Marine transgression significantly reshapes coastal landscapes by submerging land, altering ecosystems, and depositing new layers of sediment.

Marine transgression is a geological phenomenon characterized by the rise of sea levels relative to the land, causing the sea to encroach upon coastal areas. This process can dramatically transform coastal landscapes. One of the most evident impacts is the submergence of land. As sea levels rise, low-lying coastal regions may become inundated, converting previously terrestrial environments into marine ecosystems. This transformation can lead to the formation of new coastal features such as lagoons, estuaries, and bays.

Another major consequence of marine transgression is the alteration of local ecosystems. As the sea advances inland, it introduces marine species and habitats, resulting in shifts in local biodiversity. In this process, marine organisms may replace terrestrial species, potentially leading to the extinction of local species that cannot adapt to the new marine conditions. Conversely, this transition can also foster the emergence of new species as organisms adapt to their evolving environment.

Additionally, marine transgression results in the deposition of new sediment layers. As the sea moves inland, it transports sediment from the ocean floor, which is then deposited on the land. These sediment layers can reach thicknesses of several metres and offer valuable insights into historical sea levels and the types of organisms that inhabited the area during the transgression.

Moreover, marine transgression can have profound effects on human activities. Coastal communities may be compelled to relocate as their homes become submerged, and infrastructure such as roads and buildings may suffer damage or destruction. The changes in ecosystems can also impact local industries, including fishing and tourism. Thus, understanding and predicting marine transgressions is essential for effective coastal management and planning.