A new sampler for monitoring fluid and chemical fluxes in hydrologically active submarine environments

Abstract

A new sampler is presented which uses osmotic pumps that continuously monitor the chemistry and flow rate of fluids emanating from porous sediment via diffuse flow into the ocean. Flow rates as low as few cm/yr are determined using tracers injected as a point source, and by continuously sampling the sediment pore water and studying variability in tracer concentrations with time. Sampling can be conducted at various depths in the sediment and distances from the injection port, thereby allowing determination of the flow field in the shallow sub-seafloor sediments. The continuously sampled pore fluids are also analyzed for their chemistry which, combined with the flow rate data, yields the fluxes of chemical species from the sediment into the ocean.