Lau Basin Vent Expeditions 2005-6

Deep-sea vents are remote, ephemeral environments with large gradients in chemistry and temperature over very small distances. Hydrothermal vent fauna are reliant upon the productivity associated with vent flow and require special adaptations in order to tolerate the variety of challenges posed by potentially toxic chemicals and a wide range of temperatures. Thus, characterizing the habitats of the fauna is a criti.cal first step in understanding their ecology, but can be quite difficult and time consuming in these complex, remote, and relatively inaccessible environments.

The 400 km-long Eastern Lau Spreading Center (ELSC) is located in the Lau back-arc basin, bordered on the west by the remnant Lau arc and on the east by the active Tofua volcanic arc and the Kingdom of Tonga. Lau Basin fauna are generally similar to that of other back-arc basins and deep subduction zones (Manus and North Fiji Basins and Okinawa and Mariana Troughs) within the Western Pacific hydrothermal vent biogeographic province.

In 2005 and 2006, we selected four discrete vent communities within three different andesite-hosted vent fields along the ELSC (ABE, Tu’i Malila, Kilo Moana and Tow Cam) and used the ROV JASON II to photographically and physico-chemically characterize each community. One purpose of this study was to develop an explorative technique that combines high-resolution, geographically referenced imagery, in-situ physico-chemical measurements (Luther et al., 2001; Nuzzio et al., 2002), and GIS in order to identify correlations between faunal distributions and abiotic and biotic factors across significant portions of a vent community (40–50 m2).