METHODS FOR QUANTIFYING POTENTIAL MICROBIAL CONTAMINATION DURING DEEP OCEAN CORING 1,2

as a plat-form for deep-biosphere research requires that the recovered cores aresuitable for microbiological study. The major concern is whether mi-crobes from the drilling fluid are introduced into the recovered corematerial during coring. Therefore, it is critical to verify whether recov-ered cores are contaminated. Here we present details of two tracermethods used to quantify the amount of contamination. These meth-ods were modified from land-based drilling operations for use on the