Introduction to the Earth Basic Terminology and Concepts Fall 2015, Lecture 1.

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Transcript of Introduction to the Earth Basic Terminology and Concepts Fall 2015, Lecture 1.

Introduction to the Earth

Introduction to the EarthBasic Terminology and Concepts

Fall 2015 , Lecture 12EcosphereThat part of the earth consisting of five spheres:AtmosphereBiosphereCryosphereHydrosphereLithosphere

3AtmosphereThe gaseous layer which surrounds the earth, and which is held by gravitational attraction. It consists of layers, the bottom ones of which are:Thermosphere > 80 kmMesopauseMesosphere45 - 80 kmStratopauseStratosphere 12 - 45 km TropopauseTroposphere 0 -12 km

4HydrosphereEarth's water, in any physical state Gaseous LiquidSolidCryosphere

Some places on Earth are so cold that water is a solidice or snow. Scientists call these frozen places of our planet the "cryosphere." The word "cryosphere" comes from the Greek word for cold, "kryos."5 The cryosphere includes Antarctica, the Arctic, and places far away from the cold poles, at high elevations. Frozen soil can be found high in the mountains of the United States, the northern reaches of Canada, China, and Russia The cryosphere expands during the cold winter months. Seasonal areas of the cryosphere include places where snow falls, and where soil, rivers, and lakes freeze.Source:


56LithosphereThe outermost part of the solid earth, consisting of the entire crust and the upper mantle, from the surface to a depth of about 70 kilometers (km)It is stronger and mechanically more rigid than the asthenosphere (70 - 250 km), which lies under it7Interior of the EarthCrust Continental (0-40 km, to a maximum of 100km) Oceanic (0-10 km)Mantle Upper (bottom of crust to 700 km, and includes the transition zone (350 to 700 km) Lower (700 - 2900 km)Core Outer (2900 - 4980 km - liquid iron-nickel)Inner (4980 - 6370 km - solid) 8BiosphereInterface layer between earth's crust, atmosphere, cryosphere, and hydrosphere where life is foundIncludes the total ecosystem of the earth9EcosystemCommunity of interacting organisms, of all species includesPlantsAnimalsMicrobesIncludes interactions of organisms within this community, and of organism with the chemical and physical systems of earth

BiomeA large community of plants and animals that occupies a distinct regionBiomes are usually divided into terrestrial and aquaticOften said to be a group of ecosystems that have a similar climate and are therefore inhabited by particular plant and animal species10Terrestrial BiomesTerrestrial biomes, typically defined by their climate and dominant vegetation, include:GrasslandTundraDesert Tropical rainforestDeciduous and coniferous forests11Aquatic BiomesFreshwaterLakes and pondsRiversMarinePelagicBenthicIntertidal zones12Pelagic BiomesPelagic is derived from the Greek work plagos, meaning Open OceanIt is the name for oceanic water not in direct contact with a shore or the bottom


Additional information is available at this source13Benthic BiomesThe benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layersOrganisms living in this zone are called benthosThey generally live in close relationship with the substrate bottom and many are permanently attached to the bottom The superficial layer of the soil lining the given body of water, the benthic boundary layer, is an integral part of the benthic zone, as it greatly influences the biological activity which takes place there 1415AnthropogenicRefers to the impact of human activities on the natural world, causing changes in the ecosystemIncludes impacts on biophysical environments, and biodiversityImpacts vary in magnitude and temporal scale, and affect the rate at which change occurs

16Environmental IssuesChanges in the ecosphere caused by:Natural processesHuman activities17Changes By Other SpeciesHumans are not the only species to cause environmental change Cyanobacteria, the first organisms capable of photosynthesis, gradually changed the atmosphere of earth from one without oxygen to one with the present 21% oxygen content Cyanobacteria were formerly known as blue-green algae1718So What Makes Humans Different?Humans are the first species to be aware of their influenceHumans assume, to some extent, responsibility for wise management of the planetHumans affect change at rates unprecedented in the geological recordAnthropoceneTerm introduced by Nobel Prize-winning atmospheric chemist Paul Crutzen in the 1970sThe term was meant to emphasize the central role of man in geology and ecology

19Prelude to the AnthropoceneSignificant human alteration of the biosphere began more than 15,000 years ago as Paleolithic tribes evolved social learning, advanced hunting and foraging technologies, and the use of fire, and used them to open up forested landscapes and kill off megafauna20Source: of AgricultureAgriculture impacted earth beginning more than 8000 years ago. Domestication of plant and animal species Engineering ecosystems to support them Humans introduced a wide range of unambiguously anthropogenic processes into the biosphere21Source:

218000 Years Before Present (YBP)8000 years ago, with a population of just 10 million or so, humans had already altered as much as a fifth of Earth's ice-free land, primarily by using fire to clear forestSmall populations had such extensive impacts because early agriculture emphasized labor efficiencyNo plowingCultivation had to be constantly shifted to the most fertile areasMost of the landscape was in some stage of recovery, giving rise to "semi-natural" woodlandsAmong the first anthropogenic biomes, or "anthromes".22Source:

22Human Transformation of EarthHuman populations increased and expanded for millenniaVast tracts of pristine forest were converted to semi-natural woodlands and less productive land into rangelandPopulation growth created ever more intensively transformed anthromes by tillage, irrigation, manuring and cropping. By 1750, more than half of the terrestrial biosphere had been converted into anthromes,Permanent record left in soils, sediments and the atmosphere23Source:

23Industrial TransformationRise of industrial systems in the past century has transformed the majority of the terrestrial biosphere into intensively used anthromes dominated by novel ecological processesAt 7 billion+ and growing, transformation of the last wild biomes into anthromes continues Process will end soon as we reach the limits of the usable biosphereAlready, more than 12 per cent of Earth's ice-free land is used continuously for crops and 16 per cent for livestock24Source:

24Start of the AnthropoceneTogether with Eugene Stoermer, Paul Crutzen proposed a start for the anthropocene as follows:To assign a more specific date to the onset of the "anthropocene" seems somewhat arbitrary, but we propose the latter part of the 18th century, although we are aware that alternative proposals can be made (some may even want to include the entire Holocene). However, we choose this date because, during the past two centuries, the global effects of human activities have become clearly noticeable. This is the period when data retrieved from glacial ice cores show the beginning of a growth in the atmospheric concentrations of several "greenhouse gases", in particular CO2 and CH4. Such a starting date also coincides with James Watt's invention of the steam engine in 1784 (International Geosphere-Biosphere Programme Newsletter 41, 2000)

25Source: Pro and AntiThe term has raised protests from stratigraphersPart of the controversy involves a definite marker for the beginning of the anthropoceneFor those wishing to know more about the controversy about the use of Anthropocene as a geologic epoch:Pro: The Anthropocene: a new epoch of geological time? Anti: Is the Anthropocene an issue of stratigraphy or pop culture? 26Pro: (Philosophical transactions of the Royal Society, 2010)The Anthropocene: a new epoch of geological time?

Anti: Article in Geology Today July 2012 (GSA)Is the Anthropocene an issue of stratigraphy or pop culture?

2627Technology ImprovementsDuring the last fifty years Have greatly contributed to our awareness of environmental changeEspecially contributing to our knowledge of global scale processesGreatly enhanced out knowledge of the temporal scale of global change28Examples of Technological ChangeSatellite observationsComputational powerRapid communication (Internet)

Blue Marble ImagesBeginning with the Apollo 8 mission, NASA has published increasing detailed images of Planet EarthNASA's Earth Observing System (EOS) has provided striking new insights into many aspects of Earth, including its clouds, oceans, vegetation, ice, and atmosphere, for the last decadeEOS satellites are being replaced by the next generation Suomi National Polar-orbiting PartnershipSuomi NPP orbits the Earth about 14 times each day and observes nearly the entire surface

29More information about the Suomi NPP