1. J. R. Delaney, D. S. Kelley, M. D. Lilley, J. A. Baross, W. S. D. Wilcock, and M. Summit are at the School of Oceanography, University of Washington, Seattle, WA 98195, USA. D. A. Butterfield is at the Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Seattle, WA 98115, USA. R. W. Embley is at the Pacific Marine Environmental Laboratory, NOAA, Newport, OR 97365, USA.