Site of asteroid impact changed the history of life on Earth: the low probabi...Sérgio Sacani
Sixty-six million years ago, an asteroid approximately 9km in diameter hit the hydrocarbon- and
sulfur-rich sedimentary rocks in what is now Mexico. Recent studies have shown that this impact at
the Yucatan Peninsula heated the hydrocarbon and sulfur in these rocks, forming stratospheric soot
and sulfate aerosols and causing extreme global cooling and drought. These events triggered a mass
extinction, including dinosaurs, and led to the subsequent macroevolution of mammals. The amount
of hydrocarbon and sulfur in rocks varies widely, depending on location, which suggests that cooling
and extinction levels were dependent on impact site. Here we show that the probability of signifcant
global cooling, mass extinction, and the subsequent appearance of mammals was quite low after an
asteroid impact on the Earth’s surface. This signifcant event could have occurred if the asteroid hit the
hydrocarbon-rich areas occupying approximately 13% of the Earth’s surface. The site of asteroid impact,
therefore, changed the history of life on Earth.
Site of asteroid impact changed the history of life on Earth: the low probabi...Sérgio Sacani
Sixty-six million years ago, an asteroid approximately 9km in diameter hit the hydrocarbon- and
sulfur-rich sedimentary rocks in what is now Mexico. Recent studies have shown that this impact at
the Yucatan Peninsula heated the hydrocarbon and sulfur in these rocks, forming stratospheric soot
and sulfate aerosols and causing extreme global cooling and drought. These events triggered a mass
extinction, including dinosaurs, and led to the subsequent macroevolution of mammals. The amount
of hydrocarbon and sulfur in rocks varies widely, depending on location, which suggests that cooling
and extinction levels were dependent on impact site. Here we show that the probability of signifcant
global cooling, mass extinction, and the subsequent appearance of mammals was quite low after an
asteroid impact on the Earth’s surface. This signifcant event could have occurred if the asteroid hit the
hydrocarbon-rich areas occupying approximately 13% of the Earth’s surface. The site of asteroid impact,
therefore, changed the history of life on Earth.
ATMOSPHERE ENVIRONMENT
PRESENTORS ::
>> Cuevas, Jennifer
>> Doble, Rogin
>> Gutierrez, Arlene
>> Marasigan, Debie Joy
>> Sibuan, Andrew
The Atmosphere Environment
This chapter discusses:
The significance of the Atmosphere
The composition of the Atmosphere
The layers of the atmosphere
The Atmospheric Circulation
Importance
Atmosphere – a thin layer of air that forms a protective covering around Earth.
It keeps Earth’s temperature in a range that can support life.
It also care for life-forms from some of the Sun’s harmful rays.
The Composition of Atmosphere
The Atmosphere** layer of gas that surrounds Earth more commonly known as “air”.
Atmosphere. How do you know its there
Is this “air” that surrounds us considered matter? Does it weigh anything? How do you know?
Think about it and decide on an answer.
Talk in groups with the person who sits by you
Be ready to tell the class what you decided and why.
Weight of the atmosphere
Gases are in the atmosphere.
They are things we learned about in the periodic table: Nitrogen, Oxygen, Carbon Dioxide, Hydrogen
It is matter! Sound can travel through it.
Even though you can’t see them, Atoms make up gases.
Are some atoms bigger than others?
Are their atomic weights all the same?
Helium vs. Carbon Dioxide
Do you think of helium as light and floating or heavy and falling?
Do you think about Carbon Dioxide as light and floating or heavy and falling….think about the gas released from dry ice… does it go up or down?
Weight of the atmosphere
Gases are in the atmosphere.
They are things we learned about in the periodic table: Nitrogen, Oxygen, Carbon Dioxide, Hydrogen
It is matter! Sound can travel through it.
Even though you can’t see them, Atoms make up gases.
Are some atoms bigger than others?
Are their atomic weights all the same?
Helium vs. Carbon Dioxide
Do you think of helium as light and floating or heavy and falling?
Do you think about Carbon Dioxide as light and floating or heavy and falling….think about the gas released from dry ice… does it go up or down?
Weight of the atmosphere
Gases are in the atmosphere.
They are things we learned about in the periodic table: Nitrogen, Oxygen, Carbon Dioxide, Hydrogen
It is matter! Sound can travel through it.
Even though you can’t see them, Atoms make up gases.
Are some atoms bigger than others?
Are their atomic weights all the same?
Helium vs. Carbon Dioxide
Do you think of helium as light and floating or heavy and falling?
Do you think about Carbon Dioxide as light and floating or heavy and falling….think about the gas released from dry ice… does it go up or down?
Abstract: There are many situations where human activitieshave significant effects on the environment. Ozone layerdamage is one of them. The objective of this paper is to reviewthe origin, causes, mechanisms and bio effects of ozone layerdepletion as well as the protective measures of this vanishing layer. The chlorofluorocarbon and the halons are potent ozone depletors. One of the main reasons for the widespread concernabout depletion of the ozone layer is the anticipated increase inthe amounts of ultraviolet radiation received at the surface ofthe earth and the effect of this on human health and on the environment. The prospects of ozone recovery remain uncertain. In the absence of other changes, stratospheric ozoneabundances should rise in the future as the halogen loading fallsin response to regulation. However, the future behaviour ofozone will also be affected by the changing atmospheric abundances of methane, nitrous oxide, water vapour, sulphateaerosol, and changing climate.
ATMOSPHERE ENVIRONMENT
PRESENTORS ::
>> Cuevas, Jennifer
>> Doble, Rogin
>> Gutierrez, Arlene
>> Marasigan, Debie Joy
>> Sibuan, Andrew
The Atmosphere Environment
This chapter discusses:
The significance of the Atmosphere
The composition of the Atmosphere
The layers of the atmosphere
The Atmospheric Circulation
Importance
Atmosphere – a thin layer of air that forms a protective covering around Earth.
It keeps Earth’s temperature in a range that can support life.
It also care for life-forms from some of the Sun’s harmful rays.
The Composition of Atmosphere
The Atmosphere** layer of gas that surrounds Earth more commonly known as “air”.
Atmosphere. How do you know its there
Is this “air” that surrounds us considered matter? Does it weigh anything? How do you know?
Think about it and decide on an answer.
Talk in groups with the person who sits by you
Be ready to tell the class what you decided and why.
Weight of the atmosphere
Gases are in the atmosphere.
They are things we learned about in the periodic table: Nitrogen, Oxygen, Carbon Dioxide, Hydrogen
It is matter! Sound can travel through it.
Even though you can’t see them, Atoms make up gases.
Are some atoms bigger than others?
Are their atomic weights all the same?
Helium vs. Carbon Dioxide
Do you think of helium as light and floating or heavy and falling?
Do you think about Carbon Dioxide as light and floating or heavy and falling….think about the gas released from dry ice… does it go up or down?
Weight of the atmosphere
Gases are in the atmosphere.
They are things we learned about in the periodic table: Nitrogen, Oxygen, Carbon Dioxide, Hydrogen
It is matter! Sound can travel through it.
Even though you can’t see them, Atoms make up gases.
Are some atoms bigger than others?
Are their atomic weights all the same?
Helium vs. Carbon Dioxide
Do you think of helium as light and floating or heavy and falling?
Do you think about Carbon Dioxide as light and floating or heavy and falling….think about the gas released from dry ice… does it go up or down?
Weight of the atmosphere
Gases are in the atmosphere.
They are things we learned about in the periodic table: Nitrogen, Oxygen, Carbon Dioxide, Hydrogen
It is matter! Sound can travel through it.
Even though you can’t see them, Atoms make up gases.
Are some atoms bigger than others?
Are their atomic weights all the same?
Helium vs. Carbon Dioxide
Do you think of helium as light and floating or heavy and falling?
Do you think about Carbon Dioxide as light and floating or heavy and falling….think about the gas released from dry ice… does it go up or down?
Abstract: There are many situations where human activitieshave significant effects on the environment. Ozone layerdamage is one of them. The objective of this paper is to reviewthe origin, causes, mechanisms and bio effects of ozone layerdepletion as well as the protective measures of this vanishing layer. The chlorofluorocarbon and the halons are potent ozone depletors. One of the main reasons for the widespread concernabout depletion of the ozone layer is the anticipated increase inthe amounts of ultraviolet radiation received at the surface ofthe earth and the effect of this on human health and on the environment. The prospects of ozone recovery remain uncertain. In the absence of other changes, stratospheric ozoneabundances should rise in the future as the halogen loading fallsin response to regulation. However, the future behaviour ofozone will also be affected by the changing atmospheric abundances of methane, nitrous oxide, water vapour, sulphateaerosol, and changing climate.
Hello I am presenting before you a presentation on ozone layer depletion which includes the mechanism of it and even the detailed information about how they occur.Hope it will be helpful to the students in understanding the ozone layer depletion.
Thank You,
Tirthankar Majumder
MTech
Dept. of earth and environmental science
NIT- Durgapur
This presentation is about Ozone Layer and chemicals known to cause its depletion.
It also covers information about Ozone Hole and Correlation between Ozone depletion and skin diseases due to Ultra Violet light.It also contains no. of ways to limit ozone deterioration.
Learn all about Global warming and Ozone layer, find out why are we victims of global warming and what can we do to control the situation. Get a clear view of Ozone layer, Ozone Depletion as well as what to avoid in order to stop Ozone Depletion. Enjoy!!!
In this presentation, I focused on the geomorphological aspect of earthquake which means tectonic plates. Additionally, we also included the origin of the Universe and tectonic plates. And also the Nepal and Taiwan earthquakes of 2015 was also described here in perspective with tectonic plates.
• Earth, along with the other planets, is believed to have been born 4.5 billion years ago as a solidified cloud of dust and gases left over from the creation of the Sun.
• For perhaps 500 million years, the interior of Earth stayed solid and relatively cool, perhaps 2,000°F.
• The main ingredients were iron and silicates, with small amounts of other elements, some of them radioactive.
• As millions of years passed, energy released by radioactive decay—mostly of uranium, thorium, and potassium—gradually heated Earth, melting some of its constituents.
• The iron melted before the silicates, and, being heavier, sank toward the center.
• This forced up the silicates that it found there.
• After many years, the iron reached the center, almost 4,000 mi deep, and began to accumulate. No eyes were around at that time to view the turmoil that must have taken place on the face of Earth—gigantic heaves and bubblings on the surface, exploding volcanoes, and flowing lava covering everything in sight.
• Finally, the iron in the center accumulated as the core. Around it, a thin but fairly stable crust of solid rock formed as Earth cooled.
• Depressions in the crust were natural basins in which water, rising from the interior of the planet through volcanoes and fissures, collected to form the oceans. Slowly, Earth acquired its present appearance.
2. AtmosphereAtmosphere
The is the gaseous envelope ofThe is the gaseous envelope of
the Earth, which rotatesthe Earth, which rotates
together with it. Here is ozonetogether with it. Here is ozone
protection the life of the Earthprotection the life of the Earth
from hard to just live Solarfrom hard to just live Solar
radiation. The radiation energyradiation. The radiation energy
that is absorbed, convertedthat is absorbed, converted
into thermal energy of the gasinto thermal energy of the gas
molecules. Solar radiation,molecules. Solar radiation,
which passes to the earth'swhich passes to the earth's
surface, has a very securesurface, has a very secure
borders, and all UV rays withborders, and all UV rays with
shorter wavelength stall in theshorter wavelength stall in the
invisible light but imperviousinvisible light but impervious
layer of the ocean air.layer of the ocean air.
3. The air is pollutedThe air is polluted
with various gases,with various gases,
small slices and liquidsmall slices and liquid
substances thatsubstances that
negatively affect livingnegatively affect living
beings, worsening thebeings, worsening the
conditions of theirconditions of their
existence. Sources ofexistence. Sources of
pollution can bepollution can be
natural and artificialnatural and artificial
(anthropogenic)(anthropogenic)
4. The world economyThe world economy
annually emits more thanannually emits more than
15 billion tons of carbon15 billion tons of carbon
dioxide, 200 million tonsdioxide, 200 million tons
of carbon monoxide,of carbon monoxide,
more than 500 millionmore than 500 million
tons of hydrocarbons,tons of hydrocarbons,
120 million tons of ash120 million tons of ash
and other Total emissionsand other Total emissions
of pollutants into theof pollutants into the
atmosphere is more thanatmosphere is more than
19 billion tons.19 billion tons.
5. Principal pollutantsPrincipal pollutants
The main pollutants emitted to the atmosphere from fuelThe main pollutants emitted to the atmosphere from fuel
combustion, are solid particles (ash, soot), sulphurcombustion, are solid particles (ash, soot), sulphur
oxides (SO2 and SO3), nitrogen oxides (N0 and N02) byoxides (SO2 and SO3), nitrogen oxides (N0 and N02) by
incomplete combustion of fuel in the gaseous emissionsincomplete combustion of fuel in the gaseous emissions
can accumulate carbon oxide (CO), hydrocarbon typecan accumulate carbon oxide (CO), hydrocarbon type
CH4, SN, polycyclic aromatic hydrocarbons,CH4, SN, polycyclic aromatic hydrocarbons,
benzopyrene (C20 H12) and vanadium pentoxidebenzopyrene (C20 H12) and vanadium pentoxide
(V2O5). The last two compounds belong to the class of(V2O5). The last two compounds belong to the class of
extremely dangerous. Dioxide (SO2) and tungstenextremely dangerous. Dioxide (SO2) and tungsten
trioxide (SO3) sulphur are the main components oftrioxide (SO3) sulphur are the main components of
environmental pollution from fuel combustion.environmental pollution from fuel combustion.
6. The main global environmentalThe main global environmental
consequences of air pollution are:consequences of air pollution are:
The greenhouseThe greenhouse effecteffect
The ozone hole
7. AAcid raincid rain
Acid rain - all kinds ofAcid rain - all kinds of
meteorologicalmeteorological
precipitation: rain,precipitation: rain,
snow, hail, fog, rainsnow, hail, fog, rain
and snow, the acidityand snow, the acidity
of which is higherof which is higher
than normal. Athan normal. A
measure of the aciditymeasure of the acidity
is pH (hydrogen ionis pH (hydrogen ion
exponent). Normal pHexponent). Normal pH
in pure rain is 5.6.in pure rain is 5.6.
8. The greenhouse effectThe greenhouse effect
The greenhouse effect is aThe greenhouse effect is a
phenomenon in the atmosphere ofphenomenon in the atmosphere of
Earth and other planets, in whichEarth and other planets, in which
the energy of sunlight, reflectedthe energy of sunlight, reflected
from the surface, may not return tofrom the surface, may not return to
space, as delayed by thespace, as delayed by the
molecules of different gases,molecules of different gases,
which leads to increased surfacewhich leads to increased surface
temperatures. Without thetemperatures. Without the
greenhouse effect the Earth'sgreenhouse effect the Earth's
surface temperature is estimatedsurface temperature is estimated
would be about 33° lower than itwould be about 33° lower than it
actually is, and would be -18 °C.actually is, and would be -18 °C.
The greenhouse effect isThe greenhouse effect is
significant also on Mars and,significant also on Mars and,
especially, on Venus.especially, on Venus.
The greenhouse effect wasThe greenhouse effect was
discovered indiscovered in 1829 Joseph1829 Joseph
Fourier.Fourier.
9. Ozone hole
The ozone hole is a local drop in theThe ozone hole is a local drop in the
concentration of ozone in the stratosphereconcentration of ozone in the stratosphere
by 10-40%by 10-40%
The ozone hole with a diameter of more thanThe ozone hole with a diameter of more than
1000 km was first opened in 1985 in the1000 km was first opened in 1985 in the
southern hemisphere over Antarctica by asouthern hemisphere over Antarctica by a
group of British The Antarctic "ozone hole"group of British The Antarctic "ozone hole"
there is not constant. She appears at thethere is not constant. She appears at the
end of the local winter - early spring. Theend of the local winter - early spring. The
reasons why the ozone hole is formed in thereasons why the ozone hole is formed in the
Antarctic associated with the peculiarities ofAntarctic associated with the peculiarities of
local climate. Low temperatures of thelocal climate. Low temperatures of the
Antarctic winter lead to the formation of theAntarctic winter lead to the formation of the
polar vortex. The air inside this vortexpolar vortex. The air inside this vortex
moves mostly closed trajectories around themoves mostly closed trajectories around the
South pole. At this time the polar region notSouth pole. At this time the polar region not
illuminated by the Sun, and therefore theilluminated by the Sun, and therefore the
ozone there is not formed. With the onset ofozone there is not formed. With the onset of
summer, the amount of ozone increasessummer, the amount of ozone increases
and comes back to normal. That is, theand comes back to normal. That is, the
seasonal variations of ozone concentrationseasonal variations of ozone concentration
over Antarctica are natural. However, ifover Antarctica are natural. However, if
track changes averaged over a year ozonetrack changes averaged over a year ozone
concentration and size of the ozone hole inconcentration and size of the ozone hole in
recent decades, there is a definiterecent decades, there is a definite
downward trend in ozone concentration anddownward trend in ozone concentration and
the increase in the area, which covers thisthe increase in the area, which covers this
process in the winter. Over the Northernprocess in the winter. Over the Northern
hemisphere in the Arctic is formed a holehemisphere in the Arctic is formed a hole
much smaller.much smaller.
10. Ozone hole
The ozone hole is a local drop in theThe ozone hole is a local drop in the
concentration of ozone in the stratosphereconcentration of ozone in the stratosphere
by 10-40%by 10-40%
The ozone hole with a diameter of more thanThe ozone hole with a diameter of more than
1000 km was first opened in 1985 in the1000 km was first opened in 1985 in the
southern hemisphere over Antarctica by asouthern hemisphere over Antarctica by a
group of British The Antarctic "ozone hole"group of British The Antarctic "ozone hole"
there is not constant. She appears at thethere is not constant. She appears at the
end of the local winter - early spring. Theend of the local winter - early spring. The
reasons why the ozone hole is formed in thereasons why the ozone hole is formed in the
Antarctic associated with the peculiarities ofAntarctic associated with the peculiarities of
local climate. Low temperatures of thelocal climate. Low temperatures of the
Antarctic winter lead to the formation of theAntarctic winter lead to the formation of the
polar vortex. The air inside this vortexpolar vortex. The air inside this vortex
moves mostly closed trajectories around themoves mostly closed trajectories around the
South pole. At this time the polar region notSouth pole. At this time the polar region not
illuminated by the Sun, and therefore theilluminated by the Sun, and therefore the
ozone there is not formed. With the onset ofozone there is not formed. With the onset of
summer, the amount of ozone increasessummer, the amount of ozone increases
and comes back to normal. That is, theand comes back to normal. That is, the
seasonal variations of ozone concentrationseasonal variations of ozone concentration
over Antarctica are natural. However, ifover Antarctica are natural. However, if
track changes averaged over a year ozonetrack changes averaged over a year ozone
concentration and size of the ozone hole inconcentration and size of the ozone hole in
recent decades, there is a definiterecent decades, there is a definite
downward trend in ozone concentration anddownward trend in ozone concentration and
the increase in the area, which covers thisthe increase in the area, which covers this
process in the winter. Over the Northernprocess in the winter. Over the Northern
hemisphere in the Arctic is formed a holehemisphere in the Arctic is formed a hole
much smaller.much smaller.