Environmental Science Quiz

• Chapter 23 discusses global ecology, covering various concepts and applications that affect ecological systems on a global scale

The El Niño Southern Oscillation (ENSO)

• A large-scale atmospheric and oceanic phenomenon that influences ecological systems globally

Human Impact on Nitrogen Cycling

• Human activity has significantly increased the amount of nitrogen cycling through the biosphere

Land Use and Biological Diversity

• Rapid changes in global land use patterns pose threats to biological diversity

Atmospheric Composition

• Human activities are altering what the atmosphere is made up of

Atmospheric Composition

• Clean, dry air at Earth's surface contains about 78.08% nitrogen, 20.94% oxygen, 0.93% argon, and 0.03% carbon dioxide, with trace amounts of ozone, helium, hydrogen, krypton, methane, and neon

Atmospheric Layers

• The highest concentrations of atmospheric gases are in the troposphere, which extends 9 to 16 km above Earth
• The stratosphere, which extends to an altitude of 50 km, contains most of the ozone that shields Earth from UV light
• Above the troposphere, the mesosphere and the thermosphere are found

Greenhouse Effect

• The atmosphere keeps Earth's surface warm through the greenhouse effect
• Greenhouse gases include water vapor, CO2, methane,ozone, nitrous oxide, and CFCs trap heat
• Gases absorb infrared radiation and re-emit most back to Earth
• The atmosphere/surface absorbs 70% of incoming solar energy, while 30% is reflected by clouds and particles

Climate Change and Ecosystems

• It is important to study patterns across multiple taxa over long periods
• Menzel et al. used 100,000 time series records to study plant phenological shifts
• Parmesan and Yohe (2003) analyzed many studies
• They found significant, nonrandom patterns of change following climate records across >1,700 taxonomic groups

The El Niño Southern Oscillation (ENSO)

• Definition: A large-scale atmospheric and oceanic phenomenon that influences ecological systems globally
• During ENSO, a warm water current forms by Peru, usually during Christmas, and El Niño refers to the Christ child
• The Southern Oscillation refers to pressure changes across the Pacific Ocean

Historical Context

• Walker (1924) found a relationship between barometric pressure across the Pacific and rainfall during monsoons
• Barometric pressure rising in the western Pacific causes a decrease in pressure in the eastern Pacific, and vice versa, known as the Southern Oscillation
• ENSO is associated with droughts in Australia, India, Indonesia, and parts of Africa
• Winter temperatures in Canada are supposedly connected to the Southern Oscillation

El Niño and Southern Oscillation Connection

• Bjerknes linked El Niño water temperatures to the Southern Oscillation
• A gradient in sea surface temperatures over the central Pacific triggers atmospheric circulation
• Air mass flows westward accumulating moisture as it warms
• Then combines with rising air in the western Pacific

Dynamics of ENSO

• ENSO is a dynamic, large-scale system that drives global climatic variability
• The eastern tropical Pacific sea surface becomes much warmer than average during its mature phase
• The barometric pressure is lower than average
• Promotes storm formation and increases pricipitation to North and South America

El Niño and La Niña

• During El Niño, sea surface temperatures in the western Pacific are cooler than average, and barometric pressure is higher than average, causing drought over the western Pacific
• La Niña: Characterized by lower sea surface temperatures and higher than average pressure in the tropical Pacific
• It brings drought to much of North America and higher than average precipitation in the western Pacific

ENSO Marine Population

• Coastal waters by the coast of South America are relatively cool
• Cool water is brought to the surface by upwelling
• During El Niño, that warm water has now shut off that upwelling
• Nutrient supply and phytoplankton production declines
• Decreases food availability for consumers and causes the food web to decline in fish population

El Niño

• A strong El Niño in 1982-83 caused storms deep into the interior of North America.
• High precipitation in the Great Salt Lake basin.
• The lake rose 3.7 m between 1983 and 1987.
• Lake salinity dropped by 50 g/L, allowing the predaceous insect Trichocorixa verticalis to invade.
• Induced a trophic cascade with increased phytoplankton biomass.
• Lake level returned to normal by 1990, reversing these changes.

El Niño and La Niña: Australia

• El Niño effects in Australia: drought, while La Niña events bring heavy rainfall.
• Associated with perennial plants
• New narrow-leaf hopbush cohorts are made during La Niña
• Plant community structure in Australia is affected by ENSO weather pattern

El Niño: Kangaroo

• Red kangaroos (Macropus rufus) are found in Australia's semiarid interior.
• Wet years, allow females to be reproductive at different stages
• Marginal conditions: Young will die after leaving the pouch
• Because a lack of food will cause the females to stop lactating

Kangaroo Reproduction

• Prolonged droughts during El Nino, causes Red kangaroos to stop breeding
• 60 days after significant rainfall they breed quickly
• Increase offspring when weather is good, helps later through El Nino induced droughts

Human Impact on Nitrogen Cycle

• Humans began to have a massive influence through industrial agriculture
• Natural Nitrogen Levels: N-Fixing Bacteria/Plants: 100 Tg/yr, Marine: 5 to 20 Tg/yr, Lightning: 10 Tg/yr and total Natural: 130 Tg/yr
• Human Nitrogen Levels: 135 to 145 Tg/yr

Tropical Deforestation

• Tropical forests are home to at least half of the Earths species
• Tropical forests occupy 73 countries and once occupied 11,610,360 km²
• Brazil, in 1998, covered 1/3 of total and Brazil has the highest deforestation rate
• 230,000 km² had been deforested, peak deforestation in 2004 was 27,000 km²

Effects of Deforestation

• Forest fragmentation has edge effects
• Isolated, edge fragments are exposed to solar radiation and wind exposure
• Fragments change their physical environment
• There is hotter higher, drier, solar intensity
• Animal group diversity decreased

Deforestation: Global

• A global loss of 76,000 km² of tropical forest happens annually in the 2000s
• Massive deforestation occurs in temperate and boreal regions as well
• Human activity has changed half the ice-free land cover of earth
• Many terrestrial biomes are highly fragmented, some nearly eliminated
• Potential to contribute to global climate change from deforestation as well

Atmospheric CO2 Composition

• Records extracted from ice cores in Greenland and Iceland
• Ice samples contained trapped atmosphere
• Antarctic ice cores contain record of last 800,000 years of atmospheric CO2
• There is a overall oscillation between 170 and 300 ppm

Atmospheric Composition

• Low CO2 levels match up with low temperatures for ice ages
• Higher CO2 happened during interglacial periods
• In the 1800 and 1900 atmospheric CO2 increased dramatically

Fossil Fuels

• 5,600 Tg/yr of Carbon released from burning fossil fuels
• In the atmosphere, a change of 3,500 Tg/yr in annual Carbon
• World War I, Great Depression, and World War II, all interrupted three major periods of increases in atmospheric CO2

Ozone

• 1985 British surveyed reduction in atmospheric ozone in arctic
• Attention switched to stopping chlorofluorocarbons (CFCs)
• 1987 Montreal Protocol happened
• Hole reached max area in 2000
• 2003 layer started recovering

This quiz covers topics in environmental science. Questions focus on nitrogen cycling, atmospheric composition, El Niño, land use impacts, and nitrogen levels.