"Coral reefs and seashores largely look the way they do because large fish and urchins eat most of the seaweed that might otherwise cover them, but a major new study has found that the greatest impact of all comes from an unexpected quarter -- small marine snails.
The study published in the journal Ecology Letters is the largest of its kind ever undertaken into the ecological impacts of marine grazing animals: it was led by Associate Professor Alistair Poore, of the UNSW Evolution & Ecology Research Centre, who worked with an international team of 10 researchers.
It found that, on average, marine herbivores remove almost 70% of the plant material growing on the sea floor -- an effect far greater than grazing animals have on land plants."
via phys.org