Clinging to the seashore, life is a constant tug-of-war. Continually wrenched about, seashore dwellers have a range of strategies for withstanding the constant battering. Some creatures have armoured themselves to withstand the pounding, while others have chosen to go with the flow, changing shape and bending with the current. Michael Boller explains that although it is well known that seaweeds continually change shape in the surf, it wasn't clear which mechanisms protect macroalgae's delicate fronds. To find out how seaweeds adjust to the rigours of sea life, Boller and Emily Carrington measured the forces exerted on Chondrus crispus in currents ranging from 0-2 m s–1(). Filming the seaweed's movements, the pair found that at lower speeds, Chondrus crispus simply deflected to align with the direction of flow. However, as the flow increased the seaweed's crown became more compacted, reducing the drag experienced by the macroalage.
Having quantified how the macroalgae's drag coefficient and frontal area decrease as the current picks up, the scientists developed a mathematical model to calculate the drag experienced by flexible structures in water, which they suggest `improves our ability to predict drag at higher, ecologically relevant water velocities'.
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