Environmental Controls on the Temporal Evolution of Energy and CO2 Fluxes on an Arid Mangrove of Northwestern Mexico

This work explored the environmental factors that control the temporal dynamics of vertical energy and carbon fluxes between the atmosphere and arid mangroves located on the coastline of the Gulf of California, Mexico. Net ecosystem exchange (NEE), latent (lambda E) and sensible heat (H) exchange fluxes were estimated in situ using the eddy covariance technique along with meteorological and hydrological observations during the period November 2017 through November 2019. Moreover, multiyear mangrove phenology at footprint-scale was tracked using remotely sensed vegetation greenness data from Sentinel-2. Our results suggest that the seasonal energy partition and the magnitude of NEE is highly coupled with seasonal changes in the level of tidal flooding, vapor pressure deficit (VPD) and temperature. Low tidal levels facilitate heat transmission to the atmosphere leading the energy partition to H, while the increase in flooding and VPD facilitates the transmission of water vapor resulting in lambda E dominance. The lowest rate of NEE was observed during the months of highest tidal flooding (June-August) while the highest seasonal rate of NEE matched with the lowest mean flood levels (March-May). Estimated annual NEE for 2018 was -745.3 gC m(-2) y(-1) while for 2019 was -307.4 gC m(-2) y(-1). Our findings suggest a possible trend of decrease in the capacity of carbon sequestration of arid mangroves with rising sea levels and air temperature as a result of global warming.

Automated summary

The research explored the environmental factors affecting the vertical energy and carbon fluxes between arid mangroves and the atmosphere in the Gulf of California, Mexico. Results indicate that seasonal changes in tidal levels, vapor pressure deficit, and temperature are closely related to the energy partition and magnitude of NEE. The study suggests a possible trend of decreased carbon sequestration capacity of arid mangroves with rising sea levels and air temperature due to global warming.