Ecological Responses of Intertidal Microalgal Communities to Repeated Freshwater Inundation

Intertidal ecosystems are characterized by frequent environmental changes caused by tidal dynamics, precipitation, river runoff, and coastal hydrology. Frequent inundations of fresh water constitute one of the environmental disturbances that change salinity, nutrient status, sediments, and physiological processes affecting the intertidal microalgae. Intertidal microalgal communities, especially benthic diatoms, play an important role in primary production, nutrient recycling, sediments stabilization, and energy flows in coastal ecosystems. The present conceptual study attempts to identify the possible ecological reactions of intertidal microalgal communities to repeated flooding by integrating hydrologic disturbance, physiological adaptation, community reorganization, and ecosystem function into one framework. Inundation frequency, duration, intensity, and recovery periods are recognized as main environmental factors affecting community reactions. Osmoregulation, salinity tolerance of individual taxa, community structure, functional diversity, photosynthesis, and microbiological interactions are all emphasized. The theoretical model suggests that the continuous flooding with freshwater may lead to various effects based on the level of disturbance frequency, salt content of the ecosystem, nature of sediments, availability of nutrients, and adaptation mechanisms in microalgae. In addition, the conceptual framework emphasizes the value of making a distinction between short-term physiological response and long-term community reorganization. The framework serves as a basis for future experimental work and the development of microalgal indicators for hydrological disturbances.