Early Sea Travel & Navigation
This simple prehistoric vessel, found in the Netherlands, is the oldest surviving boat, dated to about 10,000 years ago.
Pessa Canoe
This German scientist proposed “continental drift,” arguing that continents like South America and Africa were once joined.
Who is Alfred Wegener?
This effect causes moving air and water to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere
What is the Coriolis effect?
These large, circular surface current systems, like the North Atlantic one containing the Gulf Stream, are driven by winds and modified by the Coriolis effect.
What are gyres?
These drifting organisms, including phytoplankton and many zooplankton, are mostly unable to swim against currents and “wander” with the water.
What are plankton?
Evidence of humans on islands like Luzon 700,000 years ago suggests that even early hominins had to use this general mode of travel to cross open water.
What is sea travel / open-water voyaging by boat or raft?
This process, proposed by Harry Hess, explains how new oceanic crust forms at mid-ocean ridges and moves away from them.
What is seafloor spreading?
These large rotating storm systems in the Atlantic are powered by warm ocean water (≥ ~26 °C) and are also called tropical cyclones.
What is a Hurricane?
Along some coasts, wind-driven Ekman transport moves surface water away from shore, causing this process that brings cold, nutrient-rich water to the surface.
What is coastal upwelling?
These tiny photosynthetic organisms at the base of the marine food web are primary producers and are responsible for much of Earth’s oxygen.
What are phytoplankton?
These expert navigators of the Pacific used stars, swells, birds, and stick charts (that were not taken on the boat) to cross huge distances.
Who are the Polynesians?
These alternating patterns seen on the seafloor record reversals of Earth’s magnetic field and helped prove seafloor spreading.
What are magnetic stripes on the seafloor?
Near the equator, where trade winds from both hemispheres converge and air rises, this low-pressure belt forms and is associated with thunderstorms and heavy rain.
What is the Intertropical Convergence Zone (ITCZ)?
This shallow-water wave, often incorrectly called a “tidal wave,” can be generated by seafloor earthquakes and has extremely long wavelengths of hundreds of kilometers.
What is a tsunami?
This classic ratio, about 106:16:1 for C:N:P, describes the average elemental composition of marine organic matter and deep-ocean nutrients.
What is the Redfield ratio?
These northern European sailors explored and colonized Iceland, Greenland, and even reached Newfoundland around 1000 AD.
Who are the Vikings?
Rigid plates about 100–250 km thick, composed of crust and the very top of the mantle, make up this mechanical layer that “floats” on the asthenosphere.
What is the lithosphere?
This term refers to the proportion of incoming sunlight that a surface reflects; snow and ice have a high value, while oceans and forests have a low one.
What is albedo?
In Boston, tides are of this general type, featuring two high tides and two low tides each day with roughly equal heights.
What are semidiurnal tides?
These single-celled, glass-shelled phytoplankton made of SiO₂ dominate many coastal spring blooms and form siliceous ooze when they die.
What are diatoms?
This 18th-century British explorer led three “scientific” voyages and carried out detailed mapping, depth soundings, and biological sampling across the Pacific.
Who is James Cook?
These pieces of oceanic crust and upper mantle thrust up onto land at convergent margins show hydrothermal alteration and are important sources of copper and other metals.
What are ophiolites?
This process describes the natural trapping of outgoing infrared radiation by gases like water vapor, CO₂, CH₄, and O₃, keeping Earth’s average temperature above freezing.
What is the greenhouse effect?
This Scottish physicist built an analog tide-predicting machine in 1871, later upgraded for D-Day tidal forecasts in 1944.
Who is Lord Kelvin?
This term describes the process by which added CO₂ lowers seawater pH, making it harder for organisms like corals and shell-forming plankton to precipitate CaCO₃.
What is ocean acidification?