ENVR 100 Exam 3: Supporting Services

lectures 11/6-11/20; textbook chapters 7, 9, 10, & 15; most definitions are pulled from the textbook

stock

a supply of something that we want to observe and measure over time

flows

the mechanism and rate by which a stock in a system changes over time

reinforcing feedback

a loop that responds to the direction of change in the stock by amplifying that same direction of change

balancing feedback

feedback that counteracts the direction in which a particular stock is changing

biogeochemical cycle

a path that shows how matter on Earth flows through different parts of the environment

macronutrients

an element that organisms require in large amounts: oxygen, phosphorus, nitrogen, & carbon

eutrophication

nitrogen fixation

a process where free nitrogen (N₂) in the air is converted to soluble ammonia (NH₄⁺) and nitrate (NO₃^-) ions that plants, algae, and bacteria can take in and use

ammonification

a process where bacteria and fungi break down nitrogen compounds in animal waste products and in dead plant and animal matter and release ammonia

nitrification

a process in which microorganisms convert ammonia to nitrogen compounds

denitrification

a process in which microorganisms use nitrogen compounds for respiration and create N₂ gas, returning it to the atmosphere

Haber-Bosch reaction

a human-made, energy and resource-intensive process of nitrogen fixation that makes synthetic nitrogen fertilizer; draws on 1% of the world’s electricity output and 4% of the global natural gas supply

photosynthesis

a series of chemical reactions involving water and carbon dioxide through which plants and some other organisms store the Sun’s energy in simple sugars

green water

water in the soils that cycles through and supports plants; does NOT include irrigation!

blue water

standing/available water in the environment such as rivers, lakes, aquifers, precipitation, etc

transpiration

the process where plants use water in the soil and then expel it as water vapor

runoff

water/soil/other substances being carried away from the surface of an area of land

GPP

gross primary production; the rate at which autotrophs produce usable chemical energy

rock cycle

the geologic process by which Earth recycles and renews its surface

3 types of rock

sedimentary, igneous, and metamorphic

weathering

physical and chemical processes that reduce rocks to smaller particles and alter minerals

erosion

a process where natural forces — such as wind, water, ice, and gravity — move weathered rock particles

lithification

the process in which sediments compact under pressure and gradually become solid rock

sediment

eroded material that is transported and accumulates in different places

minerals

a natural solid from Earth’s crust that forms rock; also provides key materials for many practical human endeavors

landforms

a surface feature of the landscape

topography

the shape of the land

watershed

an area of land that drains to a particular point along a river or stream

floodplain

a place where floods frequently send water over the banks of a river or stream channel and deposit sediment

impervious surfaces

a surface that does not allow water to pass through it

soil

the medium in which plants grow; a complex mixture of weathered rock and mineral particles (sediment), dead & decaying plant and animal matter, and the multitude of organisms that live within these materials; has components of both litho and biosphere

infiltration

a process where water (or other liquid) moves down into the soil

loam

a mixture of roughly 40% sand, 40% silt, and 20% clay particles

soil horizons

a layer in soil created by the action of living (biotic) and nonliving (abiotic) factors

topsoil

typically the first 2-6 inches of soil, encompassing the top two soil horizons

detritus

fallen leaves and other dead organic matter that supports a vast community of life

humus

a form of detritus that is even more broken down and nutrient-rich

tilth

the soil’s overall structure and conditions that facilitate plant growth

salinization

when mineral salts build up in the soil

leaching

a process driven by water where mineral elements move down to deeper soil layers, potentially beneath the reach of plant roots, to be carried away in groundwater or stream flow

tilling

preparing the soil for planting by breaking it up and turning it over with a plow

autotrophs

organisms that produce their own food

NPP

net primary production; GPP minus the rate of energy lost to metabolism; the amount of energy stored as biomass

supporting services

fundamental ecological processes controlling structure and function of ecosystems

gaseous vs sedimentary macronutrients

gaseous: carbon, nitrogen, oxygen, water; sedimentary: phosphorus

lithosphere

rock component of the Earth

biosphere

the living component of Earth

soil profiles

the collection of soil horizons at a location

order of soil horizons (top to bottom)

O, A, B, C

watershed

an area of land that drains to a particular point along a river or stream