Sediment traps are instruments used in

oceanography Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of to ...

and

limnology Limnology ( ; ) is the study of inland aquatic ecosystems. It includes aspects of the biological, chemical, physical, and geological characteristics of fresh and saline, natural and man-made bodies of water. This includes the study of lakes, ...

to measure the quantity of sinking particulate organic (and

inorganic An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inor ...

) material in aquatic systems, usually

ocean The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...

lakes A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

, or

reservoirs A reservoir (; ) is an enlarged lake behind a dam, usually built to store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrup ...

. This flux of material is the product of

biological Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of ...

and

ecological Ecology () is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely re ...

processes typically within the surface euphotic zone, and is of interest to

scientist A scientist is a person who Scientific method, researches to advance knowledge in an Branches of science, area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engag ...

s studying the role of the

biological pump The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven Carbon sequestration, sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sedim ...

in the

carbon cycle The carbon cycle is a part of the biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycl ...

. Sediments traps normally consist of an upward-facing

funnel A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening. Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its constructi ...

that directs sinking

particulate matter Particulate matter (PM) or particulates are microscopic particles of solid or liquid matter suspended in the air. An ''aerosol'' is a mixture of particulates and air, as opposed to the particulate matter alone, though it is sometimes defin ...

(e.g.

marine snow In the deep ocean, marine snow (also known as "ocean dandruff") is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to ...

) 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 a seasonal cycle). Preservation of collected material is necessary because of these long deployments, and prevents sample

decomposition Decomposition is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ess ...

and its

consumption Consumption may refer to: * Eating *Resource consumption *Tuberculosis, an infectious disease, historically known as consumption * Consumer (food chain), receipt of energy by consuming other organisms * Consumption (economics), the purchasing of n ...

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

"swimmers". Sediment trap Thermaikos 2

Traps are often moored at a specific depth in the

water column The (oceanic) water column is a concept used in oceanography to describe the physical (temperature, salinity, light penetration) and chemical ( pH, dissolved oxygen, nutrient salts) characteristics of seawater at different depths for a defined ...

(usually below the euphotic zone or

mixed layer The oceanic or limnological mixed layer is a layer in which active turbulence has homogenized some range of depths. The surface mixed layer is a layer where this turbulence is generated by winds, surface heat fluxes, or processes such as evaporat ...

) in a particular location, but some are so-called Lagrangian traps that drift with the surrounding

ocean current An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, sh ...

s (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 via

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

) in order to be recovered.

References

{{aquatic ecosystem topics Oceanographic instrumentation Limnology

See also

References