Publication loadedhomePage1/18fullscreenremove_circle_outlineadd_circle_outlinesearchgroup_addmore_horizget_appinfolistlinkDETAILSRELATIONSEcosphereVolume 13, Issue 10Oct 2022ARTICLEFire intensity and ecosystem oligotrophic status drive relative phosphorus release and retention in freshwater marshesView article pageAndrea Nocentini, John S. Kominoski, Joseph J. O'Brien, Jed Redwineformat_quoteCITE© 2022 The Authors. Ecosphere published by Wiley Periodicals LLC on behalf of The Ecological Society of America.https://doi.org/10.1002/ecs2.4263open_in_newISSN2150-8925eISSN2150-8925Online17 October 2022Accepted21 June 2022Revised4 June 2022Received10 January 2022Pagesn/a - n/aAbstractEcosystems have been shaped by fire for millions of years. Many oligotrophic ecosystems rely on fire for biogeochemical cycling and maintenance of key processes. However, it is uncertain how fire intensity interacts with nutrient limitation to drive differential responses in postfire biogeochemical cycling and ecosystem recovery. In this study, we compare pre- and postfire carbon and nutrient pools in two adjacent wetlands characterized by either lower or higher phosphorus (P) inputs and thus different levels of P limitation. Carbon (C), nitrogen (N), and P pools and litter and root decomposition rates were measured starting 1 year prefire until 1 year postfire in lower-P (LP) and higher-P (HP) freshwater marshes of the Florida Everglades. Dominant vegetation biomass and vegetation composition were monitored as well. Fire energy release was measured to link the causal mechanism, heat transfer, to nutrient fluxes. We observed temporary increases in surface water, periphyton, and leaf tissue P concentrations in both wetland types following fire. Soil P increased and soil C:P and N:P ratios decreased postfire in the LP wetland but did not change in the HP wetland. Prefire soil P was greater in the HP than the LP wetland, but did not differ 1 month or 1 year postfire. Vegetation structure and composition were marginally affected by fire. Fire intensity was highly variable within both wetlands. Increasing fire intensity correlated with increasing accumulation of soil organic matter in the LP wetland, and with increases in decomposition rates in both wetland types, between pre- and postfire. Litter and root decomposition rapidly increased with increasing fire intensity, but seemed to stabilize after a certain fire intensity threshold was reached. Our results indicate that fire can temporarily ease P limitation in oligotrophic wetlands, by affecting soil nutrient stoichiometry and organic matter processing, while maintaining vegetation community composition. Further, we identified fire dosing, expressed as the fire radiative energy release, to be an effective control of postfire biogeochemical cycling. Hence, nutrient management should be incorporated into burn prioritization tools and, when applying prescribed fires, natural resource managers should also consider how fire attributes, such as fire intensity, impact nutrient cycling and other soil processes.ARTICLEFreshwater EcologyFire intensity and ecosystem oligotrophic status driverelative phosphorus release and retention infreshwater marshesAndrea Nocentini1,2|  John S. Kominoski1|  Joseph J. O’Brien3|Jed Redwine21Institute of Environment andDepartment of Biological Sciences,Florida International University, Miami,Florida, USA2South Florida Natural Resources Center,Everglades National Park, Homestead,Florida, USA3U.S. Department of Agriculture, U.S.Forest Service, Athens, Georgia, USACorrespondenceAndrea NocentiniEmail:anocenti@fiu.eduFunding informationForest Service Southern Research Station;United States Department of Agriculture,Grant/Award Number: P18AC01041;Everglades National ParkHandling Editor:Natalie GriffithsAbstractEcosystems have been shaped by fire for millions of years. Many oligotrophicecosystems rely on fire for biogeochemical cycling and maintenance of keyprocesses. However, it is uncertain how fire intensity interacts with nutrientlimitation to drive differential responses in postfire biogeochemical cyclingand ecosystem recovery. In this study, we compare pre- and postfire carbonand nutrient pools in two adjacent wetlands characterized by either lower orhigher phosphorus (P) inputs and thus different levels of P limitation. Carbon(C), nitrogen (N), and P pools and litter and root decomposition rates weremeasured starting 1 year prefire until 1 year postfire in lower-P (LP) andhigher-P (HP) freshwater marshes of the Florida Everglades. Dominant vegeta-tion biomass and vegetation composition were monitored as well. Fire energyrelease was measured to link the causal mechanism, heat transfer, to nutrientfluxes. We observed temporary increases in surface water, periphyton, and leaftissue P concentrations in both wetland types following fire. Soil P increasedand soil C:P and N:P ratios decreased postfire in the LP wetland but did notchange in the HP wetland. Prefire soil P was greater in the HP than the LPwetland, but did not differ 1 month or 1 year postfire. Vegetation structureand composition were marginally affected by fire. Fire intensity was highlyvariable within both wetlands. Increasing fire intensity correlated withincreasing accumulation of soil organic matter in the LP wetland, and withincreases in decomposition rates in both wetland types, between pre- andpostfire. Litter and root decomposition rapidly increased with increasing fireintensity, but seemed to stabilize after a certain fire intensity threshold wasreached. Our results indicate that fire can temporarily ease P limitation in oli-gotrophic wetlands, by affecting soil nutrient stoichiometry and organic matterprocessing, while maintaining vegetation community composition. Further,we identified fire dosing, expressed as the fire radiative energy release, to bean effective control of postfire biogeochemical cycling. Hence, nutrientReceived: 10 January 2022Revised: 4 June 2022Accepted: 21 June 2022DOI: 10.1002/ecs2.4263This is an open access article under the terms of theCreative Commons AttributionLicense, which permits use, distribution and reproduction in any medium, providedthe original work is properly cited.© 2022 The Authors.Ecospherepublished by Wiley Periodicals LLC on behalf of The Ecological Society of America.Ecosphere.2022;13:e4263.https://onlinelibrary.wiley.com/r/ecs21of18https://doi.org/10.1002/ecs2.4263