Bringing Back Our Tundra

Bringing Back Our Tundra — page 9
ice age The tundra biome makes up 20 percent of Earth's surface Winter in the tundra lasts up to ten and a half months often beginning in late September and lasting until early June in the Northern Hemisphere It is bitterly cold and portions of the soil are permanently frozen In Arctic tundra the sun may stay completely below the southern horizon for days Winter temperatures average from 20 degrees Fahrenheit 29°C to 30 degrees Fahrenheit 34°C During the short summer season near Earth's poles the sun shines 24 hours a day Summer only lasts six to ten weeks Even during the summer tundra temperatures do not go above 54 degrees Fahrenheit 12 2°C The summer warmth thaws the top layer of soil This is called the active layer During the summer the tundra supports many ecosystems Wet sedge ecosystems lie along lakes and rivers and support sedges moist areas not near lakes or rivers support small shrubs mosses and lichen and dry upland Many plants lie dormant during the long tundra winters