Abstract:
Low tide rain drops directly suspend surfacial particulates of intertidal environment, and the following runoff facilitate the mobilization of substantially amounts of particles to the water column. These processes have been proposed as "hot moments". In order to demonstrate the influences of rainfall-runoff on the particle cycling and its ecological effects, rainfall related research papers between 1978 and 2018 were reviewed in this paper. These studies suggest that raindrops at low-tide destroy and discharge viscous surface sediments, and then the subsequent runoff transfers the resuspended sediments downhill. These processes lead to 2-100 times increase in suspended sediment concentrations of tidal creek water column, which is substantially higher than that of shallow water waves and tidal currents. Meanwhile, concentrations of organic matter and heavy metals correspond to the temporal dynamic of the suspended particulate matter. Finally, suspended particles driven by rainfall-runoff have great chances to export to the coastal ocean by tidal current and hereby contribute to the "Outwelling" processes. This issue is particularly relevant because global climate models highlight an intensification of the hydrologic cycle in many coastal areas. Therefore, the potential for low-tide rainfall to influence intertidal zone biogeochemical processes can be expected to increase, and therefore, a more comprehensive understanding of rainfall-runoff effects on intertidal landscape material cycling is needed.