs composition, and organic matter content of cryoconite sampled from 33 polar and mountain glaciers around the globe. Observations revealed that cryoconite is represented by various morphologies including loose and granular forms. Granular cryoconite includes smooth, rounded, or irregularly shaped forms; with some having their surfaces covered by cyanobacteria filaments. The occurrence of granules increased with the organic matter content in cryoconite. Moreover, a major driver of cryoconite colouring was the concentration of organic matter and its interplay with minerals. The structure of cyanobacteria and algae communities in cryoconite differs between glaciers, but representatives of cyanobacteria families Pseudanabaenaceae and Phormidiaceae, and algae familiesMesotaeniaceae and Ulotrichaceae were the most common. The most of detected cyanobacterial taxa are known to produce polymeric substances (EPS) that may cement granules. Organic matter content in cryoconite varied between glaciers, ranging from 1% to 38%. The geochemistry of all the investigated samples reflected local sediment sources, except of highly concentrated Pb and Hg in cryoconite collected from Europeanglaciers near indus-rialized regions, corroborating cryoconite as element-specific collector and potential environmental indicator of anthropogenic activity. Our work supports a notion that cryoconite may be more than just simple sediment and instead exhibits complex structure with relevance for biodiversity and the functioning of glacial ecosystems.Item Empirical testing of cryoconite granulation: Role of cyanobacteria in the formation of key biogenic structure darkening glaciers in polar regions(Wiley, 2023-08-13) Wejnerowski, Łukasz; Poniecka, Ewa; Buda, Jakub; Klimaszyk, Piotr; Piasecka, Agnieszka; Dziuba, Marcin Krzysztof; Mugnai, Gianmarco; Takeuchi, Nozomu; Zawierucha, KrzysztofCryoconite, the dark sediment on the surface of glaciers, often aggregates into oval or irregular granules serving as biogeochemical factories. They reduce a glacier’s albedo, act as biodiversity hotspots by supporting aerobic and anaerobic microbial communities, constitute one of the organic matter (OM) sources on glaciers and are a feeder for micrometazoans. Although cryoconite granules have multiple roles on glaciers, their formation is poorly understood. Cyanobacteria are ubiquitous and abundant engineers of cryoconite hole ecosystems. This study tested whether cyanobacteria may be responsible for cryoconite granulation as a sole biotic element. Incubation of Greenlandic, Svalbard and Scandinavian cyanobacteria in different nutrient availability and substratum for the growth (distilled water alone, and water with either quartz powder, furnaced cryoconite without OM or powdered rocks from glacial catchment) revealed that cyanobacteria bind mineral particles into granules. The structures formed in the experiment resembled those commonly observed in natural cryoconite holes: they contained numerous cyanobacterial filaments protruding from aggregated mineral particles. Moreover, all examined strains were confirmed to produce extracellular polymeric substances (EPS), which suggest that cryoconite granulation is most likely due to EPS secretion by gliding cyanobacteria. In the presence of water as the only substrate for growth, cyanobacteria formed mostly carpet-like mats. Our data empirically prove that EPS-producing oscillatorialean cyanobacteria isolated from the diverse community of cryoconite microorganisms can form granules from mineral substrate and that the presence of the mineral substrate increases the probability of the formation of these important and complex biogeochemical microstructures on glaciers.