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Abstract Long‐term ecological research can resolve effects of disturbance on ecosystem dynamics by capturing the scale of disturbance and interactions with environmental changes. To quantify how disturbances interact with long‐term directional changes (sea‐level rise, freshwater restoration), we studied 17 yr of monthly dissolved organic carbon (DOC), total nitrogen (TN), and phosphorus (TP) concentrations and bacterioplankton productivity across freshwater‐to‐marine estuary gradients exposed to multiple disturbance events (e.g., droughts, fire, hurricanes, and low‐temperature anomalies) and long‐term increases in water levels. By studying two neighboring drainages that differ in hydrologic connectivity, we additionally tested how disturbance legacies are shaped by hydrologic connectivity. We predicted that disturbance events would interact with long‐term increases in water levels in freshwater and marine ecosystems to increase spatiotemporal similarity (i.e., synchrony) of organic matter, nutrients, and microbial activities. Wetlands along the larger, deeper, and tidally influenced Shark River Slough (SRS) drainage had higher and more variable DOC, TN, and TP concentrations than wetlands along the smaller, shallower, tidally restricted Taylor River Slough/Panhandle (TS/Ph) drainage. Along SRS, DOC concentrations declined with proximity to coast, and increased in magnitude and variability following drought and flooding in 2015 and a hurricane in 2017. Along TS/Ph, DOC concentrations varied by site (higher in marine than freshwater wetlands) but not year. In both drainages, increases in TN from upstream freshwater marshes occurred following fire in 2008 and droughts in 2010 and 2015, whereas downstream increases in TP occurred with coastal storm surge from hurricanes in 2005 and 2017. Decreases in DOC:TN and DOC:TP were explained by increased TN and TP. Increases in bacterioplankton productivity occurred throughout both drainages following low‐temperature events (2010 and 2011) and a hurricane (2017). Long‐term TN and TP concentrations and bacterioplankton productivity were correlated (r > 0.5) across a range of sampling distances (1–50 km), indicating spatiotemporal synchrony. DOC concentrations were not synchronized across space or time. Our study advances disturbance ecology theory by illustrating how disturbance events interact with long‐term environmental changes and hydrologic connectivity to determine the magnitude and extent of disturbance legacies. Understanding disturbance legacies will enhance prediction and enable more effective management of rapidly changing ecosystems.
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This content will become publicly available on May 1, 2026
Increasing water depths increases nutrients and organic matter respiration in Everglades marl marshes
Climate and human modifications, including restoration, are changing freshwater availability in wetland ecosystems. Changes in spatiotemporal variability in water depth can influence biogeochemistry and aquatic metabolism (net ecosystem productivity, gross primary productivity [GPP], and ecosystem respiration [ER]). In subtropical wetlands, flocculent organic matter (floc) is a dominant form of organic matter made up of periphyton, macrophytes, and microbes. How changes in water depth with climate and human modifications of subtropical wetlands influence biogeochemistry and the metabolism of floc is uncertain and necessary to understand the consequences for carbon (C) cycling. We collected seasonal floc samples from shorter‐hydroperiod marshes (Taylor Slough Panhandle [TS/Ph]) and longer‐hydroperiod marshes (Shark River Slough [SRS]) in Everglades National Park (Florida, U.S.A.). We measured floc‐specific metabolism and biogeochemistry during the wet (May–November) and dry seasons (December–April) when marsh conditions differed in water depth, photosynthetically active radiation (PAR), floc chlorophylla, bulk density, and C and nutrients. Floc biogeochemistry was driven by hydrologic changes in water depth, while floc metabolism was influenced by floc biogeochemistry and PAR in both marshes. Floc‐specific metabolism was more net heterotrophic (GPP < ER) in TS/Ph than in SRS, driven by floc bulk density, total nitrogen, total C, total phosphorus, and total inorganic C. Increasing water depths with freshwater restoration may drive higher rates of C loss in shallower compared to deeper marshes. Understanding how hydrologic changes affect organic matter lability and respiration is important in managing C storage in ecosystems.
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- PAR ID:
- 10643701
- Publisher / Repository:
- John Wiley & Sons, Inc
- Date Published:
- Journal Name:
- Restoration Ecology
- Volume:
- 33
- Issue:
- 4
- ISSN:
- 1061-2971
- Subject(s) / Keyword(s):
- biogeochemistry carbon floc metabolism respiration wetland
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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