The benthic system of the Golfo San Jorge was characterized from physico-chemical parameters based on samplings obtained during seasonal research cruises carried out on board the INIDEP vessels from springtime 1999 through wintertime 2000. Spatial and seasonal variations of temperature, salinity, density, oxygen content and chlorophyll-a in bottom water and concentration of total organic matter, total organic carbon, total nitrogen, chlorophyll-a and phaeopigments in sediments were analysed. The origin and nutritional value of the deposited organic matter were also assessed. The behaviour of the physico-chemical characteristics of the benthic habitat, studied applying statistical techniques, defined three sectors with particular characteristics and minimum seasonal variations: sector 1, the largest and deepest one, comprises the central area of the gulf and corresponds to a depositional environment; sector 2 comprises the areas next to the extremes of the gulf and corresponds to a flow or erosive environment; sector 3 includes the coastal area and south-east part of the gulf and belongs to a transitional environment.
