(ch 1 & 2)OCS 1005: Introduction to Oceanography and Coastal Sciences Study Notes

OCS 1005: Introduction to Oceanography and Coastal Sciences

Chapter 1: Introduction to Oceanography

  • Overview of Oceans

    • The oceans cover approximately 71% of the Earth's surface, influencing climate, weather patterns, and supporting vast ecosystems.

    • Major oceans:

    • Pacific Ocean: Largest ocean, dominating one side of the globe, located around Antarctica.

    • Atlantic Ocean: Lies between the Americas and Europe/Asia.

    • Indian Ocean: Located south of Asia.

    • Southern Ocean: Found at the South Pole.

    • Arctic Ocean: Located at the North Pole.

Water Distribution on Earth

  • Total Water on Earth:

    • 97% of the water on Earth is saltwater found in the oceans.

    • Only 2.5% of Earth's water is freshwater, distributed as follows:

    • 0.3% in lakes and rivers,

    • 30.8% in groundwater (including soil moisture, swamp water, and permafrost),

    • 68.9% trapped in glaciers and permanent snow cover.

Oceanography: Four Interconnected Sciences

  • Disciplines of Oceanography:

    • Physical Oceanography: Studies ocean movement and dynamics.

    • Chemical Oceanography: Analyzes chemical compositions and reactions occurring in the ocean.

    • Geological Oceanography: Focuses on plate tectonics and the geological nature of ocean floors and coasts.

    • Biological Oceanography: Investigates marine life and biological processes within the ocean.

Earth, Oceans, and the Universe

  • The universe contains approximately 2 trillion galaxies, with an average of 100 million to 100 billion stars per galaxy. The known count of planets stands at 4,141 as of 2020.

  • The Big Bang, occurring around 13.7 billion years ago, marked the beginning of the universe from a singular geometric point, leading to instantaneous expansion.

Formation and Age of Earth

  • The Earth formed approximately 4.6 billion years ago, initially being uniform.

  • Following 100 million years of cooling and density stratification, the Earth developed distinct layers: inner core, outer core, mantle, and crust.

Chapter 2: History of Oceanography Discovery

  • Early Navigation:

    • Polynesians, around 2,000 to 3,000 years ago, navigated vast portions of the ocean, settling on remote islands in the Pacific, with significant evidence of their maritime prowess in navigating and survival.

  • Polynesian Navigation Techniques:

    • They utilized multiple navigational markers, including stars, wind directions, wave patterns, and bird flight paths.

    • Craftsmanship in navigation also involved stick charts, where wave patterns and currents were represented to aid in voyaging.

  • Chinese Contributions to Navigation:

    • The Chinese developed early navigation techniques including the invention of the magnetic spoon compass in the 4th century BCE, which significantly aided maritime navigation.

    • Advantages included:

    • Points toward the magnetic pole,

    • Assists in determining directions at sea.

Timeline of Maritime Exploration

  • Age of Exploration (1400s-1500s):

    • Significant figures and expeditions, including those led by:

    • Prince Henry of Portugal: Known for early exploration along the west coast of Africa.

    • Ferdinand Magellan: His expedition resulted in the first circumnavigation of the globe, although he did not survive the journey.

  • Innovations Facilitating Navigation:

    • The development of the chronometer by John Harrison in 1769 for accuracy on the rolling seas.

    • Ben Franklin's Gulf Stream chart showcased observational methods and their effects on navigation times.

Navigational Techniques

  • Longitude and Latitude:

    • Latitude: Measured by the angle between the horizon and the north polar star; reported in degrees (e.g., 40° 26' 46" N).

    • Longitude: Determined by the Earth’s rotation, divided into 360°.

    • The Earth rotates 15° of longitude every hour, which is crucial for timekeeping at sea.

  • Determining Longitude:

    • Utilizing time-based observational methods with celestial bodies (the Sun) alongside the clock, with specific calculations to convert time differences into degrees of longitude.

    • Example Calculation: If local noon occurs 2 hours early based on your clock, you have traveled 30° of longitude west of your original location due to each hour correlating to 15° of earth rotation.

  • Historical Importance:

    • Maritime explorations in the 1400s and 1500s helped establish baseline methods that formed the foundations of modern oceanography and navigation.

Ethical and Practical Implications in Oceanography

  • The advancements in navigation and ocean exploration underscore the historical significance of intercultural exchanges and the implications of these discoveries on trade, migration, and global interactions.

  • Understanding the interconnectedness of ocean systems and their influence on global climate remains a crucial area for future research and preservation efforts.