🕸️ Food Web: Trophic Cascades
Ecosystems are intricate living networks. What happens when a keystone predator disappears or an energy tier collapses?
How to play
- Journey across 8 real-world biomes, from Pacific kelp forests and Yellowstone to coral reefs and the deep Southern Ocean.
- Predict trophic cascades triggered by the removal or recovery of keystone species and ecosystem engineers.
- Apply Lindeman's 10% ecological energy rule to calculate how much biomass reaches apex predators.
- Trace persistent biomagnification of lipophilic toxins across ascending food tiers.
- Tap your answer or press 1–4. Right answers build a 🔥 streak bonus!
Pacific Kelp Forest
Northeast Pacific Coast
Interactive Trophic Energy & Cascade Network (Tap any tier or adjust simulator)
About Food Webs, Trophic Cascades & Energy Dynamics
In 1966, ecologist Robert T. Paine published a foundational study removing the predatory ochre sea star (Pisaster ochraceus) from rocky tidal pools in Washington state. Without the sea star, the California mussel multiplied unchecked and crowded out algae, limpets, and barnacles, slashing species diversity from 15 to 1. Paine coined the term keystone species to describe organisms whose ecological impact is disproportionately large relative to their abundance.
A trophic cascade occurs when changes at the top of a food chain propagate downward through multiple trophic levels. Famous examples include the 1995 gray wolf reintroduction to Yellowstone National Park (which changed elk browsing behavior and allowed willows and beavers to flourish, documented by Ripple & Beschta) and the classic kelp-otter-urchin dynamic documented by James Estes.
Lindeman's 10% Law (1942) calculates the thermodynamic reality of ecosystems: only about 10% of the chemical energy captured at one trophic level is converted into new biomass at the next level; the remaining 90% is dissipated as metabolic heat and waste through cellular respiration. This explains why food chains rarely exceed four or five trophic levels and why giant baleen whales feed directly on Level 2/3 krill to sustain their massive bodies.
Conversely, persistent, non-biodegradable, fat-soluble compounds (such as methylmercury, PCBs, and ciguatoxins) cannot be metabolized or excreted efficiently. In a process known as biomagnification, their concentration multiplies at each trophic tier, reaching hazardous levels in top predators such as raptors, sharks, and humans.