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Cruise Data
Oceanographic data has been collected on cruises all over the world for hundreds of years. People were initially interested in winds, currents, tides, and bathymetry for navigation. Today's techniques of sampling from a ship are quite sophisticated.
CTD
A Conductivity-Temperature-Depth (CTD) instrument is used to measure salinity, temperature, and depth in the water. A conductivity probe measures induction in a parcel of water, which is dependent upon the salinity of the water. Temperature is measured with a thermistor. Depth is inferred by a pressure measurement, as 1 decibar (dbar) of pressure approximately equals 1 meter of depth. Thus a pressure of 2500 dbar is roughly equal toa depth of 2500 m.
 Data from the CTD can be used to create a vertical profile of the water at a specific station. An example of a Temperature vs. Salinity (TS) plot is shown at left.
The graph shows how temperature and salinity change from the sea surface to the bottom. In most areas, temperature tends to decrease with depth while salinity tends to decrease, although this is not always the case. The region of rapidly changing temperature near the surface is called the thermocline, and the region where salinity changes the most is called the halocline. The density of seawater is dependent upon temperature, salinity, and pressure.
If researchers steer a ship along a transect in the ocean, and deploy the CTD at several different stations, they can obtain several measurements of pressure. Depths of similar pressure are termed isobars. The isobars are compared to depths with similar geopotentials, or level surfaces with respect to the earths gravity. If these are sloped with respect to each other, there is a horizontal pressure gradient. Water in the ocean flowsfrom high pressure to low pressure; similar to the situation in which you turn on the faucet in your sink. Therefore, researchers can calculate the speedand direction of the oceans major currents.
Nutirent
A CTD is often equipped with Niskin Bottles, which are triggered to close at specific depths. This water is then chemically analyzed in a laboratory to determine its constituents. Specifically, researchers are interested in the concentration of nutrients at each depth. Nutrients include compounds which contain nitrogen and phosphorous, and they are very important to phytoplankton and biological productivity in general. Areas with depleted nutrient concentrations near the surface indicate that large amounts of phytoplankton might be growing.
Most plants in the world produce chlorophyll, a compound which enables them to produce energy from the sunlight in a chemical reaction termed photosynthesis. Phytoplankton are the plants of the sea, and also utilize chlorophyll. Biological Oceanographers are interested in locating regions with high amounts of chlorophyll, as it implies that biological productivity is high. High abundances of phytoplankton can cascade up the food chain and possibly support high stocks of salmon and other commercially important fish. Many CTDs are outfitted with a fluorometer, which can measure the concentration of chlorophyll. Chlorophyll is usually concentrated near the sea surface as phytoplankton need sunlight to survive.
Biological
Arctic Ocean Diversity (ArcOD)
"An international collaborative effort to inventory biodiversity in the Arctic sea ice, water column and sea floor from the shallow shelves to the deep basins using a three-step approach: compilation of existing data, taxonomic identification of existing samples, and new collections focusing on taxonomic and regional gaps."
http://www.coml.org/descrip/aobio.htm
http://www.sfos.uaf.edu/research/arcdiv/index.html
Data Access
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