Chapter 10 Flashcards
what is decomposition?
Breakdown of chemical bonds
formed during the construction
of plant and animal tissue
soils of old cemeteries have higher P content than control soil.
true
what are the benefits of composting?
concentrates plant-available nutrients and C:N decreases
who is a decomposer?
Organisms which feed on dead organic
matter
Saprophytes/Saprophages
Feeding or growing upon dead
organic matter. Microbial decomposers
(bacteria, fungi, protozoa)
Detritivores
An animal that feeds on
dead organic material
Scavengers
Large animals that mosty
consume carcasses
of other animals
Some plants without
chlorophyll are called
“saprophytic”.
Corallorhiza maculata
“Saprophytic” plants
actually get their energy
from saprophytic fungi
12
But they are not truly
saprophytic.
Decomposers support diverse foodwebs.
true
Centipedes are fierce predators.
true
the more tree is removed, the more springtail diversity reduced
microbial decomposers
Plant material, esp. wood, decomposed to a
large extent by fungi, animal material by bacteria
Mineralization
Release of inorganic nutrients from organic
matter
Immobilization
Incorporation of mineral nutrients into an organic
form in organisms
what is the role of mineralization and immobilization ?
During decomposition, both mineralization and
immobilization happens. While decomposers set
inorganic molecules free, they also immobilize
some of them in their own body, as they grow
both hay and straw are dead grass
true
what is hay?
Hay is grass, legumes or other
herbaceous plants that have been
cut, dried, and stored for use as
animal fodder, particularly for
grazing livestock such as cattle,
horses, goats, and sheep. It has a
low C/N ratio, it is cut when growing
what is straw?
Straw is an agricultural by-
product, the dry stalks of cereal
plants, after the grain and chaff
have been removed. It has a high
C/N ratio. it is cut after senescence
what happens when you add straw to the field?
- Increased amount of micro-organisms, because
straw is a source of energy for them - Availability of nitrogen in soil decreases, because
the micro-organisms immobilize it .
how to balance mineralization and immobilization ?
add:
1. Undecomposed nutrient-rich organic matter
2. Composted organic matter
3. Nutrient-poor organic matter
sockeye salmon lays egg in down stream riverbed
False: A female sockeye lays eggs in an
upstream riverbed. The eggs
hatch to alevins
Alevin
when the egg of sockeye salmon hatches
anadromous behaviour
fish live in the sea mostly,
breed in fresh water
catadromous behaviour
fish live in freshwater rivers, migrate to ocean to breed.
Nutrients released from the carcasses increase
procuctivity of these nutrient-poor ecosystems.
This is important for the survival of sockeye offspring
true
Example of semalparous behaviour
Lake Huron has an introduced chinook salmon that shows
similar semelparous (reproduce and die) behaviour.
Exports out of an ecosystem
Gaseous, harvest, with water flow, with animal movement
Gaseous export in the ecosystem
Respiration (CO2)
Denitrification (NO3-→N 2)
Volatilization of ammonium
(NH 4+→NH 3⇡)
export with water flow
litter, particles, dissolved mineral
clearcut
Removal of nutrients with the harvest
impacts of clearcut
Increased export of nutrients
with water. More dead plant parts, and
increased solar radiation → High mineralisation rates.
Not enough plants there to take up the
nutrients
nitrate production is higher after clearcut.
true
deadwood is an
important source of forest biodiversity: less
deadwood, less fungi and insects, less birds
true
what is the affect of forest fires?
Based on its intensity:
1. volatilization of nutrients
2. increase of accessibility of nutrients for plants(P, Ca, Mg)
Pyromineralization
Increased accessibility
of nutrients for plants (P, Ca, Mg)
Nutrient exports out of undisturbed
ecosystems are generally low
due to immobilization
true
Spring ephemerals
reduce nutrient
exports: they
immobilize nutrients
when mineralization
increases but trees
are not yet growing
nutrient spiraling
On their way downstream, nutrients are repeatedly
taken up by organisms and immobilized for a
while. this slows down the downstream movement of nutrients.
Coastal and equatorial upwelling brings
deep, nutrient-rich waters to the surface.
true
Areas of coastal and equatorial upwelling are generally
highly productive ecosystems
specific horse intestinal throughput
or sHIT
