Puerto Cuatreros Bahia Blanca Estuary Latitude:   -38.8333     Longitude:   -62.3333 Associated Investigators: Jorge Marcovecchio , Valeria Guinder (phytoplankton) ,   Carla Spetter (nutrients and hydrography)   The Bahia Blanca Estuary located in the SW area of the Buenos Aires Province, Argentina is a mesotidal estuary (Perillo et al., 2001). The mean tidal amplitude ranges from 2.2 to 3.5 m, the spring tidal amplitude ranges from 3 to 4 m, and the highest tidal amplitudes occur near the head of the estuary (Perillo et al., 2001). The estuary is formed by a series of NW- to SE oriented tidal channels separated by extensive tidal flats, salt marsh patches, and islands (Perillo, 1995). The sampling site is located at the inner zone of this estuary, in Cuatreros Port, which is considered a chemically representative site of this zone (Freije and Marcovecchio, 2004).