Climate

Ecosystems - made of abiotic and biotic Abiotic Factors: Temperature: usually a function of the ability of an organism to maintain homeostasis in the optimal range of its enzymes Water: precipitation, bodies of water Sunlight: base energy source for all trophic levels Provides energy for heat  warmth, weather cycles, water cycle, ocean currents Wind: moves air, moisture, pollution, seeds, animals Rocks and Soils – affects plant distribution which determines animal populations Climate: Prevailing weather conditions in the environments – mainly determined by temperature, water, sunlight and wind

Factors Affecting Climate: 1. Sunlight – amount and intensity is determined by latitude and tilt of earths axis - determines how directly the sun’s rays strike the earth – more direct = higher amounts of energy – Pg 96 – 97 Changes with Latitude: Sunlight becomes less direct moving away from the equator  rays are spread out more due to curvature of the earth – less concentrated rays = less energy - also, a greater angle of entry causes the sunlight to travel through more of the atmosphere = more scattering and reflection (less direct light)

LATITUDINAL VARIATION IN SUNLIGHT INTENSITY Figure 50.10 Low angle of incoming sunlight Sunlight directly overhead North Pole 60N 30N Tropic of Cancer 0 (equator) 30S 60S Atmosphere LATITUDINAL VARIATION IN SUNLIGHT INTENSITY Tropic of Capricorn South pole

Albedo Effect: reflected sunlight - clouds  30% of sunlight - glaciers and ice  80 – 90% - asphalt  10 – 15% - oceans and forests  5 % Non Reflected light = energy for hydrologic cycle, wind and ocean currents, photosynthesis and thermal energy for planet - UPS trucks and School Bus tops

2. Global Air Circulation: Page 99 Vertical Movement of Air Moist air near the ground is heated causing it to rise Ascending moist air cools resulting in condensation of the water High, cool, dry air descends drying out the land it hits Result of pattern: areas of wet and dry Areas of descending air = deserts Areas of rising air = Rain fall Other Results: Dispersion of hot and cold air - heat from the equator is moved away and cool air from the poles is moved down – helps regulate global temperatures

GLOBAL AIR CIRCULATION AND PRECIPITATION PATTERNS Descending dry air absorbs moisture Ascending moist air releases 30 23.5 0 Arid zone Tropics 60N 30N 0 (equator) 30S 60S GLOBAL AIR CIRCULATION AND PRECIPITATION PATTERNS

Wind: horizontal movement of air generated from different air pressures that result from temperature differentials and the Earth’s rotation Air Pressure: based on altitude, water content (humidity), air temperature Altitude: go up, pressure goes down Humidity: go up, pressure goes up Temperature: go up, pressure goes up Changes in these factors causes the pressure of the air to change – differences in the air pressures results in wind – wind blows from high pressure to low pressure – greater the difference the stronger the wind Mount Washington Video

Coriolis Effect: influence of the Earth’s rotation on the movement of the wind (inertia of the wind) Rotation: West to East – changes the direction of the wind In Northern Hemisphere – wind swirls to the right In Southern Hemisphere – wind swirls to the left

Earth’s Rotation

Global Wind Patterns (Prevailing Winds) Polar Easterlies: Originate from the North and South poles Northern Hemisphere: move from north east Southern Hemisphere: move from south east Westerlies: Originate in the mid-latitudes – move from the west Tradewinds: Tropical winds – movement in 23.5 degree Latitude NH – move from the northeast SH – move from the southeast

Effects of Wind on Climate Evaporative Cooling and Drying Wind Force on Plant Growth  Flagging

3. Bodies of Water: High specific heat of water allows for climate regulation Water absorbs and releases heat more slowly than land keeping areas near large bodies of water more moderate Convection Cell

moves inland, replacing rising warm air over land. Cooler air sinks over water. 3 Air cools at high elevation. 2 1 Warm air over land rises. 4 Cool air over water moves inland, replacing rising warm air over land.

Oceans currents: pg 102 Produced by: 1) the prevailing winds which produce gyres (swirling masses of water) 2) influenced by the Coriolis Effect 3) Density of water in ocean - cold, salty water is more dense than warm, less salty water - water is densest at 4 oC - deeper colder water moves at a different rate than the warmer surface water due to Coriolis effect

move warm and cool water which then heats and cools the air causing wind patterns and climate differentials Warm water from tropics flows and heats the air and land changing the climate Ex: England is farther north than New England but the UK is warmer because of warm ocean currents that pass by it. New England is brushed by a cold ocean current from Greenland making its climate cooler. - water then cools, sinks and returns to the tropics to reheat moves nutrients from place to place causing plankton blooms when the water rises from the ocean floor - Ocean currents can change causing severe climate changes in different regions

4. Mountains: Increase in altitude causes for cooler temperatures and greater wind - 6oC for every 1000 m - matches the decline in temperature as you move north by 880 km South sides receive more sun.

Windward sides receive more moisture than the leeward side – wind causes air to rise up and cool its moisture is lost – as it passes over the top of the mountain, the eastern side is hit by dry air  Rain Shadow (deserts) - deserts are often found on the leeward side of very high mountain ranges

Rain Shadow Windward Leeward

5. Seasonality: changes in the angle of the sun on the earth due to the rotation of the earth around the sun and the tilt of the earth of its axis – pg 97 changes in solar intensity cause for cooler and warmer seasons – changes in temperature alter ocean currents and thus wind currents changes the distribution of nutrients in the water which affects life cycles of organisms in the oceans can also result in changes in weather patterns (Ex: Hurricanes)

SEASONAL VARIATION IN SUNLIGHT INTENSITY June solstice: Northern Hemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins in Southern Hemisphere. March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. 60N 30N 0 (equator) 30S Constant tilt of 23.5 September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. December solstice: Northern Hemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere. SEASONAL VARIATION IN SUNLIGHT INTENSITY

http://physics.weber.edu/schroeder/ua/SunAndSeasons.html

6. Weather: Precipitation: Average Precipitation, Seasonal Distribution, Variation Rain - determines the plant life of the area Snow – helps replenish water supplies Fog – Distributes moisture Temperature: Temp and Precipitation  Main two factors that determine plant communities Lightning: Can start fires

7. Natural Disturbances: Tornados, Hurricanes, Earthquakes, Fires Fire Ecology: Removes standing biomass Rapid recycling of nutrients Plant life adapted to areas with periodic fires - seeds need fire to crack seed coat to germinate - smoke and heat to open cones of some pine trees - some have protective coatings Firestick Farming

8. Microclimates: protected areas in a larger climate that make for different smaller climates – Ex: Shade of a tree, under a log  specialize niches Variations in the abiotic factors result in different types of regions called biomes. Each biome has a specific type of climate which results in a particular type of organismal community.

Seasonal Changes on Lake Stratification  Turn Over – Pg 131 - Based on Thermal Stratification of Water Layers Winter: Coldest at Top of Water – decomposition of detritus in the benthic layer occurs – nutrient levels increase on the bottom of the lake

Spring: Surface Heats to 4oC – becomes more dense than the slightly cooler layers and all the water mixes causing the loss of thermal stratification – Wind also causes the water to move and mix – Oxygen is brought to the bottom of the lake and nutrients at the bottom are brought to the top – increased solar radiation gives energy to the producers (algae and plants) that use the nutrients to grow

Summer – Thermal Stratification is reestablished by the heating of the surface of the water - cooler water sinks to the bottom of the lake – establishes a thermocline – layer between the warm and cold water– lots of growth in the photic layer of the lake – dead things move to the benthic layer Autumn – water cools to the same temperature so the thermal stratification is once again removed until the winter profile is reestablished – oxygen is brought to the bottom of the lake – more decomposition can occur

Seasonal Changes in a Lake

Autumn – water cools to the same temperature so the thermal stratification is once again removed until the winter profile is reestablished – oxygen is brought to the bottom of the lake – more decomposition can occur