Preparation by Sopel O.Preparation by Sopel O.

The lectureThe lecture

Ecology as a science and learning subject, Ecology as a science and learning subject, objectives, main environmental laws. The objectives, main environmental laws. The history of ecology. The environment. Global history of ecology. The environment. Global environmental problemsenvironmental problems. .   

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EcologyEcology is the

scientific study of the processes influencing the distribution and abundance of organisms, the interactions among organisms, and the interactions between organisms and the transformation and flux of energy and matter.

Ecology (from Greek: οἶκος, "house"; -λογία, "study of") is the scientific study of the relations that living organisms have with respect to each other and their natural environment

The environment encompasses the whole of life on earth and the complex interactions that link the living world with the physical world. In a general sense, this covers everything contained within the air, land and water. Sudden and dramatic natural changes to the environment have occurred, and continue to occur, which have the potential to upset the whole balance of the Earth's ecosystem. Significant environmental issues cause impacts throughout the world.

What is the Environment?• The environment encompasses the whole of life on earth and the complex interactions that link the living world with the physical world• In a general sense, this covers everything contained within the air, land and water• Time also is a key factor as historic issues have an influence on the status of the environment - locally and globally, both now and in the future

Environmental Change

• Sudden and dramatic natural changes to the environment have occurred in the distant past, but only relatively recently has one species had the potential to upset the whole balance of the Earth's ecosystem• The global population has risen dramatically during the last century• The rise of industry and its rapid expansion has been a major source of pollution. This has caused changes in the balanceof our environment

Ecosystems

• an assemblage of different species and their physical environment, all organized in a way that each population of organisms obtains energy and nutrients through specific pathways within the ecosystem.

Global Environmental Issues

• Global Warming• Ozone Layer Depletion• Acid Rain• Deforestation• Loss of Biodiversity• Water Pollution• Desertification• Waste disposal

Air pollutant impacts

• Greenhouse effect

• Ozone depletion

• acidification

• smog formation

• eutrophication

• human health

• ecosystem health

Outdoor air pollution

•Air pollution = material added to the atmosphere that can affect climate and harm organisms, including humans

•Air pollution can come from human-made chemicals and causes, but the majority is from natural sources.

Natural sources of air pollution

dust storms

fires

volcanoes

Artificial sources of air pollution•Human-caused air pollution includes:

• Point sources = specific spots where large amounts of pollution are discharged• (factory smokestacks)

• Non-point sources = diffuse, often made up of many small sources• (charcoal fires from thousands of homes)

Artificial sources of air pollution

•Human-caused air pollution includes:

•Primary pollutants = emitted into troposphere in a directly harmful form• (soot, carbon monoxide)

•Secondary pollutants = produced via reaction of substances added to the atmosphere with chemicals already present in the atmosphere• (ozone in troposphere)

Six “criteria pollutants”

• The EPA closely tracks 6 major types of pollutants:

–• Carbon monoxide (CO)

–• Sulfur dioxide (SO2)

–• Nitrogen dioxide (NO2)

–• Troposphere ozone (O3)

–• Lead (Pb)

–• Particulate matter

CO / SO2 / NO2

•Carbon monoxide (CO) = colorless, odorless gas. From vehicle exhaust and other sources. Dangerous; prevents oxygen uptake.

•Sulfur dioxide (SO2) = colorless gas. From coal burning for electricity and industry. Contributes to acid precipitation.

•Nitrogen dioxide (NO2) = foul-smelling red gas. From vehicle exhaust, industry, electricity. Contributes to smog and acid precipitation.

O3 / Pb / particulate matter

•Tropospheric ozone (O3) = colorless gas. Secondary pollutant from sunlight, heat, nitrogen oxides (NOx), and C-containing chemicals. Contributes to smog; harmful to living tissues.

•Lead (Pb) = metal in atmosphere as particulate. From gasoline additive, phased out in 1980s. Diverse health impacts, all bad.

•Particulate matter = any solid (or liquid) particles small enough to be carried aloft in air. Dust, soot, sulfates, nitrates. Causes respiratory damage.

CITY

PARTICLES

(μg/m3) [1995]

SO2

(μg/m3) [1998]

NO2

(μg/m3) [1998]

WHO STANDARDS < 90 < 50 < 50

PARIS 14 14 57

NEW YORK .. 26 79

BEIJING 377 90 122

BOMBAY 240 33 39

TOKYO 49 18 68

STOCKHOLM 9 3 20

- Main environmental threat to human health- SO2 and NO2 emissions Acid rain

Air pollution

Industrial smog

•Smog from industrial pollution, fossil-fuel combustion

•The kind that blanketed London in 1952

•“Gray air smog”

•Contains soot, sulfur, CO, CO2…

Industrial smog

•The U.S. had its own “killer smog” from industrial pollution. Shown is Donora, Pennsylvania, in 1948, at mid-day. Subsequent demand for legislation against pollution made U.S. air much cleaner.

Figure 11.14b

Industrial smog• Chemistry of

industrial smog:

– • Burning sulfur-rich oil or coal creates SO2, SO3, sulfuric acid, ammonium sulfate.

– • Carbon leads to CO2 and CO.

Photochemical smog•Smog from reaction of sunlight with pollutants

•The kind that blankets so many American cities today

•“Brown air smog”

•Contains tropospheric ozone, NO2, VOCs, 100 more…

•Hot sunny days in urban areas create perfect conditions.

Photochemical Smog

VOCs breakCycle, allowingPAN to form fromNO +VOC

PAN = Peroxyacetyl nitrate

Examples of Smog

Photochemical smog

•Mexico City and many of the world’s cities suffer from the brownish haze of photochemical smog.•Inversion layers and mountains can trap smog over certain cities.

Chemistry of photochemical smog:

• Nitric oxide starts a chain reaction.

• Reaction with sunlight, water vapor, hydrocarbons, results in over 100 secondary pollutants.

Figure 11.15b

Photochemical smog

Stratospheric ozone depletion•Ozone in troposphere = harmful pollutant•Ozone in stratosphere = beneficial layer protecting us

from UV radiation•“Ozone layer”— ~ 12 parts per million in lower stratosphere—is enough to absorb UV and protect us.

But in the 1960s scientists noticed ozone concentrations were dropping.

In 1974, Sherwood Rowland and Mario Molina pegged the blame on chlorofluorocarbons (CFCs).They won the Nobel Prize for this scientific detective work.•CFCs = human-made molecules in which hydrogen of hydrocarbons are replaced by chlorine and fluorine atoms•Mass-produced by industry, in refrigerants and consumer products like aerosol sprays

•In 1987, over 180 nations signed the Montreal Protocol, which restricted CFC production globally.

Stratospheric ozone depletion• In 1985, the “ozone hole” was detected over Antarctica.

•Ozone levels had declined 40–60% over the previous decade.

Stratospheric Ozone Depletion

October 1999 (average)Historically, the Antarctic ozone hole is largest during October. This image shows the data from the Total Ozone Mapping Spectrometer (TOMS) Earth Probe, for the month of October 1999.

September 17th 2001Satellite data show the area of the 2001 Antarctic ozone hole peaked at a size roughly equal to that of recent years about the same area as North America. Researchers have observed a levelling-off of the hole size and predict a slow recovery.

Acid precipitation•Acid rain, acid fog, acid snow

•Caused by reaction of pollutants like SO2 and NO with water, oxygen, and oxidants to form acids that fall to surface in precipitation:

• sulfuric acid (H2SO4)

• nitric acid (HNO3)

Acid precipitation

•Acid precipitation is created by reactions in the atmosphere, and can fall many miles from where pollution originated. Reactions to convert to acid take place in ~2 days - travel 1000 miles

Acid precipitation

•Acid precipitation has killed these conifer trees in the mountains of North Carolina.

From The Science behind the Stories

Forests affected by Acid RainNortheast USCanadaNorthern EuropeAsia

Acid Rain and Trees

Acid Rain and BuildingsMany buildings are made of concrete and or stoneThese compounds act as bases and react with acidThe building technically “weathers” very fast, or Non technically “crumbles”

The Greenhouse Effect

Radiation, atmosphere, and temperature

•Atmospheric gases that absorb the emanating radiation are greenhouse gases.•By absorbing and re-emitting this radiation, they warm Earth’s atmosphere and surface, like a greenhouse.•This popularly called the greenhouse effect.

•Rising concentrations of greenhouse gases in recent decades have resulted in global warming, an increase in Earth’s average surface temperature.

                                                                                                                                         

The continuous decrease in animal and plant populations results in a loss of genetic diversity

Global biological diversity is decreasing, due to direct and indirect human activity: hunting, loss of natural habitat (deforestation, desertification), etc.

Biodiversity

Loss of Biodiversity

Biodiversity has three key components:•Genetic diversity•Species diversity•Ecological diversity

Approximately 2.1 million species are known to exist, but up to 50 million still to be discovered

Biodiversity is important for food, drugs, maintaining ecological stability, aesthetic and cultural benefits

Natural causes and human activity can threaten biodiversity

The loss of biodiversity means ecosystems are destabilised, vital resources are lost and genetic variation is reduced

Deforestation

Biodiversity Loss from

Wetlands Destruction

Biodiversity Loss from

Deforestation

Deforestation

The deforestation of tropical rainforests is a major global problem-each year millions of hectares are lostDeforestation rates in some countries continue to increase despite worldwide pressuresRainforests are destroyed for wood products, and to make way for agricultural activities, mining and damsThe impacts of deforestation include:

Loss of livelihood for local inhabitantsVariable environmental conditions (susceptibility to flood, aggravated droughts, soil erosion etc)Loss of biodiversity and disturbance to ecosystems

Toxic, Carcinogenic,

Endocrine, Immune System

Disrupting…

Pollution

Humans depend on very small reservoirs of water for all our needs

These reservoirs cycle/ turnover very quickly

As they cycle they can either

collect pollution from other sources, or

be cleaned by passing through functioning ecosystems

Water Pollution

Dr. A. B. M. BadruzzamanDr. A. B. M. Badruzzaman 4545

Water Pollution

Water Pollution

Point Source - Example

• LUST - Leaky Underground Storage Tanks• 22% of the 1.2 million UST are LUSTy• Look at water pollution from gasoline...

Point sourceexamples