In an ecosystem, the strongest links between species are often dietary. A food chain is a sequence of living beings in which each individual consumes its predecessor.(48 kb)
The first link in the chain is usually a chlorphyllous (photosynthesizing) plant. In seas and oceans, phytoplankton plays this role.
Many clues allow paleontologists to reconstruct the links in the Miguasha estuary food chain, all the way from plant material and aquatic microorganisms to large predators.
Animal types, fish anatomy, stomach contents and fossilized excrement all provide insight into predators and their prey, and the mode of life for each of these species.
At the top of the food chain are bacteria that decompose organisms after they die. Numerous concretions in the Escuminac Formation contain organic remains, sometimes whole fish, and are thought to have formed as the result of bacterial metabolism.