Mass balance implies Holocene development of a low-relief karst patterned landscape
- Duke Univ., Durham, NC (United States). Nicholas School of the Environment
- Univ. of Florida, Gainesville, FL (United States). Dept. of Geological Sciences
- Univ. of Florida, Gainesville, FL (United States). School of Forest Resources and Conservation
- Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Forest Resources and Environmental Conservation
- Univ. of Florida, Gainesville, FL (United States). Dept. of Soil and Water Sciences
- Univ. of Florida, Gainesville, FL (United States). Dept. of Geological Sciences; Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.
We constructed mass balances of both calcium and phosphorus for two watersheds in Big Cypress National Preserve in southwest Florida (USA) to evaluate the time scales over which its striking landscape pattern developed. This low-relief carbonate landscape is dotted with evenly spaced, evenly sized, shallow surface depressions that annually fill with surface water and thus support wetland ecosystems (e.g. cypress domes) embedded in a pine-dominated upland matrix with exposed bedrock. Local and landscape scale feedbacks between hydrology, ecological dynamics and limestone dissolution are hypothesized to explain this karst dissolution patterning. This hypothesis requires the region to be wet enough to initiate surface water storage, which constrains landscape formation to interglacial periods. The time scale therefore would be relatively recent if creation of the observed pattern occurred in the current interglacial period (i.e. Holocene), and older time scales could reflect inherited patterns from previous inter-glacial periods, or from other processes of abiotic karstification. We then determined phosphorus stocks across four landscape compartments and estimated the limestone void space (i.e., wetland depression volume) across the landscape to represent cumulative calcium export. We calculated fluxes in (e.g., atmospheric deposition) and out (i.e., solute export) of the landscape to determine landscape denudation rates through mass balance. Comparing stocks and annual fluxes yielded independent estimates of landscape age from the calcium and phosphorus budgets. Our mass balance results indicate that the landscape began to develop in the early-mid Holocene (12,000–5000 ybp). Radiocarbon dating estimates implied similar rates of dissolution (~1 m per 3000–3500 years), and were in agreement with Holocene origin. This supports the hypothesis that ecohydrologic feedbacks between hydrology and vegetation occurring during the present interglacial period are sufficient to shape this landscape into the patterns we see today, and more broadly suggests the potential importance of biota in the development of macro-scale karst features.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1457744
- Report Number(s):
- PNNL-SA-128697; PII: S0009254118302729
- Journal Information:
- Chemical Geology, Journal Name: Chemical Geology Journal Issue: C Vol. 527; ISSN 0009-2541
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Ecohydrologic feedbacks controlling sizes of cypress wetlands in a patterned karst landscape
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journal | December 2018 |
Initiation and Development of Wetlands in Southern Florida Karst Landscape Associated With Accumulation of Organic Matter and Vegetation Evolution
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journal | June 2019 |
Wetland Connectivity Thresholds and Flow Dynamics From Stage Measurements
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journal | July 2019 |
Scale‐Dependent Patterning of Wetland Depressions in a Low‐Relief Karst Landscape
|
journal | August 2019 |
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Related Subjects
58 GEOSCIENCES
Biokarst
Calcium
Chemical denudation
Mass balance
Phosphorus
Self-organization
Weathering
aquatic
biogeochemistry
calcium
carbon
carbon cycling
ecosystem
erosion
export
geology
global change
holocene
hydrogeology
hydrogeomorphic
inorganic
interface
karst
marsh
pattern
patterned landscape
potassium
radiocarbon
terrestial aquatic interface
terrestrial
wetland
wetland inundation
wetland model
wetland soils