OCEAN 2001: Multiple Choice

Human Population Genesis/Exodus

o   Modern humans populated the globe relatively rapidly

o   In North America by 20,000 yBP at the latest

o   3 hypotheses for how humans were able to cross the ocean:

• Kelp Highway via boat

• Bering Strait exposed via low sea levels

• Humans living in the arctic moved down to North America

Iron Catastrophe

• During the Iron Catastrophe the Earth became molten

  • Solar system formed …

  • Earth formed …

  • Then it became molten …

• Heavier elements migrated to the interior

• Legacies:

  • Magnetic field

  • Low-density crust

Where Did Life Begin?

Several potential theories:

• Darwin: warm surface pool, but rejected

• Hydrothermal vents on the bottom of the ocean, live off chemical energy

• Introduced from an extra-terrestrial object

• Formed deep in the earth

2011 Tōhuku Earthquake

• Japan; on top of convergent plates

  • 4^th biggest earthquake of all time

  • Megathrust: where one plate dives down beneath another plate, and when they get unstuck, lots of damage occurs (define better)

• Lots of damage

  • 10,000s death

  • Caused a nuclear meltdown

Long-term Carbon Cycle

o   Cycling of carbon between the ocean atmosphere and crust

o   Crustal rocks and ocean are major reservoirs of carbon Earth-ocean-atmosphere system

o   Carbon exchanges actively between crust and ocean

Planetary Technologies: Ocean Alkalinity

• Will Burt, Planetary Technologies

• Manipulate ocean chemistry to remove CO₂ from the atmosphere in a relatively natural way

• Achieved by adding alkalinity to the ocean by introducing crushed rock that dissolves in seawater

  • This moves carbon from atmosphere to the ocean

Light Demonstration

• Simple demonstrations to illustrate principles of scattering and absorption

• Perception of colour is determined by light that is scattered towards our eyes

  • Blue dye absorbs the red, orange, and yellow, and lets blue, green and violet through

  • The ocean is blue because sea water absorbs the longer wavelengths (reds) more than the blues, and scatters the blues much more effectively.

• Preferential absorption of some colours means they will not be available for scatter towards our eyes

2025 Hurricane Season

• NS hurricane season was about as predicted for named and major storms

• Lull in formation during peak season

  • Perhaps due to Saharan dust

• Storms steered away from land

  • Nearly all hurricanes went out to the sea (except Mellissa)

• Rapid intensification of major storms

  • Hallmark of climate change, makes it harder to predict when things are going to get bad/how fast

SWOT JPL

• SWOT: Surface Water and Ocean Topography

• JPL: jet propulsion laboratory

o   satellite mission

o   High resolution data on sea surface height

o   Big advance in monitoring local sea level rise in coastal zone

Ocean Re-analyses

o  ORAs

o   Simulate past behaviour of the ocean

o   Combine computer models and observations

o   Assimilate data to correct model drift

AMOC

• Atlantic Meridional Overturning Circulation

• Premise of the movie The Day After Tomorrow:

  • Iceberg causes current to stall

  • Extreme temperature plunge across N hemisphere

  • Climate shift happens within a couple days

• Former 2 are accurate representations of what could possibly happen, latter is impossible (would occur over decades)

Wave Orbital Overview

o   Parcels of water follow orbital paths

o   Move in direction of wave propagation under wave crest

o   Opposite direction of wave propagation under wave trough

o   Diminish size with increasing depth

• Bottom line depth where little/no motion occurs = ƛ/2

Internal Waves (& generation mechanisms)

o   Waves that form at boundary between different density fluids

o   3 generation mechanisms:

• Wind

• Tides

• Currents

o   Form throughout the ocean

Wave Groups

o   Caused by interference between wave trains of different wavelengths

o   Groups of waves where wave heights are larger caused by constructive interference

o   Group speed is about half the speed of the interacting wave trains

CITES

o   Conventional on International Trade of Endangered Species

o   To conserve species, we must limit their trade

o   Latest COP saw the biggest win ever for sharks and rays

• COP: conference of parties