Moss-cyanobacteria associations as a novel source of biological N2-fixation in temperate grasslands
| Autor: | Sarah T. Hamman, Amanda Bidwell, Lalita M. Calabria, Kate Petersen |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Plant and Soil. 456:307-321 |
| ISSN: | 1573-5036 0032-079X |
| DOI: | 10.1007/s11104-020-04695-x |
| Popis: | We investigated N2-fixation by moss-cyanobacterial associations in a North American prairie ecosystem, identifying cyanobacteria associated with moss species, and evaluating spatio-temporal dynamics in N2-fixation rates. We confirmed the presence and abundance of N2-fixing cyanobacteria on three moss species (Pleurozium schreberi (Brid.) Mitt., Racomitrium elongatum Frisvoll, Rhytidiadelphus triquetrus (Hedw) Warnst.) using epi-fluorescence light microscopy. To estimate monthly N2-fixation rates on mosses from three sites, we conducted laboratory-based acetylene reduction assays with constant incubation temperatures and natural daylight. We evaluated the relationship between daylength and N2-fixation, and daylength and weather variables. N2-fixation rates varied by species, site, and month. R. elongatum exhibited the highest rates and P. schreberi had the lowest. Rates for R. elongatum and R. triquetrus were positively correlated with daylength, with peaks occurring at 13–14 h daylight, suggesting spring and fall conditions support N2-fixation in this system. Annual median N2-fixation for R. elongatum and R. triquetrus ranged from 0.008–0.124 kg N ha−1 yr−1 based on cover of 11–100%. Our results highlight a previously undescribed source of biological N2-fixation in temperate grasslands. Changes in the distribution or activity of N2-fixing moss-cyanobacterial associations due to management practices and climate change could impact future stand-level nitrogen dynamics. |
| Databáze: | OpenAIRE |
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