Benthic lander on:
[Wikipedia]
[Google]
[Amazon]
A benthic lander is an autonomous observational platform that sits on the
A benthic lander is an autonomous observational platform that sits on the seabed
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
or benthic zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...
to record physical, chemical
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...
or biological activity.
Benthic landers have deployment durations from a few days (for 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 ...
studies) to several years (for physical oceanography
Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.
Physical oceanography is one of several sub-domains into which oceanography is div ...
studies). In these studies they conduct a variety of underwater measurements, and thus different lander configurations exist to meet differing needs for different measurements.
Purpose
Samples that are brought up from the seabed undergo large changes intemperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
and pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...
, thus changing their physical and chemical composition and properties. This change in properties means that any measurements taken from samples brought to the surface do not provide accurate data. In order to avoid this, it is best that the measurements are taken directly at the seabed level, without moving the samples. Initially, to prevent altering samples, divers would go to the sea bed and carry out the experiments. However, divers have a very small range of depth and a short time under water and cause a large disturbance to the sea bed, thereby introducing more error into the measurements. These shortcomings are improved by using benthic landers as they have a much larger depth and time capacity than divers and can be designed to cause minimal disturbance to the sea floor. Some common uses for the collected seabed data include studying currents
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (hy ...
, tides
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables ...
, and microseismic and magnetic field
A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...
activity and monitoring marine life
Marine life, sea life or ocean life is the collective ecological communities that encompass all aquatic animals, aquatic plant, plants, algae, marine fungi, fungi, marine protists, protists, single-celled marine microorganisms, microorganisms ...
.
Variations
Benthic landers come in a variety of shapes and sizes depending upon theinstrumentation
Instrumentation is a collective term for measuring instruments, used for indicating, measuring, and recording physical quantities. It is also a field of study about the art and science about making measurement instruments, involving the related ...
they carry, and are typically capable of working at any ocean depth. One type of instrumentation that is often used on benthic landers is an eddy correlation instrument that measures oxygen flux
Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications in physics. For transport phe ...
. Different types of landers are used depending on the length and nature of the mission. Longer duration mission landers are typically equipped with ultrasonic sensors, LiDAR
Lidar (, also LIDAR, an acronym of "light detection and ranging" or "laser imaging, detection, and ranging") is a method for determining ranging, ranges by targeting an object or a surface with a laser and measuring the time for the reflected li ...
, and cameras
A camera is an instrument used to capture and store images and videos, either digitally via an electronic image sensor, or chemically via a light-sensitive material such as photographic film. As a pivotal technology in the fields of photograp ...
in order to intelligently navigate the seabed. Additionally, depending on what measurements the mission is intended to take, the lander can be configured to disrupt the environment in different ways enabling for higher precision of certain data sets at the tradeoff of others. New technologies are constantly being developed to improve lander data collection, one example being holography
Holography is a technique that allows a wavefront to be recorded and later reconstructed. It is best known as a method of generating three-dimensional images, and has a wide range of other uses, including data storage, microscopy, and interfe ...
, which is meant to be utilized to take measurements of the seabed far from the lander.
See also
*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 ...
* Mooring (oceanography)
A mooring in oceanography is a collection of devices connected to a wire and anchored on the sea floor. It is the ''Lagrangian and Eulerian specification of the flow field, Eulerian way'' of measuring ocean currents, since a mooring is stationar ...
* Bottom crawler
References