Green New World: Unraveling microbial community assembly patterns in vanishing glacier-fed streams.
Glacier-fed streams (GFSs) support downstream ecosystems with life-sustaining glacial meltwater, and are dominated by highly-specialized and biogeochemically active prokaryotes and micro-eukaryotes. Because of the simplified trophic structure and well-defined sources of water, nutrients, and organic matter, GFSs are ideal model systems for studying microbial community assembly in streams. However, alpine glaciers are rapidly retreating, and only a small proportion of the current volume is expected to persist through 2100.
As glaciers recede, meltwater and sediment fluxes will decrease, temperatures warm, and hydrographs stabilize. The reduction of light-attenuating particles in particular will favor photoautotrophs, ‘greening’ GFS communities, resulting in fundamental changes to ecosystem structure. Yet, at present, the identity of these photoautrophs remains little explored, and even less is known about how their communities are likely to change in the future.
Among GFS photosynthetic organisms, diatoms (siliceous unicellular eukaryotes) dominate diversity and often biomass. Their unique ornamented cell walls are taxon-specific, making morphological identification possible, and coupled with their propensity to reflect their chemical-physical habitat makes them useful bioindicators. Yet, their diversity, and controls on their communities in GFSs, is poorly understood despite their expected future proliferation.
In this 4-year project, our aims are to a) identify diatom taxa/clades specific to GFSs, b) quantify processes in structuring their communities, and c) use these results to project their status into the future. To address these aims, we will concentrate our efforts in our own backyard of the European Alps, which are rapidly changing in response to a changing climate. The results of this project will provide a step forward in understanding microbial community dynamics in running waters, and promote a better understanding of the microbial life we will lose following the eventual disappearance of GFSs.
Principal investigator: Tyler J. Kohler
Grantor: Charles University Primus Research Programme
Duration: 07-2022 to 06-2025
Grant number: PRIMUS/22/SCI/001
The past is the key to the future: Ecology and Holocene evolution of freshwater diatom communities in the northern Antarctic Peninsula region.
Climatic changes in the Maritime Antarctic Region have had a rapid and substantial influence on the composition and functioning of polar lake ecosystems. The Antarctic Peninsula, including the James Ross Island archipelago, represent some of the largest deglaciated parts of Antarctica, and provide excellent research localities to study lacustrine communities and the history of recent environmental changes through their sediments. In this project, we used detailed multi-proxy analyses, including freshwater diatoms, to study sediment cores from different Antarctic Peninsula lakes to reconstruct past changes of lake ecosystems, and to compare the impact of present warming to former Holocene environmental changes.
Principal investigator: Kateřina Kopalová
Grantor: Czech Science Foundation Junior GAČR
Duration: 01-2016 to 12-2018
Grant number: 16-17346Y