Samples were provided through the ODP. M.L.D. is grateful to the ODP and to the co-chief scientists and other shipboard scientists for her shipboard participation during Leg 167. We thank M. Lyle, R. Murray, and D. Rea for their reviews. This research was supported by postcruise science support from JOI/USSAC to M.L.D. and by NSF OCE-9416593 to M.L.D. We thank Rob Franks and the UCSC Institute of Marine Sciences Marine Analytical Laboratories for the high-quality research support provided. We thank Henry Lao and Kathy Motte for laboratory assistance.