 The water column is generally well-mixed, with no evidence of a significant halocline or thermocline.Mean differences in water temperature between sea surface and sea bed range from only half a degree (Celsius; 1 °F) in summer to almost zero in winter, and differences in salinity are very small even when the Leeuwin Current is at its strongest.As with the rest of southwestern Australia, tides at the Houtman Abrolhos are small and irregular.