Fish extinctions alter critical nutrients in water, study shows

When fish become extinct, the cycling of critical nutrients in ecosystems changes, Cornell study finds

By Krishna Ramanujan

Ecosystems are such intricate webs of connections that few studies have been able to explore exactly what happens when a species dies out.

Now, a Cornell study using computer simulations has teased out how the disappearance of a freshwater fish can affect the availability of certain nutrients that other species rely on.

Algae, at the base of the food chain, for example, rely on fish to cycle back into the water such nutrients as nitrogen and phosphorus, which are otherwise locked up in animal or plant cells. Fish excrete dissolved nutrients back into the water, making them available to algae, which need them to grow.