Annual Fluctuations in Sulphate and Bicarbonate Hardness in Ponds

Abstract

In four ponds studied, sulphate in solution was high in spring, low in autumn, while bicarbonate was low in spring, high in autumn. The fall in sulphate was probably due to reduction to sulphide which became locked up in the mud as ferrous sulphide. The fluctuation in bicarbonate was partly due to the removal of CO 2 during photosynthesis and partly to the action of sulphuric acid when the sulphide was oxidized in winter.