The rising water temperature around the British Isles over the last forty years has caused species of zoo-plankton to march poleward by around ten degrees in latitude, the equivalent of twenty-five kilometers a year. This fundamental shift near the base of the oceanic food chain – since the majority of sea creatures eat either zooplankton or the predators of zooplankton – has sent ripples of change through the rest of the ecosystem. Sand eel populations have crashed, unable to follow their preferred zooplankton food as it moved north; consequently seabird populations, including puffins and guillemots, have collapsed because, without sand eels, they too are starving.