Definitions: Module 16-20 Flashcards
soil
- a natural body consisting of layers, horizons and/or organic material of variable thickness
- differs from parent material by its morphology, chemical and physical properties, its mineralogy, and its biology
soil profile
- a vertical arrangement of all the soil horizons down to the parent material
- known as bedrock
soil horizon
a layer of mineral, organic soil or soil material approximately parallel to the land surface and has characteristics representing alteration by soil formation processes
topsoil
- outermost layer of an organic soil and is made up of organic matter, mineral particles, and an interactive food web
- area of intense biological activity
- crucial for the cycling of nutrients
soil texture
size of grains
grains
small fragments produced by the weathering of rocks
soil porosity
determines how air and water can travel between soil particles
nutrient
any chemical required for the proper functioning of living organisms
nutrient holding capacity
soil’s capacity to bind and hold nutrients
water holding capacity
soil’s capacity to bind and hold water
leaching
process by which materials are removed from the soil by water
groundwater
this is the water contained within the saturated zone of soil
water table
boundary between saturated and unsaturated zone of soil
infiltration rate
speed at which water can percolate into the ground
evaporative water loss
depth of water lost from the soil through evaporation
aquifer
layer of porous rock/sediment that can hold and transmit water
aquiclude
layer of non-porous rock/sediment that can hinder water movement
salinization
accumulation of salts in and out on soil to the point where plant growth is suppressed
desertification
- the deterioration of land in arid, semi-arid, and dry subsumed areas
- largely due to changes in Earth’s climate and human activities
- made worse by salinization
splash erosion
soil gets compacted as drops of rainfall his the bare soil
fluxes
- transfers of material between compartments
- occur at specific rates
- vary over time
nutrient budget
quantitative estimate of rates of nutrient input and output to and from an ecosystem and within the system
sources
compartments that release their nutrients faster than they get replenished
sinks
accumulate nutrients at a faster rate than they release them
eplimnion
shallow, wind stirred portion of the lake, depth determined by strength of wind
metalimnion
below epilimnion, thermocline is located here, depth at which temperature decreases rapidly
hypolimnion
deep, cold portion of the lake
eutrophication
- a natural process taking place in water bodies
- characterized by a development towards an environment rich in nutrients and increasing primary productivity
- this process may take years to develop
ecosystems
a community of different species interacting with one another an with their environment in order to sustain their grouping
ecotones
- a transitional region between different ecosystems
- shares many of the species and characteristics of both ecosystems
- may also contain unique conditions
- greater biodiversity
biomass pyramid
- this pyramid considers the total mass of all members of an ecosystem
- as we move up the pyramid to higher levels, the efficiency to energy conversion decreases
trophic level
- each level of a pyramid
- each one has all the organisms in the food web that are the same number of feeding levels away from the original source of energy
food chain
- represents a single feeding relationship
- starting from original source of energy to highest trophic level
- energy flows linearly in one way direction
- heat is lost at every conversion
first law of thermodynamics
energy is neither created nor destroyed
second law of thermodynamics
any energy conversion leads to less usable energy than initially
biodiversity
the sum of all organisms in the area
point source
specific spot where large quantities of pollutants are discharged
none-point source
diffuse source of pollutants
non-persistent pollutants
these pollutants can be broken down by chemical reactions or by bacteria into simple substances
persistent pollutants
these are substances that degrade very slowly or cannot be broken down at all
biochemical oxygen demand (BOD)
- measure the amount of oxygen consumed by microbes as they break down organic mater within water samples
- part of water quality testing
assimilative capacity
- capability of streams to degrade organic waste
- varies from stream to stream
sediments
rock and mineral fragments from gravel particles less than 2 millimetres in diameter, to finer sand, silt, and clay particles
