Sediment traps are instruments used inoceanography andlimnology to measure the quantity of sinking particulateorganic (andinorganic) material inaquatic systems, usuallyoceans,lakes, orreservoirs. This flux of material is the product ofbiological andecological processes typically within the surface euphotic zone, and is of interest toscientists studying the role of thebiological pump in thecarbon cycle.[1]
Sediments traps normally consist of an upward-facingfunnel that directs sinkingparticulate matter (e.g.marine snow) towards a mechanism for collection and preservation. Typically, traps operate over an extended period of time (weeks to months) and their collection mechanisms may consist of a series of sampling vessels that are cycled through to allow the trap to record the changes in sinking flux with time (for instance, across aseasonal cycle). Preservation of collected material is necessary because of these long deployments, and prevents sampledecomposition and itsconsumption byzooplankton "swimmers".[2]
Traps are oftenmoored at a specific depth in thewater column (usually below the euphotic zone ormixed layer) in a particular location, but some are so-called Lagrangian traps that drift with the surroundingocean currents (though they may remain at a fixed depth). These latter traps travel with the biological systems that they study, while moored traps are subject to variability introduced by different systems (or states of systems) "passing by". However, because of their fixed location moored traps are straightforward to recover for analysis of their measurements. Lagrangian traps must surface at a predetermined time, and report their position (usually viasatellite) in order to be recovered.
