The oceanographic cruises were carried out in the Patos Lagoon estuarine area by the 'Laboratório de Hidroquímica', at FURG. This dataset is composed of groups of data made available by Niencheski and Windom (1994; doi:10.1016/0048-9697(94)90004-3) and Baumgarten et al. (2001). The first group of data were obtained in cruises carried out from 1989 to 1991. Water samples were collected at 20 fixed stations along the estuary and at 1 fixed station in São Gonçalo Channel. At each station, both surface and bottom water samples were collected using Van Dorn bottles, and placed into clean plastic bottles. Analysis of SPM followed the procedures described in Aminot and Chaussepied (Aminot, A. and Chaussepied, M.: Manuel des Analyses Chimiques en milieu Matin, CNEXO, Bres, p. 396, 1983.). Nutrients, ammonia, nitrite, nitrate, phosphate and silicate were also sampled by the authors but data is not assessed here. Baumgarten et al. (2001) presented data collected in a shallow and small bay (Saco da Mangueira) located in Patos Lagoon estuary. In this area, 3 sites were sampled monthly for 15 months (April 1994 to September 1995). The sites location was distributed in areas receiving high loads of nutrients from different sources: INCA, Arroio Simão, and Fábrica de Fertilizantes. Water sampling on the surface and bottom was executed using a Van Dorn-type bottle and SPM concentrations were estimated according to the protocols latter published by Baumgarten et al. (Baumgarten, M., Rocha, J., and Niencheski, L.: Manual de Análises em Oceanografia Química, FURG, Rio Grande, Brazil, 1996)