Summertime influences of tidal energy advection on the surface energy balance in a mangrove forest

Abstract

Abstract. Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive 10-day study was conducted in a mangrove forest located along the Shark River in the Everglades National Park, FL, USA. Forest-atmosphere turbulent exchanges of energy were quantified with an eddy covariance system installed on a 30-m-tall flux tower. Energy transport associated with tidal activity was calculated based on a coupled mass and energy balance approach. The mass balance included tidal flows and accumulation of water on the forest floor. The energy balance included temporal changes in enthalpy, resulting from tidal flows and temperature changes in the water column. By serving as a net sink or a source of available energy, flood waters reduced the impact of high radiational loads on the mangrove forest. Also, the regression slope of available energy versus sink terms increased from 0.730 to 0.754 and from 0.798 to 0.857, including total enthalpy change in the water column in the surface energy balance for 30-min periods and daily daytime sums, respectively. Results indicated that tidal inundation provides an important mechanism for heat removal and that tidal exchange should be considered in surface energy budgets of coastal ecosystems. Results also demonstrated the importance of including tidal energy advection in mangrove biophysical models that are used for predicting ecosystem response to changing climate and regional freshwater management practices.

Dissolved carbon biogeochemistry and export in mangrove-dominated rivers of the Florida Everglades

“…For example, Bergamaschi et al (2011) found that DOC fluxes were 6 times higher during the wet season (September) than the dry season (April), whereas Cawley et al (2013) found that the DOC fluxes were 4 and 10 times higher during the wet vs. dry season (November vs. March) in the Shark and Harney rivers, respectively. Barr et al (2013) showed that forest respiration rates derived from NEE data are greater during the wet than dry seasons.…”

Climate Change Projected Effects on Coastal Foundation Communities of the Greater Everglades Using a 2060 Scenario: Need for a New Management Paradigm

“…The most relevant studies are those from eddy covariance towers measuring atmospheric parameters (e.g., temperature, wind) in and above the canopy simultaneously, along with determinants of forest productivity (CO 2 flux). Using towers in southwestern mangrove forests adjacent to Shark River, the highest productivity rates (shown as a more negative CO 2 flux) were found between 25 and 30°C and optimal photosynthetic rates declined at higher temperatures (Barr et al 2013). Also, the CO 2 Environmental Management uptake or productivity was positively affected by freshwater flows and constrained by salinity higher than 29 ppt (Barr et al 2013).…”

“…Using towers in southwestern mangrove forests adjacent to Shark River, the highest productivity rates (shown as a more negative CO 2 flux) were found between 25 and 30°C and optimal photosynthetic rates declined at higher temperatures (Barr et al 2013). Also, the CO 2 Environmental Management uptake or productivity was positively affected by freshwater flows and constrained by salinity higher than 29 ppt (Barr et al 2013). Elevated CO 2 could ameliorate high temperature and salinity stress in mangrove forests, as the availability of CO 2 for photosynthesis can counter negative temperature effects in terrestrial plants (Sage and Kubien 2007), but research on this potential resilience in mangroves is lacking.…”

Approximations of stand water use versus evapotranspiration from three mangrove forests in southwest Florida, USA

“…8); evaporation from the water surface is expected to represent more of the ET balance with net surface flooding. Tidal flooding affects storage and advection of energy in mangrove forests, providing a net sink for heat during high radiation loads (Barr et al, 2013a). In addition, canopy interception from Rookery Bay was estimated at 109 mm year −1 (Twilley and Chen, 1998), or about 10% of ET.…”