Antarctica and the Southern Ocean Overview

These flashcards provide key vocabulary terms and their definitions related to the geography, climate, and ecology of Antarctica and the Southern Ocean.

Krill Biomass

Total biomass is estimated at 500 million tonnes, making them one of the most abundant animal species on Earth.

Krill: Ecosystem Role

They are the primary food source for whales, seals, and penguins, and help sequester carbon through waste.

Krill: Climate Con

Highly vulnerable to rising ocean temperatures and the loss of sea ice, which serves as a nursery for larvae.

Antarctic Convergence Width

A biological boundary circling the continent that is approximately 20 to 50 km wide.

Antarctic Convergence: Pro

The upwelling of nutrient-rich water creates a massive surge in phytoplankton and marine diversity.

Southern Ocean Carbon Sink

Absorbs roughly 40\% of all human-induced oceanic carbon dioxide (CO_{2}).

Southern Ocean: Con

The region is highly susceptible to acidification, which threatens the survival of shell-forming organisms.

ACC Flow Strength

The Antarctic Circumpolar Current (ACC) transports between 100 and 150 million m^{3}/s of water.

ACC: Isolation Pro

It acts as a thermal barrier that prevents warmer northern waters from melting the Antarctic ice sheets.

ACC: Isolation Con

It restricts the migration of many marine species, creating a highly specialized but isolated ecosystem.

Fresh Water Storage

Antarctica contains roughly 70\% of the world’s fresh water and 90\% of the Earth's ice.

Transantarctic Mountains Scale

One of the longest ranges on Earth, stretching 3,500 km and dividing the continent into East and West.

Mount Vinson

The highest peak in Antarctica with an elevation of 4,892 meters (16,050 feet).

Polar Desert Precipitation

The continent receives less than 50 mm of precipitation annually, lower than several hot deserts.

Ice-Free Land Percentage

Only about 0.18\% of the continent's surface is ice-free, consisting of Nunataks and Dry Valleys.

Dry Valleys Record

The McMurdo Dry Valleys are the driest places on Earth, with some areas receiving no rain for 2 million years.

Katabatic Wind Velocity

Gravity-driven interior winds that can accelerate down steep slopes to reach speeds of 320 km/h.

Katabatic Winds: Cons

Causes extreme wind-chill and visibility-reducing blizzards by whipping up loose snow.

Antarctic Treaty (1959)

An international agreement dedicating the continent to peaceful scientific research and banning military activity.

Antarctic Treaty: Pro

Promotes global scientific cooperation and prevents industrial exploitation or mineral mining.

Antarctic Treaty: Con

Territorial claims remain 'frozen' rather than settled, leading to potential future geopolitical tensions.

Ice Shelf Function: Pro

Floating ice shelves 'buttress' land-based glaciers, significantly slowing their flow into the ocean.

Ice Shelf Collapse: Con

When shelves collapse (e.g., Larsen B), inland glaciers accelerate, causing a rapid rise in global sea levels.

Subglacial Lakes

There are over 400 liquid water bodies located beneath the Antarctic ice sheet; Lake Vostok is the largest and most well-known subglacial lake.