Measuring toxic elements and toxicity in marine shallow-water hydrothermal systems

Marine shallow-water hydrothermal systems are often enriched in biologically toxic elements. Here, we report our investigation of the bioavailability, uptake, and bioaccumulation of hydrothermally-derived arsenic into several coral reef organisms from the arsenic-rich marine shallow-water hydrothermal system of Tutum Bay, Ambitle Island, in northeastern Papua New Guinea. Hydrothermal venting provides bioavailable As by two major pathways throughout Tutum Bay: 1) easily-exchangeable As from hydrothermally influenced sediments to as far away as 200 m from focused venting, and 2) in surface seawaters, which may allow for biological uptake by phytoplankton and transfer up the food web. The soft coral Clavularia sp., the calcareous algae Halimeda sp., and the tunicate Polycarpa sp. collected from the hydrothermal area displayed distinctly higher total arsenic (2 to 20 times) compared to the control site, with increasing trends while approaching focused hydrothermal venting.