A multilevel in situ pore‐water sampler for use in intertidal sediments and laboratory microcosms

A sampler for in situ separation of pore fluids from intertidal sediments and in laboratory microcosms offers marked improvements in resolution, number of sampling depths, compactness, and simplicity over previously reported devices. The sampler is operated by applying a vacuum to chambers linked, through porous segments, to successive depths in the sediment profile. Analyses of replicate samples taken at hourly intervals [total alkalinity, pH, dissolved Fe(II), and Mn(II)] show that concentration changes induced by the sampler with time are small compared to those due to natural sediment variability. Sampling accuracy is assessed from comparative analyses of pore waters obtained with samplers and by centrifuging core sections. Applications include field sampling of intertidal pore waters, deployment inside benthic chambers, laboratory studies of temporal changes in porewater compositions, and shipboard sampling of cores collected subtidally.