What Ocean Surrounds Antarctica? The Definitive Guide
The ocean that surrounds Antarctica is officially recognized as the Southern Ocean, although its existence as a distinct oceanic body was debated for centuries. This vast, frigid body of water plays a crucial role in global climate regulation and supports a unique ecosystem found nowhere else on Earth.
Defining the Southern Ocean: A History of Recognition
The concept of a “Southern Ocean” has been around for a long time, with explorers and scientists recognizing the unique characteristics of the waters surrounding Antarctica. However, its official recognition as the fifth world ocean (alongside the Atlantic, Pacific, Indian, and Arctic) was relatively recent.
The Role of the International Hydrographic Organization (IHO)
The International Hydrographic Organization (IHO) is the body responsible for defining and naming oceans and seas. While the IHO initially recognized the Southern Ocean in 1937, this recognition was rescinded in 1953 due to disagreements amongst member states about its northern boundary. The debate revolved around whether the waters around Antarctica possessed sufficiently unique characteristics to warrant separate oceanic status.
Re-establishment and Ongoing Debate
The Southern Ocean was officially re-established by the IHO in 2000, although this decision has not been universally accepted. Some countries, including Australia, have always recognized it. Others, such as the United States, officially acknowledged it in 1999. The primary reason for its renewed recognition lies in the Antarctic Circumpolar Current (ACC), a powerful and unique current that flows eastward around Antarctica.
The Antarctic Circumpolar Current: The Key to Identity
The ACC is the strongest ocean current on Earth, connecting the Atlantic, Pacific, and Indian Oceans. This current is a defining feature of the Southern Ocean, isolating Antarctica from warmer waters to the north and creating distinct physical and biological conditions.
Driving Global Ocean Circulation
The ACC plays a critical role in global ocean circulation by redistributing heat and nutrients around the planet. It helps to regulate Earth’s climate and influences weather patterns worldwide. Understanding the ACC is crucial for comprehending the dynamics of the global ocean system.
Unique Characteristics of the ACC
The ACC is characterized by its high velocity, large volume transport, and circumpolar extent. It moves approximately 130 million cubic meters of water per second, significantly more than any other ocean current. The ACC is also responsible for the upwelling of nutrient-rich waters, supporting a highly productive ecosystem in the Southern Ocean.
The Unique Ecosystem of the Southern Ocean
The Southern Ocean supports a remarkably diverse and abundant ecosystem despite its harsh conditions. This ecosystem is built upon phytoplankton, microscopic marine algae that form the base of the food web.
Krill: A Keystone Species
Antarctic krill are a small, shrimp-like crustacean that plays a crucial role in the Southern Ocean ecosystem. They feed on phytoplankton and are, in turn, a vital food source for many larger animals, including whales, seals, penguins, and seabirds.
Vulnerability to Climate Change
The Southern Ocean ecosystem is particularly vulnerable to the effects of climate change. Rising ocean temperatures, ocean acidification, and changes in sea ice extent are all threatening the delicate balance of this unique environment. The loss of krill populations, for example, could have devastating consequences for the entire ecosystem.
Southern Ocean FAQs
1. What are the boundaries of the Southern Ocean?
The Southern Ocean is generally defined as the waters south of 60°S latitude, encompassing all waters surrounding Antarctica. However, some definitions extend further north based on the location of the Subantarctic Front, a region where cold Antarctic waters meet warmer subtropical waters.
2. Why is the Southern Ocean colder than other oceans?
The Southern Ocean is colder due to its proximity to Antarctica, the presence of extensive sea ice, and the isolation provided by the Antarctic Circumpolar Current. The ACC prevents warmer waters from the north from reaching the Antarctic continent, maintaining its frigid environment.
3. What is the depth of the Southern Ocean?
The average depth of the Southern Ocean is between 4,000 and 5,000 meters (13,000 and 16,000 feet). However, there are several deep trenches and basins in the region, with some reaching depths of over 7,000 meters (23,000 feet).
4. What kind of ice is found in the Southern Ocean?
The Southern Ocean is characterized by both sea ice and icebergs. Sea ice forms directly from the freezing of seawater, while icebergs are broken-off fragments of glaciers and ice shelves.
5. What are some of the marine animals that live in the Southern Ocean?
The Southern Ocean is home to a wide variety of marine animals, including whales, seals, penguins, seabirds, fish, crustaceans (such as krill), and various invertebrates. Many of these species are endemic, meaning they are found nowhere else on Earth.
6. How does the Southern Ocean affect global climate?
The Southern Ocean plays a significant role in regulating global climate by absorbing carbon dioxide from the atmosphere and redistributing heat around the planet. The ACC helps to mix ocean waters, influencing temperature and salinity patterns worldwide.
7. What are some of the environmental concerns facing the Southern Ocean?
The Southern Ocean faces numerous environmental threats, including climate change, ocean acidification, pollution, overfishing, and invasive species. These threats are impacting the health and stability of the Southern Ocean ecosystem.
8. What is the Antarctic Treaty System?
The Antarctic Treaty System is an international agreement that governs activities in Antarctica and the Southern Ocean. It promotes peace, cooperation, and scientific research, and prohibits military activities and mining.
9. What is the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR)?
CCAMLR is an international organization responsible for the conservation and management of marine living resources in the Southern Ocean. Its primary goal is to ensure the sustainable use of these resources while protecting the integrity of the ecosystem.
10. What research is being conducted in the Southern Ocean?
Scientists are conducting a wide range of research in the Southern Ocean, focusing on topics such as climate change, ocean acidification, sea ice dynamics, marine biology, and ocean circulation. This research is crucial for understanding the complex processes that govern the Southern Ocean and its role in the global environment.
11. How can I help protect the Southern Ocean?
Individuals can help protect the Southern Ocean by reducing their carbon footprint, supporting sustainable fishing practices, avoiding single-use plastics, and advocating for strong environmental policies. Education and awareness are also key to promoting conservation efforts.
12. Is it possible to visit the Southern Ocean and Antarctica?
Yes, it is possible to visit the Southern Ocean and Antarctica, typically on expedition cruises. These trips offer a unique opportunity to experience the beauty and wonder of this remote and fragile environment, while also learning about its importance and the challenges it faces. However, it’s important to choose operators committed to responsible tourism practices to minimize environmental impact.
The Southern Ocean remains a crucial, yet often overlooked, component of the global ecosystem. Understanding its significance and the threats it faces is essential for ensuring its preservation for future generations.