Tidal influence on heat exchange and temperature dynamics in salt marshes

Soil temperature has a marked effect on ecological processes in salt marshes and is significantly affected by tidal fluctuations. Periodic tidal inundation modifies the heat exchange between marsh sediments and the atmosphere, and also induces additional heat exchange between the sediments and tidal water. Tide-driven porewater flow further modulates heat transfer within the sediment, a process complicated by seasonal variations in atmospheric and tidal temperatures. In addition, macropores such as crab burrows are common in salt marsh sediments, and they are expected to regulate heat exchange and temperature distribution within the salt marshes by altering water movements. This study aims to explore how spring-neap tides and atmospheric conditions collectively influence heat exchange and temperature dynamics in salt marshes. We developed a marsh-creek model incorporating sediment-atmosphere/water heat exchange and validated it against laboratory experiments. Extending the model to the field scale, we analyzed temperature dynamics across the marsh and heat fluxes at the sediment-atmosphere/water interfaces over an annual cycle. We also compared simulation outcomes of water and heat dynamics in scenarios with and without macropores. Finally, we discussed the implications of our findings for accurately assessing tidal and atmospheric heat exchange and the associated temperature variations.