Open AccessIntegrating Aquatic Metabolism and Net Ecosystem CO2 Balance in Short- and Long-Hydroperiod Subtropical Freshwater Wetlands
Author(s) -
Sparkle L. Malone,
Junbin Zhao,
John S. Kominoski,
Gregory Starr,
Christina L. Staudhammer,
Paulo C. Olivas,
Justin C. Cummings,
Steven F. Oberbauer
Publication year - 2021
Publication title -
ecosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.643
H-Index - 148
eISSN - 1435-0629
pISSN - 1432-9840
DOI - 10.1007/s10021-021-00672-2
Subject(s) - primary production , environmental science , wetland , aquatic ecosystem , ecosystem , ecosystem respiration , freshwater ecosystem , ecology , productivity , macrophyte , hydrology (agriculture) , biology , geotechnical engineering , engineering , economics , macroeconomics
How aquatic primary productivity influences the carbon (C) sequestering capacity of wetlands is uncertain. We evaluated the magnitude and variability in aquatic C dynamics and compared them to net ecosystem CO 2 exchange (NEE) and ecosystem respiration ( R eco ) rates within calcareous freshwater wetlands in Everglades National Park. We continuously recorded 30-min measurements of dissolved oxygen (DO), water level, water temperature ( T water ), and photosynthetically active radiation (PAR). These measurements were coupled with ecosystem CO 2 fluxes over 5 years (2012–2016) in a long-hydroperiod peat-rich, freshwater marsh and a short-hydroperiod, freshwater marl prairie. Daily net aquatic primary productivity (NAPP) rates indicated both wetlands were generally net heterotrophic. Gross aquatic primary productivity (GAPP) ranged from 0 to − 6.3 g C m −2 day −1 and aquatic respiration ( R Aq ) from 0 to 6.13 g C m −2 day −1 . Nonlinear interactions between water level, T water , and GAPP and R Aq resulted in high variability in NAPP that contributed to NEE. Net aquatic primary productivity accounted for 4–5% of the deviance explained in NEE rates. With respect to the flux magnitude, daily NAPP was a greater proportion of daily NEE at the long-hydroperiod site (mean = 95%) compared to the short-hydroperiod site (mean = 64%). Although we have confirmed the significant contribution of NAPP to NEE in both long- and short-hydroperiod freshwater wetlands, the decoupling of the aquatic and ecosystem fluxes could largely depend on emergent vegetation, the carbonate cycle, and the lateral C flux.