Upper water column

{
  "id": "MLC-T-ENV-029247",
  "term": "Upper water column",
  "field": "Environment",
  "term_source": "Upper Water Column",
  "definition": "The area from just below the surface to the boundary of the pycnocline, if present. (If a pycnocline is not present or is not detected, the region above mid-depth in the water column is defined as the Upper Water Column.) The upper water column layer is in close contact with the atmosphere; usually oxygenated, well-mixed and well-lighted; and is generally marked by high rates of photosynthesis and net autotrophic production.",
  "subject": "Natural environments",
  "references": [
    "Federal Geographic Data Committee Coastal and Marine Ecological Classification Standard, June 2012 FGDC-STD-018-2012"
  ],
  "url": "https://mlchart.com/terminology/environment/upper-water-column/"
}