Algunos aspectos limnológicos de la laguna Herradura (Formosa, Argentina)

Resumen

The main limnological features of a shallow lenitic waterbody (Laguna Herradura) in permanent contact with the Paraguay River have been studied. Water turbidity, conductivity and Chemical oxigen demand changed in response to the hidrometric level fluetuations of the river. The higher valúes were attained during the low water period and the lower ones during the flood period.
In summer, a strong temperature gradient was developed, resulting in a clinograde trend in the oxigen, carbón dioxide and pH profiles. The rest of the year no vertical differences were found. Phytoplankton density and primaiy production followed a similar pattem. The higher valúes of 1500 ind/ml and 450 mg C/m^d were observed in November 1978 during the low water period, before the stratification. The lower valúes of 160 ind/ml and 14 mg C/m^ were registered in June-July 1979, during the flood period.