Drivers of CO2 Fluxes in the Aquatic and Dry Phases of Patagonian Temporary Wetlands

Abstract

We aimed to evaluate how hydrological condition in temporary wetlands influence CO2 fluxes and to assess the effect of landscape on the environmental drivers controlling these fluxes. We investigated CO2 fluxes in Patagonian temporary wetlands during two hydrological phases (dry and aquatic) and three contrasting landscapes (forest, suburban, steppe) to identify the key drivers influencing respiration and gross primary production. We hypothesized that the CO2 fluxes from wetlands and their drivers are influenced by the hydrological phases and the surrounding landscape. We found that wetlands are net CO2 sinks during the dry phase (Net Ecosystem Exchange − NEEdry: -84±16 mmol CO2 m−2 d−1 ) and net sources during the aquatic phase (NEEaquatic: 68±6 mmol CO2 m−2 d−1 ). The highest CO2 emissions originated from bare soil. The wetland landscape did not influence NEE, but respiration and gross primary productivity fluxes were higher in the suburban landscape. The main drivers of NEE were soil temperature, moisture, organic matter content, and vegetation biomass during the dry phase, and dissolved organic carbon and nitrogen concentration during the aquatic phase. Our results show that global change threats in Patagonia, which include warmer and drier climate, increasing livestock pressure, and localized urbanization, will increase CO2 emissions. Our findings provide insights into CO2 fluxes from low-disturbance wetlands and can help predict the impacts of global change on CO2 emissions across this ecologically and economically vital ecosystems.