Hydrographic observations in the Irish Sea during the unusually hot summer of 1975

Data on the surface and depth distributions of salinity, temperature and dissolved inorganic nutrients were obtained during a survey of the Irish Sea in late August and early September, 1975. The observations followed one of the warmest summers of the century. Nutrient concentrations in the surface waters were low and their distributions patchy. Significant concentrations of dissolved inorganic nitrogen were present only in deep waters overlaid by strong density gradients.Surface temperature distributions showed large and widespread positive anomalies compared with the seasonal norm. The greatest anomalies occurred in regions of intense stratification. Despite shallow depths and strong tidal streams, the above-average seasonal heat input induced significant stratification in waters off the west coast of the British Isles.