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Sharks, marine scientists say, are often misunderstood, described as ravenous man-eaters. But researchers have discovered that sharks are critically important to the health of the world's oceans. For more than two decades, marine scientist Michael Heithaus of Florida International University (FIU) has been immersed in the world of sharks and other predators that help the sea maintain a delicately balanced food web.
Heithaus' work is focused on predators in the waters of South Florida -- and across the globe in Shark Bay, Australia. In 2011, some 15 years into a long-term study of the ecological importance of tiger sharks in Shark Bay, a heat wave struck the region. Warm ocean waters caused the widespread loss of seagrasses, a main food source for dugongs (sea cows) and other species that are the sharks' prey. Now, Shark Bay's seagrasses are struggling to bounce back from the heat wave. They have some unexpected help. Sharks, it turns out, are one of the seagrasses' best allies in the fight to survive.Image credit: FIU
