How could a message in a bottle that was thrown from a ship near England end up on a Perth beach? The enormous forces that affect the earth’s oceans cause the sea to flow in various directions – what we know as currents. This results in the movement of materials, sometimes extremely far from where they started and with some things appearing on our coast that might not be expected.

Winds, temperature, salinity, rotation of the earth and tides all combine to interact and move oceanic water around the world. This forms a conveyor belt-like movement, resulting in the exchange of nutrients, organisms and water around the entire globe. The strength and direction of currents become affected as they interact with coastlines, ocean depths and other water movement in local areas. From this we get both major and minor currents.

Currents are important for many reasons. They determine the climate that each country experiences and they effect the movement of organisms in the ocean, recreation on the water, and the movement of marine debris. Currents have even played a part in history as they have influenced ocean transport, and still continue to do so. They determine how coastlines are shaped, what can be built and where, and where we can live. Currents are a vital part of the ocean environment.