STUDIES ON THE SEASONAL VARIATION OF THE SUSPENDED MATTER IN THE MENAI STRAITS. I. THE INORGANIC FRACTION

Abstract

The ash weight of material suspended in the waters of the Menai Straits was measured twice weekly between May 1962 and May 1963. The amount was much greater in winter than in summer and greater during spring than during neap tide periods. No differences could be detected between the ebb and flood periods within a single tidal cycle. The variations in ash weight correlated strongly with temperature but not with rainfall. There was a significant correlation between ash weight and the temperature‐related variables, σ t and estimated freshwater runoff, but neither was significant after the effect of temperature was eliminated. The suspended burden was greater during periods of easterly winds, but no relationship could be established with wind velocity. The seasonal changes could not be attributed to changes in thermal instability or viscosity. The variations are thought to be caused by biological rather than by physical processes.