Chapter 1

life zone

The place where Earth's four reservoirs interact most intensively in a narrow zone

Negative feedback

-the system's response is in the opposite direction of initial input -Often self-limiting or self-regulating (having the property of homeostasis, implying a state of dynamic equilibrium)

Two important implications of Earth being a closed system

1.The amount of matter in a closed system is fixed and finite 2.If changes are made in one part of a closed system, the results of those changes eventually will affect other parts of the system

TYPES OF SYSTEMS

Isolated system Closed system Open System

Sun-synchronous or polar-orbiting

POES, polar orbiting environmental satellites), 830 km,

important cycles

The Hydrologic Cycle The Energy Cycle The Rock Cycle The Tectonic Cycle Biogeochemical Cycle

residence time

The length of time energy or matter spends in a reservoir

Closed system

boundary permits the exchange of energy, but not matter with the surroundings

Isolated system

boundary prevents the system from exchanging either matter or energy with its surroundings

Conditions favorable for life

created by interactions between the lithosphere, hydrosphere and atmosphere, and modified by the biosphere

Geostationary (Geosynchronous orbits, 35,800 km above equator) satellites

fixed their orbits above one point one Earth's surface, orbit at high altitude, very broad perspective on the surface. Geostationary Operational Environmental Satellites, GOES)

The amount and of energy or matter that is transferred

flux

sink

flux into a reservoir is greater than the flux out

Open System

one can exchange both energy and matter across its boundary

Geographic Information Systems(GIS)

provide ways for scientists to store and analyze vast amounts of data

cycle

the constant movement of material from one reservoir to another

source

the flux into a reservoir is less than the flux out

sequestration

when this time is so great that matter is isolated for very long periods, it is called

The Atmosphere

• The mixture of gases that surrounds Earth •Predominantly N2, O2, Ar, CO2, and H2O •In the context of the planet it is a very very thin layer, but it protects life from damaging solar radiation, is the reservoir for oxygen and carbon dioxide •It is the outer boundary of the Earth system

system

any portion of the universe that can be isolated from the rest for the purpose of observing and measuring changes. By observing and measuring changes, systems can be used to study complex problems

DYNAMIC INTERACTIONS AMONG RESERVOIRS

-all systems respond to inputs and, as a result, have outputs -A special kind of response, feedback, occurs when the output of the system also serves as an input -

Positive feedback

-an increase in output leads to a further increase in output -vicious cycle -destabilization

what system is the earth as a whole?

a closed system

model

a representation of something, typically a simplification of a complex original. Models of Earth processes can be physical, or graphical.

box model

a simple graphical representation of a system t can show essential features •The processes and rates by which matter or energy enters and leaves the system •The processes and rates by which matter or energy moves within the system •The amount of matter or energy in the system and its distribution

The Biosphere

•Includes all of Earth's organisms and matter that has not yet decomposed •The biosphere greatly affects every other of Earth's systems •Photosynthesis •Oxygen as a highly reactive gas

The Geosphere

•Is the solid earth •Composed mainly of rock and regolith •Where energy that comes into the Earth system from outside sources meets energy that comes from within the planet •Energy sources combine and compete to build up and wear down the materials of Earth's surface

How science works

•Observe and gather data •Formulate a hypothesis •Test the hypothesis •Subject the hypothesis to peer review •Formulate a theory •Formulate a law or principle

The Anthroposphere

•The "human sphere" •Comprises people, their interests, and their impacts on the Earth system •The part of the natural system that has been modified by humans •Includes the technosphere, specifically to technology, machines, and the built environment

Earth comprises four vast reservoirs with constant flows of energy and matter among them

•The atmosphere •The hydrosphere •The biosphere •The geosphere

The Hydrosphere

•The totality of Earth's water •Includes oceans, lakes, streams, underground water, and all snow and ice •The perennially frozen parts of the hydrosphere are collectively the cryosphere •The hydrosphere and the atmosphere store, purify, and continually redistribute water

examples of residence time

•Water typically has very short residence time in plants and animals •But somewhat longer in atmosphere (days) •Rivers (months) •Lakes(tens of years) •Groundwater (tens of hundreds of years) • Glaciers and the deep ocean (tens to many thousands of years)