Geography and Exploration:
– Atlantic Ocean is the second-largest oceanic division, covering 17% of Earth’s surface.
– It separates the New World from the Old World and played a central role in human society and globalization.
– The Norse were the first known to cross the Atlantic, followed by Christopher Columbus in 1492.
– The Atlantic was a center for exploration, colonization by European powers, and the slave trade.
– It hosted naval battles, trade routes, and increased trade and naval activities in the early 20th century.
Bathymetry and Ocean Floor:
– The Atlantic Ocean has an average depth of 3,646m and a maximum depth of 8,376m in the Puerto Rico Trench.
– The Mid-Atlantic Ridge dominates the ocean floor, extending from 87°N to 54°S.
– Submarine mountain ranges influence the ocean floor configuration, with various features like abyssal plains, trenches, and seamounts.
– Continental shelves are wide at specific locations, while the Western Atlantic is dominated by carbonate platforms.
– Walvis Ridge and Rio Grande Rise act as barriers to ocean currents.
Water Characteristics and Salinity:
– The Atlantic Ocean is the saltiest major ocean, with surface salinity ranging from 33 to 37 parts per thousand.
– Water masses in the Atlantic have distinct temperature and salinity characteristics, with four major upper water masses and various intermediate and deep waters.
– The Gulf Stream temperature drops significantly across the North Atlantic, with surface water temperatures varying with latitude and season.
– The Coriolis effect influences water circulation, leading to clockwise circulation in the North Atlantic.
– Salinity varies with latitude, season, and oceanic processes, with high salinity maintained by specific mechanisms like Agulhas Leakage/Rings and Atmospheric Bridge.
Gyres and Sargasso Sea:
– The Atlantic Ocean has warm-water gyres like the North Atlantic Gyre and South Atlantic Gyre.
– The North Atlantic has significant currents like the Gulf Stream, North Atlantic Current, and Subpolar Front, influencing climate variability.
– The Sargasso Sea, enclosed by major currents, hosts unique species like the sargassum fish and serves as a spawning ground for eels.
– The Sargasso Sea’s origin was enigmatic for centuries, with recent research suggesting eels may use Earth’s magnetic field for navigation.
– The Atlantic Ocean’s gyres and currents play a crucial role in climate and oceanic ecosystems.
Climate and Natural Hazards:
– Trade winds in the Atlantic can lead to hurricane formation, with maritime climates having less extreme seasonal variations.
– Oceans are a major source of atmospheric moisture through evaporation, influencing climatic zones across latitudes.
– Natural hazards in the Atlantic include icebergs near Newfoundland, storms from the Icelandic Low, and hurricanes in the western North Atlantic.
– South Atlantic tropical cyclones are rare due to strong wind shear, with polar regions experiencing longer ice seasons but little shipping.
– The Atlantic’s climate and natural hazards are influenced by its geographic location, water characteristics, and oceanic currents.
