Marine Systems and El Nino

Terms:
photic zone, pelagic and benthic zones, Langmuir cells, Ekman spiral, estuaries, upwelling, downwelling, El Nino Southern Oscillation, La Nina, Kelvin wave

benthic zone: The sea bottom.

Ekman spiral:  A form of ocean circulation driven by wind where water moves in a spiral pattern from the surface to deeper layers, based on coriolis force. 

downwelling: Process by which winds and coriolis force act together to push surface waters towards a coastline causing surface waters to downwell and thicken the surface layer.

El Nino Southern Oscillation:  A periodic ocean anomoly caused by upper atmosphere changes in the Southern Hemisphere that weaken or reverse the trade winds and cause warm water to move eastward across the Pacific basin.

estuaries: Aquatic zones where river mouths open into the sea and mixing of fresh and salt water occurs.

Kelvin wave:  A large mass of surface and subsurface warm water that moves from west to east across the Pacific basin during an ENSO event when the Trade Winds slow, stop, or reverse.

La Nina: Follows an El Nino event, when trade winds resume normal strength and warm ocean waters move westward across the Pacific basin and cold waters upwell on the east side of the basin.

Langmuir cell:  A cell of mixing water that forms quickly with wind and evaporative cooling at the water’s surface and is oriented parallel with wind direction.

pelagic zone: The open ocean.

photic zone:  Zone of light penetration in the ocean where the lower limit is defined by the light compensation point. 

thermohaline circulation: density-driven circulation in a marine environment that is dependent on temperature and salinity

upwelling:  Process by which winds and coriolis force act together to push surface waters away from a coastline causing waters below to upwell to the surface.