AP BIOLOGY

Detailed explanation-1: -Permafrost is soil that is permanently frozen.

Detailed explanation-2: -Tundra winters are long, dark, and cold, with mean temperatures below 0°C for six to 10 months of the year. The temperatures are so cold that there is a layer of permanently frozen ground below the surface, called permafrost. This permafrost is a defining characteristic of the tundra biome.

Detailed explanation-3: -By definition, permafrost is ground that remains frozen for two or more years. The ground can consist of many substrate materials, including bedrock, sediment, organic matter, water or ice. Frozen ground is that which is below the freezing point of water, whether or not water is present in the substrate.

Detailed explanation-4: -When permafrost is frozen, plant material in the soil-called organic carbon-can’t decompose, or rot away. As permafrost thaws, microbes begin decomposing this material. This process releases greenhouse gases like carbon dioxide and methane to the atmosphere.

Detailed explanation-5: -Permafrost can be found on land and below the ocean floor. Permafrost is found in places where the average annual temperature is below about 23°F (-5° C), including most of the Arctic and all of Antarctica. Land with underlying permafrost is called tundra.