Tidal freshwater wetlands, the fresh dimension of the estuary

Abstract

Upstream in the estuary, where the river ends, the tidal energy is still present but the constant input from the river creates permanent fresh water conditions. The physical, chemical and biological conditions differ from the brackish part of the tidal area, but by processes from the tidal wave also from the river ecosystem. Just like in the brackish estuary, the variation runs from tidal flats till higher elevated forests. Chemical processes and accretion are prominent, creating wetlands with high turnover. Fertility of the soil and presence of many cities resulted that many tidal freshwater wetlands have been reclaimed. Many characteristic flora and fauna species are represented; biomass is mostly very high. Because this system is at the interface of salt – fresh conditions, it can be disturbed soon by sea level rise or global warming.