Between estuaries and the sea

Dissolved and particulate materials and living organisms are exchanged between estuaries and the sea. Net material fluxes, import or export, appear to depend on physical and biological processes within both estuarine and coastal ecosystems. In temperate zone lagoonal systems, the marsh-estuarine continuum hypothesis can provide a reasonable synthetic explanation of transport based on the level of ecosystem maturity within the system. The relative importance of riverine and lagoonal material exchanges with the coastal ocean are at present entirely speculative and make the estimation of the regional influences of material transports between estuaries and the coastal ocean uncertain. Organismic exchanges depend on both passive and active behavior mechanisms and are species specific. Few quantitative estimates of organismic fluxes exist and the role of non-commercial invertebrates and fish in these fluxes are unknown.