EAS 201: Lecture 22
February 25, 2019
• Lecture notes/images borrowed from Karlis Muehlenbachs’ slides February 25, 2019.
• Ocean Layering:
o Biotic Zones
▪ Plants/animals living in uppermost level occupy the pelagic zone.
▪ Benthonic organisms live on/within bottom sediment.
▪ Floating organisms are planktonic.
▪ Plant life is exclusively within the photic zone.
▪ Free swimmers are restricted by their own locomotion (squid, fish,
▪ Black smoker communities on mid ocean ridges.
o Oceanic sediment is dominated by skeletal remains of single-celled planktonic &
benthonic animals; when > 30% of bottom sediment consists of these remains:
▪ If carbonate-based is called Calcareous Ooze.
▪ If silica-based is called Siliceous Ooze.
o Lithic sediment – consists of rock fragments, mantles continental shelves/slopes.
• Oceans Basins’ Sediments:
o Note, volcanoes along “Ring of Fire” will vary predictable due to differing
sediment types subducted under them.
• Ocean Circulation:
o Surface ocean currents are slow drifts of water caused by friction b/w the ocean
& air flowing over it.
▪ 50-100m deep.
o Coriolis Effect:
▪ Influences ocean current direction.
▪ The Earth rotates; imagine shooting something at a target, the rotation
moves the target → you miss.