A comparison of methods for the accurate measurement of epiphytic carbonate

The accurate measurement of epiphytic carbonate is vital in the construction of carbonate budgets. Prior studies have produced estimates of epiphytic carbonate production, but the results of these investigations are not directly comparable due to the variety of methods employed by the investigators. This investigation field-tested four methods of measuring epiphytic carbonate. These four methods were the gravimetric leaf acidification technique, the EDTA titration of epiphytized leaves, the EDTA titration with seagrass blanks, and the scrape and titrate method. The leaf acidification method and the EDTA titrimetric method without seagrass blanks resulted in significantly larger estimates of epiphytic carbonate than those produced using the other two methods. It is believed that the leaf acidification technique and the EDTA titration of epiphytized leaves results in overestimates of epiphytic carbonate due to the leaching of organic matter during acidification. The scrape and titrate method, involving the separation of epiphyte material from the seagrass leaves, is believed to most accurately measure epiphytic carbonate.