Chapter 5 Ecosystems and the Physical Environment

Overview of Chapter 5  Biogeochemical Cycles  Solar Radiation  The Atmosphere  The Global Ocean  Weather and Climate  Internal Planetary Processes

Biogeochemical Cycles  Matter moves between ecosystems, biotic & abiotic environments, and organisms Unlike energy Unlike energy  Biogeochemical cycling involves Biological, geologic and chemical interactions Biological, geologic and chemical interactions  Five major cycles: Carbon, Nitrogen, Phosphorus, Sulfur and Water (hydrologic) Carbon, Nitrogen, Phosphorus, Sulfur and Water (hydrologic)

The Carbon Cycle

Carbon Cycle  The global movement of carbon between organisms and the abiotic environment is known as the carbon cycle  1. Carbon is present in the atmosphere as carbon dioxide(CO 2 ), the ocean as carbonate and bicarbonate (CO 3 2-, HCO 3 -) and sedimentary rock as calcium carbonate (CaCO 3 )  2. Proteins, carbohydrates, and other molecules essential to life contain carbon  Carbon makes up approximately 0.04% of the atmosphere as a gas

Carbon Cycle  ii.Carbon primarily cycles through both biotic and abiotic environments via photosynthesis, cellular respiration and combustion (CO 2 )  1. Photosynthesis incorporates carbon from the abiotic environment (CO 2 ) into the biological compounds of producers (sugars) 6CO H energy C 6 H 12 O 6 + 6O 2 + 6H 2 O  2. Producers, consumers and decomposers use sugars as fuel and return CO2 to the atmosphere in a process called cellular respiration C 6 H 12 O 6 + 6O 2 + 6H 2 O 6CO H 2 O + Energy

Carbon Cycle…  3. Carbon present in wood and fossil fuels (coal, oil, natural gas) is returned to the atmosphere by the process of combustion (burning)  The carbon-silicate cycle (which occurs on a geological timescale involving millions of years) returns CO 2 to the atmosphere through volcanic eruptions and both chemical and physical weathering processes

The Carbon Cycle

The Nitrogen Cycle

Nitrogen Cycle i. The global circulation of nitrogen between organisms and the abiotic environment is know as the nitrogen cycle 1. Atmospheric nitrogen (N 2 ) is so stable that it must first be broken apart in a series of steps before it can combine with other elements to form biological molecules 2. Nitrogen is an essential part of proteins and nucleic acids (DNA) 3. The atmosphere is 78% nitrogen gas (N 2 )

Nitrogen Cycle ii. Five steps of the nitrogen cycle 1. Nitrogen fixation a. Conversion of gaseous nitrogen (N 2 ) to ammonia (NH 3 ) Formula: N 2 + 3H 2 2NH 3 (Ammonia), which dissolves to form NH 4 + (Ammonium)

Nitrogen Cycle b. Nitrogen-fixing bacteria (including cyanobacteria) fixes nitrogen in soil and aquatic environments (anaerobic process) c. Combustion, volcanic action, lightning discharges, and industrial processes also fix nitrogen d. Nitrogen-fixing bacteria contain a special enzyme called Nitrogenase that is used to split atmospheric nitrogen. e. Legumes such as alfalfa and beans are planted to reduce nitrogen loss in soil, since they contain helpful Rhizobium nitrogen-fixing bacteria which live inside special nodules on their roots!

Nitrogen Cycle 2. Nitrification a. Conversion of ammonia (NH 3 ) or ammonium (NH 4 +) to nitrate (NO 3 -) b. Soil bacteria perform nitrification in a two-step process (NH 3 or NH 4 + is converted to nitrite (NO 2 -) then to NO 3 -) c. Nitrifying bacteria is used in this process Formula: NH 3 + NH 4 + NO 2 - (nitrite) + NO 3 - (nitrate)

Nitrogen Cycle 3. Assimilation a. Plant roots absorb NO 3 -, NO 3 or NO 4 + and assimilate the nitrogen of these molecules into plant proteins and nucleic acids b. Animals assimilate nitrogen by consuming plant tissues (conversion of amino acids to proteins) c. This step does not involve bacteria Formula: NH 3 + NH NO 3 - DNA, Proteins, Amino Acids

The Nitrogen Cycle

Nitrogen Cycle 4. Ammonification – when plants or animals die, or when animals emit wastes, the nitrogen in the organic matter re-enters the soil, where it is broken down by decomposers. This decomposition produces ammonia! a. Conversion of biological nitrogen compounds into NH 3 (ammonia) and NH 4 + (ammonium) b. NH 3 is released into the abiotic environment through the decomposition of nitrogen-containing waste products such as urea and uric acid (birds), as well as the nitrogen compounds that occur in dead organisms c. Ammonifying bacteria is used in this process

Nitrogen Cycle 5. Denitrification a. Reduction of NO 3 - to N 2 b. Anaerobic denitrifying bacteria reverse the action of nitrogen-fixing and nitrifying bacteria

The Phosphorus Cycle

Phosphorous Cycle i.Phosphorus cycles from land to sediments in the ocean and back to land 1. Phosphorus erodes from rock as inorganic phosphates and plants absorb it from the soil 2. Animals obtain phosphorus from their diets, and decomposers release inorganic phosphate into the environment ii. Once in cells, phosphates are incorporated into biological molecules such as nucleic acids and ATP (adenosine triphosphate) iii. This cycle has no biologically important gaseous compounds, so it is essentially NOT found in the atmosphere!

Phosphorous Cycle…  iv. Phosphorous exists in the hydrosphere primarily due to absorption and assimilation of phosphorous by algae & plants in the oceans, which are then eaten by larger plankton, moves phosphorous up the food chain into fish, birds, humans, etc. Decomposers then release the inorganic phosphates back into the seawater. Decomposers then release the inorganic phosphates back into the seawater.

The Phosphorus Cycle

The Sulfur Cycle

Sulfur Cycle  i. Most sulfur is underground in sedimentary rocks and minerals or dissolved in the ocean  ii. Sulfur gases enter the atmosphere from natural sources in both ocean and land 1. Sea spray, forest fires and dust storms deliver sulfates (SO 4 2- ) into the air 1. Sea spray, forest fires and dust storms deliver sulfates (SO 4 2- ) into the air 2. Volcanoes release both hydrogen sulfide (H 2 S) and sulfur oxides (SO x ) 2. Volcanoes release both hydrogen sulfide (H 2 S) and sulfur oxides (SO x )

Sulfur Cycle  iii. A tiny fraction of global sulfur is present in living organisms 1. Sulfur is an essential component of proteins 1. Sulfur is an essential component of proteins 2. Plant roots absorb SO 4 2- and assimilate it by incorporating the sulfur into plant proteins 2. Plant roots absorb SO 4 2- and assimilate it by incorporating the sulfur into plant proteins  Animals assimilate sulfur when they consume plant proteins and covert them to animal proteins  iv. Bacteria drive the sulfur cycle

The Sulfur Cycle

The Water (Hydrologic) Cycle

Hydrologic Cycle i. The hydrologic cycle is the global circulation of water for the environment to living organisms and back to the environment 1. It provides a renewable supply of purified water for terrestrial organisms 2. the hydrologic cycle results in a balance between water in the ocean, on the land, and in the atmosphere ii. Water moves from the atmosphere to the land and ocean in the form of precipitation iii. Water enters the atmosphere by evaporation and transpiration i. The volume of water entering the atmosphere each year is about 389,500 km3

Hydrologic Cycle…  Water is returned to the oceans quickly by runoff of surface water, or more slowly by the processes of infiltration and groundwater flow.

Incoming Solar Radiation…

Solar Radiation  70% of incoming solar radiation is absorbed by atmosphere and earth Remainder is reflected Remainder is reflected  Albedo The reflectance of solar energy off earth’s surface The reflectance of solar energy off earth’s surface Dark colors = low albedo Dark colors = low albedo Forests and oceanForests and ocean Light colors = high albedo Light colors = high albedo Ice capsIce caps  Sun provides energy for life, powers biogeochemical cycles, and determines climate

Incoming Solar Radiation (Insolation)  On a typical day, 49% the Incoming Solar Radiation reaches Earth’s surface and is absorbed by the ground.  After Visible Light is absorbed, the Earth heats up and re- radiates the energy as Infrared radiation, which is also called Terrestrial radiation.

Temperature Changes with Latitude  Solar energy does not hit earth uniformly Due to earth’s spherical shape and tilt Due to earth’s spherical shape and tilt Equator (a) High concentration Little Reflection High Temperature Closer to Poles (c) Low concentration Higher Reflection Low Temperature From (a) to (c) In diagram below

January Global Temperatures

July Global Temperatures…

Temperature Changes with Season  Seasons determined by earth’s tilt (23.5°)  Causes each hemisphere to tilt toward the sun for half the year  Northern Hemisphere tilts towards the sun from March 21- September 22 (warm season)

Temperature Changes with Season  On June 21 st, the northern hemisphere experiences the longest day of the year (sun is out the longest), and the sun is at it’s highest altitude in the sky (highest angle of insolation); This day is called the summer solstice!  Earth is actually further from the Sun in July than January…so the ANGLE of insolation is the main cause of warmer temps. In summer!

Temperature Changes with Season  Places on earth receiving a lower angle of insolation will be colder, while locations receiving a higher sun angle will be hotter!

Yearly Daylight Analemma for Quito, Ecuador

Yearly Daylight Analemma for Melbourne, Australia

Yearly Daylight Analemma for Poughkeepsie, NY

The Atmosphere  Invisible layer of gases that envelopes earth  Content 21% Oxygen 21% Oxygen 78% Nitrogen 78% Nitrogen 1% Argon, Carbon dioxide, Neon and Helium 1% Argon, Carbon dioxide, Neon and Helium  Density decreases with distance from Earth’s surface!  Pressure decreases with distance from Earth’s surface!  Our atmosphere shields earth from high energy radiation

Atmospheric Layers  Troposphere (0-10km) Where weather occurs Temperature decreases with altitude Highest airplanes fly near the top of the troposphere This layer is warming up due to the trapping of greenhouse gases (carbon dioxide mainly)

Atmospheric Layers  Stratosphere (10-45km) Temperature increases with altitude- very stable Ozone layer absorbs UV radiation, which is why temperature rises here!  Mesosphere (45-80km) Temperature decreases with altitude

Atmospheric Layers  Thermosphere (80-500km) Gases in thin air absorb x-rays and short-wave UV radiation = very hot Gases in thin air absorb x-rays and short-wave UV radiation = very hot Source of aurora Source of aurora  Exosphere (500km and up) Outermost layer Outermost layer Atmosphere continues to thin until converges with interplanetary space Atmosphere continues to thin until converges with interplanetary space

Atmospheric Circulation  Near Equator Warm air rises, cools and splits to flow towards the poles Warm air rises, cools and splits to flow towards the poles  ~30°N&S sinks back to surface Air moves along surface back towards equator Air moves along surface back towards equator  This occurs at higher latitudes as well Moves heat from equator to the poles Moves heat from equator to the poles

Surface Winds  Large winds due in part to differences in pressure caused by global circulation of air Left side of diagram Left side of diagram  Winds blow from high to low pressure Right side of diagram Right side of diagram Low Low Low High High High High

Coriolis Effect  Earth’s rotation influences direction of wind Earth rotates from East to West Earth rotates from East to West Deflects wind from straight-line path Deflects wind from straight-line path  Coriolis Effect Influence of the earth’s rotation on movement of air and fluids Influence of the earth’s rotation on movement of air and fluids Turns them Right in the Northern Hemisphere Turns them Right in the Northern Hemisphere Turns them Left in the Southern Hemisphere Turns them Left in the Southern Hemisphere

Coriolis Effect  Visualize it as a Merry-Go-Round (see below)

Global Ocean Circulation  Prevailing winds produce ocean currents and generate gyres  Example: the North Atlantic Ocean Trade winds blow west Trade winds blow west Westerlies blow east Westerlies blow east Creates a clockwise gyre in the North Atlantic Creates a clockwise gyre in the North Atlantic  Circular pattern influenced by coriolis effect

Global Ocean Circulation Trade winds Westerlies

Position of Landmasses Very little land in the Southern Hemisphere Large landmasses in the Northern Hemisphere help to dictate ocean currents and flow

Vertical Mixing of Ocean

 Warmed water will rise, while colder, more salty water will sink.  Creates a global circulation of ocean water  Wind may blow warm water away from a location, allowing for upwelling of colder, nutrient-rich waters from depth.

Ocean Interaction with Atmosphere- ENSO  El Niño-Southern Oscillation (ENSO) Def: periodic large scale warming of surface waters of tropical eastern Pacific Ocean Def: periodic large scale warming of surface waters of tropical eastern Pacific Ocean  Alters ocean and atmospheric circulation patterns  Normal conditions- westward blowing tradewinds keep warmest water in western Pacific  ENSO conditions- trade winds weaken and warm water expands eastward to South America Big effect on fishing industry off South America Big effect on fishing industry off South America

ENSO Climate Patterns

El Nino & La Nina Events What is an “El Nino” or a “La Nina”? What is an “El Nino” or a “La Nina”? –An El Niño/La Nina event is an oscillation of the ocean-atmosphere system in the tropical Pacific having important consequences for weather around the globe. –This interaction is sometimes called ENSO = El Nino/Southern Oscillation –El Nino & La Nina are the changes that occur in the ocean sea surface temperatures –The “Southern Oscillation” refers to the atmospheric changes occurring, specifically the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin, Australia.

El Nino & La Nina cause major world wide climate consequences: (El Nino Climate Consequences Shown Here)

Normal Conditions in the Tropical Pacific Ocean…

Typically, strong trade winds (from both North and South), meet up and blow ocean water AWAY from coast of Peru, pushing warm water toward the western tropical Pacific (near Australia) Typically, strong trade winds (from both North and South), meet up and blow ocean water AWAY from coast of Peru, pushing warm water toward the western tropical Pacific (near Australia) This allows cold water upwelling off the coast to replace the warm water that has departed. This allows cold water upwelling off the coast to replace the warm water that has departed. Fishing industry benefits greatly, because cold water upwelling brings nutrients to supply base of elaborate food web! Fishing industry benefits greatly, because cold water upwelling brings nutrients to supply base of elaborate food web!

Normal Conditions in the Tropical Pacific Ocean…

El Nino Conditions During El Niño, the trade winds weaken in the central and western Pacific leading to a depression of the thermocline in the eastern Pacific (typically off the coast of Peru). During El Niño, the trade winds weaken in the central and western Pacific leading to a depression of the thermocline in the eastern Pacific (typically off the coast of Peru).

El Nino The deeper thermocline results in less upwelling, lack of nutrients, and a loss of productivity and fish! The deeper thermocline results in less upwelling, lack of nutrients, and a loss of productivity and fish! The deeper thermocline impacts climate world- wide! The deeper thermocline impacts climate world- wide!

El Nino Conditions…

Recognizing El Nino… El Nino can be identified by monitoring Sea Surface Temperatures in the tropical Pacific ocean, using moored buoys (see diagram). El Nino can be identified by monitoring Sea Surface Temperatures in the tropical Pacific ocean, using moored buoys (see diagram). Buoys send data continuously to satellite, which transmits back to NOAA computers Buoys send data continuously to satellite, which transmits back to NOAA computers

NORMAL CONDITIONS EL NINO CONDITIONS

El Nino Impacts

La Nina Conditions: During La Nina, trade winds strengthen, thereby more effectively pushing warm surface water westward, away from the coast of Peru, and allowing for increased cold water upwelling off the coast, enhancing the productivity and fishing habitats. During La Nina, trade winds strengthen, thereby more effectively pushing warm surface water westward, away from the coast of Peru, and allowing for increased cold water upwelling off the coast, enhancing the productivity and fishing habitats.

La Nina Conditions

A look at all three conditions…

Where did the name come from? El Niño was originally recognized by fisherman off the coast of South America as the appearance of unusually warm water in the Pacific ocean, occurring near the beginning of the year. El Niño was originally recognized by fisherman off the coast of South America as the appearance of unusually warm water in the Pacific ocean, occurring near the beginning of the year. El Niño means The Little Boy or Christ child in Spanish. This name was used for the tendency of the phenomenon to arrive around Christmas. El Niño means The Little Boy or Christ child in Spanish. This name was used for the tendency of the phenomenon to arrive around Christmas. La Niña means The Little Girl. La Niña means The Little Girl.

La Nina Impacts …

Animated SST Sequence: ENSO

Most Recent ENSO Index

Weather and Climate  Weather The conditions in the atmosphere at a given place and time The conditions in the atmosphere at a given place and time Temperature, precipitation, cloudiness, etc. Temperature, precipitation, cloudiness, etc.  Climate The average weather conditions that occur in a place over a period of years The average weather conditions that occur in a place over a period of years 2 most important factors: temperature and precipitation 2 most important factors: temperature and precipitation Earth as many climates Earth as many climates

Rain Shadows  Mountains force humid air to rise  Air cools with altitude, clouds form and precipitation occurs (windward side)  Dry air mass moves down opposite leeward side of mountain

Tornadoes  Powerful funnel of air associated with a severe thunderstorm  Formation Mass of cool dry air collides with warm humid air Mass of cool dry air collides with warm humid air Produces a strong updraft of spinning air under a cloud Produces a strong updraft of spinning air under a cloud Spinning funnel becomes tornado when it descends from cloud Spinning funnel becomes tornado when it descends from cloud  Wind velocity= up to 300mph  Width ranges from 1m to 3.2km

Tropical Cyclone  Giant rotating tropical storms  Wind >119km per hour  Formation Strong winds pick up moisture over warm surface waters Strong winds pick up moisture over warm surface waters Starts to spin due to Earth’s Starts to spin due to Earth’s rotation rotation Spin causes upward spiral Spin causes upward spiral of clouds of clouds  Damaging on land High winds High winds Storm surges Storm surges

Internal Planetary Processes  Layers of the earth Lithosphere Lithosphere Outermost rigid rock layer composed of platesOutermost rigid rock layer composed of plates Asthenosphere Asthenosphere Uppermost mantle comprised of hot soft rock (rock behaves “plastically” here)Uppermost mantle comprised of hot soft rock (rock behaves “plastically” here)  Plate Tectonics- study of the processes by which the lithospheric plates move over the asthenosphere  Plate Boundary- where 2 plates meet Common site of earthquakes and volcanoes Common site of earthquakes and volcanoes

Plates and Plate Boundaries

Types of Plate Boundaries  Divergent Plate Boundary-2 plates move apart  Convergent Plate Boundary-2 plates move together (may get subduction)

Types of Plate Boundaries  Transform Plate Boundary- 2 plates move horizontally in opposite, parallel directions

Earthquakes  Caused by the release of accumulated energy as rocks in the lithosphere suddenly shift or break Occur along faults Occur along faults Energy released as seismic wave Energy released as seismic wave  Focus- the site where the earthquake originates below the surface  Epicenter- located on the earth’s surface, directly above the focus  Richter scale and the moment magnitude scales are used to measure the magnitude

Tsunami  Giant undersea wave caused by an earthquake, volcanic eruption or landslide Travel > 450mph Travel > 450mph  Tsunami wave may be 1m deep in ocean Becomes 30.5m high on shore Becomes 30.5m high on shore  Magnitude 9.3 earthquake in Indian Ocean Triggered tsunami that killed over 230,000 people in South Asia and Africa Triggered tsunami that killed over 230,000 people in South Asia and Africa