[Extract] The residence time is the characteristic time that a parcel of water will remain within a water body. The quantitative definition of "residence time" varies in the literature (Monsen et al., 2002). Generally, it is implied that a complete exchange of the water does not occur in this time. For this reason, the residence time is sometimes defined as the time for some fraction of the water to be exchanged. The residence time in a partially enclosed water body varies with oceanographic conditions, such as tides, waves and oceanic currents, and depends on the size of the water body and the degree of hydrodynamic connection with adjacent water bodies. Residence time is one of the key parameters controlling the fate of solutes in an enclosed water body such as a coral reef lagoon. A long residence time could, for example, allow accumulation of pollutants. Residence time can also be very important in the (passive) dispersal of larvae.