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 geographical point.

[1] The water column is the largest, yet one of the most under-explored, habitats on the planet; it is explored to better understand the ocean as a whole, including the huge biomass that lives there and its importance to the global carbon and other biogeochemical cycles.

[1] Water columns are used chiefly for environmental studies evaluating the stratification or mixing of thermal or chemically stratified layers in a lake, stream or ocean.

Some of the common parameters analyzed in the water column are pH, turbidity, temperature, hydrostatic pressure, salinity, total dissolved solids, various pesticides, pathogens and a wide variety of chemicals and biota.

Because food is scarce in this region, most mesopelagic organisms migrate to the surface to feed at night or live off the falling detritus from the epipelagic ecosystem.

The sheer size of this area, coupled with the challenges of descending to depths where water pressure can reach 600 atmospheres, makes exploration difficult—but by no means impossible.