Rio de la Plata Estuary Food Web
Freshwater
South America — Argentina and Uruguay border
Description
The Rio de la Plata is the widest river estuary in the world, where the Parana and Uruguay rivers discharge into the South Atlantic. This turbid estuary supports the Franciscana dolphin, the smallest and most endangered river dolphin. Salinity gradients create distinct zooplankton and fish communities from freshwater to marine zones.
Trophic Pyramid
Level 5
Decomposers
Estuarine bacteria
Polychaete worms
Detritivorous crabs
3 species
Level 4
Tertiary Consumers
Franciscana dolphin
South American sea lion
Hammerhead shark
3 species
Level 3
Secondary Consumers
Whitemouth croaker
Striped weakfish
Black skimmer
3 species
Level 2
Primary Consumers
Silversides
Estuarine copepods
Freshwater shrimp
3 species
Level 1
Producers
Estuarine phytoplankton
Spartina marsh
Diatoms
3 species
Apex Predators
Tertiary Consumers
Secondary Consumers
Primary Consumers
Producers
Key Interactions
- Franciscana dolphins use echolocation to hunt croaker and silversides in turbid water
- Freshwater discharge creates a salinity front that concentrates fish and plankton
- South American sea lions haul out on rocky shores and forage in the estuary
- Agricultural nutrient loading from the Parana watershed drives eutrophication