Chapter 5: Environmental Systems and Ecosystem Ecology

what you need to know after this chapter.

Describe environmental systems.

Define ecosystems and discuss how living and nonliving entities interact in ecosystem-level ecology.

Discuss the fundamentals of landscape ecology, GIS, and ecological modeling.

Explain ecosystem services and discuss how they benefit our lives.

Compare and contrast how water, carbon, nitrogen, and phosphorus cycle through the environment.

Explain how human activities affect biogeochemical cycles.

Watershed

An ecosystem where all water runoff drains into a single body of water

Phosphorus

The chemical element with 15 protons and 15 neutrons. An abundant element in the lithosphere, a key element in macromolecules, and a crucial plant nutrient.

hypoxia

Low oxygen saturation of the body, not enough oxygen in the blood

System

A group of interacting, interrelated, or interdependent elements or parts that function together as a whole to accomplish a goal.

feedback loop

A systems output can serve as an input to that system

negative feedback loop

A feedback loop that causes a system to change in the opposite direction from which it is moving

positive feedback loops

a feedback loop in which change in a system is amplified

dynamic equilibrium

Result of diffusion where there is continuous movement of particles but no overall change in concentration

Hemeostasis

a state of equilibrium or constant state of natural balance in the internal environment of the body.

emergent properties

characteristics not evident in the components alone

Runoff

water that flows over the ground surface rather than soaking into the ground

airshed

the geographic area that produces air pollutants that are likely to end up in a waterway

Eutrophication

A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae or cyanobacteria.

Lithosphere

Rock and sediment beneath our feet.

atmosphere

Composed of air surrounding our plante

Hydrosphere

Encompasses all water— salt or fresh, liquid, ice, or vapor—in surface bodies, underground, and in the atmosphere.

Biosphere

part of Earth in which life exists including land, water, and air or atmosphere

Ecosystem

A biological community of interacting organisms and their physical environment.

primary production

Amount of light energy converted to chemical energy by autotrophs.

gross primary production

The total primary production of an ecosystem.

net primary production

the gross primary production of an ecosystem minus the energy used by the producers for respiration.

secondary production

Amount of chemical energy in consumers' food that is converted to new biomass.

Productivity

The value of a particular product compared to the amount of labor needed to make it.

net primary productivity

the rate at which biomass accumulates in an ecosystem

Nutrients

Substances in food that your body needs to grow, to repair itself, and to supply you with energy

Macronutrients

A chemical substance that an organism must obtain in relatively large amounts

Micronurtients

vitamins and minerals

Ecotones

Areas where ecosystems meet may consist of transitional zones

landscape ecology

The study of past, present, and future patterns of landscape use, as well as ecosystem management and the biodiversity of interacting ecosystems

patches

An area of habitat that differs from its surroundings

mosaic

Patches that are spread spatially in complex patterns

metapopulation

A group of spatially separated populations of one species that interact through immigration and emigration.

conservation biologists

scientists who study the loss, protection, and restoration of biodiversity

Geographic Information System (GIS)

A computer system that stores, organizes, analyzes, and displays geographic data.

model

A representation of an object or event

ecological modeling

the practice of constructing and testing models that aim to explain and predict how ecological systems function

nutrient cycle

Continuous flow of nutrients into and out of stores in the ecosystem; balanced, unless disturbed by human activity

Biogeo-chemical Cycles

The movement of abiotic factors between living and nonliving components with in an ecosystem: Also known as nutrient cycles

reservoir

A lake that stores water for human use.

residence time

The average time a given particle will stay in a given system

flux

The rate at which materials move between reservoirs.

source

When a reservoir releases more materials than it accepts.

sink

when a reservoir accepts more materials than it releases

hydrologic cycle

The cycle through which water in the hydrosphere moves; includes such processes as evaporation, precipitation, and surface and groundwater runoff

Evaporation

The change of a substance from a liquid to a gas

transpiration

Evaporation of water from the leaves of a plant

precipitation

Any form of water that falls from clouds and reaches Earth's surface.

Groundwater

water that fills the cracks and spaces in underground soil and rock layers

Aquifers

Subterranean, porous, water-holding rocks that provide millions of wells with steady flows of water.

water table

The upper level of the saturated zone of groundwater

carbon cycle

The organic circulation of carbon from the atmosphere into organisms and back again

nitrogen fixation

Process of converting nitrogen gas into ammonia

nitrogen-fixing bacteria

bacteria that can use nitrogen in soil to make nitrogen compounds

Nitrification

the process by which nitrites and nitrates are produced by bacteria in the soil

denitrifying bacteria

Bacteria that convert the nitrates in soil or water to gaseous nitrogen and release it back into the atmosphere.

bottleneck

A step that limited the flux of nitrogen out of the atmosphere.

Haber-Bosch process

A process to synthesize ammonia on an industrial scale. Developed by German chemists Fritz Haber + Carl Bosch, the process has enabled humans to double the natural rate of nitrogen fixation on Earth and thereby increase agricultural productivity, but also altered the nitrogen cycle.

phosphorus cycle

The movement of phosphorus atoms from rocks through the biosphere and hydrosphere and back to rocks.