King Tides Broome

annabelleIn the field

Wet season storm clouds build up behind Broome jetty at the Port.
Wet season storm clouds build up behind Broome jetty at the Port.

Wet season storm clouds build up behind Broome jetty at the Port.

Squelching around near the Broome jetty in soft, velvety mud to mid calf on the Easter weekend, I noticed a featherstar waving delicate, feathery arms with stripes in shades of milky coffee in a shallow, sandy pool. Broome is famous for its large tidal variations and the King tides over Easter brought super highs and super lows with a difference of up to 10m.

These super low tides reveal the rich marine life on the mudflats and sandbanks of Roebuck Bay, which has some of the most productive benthic mudflats in the world, with 300-500 invertebrate species.

Tides are caused by the gravitational forces exerted by the sun and the moon, and the Kimberley is an area of macromareal tides, where the difference between high and low tide is greater than 4m. The shallow, shelving bathymetry together with the extreme tidal variation gives Broome a large land-sea interaction.