CH 47: The Biosphere

the biosphere

all spaces on Earth where life exists

climate

average weather conditions of an area over a long period of time. cloud cover, temp., humidity, and wind speed

where do air circulation patterns begin?

at the equator

30° latitude

many of the world’s great deserts are located here, including the Sahara

prevailing winds

a wind from the direction that is predominate a particular place or season

winds are named..

for the direction from which they blow.

influences on the directional movement of ocean currents

the force of major winds, Earth’s rotation, topography

coastal breezes

arise because of differences between the ability of water and land to absorb and release heat

monsoon

also arises from differential heating of water and land. wind that reverses direction seasonally

rain shadow

dry region downwind (leeward) of a coastal mountain range

leeward

mountain side facing away from the wind

ENSO

The El Niño Southern Oscillation. naturally occurring, irregularly timed fluctuations in sea surface temperature and wind patterns. occurs in equatorial pacific

biomes

distinctive biological communities that are adapted to particular physical conditions, characterized by predominant vegitation

deserts

receive an average of 10cm (4 inches) or less rainfall per year. located mainly at 30° latitude or in the rain shadow of a mountain range.

desert crust

a community that can include cyanobacteria, lichens, mosses, and fungi. secrete organic molecules that glue them to the soil. holds soil particles in place

temperate grassland

warm in the summer, cold in the winter. annual rainfall 10-40 in, with rains throughout the year. form in the interior of continents between deserts and temperate forests. cannot support woodlands.

tropical savannas

broad belts of grasslands with a few scattered shrubs and trees. 35-60in of rain during rainy season. abundant wildlife. lie between the tropical forests and hot deserts of Africa, India, and Australia

dry shrubland

biome dominated by fire-adapted shrubs. typically occurs on continent’s western coasts between 30 and 40° latitude. hot, dry summers and mild, wet winters. plants tend to have small, leathery leaves to withstand summer droughts.

temperate deciduous forests

form in the Northern Hemisphere. 20-60in precipitation/year. warm summers, cool winters. rich soil, somewhat open canopy

tropical rain forests

Occur between latitudes 10 degrees north and south of \n the Equator in Africa, the East Indies, Southeast Asia, \n South America, and Central America. 50-80 in rain yearly. greatest primary production of any land biome. most structurally complex and species-rich biome. soils are poor in nutrients

conifers

evergreen trees with seed-bearing cones. leaves are typically needle-shaped tolerant of cold, drought, and poor soil

Boreal forests

also known as taiga or “swamp forest”. Extensive high-latitude forest of the Northern Hemisphere; conifers are the predominate vegetation. Sweeps across northern Asia, Europe, and North \n America

montane coniferous forests

\
Extend southward through the great mountain ranges of \n North America

arctic tundra

Occurs between the polar ice cap and the belts of boreal \n forests in the Northern Hemisphere. most in Russia and China. annual precipitation is less than 10 in. harsh condition, permafrost, home to lichens and shallow rooted low growing plants.

permafrost

under top layer of soil – continually frozen soil layer \n that lies beneath artic tundra and prevents water from draining

alpine tundra

occurs at high altitudes throughout the world, no permafrost. thin, nutrient-poor soil. has grasses and small leafed woody shrubs, strong winds discourage tree growth.

lake

body of freshwater divided into zones that differ in physical characteristics and species composition. undergo succession - change over time

littoral zone

extends around the shore to a depth where \n rooted aquatic plants stop growing

limnetic zone

\
is the open waters where light penetrates and \n photosynthesis occurs

profundal zone

area deep enough light cannot penetrate

new lakes

are oligotrophic. deep, clear, and nutrient poor

spring overturn

in temperate zone lakes, a \n downward movement of oxygenated surface water and \n an upward movement of nutrient-rich water in spring

thermocline

thermal stratification in a large body of \n water; a cool mid-layer stops vertical mixing between \n warm surface water above it and cold water below it

fall overturn

\
During the fall, water of a temperate \n zone lake mix. Upper oxygenated water cools, gets \n dense, and sinks; nutrient-rich water from the bottom \n moves up

estuary

partly enclosed body of water where freshwater from a \n nutrient-rich river meets and mixes with seawater. Freshwater floats on top of seawater where they meet

spartina

\
Dominant plant in salt marshes of the Atlantic \n coast. Has a gland on its leaves that allows it to \n excrete salt taken up by roots

coral reefs

wave-resistant formations of calcium carbonate secreted by coral polyps

pelagic province

“the oceans waters” water over continental shelves and more extensive water further offshore

benthic province

ocean bottom; sediments and rocks

seamounts

undersea mountains, abundance of life makes these attractive to commercial fishing vessels

hydrothermal vents

hot, mineral rich water spews out from an opening on the ocean floor