Tides Effects on Short-Time Freshwater Habitat Modifications of Lower Mekong River Delta (SE Vietnam)

Evaluation of short-time freshwater habitat fluctuations was provided in the period October 2019 - February 2020 in the Mekong River delta in Vietnam. Three phases of water flow direction were documented in the diurnal tide cycle. In the middle - “stagnation” state, a daily maximal oxygen concentration in the river occurs, regardless of the sun’s position above the horizon. Each tide cycle also creates a periodic water mass friction zone in the nearshore part of the riverbed and increases the sedimentation rate within the opposite direction of water mass flow. The biotic effects of freshwater habitat modification in the river branches are discussed.