The Mallorquin Swamp is a shallow coastal lagoon, which depends on the permanent water intake from the
Magdalena River, the Caribbean Sea and the stream runoff from the León creak. The meeting of these waters promotes the
variability in the physical, chemical and biological factors of the environment. Thus, the dynamics of nutrients, chlorophyll
a and their relationship with the physical and chemical variables of the water were analyzed during March to June 2008. The
salinity of the swamp is influenced by different water inputs, mainly by sea water, freshwater and evaporation processes.
Dissolved oxygen showed a deficit during the sampled months, with values <3,5 mgl-1 in the first three months and in the
whole area of the swamp. An allochthonous origin of nutrients, NO3-, PO4-3, NH4+ is suggested, being the highest recorded
values: NO3-> 5 mgl-1, PO4-3 > 2 mgl-1 and NH4 + 0,008 mgl-1. The values of NO3-and PO4- are correlated because both
are derived from the decomposition of organic matter. Chlorophyll a, concentration showed an average of 5,04 mg/m3, which
indicates a high primary productivity in the zone.