Food Web

Aquatic food webs are typically longer than terrestrial webs — the energy transfer from phytoplankton to tuna spans 4–5 trophic steps — and each step loses roughly 90% of energy as metabolic heat. Forage fish (anchovies, herrings, sand eels) are critical intermediate links, converting zooplankton into a form accessible to top predators. Trophic cascades demonstrate the web's interdependence: the removal of sharks from Caribbean reefs triggered population explosions of rays, which decimated scallop populations through overgrazing. Stable isotope analysis (δ¹³C, δ¹⁵N) allows reconstruction of food web structure without direct observation of feeding events.