An Ecological Drill: Biogeomorphic Pattern Evolution in a Low-Relief Carbonate Landscape

Abstract:

Feedbacks between hydrology, ecosystem metabolism, and mineral weathering are proposed to explain the striking geometric patterning of wetland basins in the low-relief carbonate landscape of Big Cypress (BICY) National Preserve in southwest Florida. In contrast to critical zone evolution in systems dominated by siliciclastic rocks, our conceptual model for this and other carbonate landscapes highlights the importance of congruent mineral weathering, which alters both the depth and geometry of the critical zone, and invokes metabolism as a core control on landscape morphology via impacts to CO₂ acidity. In the case of BICY, our motivation is to understand the origins of visually compelling, and geostatistically regular, landscape patterning. Using preliminary evidence from archival data synthesis, lidar-derived elevations, field surveys of sediment thickness and vegetation biomass, characterization of deep sediment cores, and high temporal resolution measurements of water levels, solute concentrations, and gas fluxes we offer support for a conceptual model that invokes critical zone processes as the basis for Holocene pattern emergence. Of particular interest is our invocation of episodic landscape hydrologic connectivity as integral to pattern emergence. While our findings are specific to the unique features of this extremely flat eogenetic karst landscape where a clay confining unit precludes deep drainage feature evolution, we posit that the feedbacks between hydrology, ecosystem metabolism and carbonate weathering are general to critical zone processes in karst areas globally.