Seine River Food Web: From Phytoplankton to Osprey

The Seine's food web reflects a temperate European river heavily influenced by Parisian urbanization yet retaining remarkable ecological structure.

Primary Producers

• Phytoplankton — diatoms, green algae (base of pelagic web).
• Periphyton / biofilms — on substrates (base of benthic web).
• Macrophytes — submerged/emergent plants (habitat + food).

Primary Consumers

• Zooplankton — rotifers, cladocerans, copepods.
• Benthic invertebrates — chironomids, oligochaetes, mollusks (Dreissena, Corbicula).
• Herbivorous fish — roach, rudd, bleak.
• Grazers — snails, caddisfly larvae, mayfly nymphs.

Secondary Consumers

• Insectivorous fish — perch, chub, dace.
• Benthivorous fish — gudgeon, barbel.
• Birds — kingfisher, dipper, grey wagtail, mallard.

Tertiary Consumers

• Piscivorous fish — pike, zander, catfish (wels), asp.
• Birds — grey heron, great cormorant, goosander.
• Mammals — otter (recovering), mink (invasive).

Apex Predators

• Birds of prey — osprey (recolonizing), white-tailed eagle (rare).
• Human anglers — top consumptive predator.

Decomposers

Bacteria, fungi, detritivores recycle nutrients—closing the loop.

Water quality improvements since the 1990s (oxygenation, fish passes) have restored migratory pathways (salmon, shad, lamprey), rewilding the Seine's trophic architecture.