On the use of some phosphates in the preparation of ostracod shells

Abstract. Common preparation techniques for ostracods include the use of water-softeners containing sodium hexametaphosphate and/or sodium tripolyphosphate, to disaggregate sediments. Here, ostracod shells were treated with phosphatic water-softener in tap and distilled water. Concentrations as low as 2.5% in as little as six hours caused significant damage. The worst damage occurred in concentrations of water-softener at the middle of the range used (0 – 20%). Alteration could be misinterpreted as taphonomic. Taxa are not equally resistant and assemblages could be altered, leading to erroneous conclusions about diversity, dominance, and differential transport.