Wave-Energy Dissipation: Seaweeds and Marine Plants Are Ecosystem Engineers

Ocean waves deliver an immense amount of energy to coasts around the planet, powering high-velocity flows that interact with nearshore marine plants and animals. Although some of these interactions are beneficial, it is often advantageous for subtidal and intertidal ecological communities if wave-induced water velocities can be reduced by safely dissipating wave energy. This function is often fulfilled by seaweeds and marine plants, which thereby act as ecosystem engineers, modifying the environment to the benefit of the community. Recent advances in hydro-mechanical theory help to explain the mechanisms by which vegetation dissipates wave energy, highlighting the role that organisms' tendency to bend in flow-their structural flexibility-plays in their ability to engineer wave-induced flows. Here, I review these theories and their application to salt marsh plants, seagrasses, mangroves, and seaweeds, focusing on the ways that marine vegetation serves a foundational role in community function.