Initiation and Development of Wetlands in Southern Florida Karst Landscape Associated With Accumulation of Organic Matter and Vegetation Evolution
- Univ. of Florida, Gainesville, FL (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Univ. of Florida, Gainesville, FL (United States)
- Univ. of Florida, Gainesville, FL (United States); Suwannee River Water Management District, Live Oak, FL (United States)
- Duke Univ., Durham, NC (United States)
- Univ. of Florida, Gainesville, FL (United States); Pacific Northwest National Lab. (PNNL), Sequim, WA (United States)
- Univ. of Florida, Gainesville, FL (United States); Univ. of Florida, St. Augustine, FL (United States)
Biological processes can exert important controls on geomorphic evolution in karst landscapes, because carbonate mineral dissolution is augmented and spatially focused by the production of CO2 and biogenic acids from organic matter (OM) decomposition. In Big Cypress National Preserve (BICY) in southwest Florida (USA), depressional wetlands embedded in a mosaic of pine uplands exhibit regular patterning. To understand the impact of OM decomposition as well as different OM sources on carbonate dissolution and landscape patterning, we measured bulk OM property and biomarker proxies (fatty acids and lignin phenols) in different zones (center vs. edge) of the depressional wetlands. We also constructed age profiles of sediment accretion and pattern genesis using 210Pb activities and compound- specific radiocarbon analysis (CSRA) of long-chain fatty acids. Bulk OM and biomarker data indicate rapid OM accumulation in wetland centers resulting from high primary production and near permanent inundation, in contrast to negligible OM accumulation at wetland edges. Age discontinuities suggest episodic periods of near complete OM loss due to decomposition and/or fire. Based on CSRA, landscape patterning likely initiated in the mid-to-late Holocene, with wetlands at slight higher elevation initiated earlier than wetlands at lower elevation. Bulk stable isotope and lignin phenol biomarkers indicate wetland vegetation was initially dominated by herbaceous species and shifted to woody dominated vegetation as landscape hydrology adjusted to changing precipitation. The rate of weathering is likely impacted by hydrological conditions, vegetation dynamics and environmental perturbations like precipitation and fires, suggesting that this karst landscape is a manifestation of complex ecosystem feedbacks.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1560137
- Report Number(s):
- PNNL-SA-136524
- Journal Information:
- Journal of Geophysical Research. Biogeosciences, Vol. 124, Issue 6; ISSN 2169-8953
- Publisher:
- American Geophysical UnionCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Scale‐Dependent Patterning of Wetland Depressions in a Low‐Relief Karst Landscape
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journal | August 2019 |
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Related Subjects
aquatic
biogeochemistry
biomarker
carbon
carbon cycling
carbon dioxide
climate change
decomposition
dissolved organic carbon
ecosystem
erosion
export
flood
global change
gradients
hydrogeology
hydrogeomorphic
karst
microbes
organic matter
patterned landscape
terrestial aquatic interface
wetland
wetland inundation
wetland soils
Big Cypress National Preserve
radiocarbon
fatty acid
lignin