Oceanic Zones
What zone oceanic zone is a depth of 0-200 meters, known for having sunlight, is the warmest and most biologically active and commonly house. Plankton, fish and marine mammals.
Epipelagic Zone ( Sunlight Zone)
Uses sound waves to map seafloor and detect underwater objects. 1910s
SONAR (Sound navigation and ranging)
- **What they are:** Formed by wind blowing over the surface of the water. - **Types:** - **Capillary Waves (Ripples):** Small, short-lived waves created by light winds. - **Gravity Waves:** Larger waves where gravity acts as the restoring force. - **Swell:** Long-wavelength waves that travel across oceans after a storm.
Wind-Generated Waves*
Description:** The outermost layer of the Earth, composed of solid rock. It is relatively thin compared to other layers, ranging from about **5 to 70 kilometers (3 to 44 miles)** in thickness.
- **Types:** - **Continental Crust:** Thicker and composed mainly of granitic rocks. - **Oceanic Crust:** Thinner, denser, and primarily made of basalt.
- **Importance to Oceanography:**
- The oceanic crust forms the **sea floor**, influencing ocean depth and topography.
- The interaction between continental and oceanic crust (subduction zones) affects **tectonic activity**, which can lead to **tsunamis** and **earthquakes**.
Crust**
**Location:** North Atlantic Ocean
- **Major Currents:**
- **Gulf Stream:** Warm current flowing north along the eastern coast of North America.
- **North Atlantic Current:** A continuation of the Gulf Stream across the Atlantic.
- **Canary Current:** A cooler current flowing south along the northwest coast of Africa.
- **Importance:**
- Influences climate in North America and Europe (mild winters in Western Europe).
- Plays a role in nutrient distribution, supporting diverse marine ecosystems.
North Atlantic Gyre**
Mesopelagic Zone
Measures Salinity, temperature, and depth of seawater. Helps to understand ocean currents climate change and water column properties, and water column properties. 1960s
CTD (Conductivity, temperature, depth)
*What they are:** Large, powerful waves caused by **seismic activity** (earthquakes, volcanic eruptions, landslides). - **Characteristics:** - Long wavelengths (can be over 100 km). - Travel fast in deep water (up to 500-800 km/h). - Grow in height when reaching shallow coastal waters.
Tsunamis**
Mantle**
*Description:** Located beneath the crust, the mantle extends to about **2,900 kilometers (1,800 miles)** deep and is composed of semi-solid rock that can flow slowly over geological time. - **Importance to Oceanography:** - The mantle's convection currents drive **plate tectonics**, affecting the formation of ocean basins, mid-ocean ridges, and volcanic activity. - The movement of tectonic plates influences **ocean currents** and **climate** over long periods.
- **Location:** South Atlantic Ocean
- **Major Currents:**
- **Brazil Current:** Warm current flowing south along the Brazilian coast.
- **South Atlantic Current:** Flows eastward across the southern Atlantic.
- **Benguela Current:** A cold current flowing north along the southwestern coast of Africa.
- **Importance:**
- Influences weather patterns in South America and Africa.
- Supports rich fisheries, particularly off the coast of Namibia due to upwelling of nutrient-rich waters.
South Atlantic Gyre**
Depth 1000-4000 meters, no sunlight, cold high pressure slow moving life, angler fish, viper fish, gulper eel, and giant squid
Bathypelagic Zone (Midnight Zone)
Autonomous floats that drift through the ocean collecting temperature, salinity and depth data. Provide Realtime data. Fist used in 1999 over 4000 globally
Argo Floats
**What they are:** Waves generated by the **gravitational pull of the Moon and Sun**.
- **Types:** - **Spring Tide:** When the Sun, Moon, and Earth align, causing **higher high tides and lower low tides**. - **Neap Tide:** When the Sun and Moon are at right angles to Earth, causing **less extreme tides**.
Tidal Waves (Tides)*
Description:** A liquid layer composed mainly of iron and nickel, extending from about **2,900 kilometers (1,800 miles)** to **5,150 kilometers (3,200 miles)** deep. - **Importance to Oceanography:** - The motion of the outer core generates the Earth's **magnetic field**, which can impact marine navigation and the behavior of certain marine organisms sensitive to magnetic fields.
Outer Core
*Location:** North Pacific Ocean
- **Major Currents:**
- **Kuroshio Current:** Warm current flowing north along the Japanese coast.
- **North Pacific Current:** Flows eastward across the Pacific.
- **California Current:** A cold current flowing south along the U.S. West Coast.
- **Importance:**
- Affects climate and weather patterns in North America and Asia.
- Hosts significant marine biodiversity, including important fisheries (e.g., salmon).
North Pacific Gyre**
Abyssopelagic Zone(Abyss Zone)
Collects seawater samples at different depths without contamination to measure biological and chemical properties. (nutrients, oxygen, and pH)
Niskin Bottles (1966)
**What they are:** Waves that occur within the ocean, between layers of different densities. - **Characteristics:** - Move **slowly** compared to surface waves. - Can be **hundreds of meters high** but barely visible at the surface. - Important for **mixing ocean water** and transporting nutrients.
Internal Waves**
Description:** The innermost layer, composed of solid iron and nickel, with temperatures reaching up to **5,700 °C (10,300 °F)**. It is about **1,220 kilometers (760 miles)** in radius. - **Importance to Oceanography:** - While the inner core does not directly influence ocean processes, its existence contributes to the Earth's **geological stability** and overall heat budget, which affects mantle convection and plate movements.
Inner Core**
ocation:** South Pacific Ocean
- **Major Currents:**
- **East Australian Current:** Warm current flowing south along the eastern coast of Australia.
- **South Pacific Current:** Flows eastward across the South Pacific.
- **Peru Current:** A cold current flowing north along the west coast of South America.
- **Importance:**
- Influences weather patterns and marine life along the coasts of Australia and South America.
- Significant for upwelling zones that support rich fishing grounds, particularly off the coast of Peru.
South Pacific Gyre**
Hadalpelagic zone(Deepest Ocean/Trenches)
Measures temperature profiles in the upper ocean by dropping probe that transmits as it sinks is used on research ships and commercial vessels to monitor ocean heat content.
XBT( Expendable Bathythermograph) - 1940s
*What they are:** Sudden, unexpected waves much larger than surrounding waves.
- **Causes:** - Constructive interference (multiple waves combining). - Strong ocean currents against wave movement. - **Characteristics:** Can reach over **30 meters (100 feet)** and are dangerous to ships.
Rogue Waves**
- **Geological Features:** The Earth's layers play a crucial role in forming oceanic features like **mid-ocean ridges**, **trenches**, and **volcanic islands**, impacting ocean circulation patterns and marine habitats. - **Climate and Currents:** The geological processes governed by the layers influence **ocean currents**, which are essential for regulating global climate, nutrient distribution, and marine ecosystems. - **Natural Disasters:** Understanding the Earth’s structure helps predict and manage **natural disasters** (like tsunamis and earthquakes) that can profoundly affect coastal communities and marine environments.
Significance to Oceanography**
*Location:** Indian Ocean
- **Major Currents:**
- **Agulhas Current:** Warm current flowing south along the southeast coast of Africa.
- **North Equatorial Current:** Flows westward across the Indian Ocean.
- **West Australian Current:** A cold current flowing north along the southwestern coast of Australia.
- **Importance:**
Indian Ocean Gyre**