Chapter 17: Exploring the Arctic and Subarctic Oceans: A Comprehensive Guide

The Arctic and Subarctic Oceans, vast and frigid, hold a wealth of scientific secrets that have fascinated researchers for centuries. Covering an area of over 30 million square kilometers, these oceans are characterized by their unique physical, chemical, and biological processes that shape their ecosystems and influence global climate patterns.

Ocean Circulation and Climate: Chapter 17. The Arctic and Subarctic Oceans/Seas (International Geophysics Book 103)

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Physical Oceanography

Seafloor Topography and Structure

The Arctic Ocean basin is characterized by a complex seafloor topography. The fabled North Pole lies atop the Lomonosov Ridge, a submarine mountain range that bisects the basin. The Arctic Mid-Ocean Ridge, a divergent plate boundary where new oceanic crust is formed, winds its way through the Fram Strait, separating Greenland from Svalbard. The Chukchi Plateau, Siberian Shelf, and Alpha-Mendeleev Ridge, among other features, add to the diverse underwater landscape.

Ocean Currents and Circulation

The Arctic Ocean's circulation is primarily driven by the Transpolar Drift, a clockwise current that transports water from the North Atlantic into the Arctic Basin. The Beaufort Gyre, a large anticyclonic circulation pattern, dominates the Canadian Arctic, while the East Greenland Current and Irminger Current carry warm, saline Atlantic waters into the Nordic Seas. These currents play a crucial role in shaping the Arctic's climate and ecosystem.

Sea Ice and Icebergs

Sea ice, a defining feature of the Arctic Ocean, forms when seawater freezes and covers the ocean's surface. The Arctic sea ice cover varies seasonally, reaching its maximum extent in March and its minimum in September. Icebergs, massive chunks of ice that calve from glaciers, drift throughout the Arctic and pose navigation hazards.

Chemical Oceanography

Salinity and Temperature

The Arctic Ocean's salinity and temperature distribution is influenced by the influx of freshwater from rivers, melting sea ice, and the exchange of water with the Atlantic Ocean. Salinity levels are generally low, with higher salinity found in the deeper waters. Surface temperatures range from near freezing at the North Pole to around 5°C (41°F) in the Nordic Seas.

Dissolved Oxygen and Nutrients

The Arctic Ocean is generally well-oxygenated, thanks to the influx of oxygen-rich Atlantic waters. However, pockets of low oxygen concentration can occur in areas with high biological activity or reduced circulation. Nutrient levels are relatively low, but can vary seasonally and with depth.

Biological Oceanography

Phytoplankton and Zooplankton

Phytoplankton, microscopic algae that form the base of the Arctic food web, thrive in the nutrient-rich waters of the Arctic spring and summer. Zooplankton, small animals that feed on phytoplankton, are abundant and diverse, providing sustenance for higher trophic levels.

Fish and Marine Mammals

The Arctic Ocean supports a diverse array of fish species, including cod, salmon, and halibut. Marine mammals, such as polar bears, seals, and whales, are well-adapted to the harsh Arctic environment and play crucial roles in the ecosystem.

Seabirds and Other Wildlife

Seabirds, including puffins, guillemots, and ivory gulls, flock to the Arctic during the summer months to breed and feed. Other wildlife, such as walruses, arctic foxes, and snow geese, inhabit the Arctic's coastal and tundra regions.

Human Activities and Impacts

The Arctic and Subarctic Oceans have long been the domain of indigenous communities, who have relied on their resources for sustenance and cultural practices. However, in recent decades, human activities have increased significantly in the region, presenting both opportunities and challenges.

Oil and Gas Exploration

The Arctic Ocean holds vast potential for oil and gas reserves. However, exploration and extraction activities pose environmental risks and can disrupt marine ecosystems. Careful management and regulation are critical to minimize these impacts.

Commercial Fishing

Commercial fishing has a significant presence in the Arctic and Subarctic Oceans. Sustainable practices are essential to prevent overfishing and protect marine biodiversity.

Tourism

Tourism provides economic opportunities for Arctic communities. However, it is important to manage tourism responsibly to minimize environmental impacts and cultural disruptions.

Climate Change Impacts

The Arctic is experiencing rapid climate change, with rising temperatures leading to declining sea ice cover, melting glaciers, and changes in ocean circulation. These impacts have profound consequences for the Arctic ecosystem, indigenous communities, and global climate patterns.

International Geophysics

The Arctic and Subarctic Oceans have been the focus of extensive international geophysical research efforts. Notable projects include:

• International Geophysical Year (1957-1958): A collaborative effort to study the Earth's geophysical processes, including the Arctic Ocean.
• Arctic Mid-Ocean Ridge Expedition (1999-2000): A major expedition that explored the Lomonosov Ridge and Mid-Atlantic Ridge.
• International Polar Year (2007-2008): A global research effort with a significant focus on the Arctic.

These projects have advanced our understanding of Arctic and Subarctic oceanography, providing valuable insights into the region's complex ecosystems and environmental challenges.

The Arctic and Subarctic Oceans are vast and enigmatic bodies of water that play a crucial role in shaping the Earth's climate and ecosystems. Understanding these oceans is essential for addressing global challenges such as climate change and sustainable resource management. Continued scientific exploration and international cooperation are vital to unraveling the mysteries and safeguarding the future of these unique regions.

Ocean Circulation and Climate: Chapter 17. The Arctic and Subarctic Oceans/Seas (International Geophysics Book 103)

5 out of 5

Language	:	English
File size	:	2095 KB
Text-to-Speech	:	Enabled
Screen Reader	:	Supported
Enhanced typesetting	:	Enabled
Word Wise	:	Enabled
Print length	:	57 pages

FREE