The water-sediment interface is a dynamic zone where the benthic and pelagic environments are linked through exchange and recycling of organic matter and nutrients. However, it is often difficult to measure rate processes in this zone. To that end, we designed an experimental apparatus for continuous and homogeneous perfusion of sediment porewater with dissolved conservative (SF₆, Rhodamine WT dye) and isotopic (H¹³CO₃¯ and ¹⁵NH₄⁺) tracers to study nitrogen and carbon cycling by the sediment microbial community of shallow illuminated sediments. The perfusionator consists of a 60-cm ID x 60-cm high cylinder that includes a reservoir for porewater at the base of the sediment column. Porewater amended with conservative and stable isotopic tracers was pumped through a mixing reservoir and upward through the overlying sediments. We tested the perfusionator in a laboratory setting, as part of an outdoor mesocosm array, and buried in coastal sediments. Conservative and isotopic tracers demonstrated that the porewater tracers were distributed homogeneously through the sediment column in all settings. The perfusionator was designed to introduce dissolved stable isotope tracers but is capable of delivering any dissolved ionic, organic, or gaseous constituent. We see a potentially wide application of this technique in the aquatic and marine sciences in laboratory and field settings.
Estuaries & Coasts is the journal of the Coastal and Estuarine Research Federation. Begun in 1977 as Chesapeake Science, the journal has gradually expanded its scope and circulation. Today, the journal publishes manuscripts covering aspects of research on physical, chemical, geological or biological systems, as well as management of those systems, at the interface between the land and the sea. The interface is broadly defined to include areas within estuaries, lagoons, wetlands, tidal rivers, watersheds that include estuaries, and near-shore coastal waters. The journal publishes original research findings, reviews, techniques, and comments.
The Coastal and Estuarine Research Federation is a private, nonprofit non partisan organization. The Federation was created in 1971, when the members of two older, regionally-based estuarine research societies (AERS and NEERS) decided that a national organization was needed to address estuarine and coastal issues more broadly. The regionally based Affiliate Societies now number seven and encompass all of the coastal regions that border the United States, Canada and Mexico.