Chapter 21: Movement of Elements in Ecosystems (water, carbon, nitrogen, phosphorous)

Question 1

dead zone

Answer 1

aquatic ecosystems that experience algal blooms + large animal die-offs
- Mississippi river flows into Gulf of Mexico every summer

Question 2

direct effects of summer algal blooms

Answer 2

some algae or cyanobacteria produce toxins when the bloom

Question 3

indirect effects of summer algal blooms

Answer 3

phytoplankton bloom and die
- Bacteria consume dead biomass and use lots of O2
- Aquatic life dies from oxygen deprivation

Question 4

causes of summer algal blooms

Answer 4

nitrogen + phosphorous from fertilizers run-off into streams/rivers, phosphorous from detergents and sewage cause rapid algal growth
- Along with warm temps

Question 5

required nutrients from biotic and abiotic ecosystems

Answer 5

Hydrogen, oxygen, carbon, nitrogen, and phosphorous

Question 6

nutrient / biogeochemical cycle

Answer 6

path an element takes as it moves from abiotic systems through living organisms
- via assimilation, consumption, and decomposition

Question 7

Organisms need 7 major nutrients

Answer 7

nitrogen, phosphorous, sulfur, potassium, calcium, magnesium, and iron

Question 8

what controls the rate of nutrient cycling?

Answer 8

decomposition of detritus limits the rate at which nutrients move through an ecosystem.

Question 9

what controls decomposition rate

Answer 9

temperature and moisture

Question 10

the hydrologic cycle

Answer 10

movement of water through ecosystems and atmosphere

Question 11

hydrologic cycle components/transfers

Answer 11

evaporation, transpiration, and precipitation

Question 12

97% of earth’s water is in ___

Answer 12

oceans

Question 13

Human impacts on the Hydrologic Cycle:

Answer 13

• Roofing/pavement/concrete create surface runoff (can’t hold water like soil)
• Logging (removing trees) decreases precipitation and evapotranspiration
• Draining aquifers quicker than they can be replenished
• Global warming causing temperature rise increasing water evaporation

Question 14

all organisms are composed of ___

Answer 14

carbon

Question 15

6 transformations of the carbon cycle

Answer 15

photosynthesis, respiration, sedimentation and burial, extraction, and combustion

Question 16

nutrient loss from leaching and water transport is balanced by inputs of ___ from the ___ and from ___ of bedrock under the soil

Answer 16

nutrients from the air
the weathering of bedrock

Question 17

weathering rates can be determined by

Answer 17

measuring nutrients entering a system from rainfall and leaving a system by leaching
- the balance b/w loss and gain of nutrients

Question 18

watershed

Answer 18

area of land draining into a single stream or river

Question 19

Photosynthesis and respiration do what?

Answer 19

take CO2 from air and water –> carbohydrates, release some CO2 back

Question 20

Human impacts on the carbon cycle:

Answer 20

• Extraction and combustion of fossil fuels

Question 21

previously, CO2 ppm had never surpassed ___, but now its over ___

Answer 21

300 ppm, 405 ppm

Question 22

Nitrogen is important for:

Answer 22

building proteins and nucleic acids for DNA

Question 23

Nitrogen fixation

Answer 23

converting atmospheric N2 –> forms producers can use
o N2–> NH3 (ammonia) or NH4+
o Occurs in 3 ways: cyanobacteria/4 types of bacteria, lightening/rain, and production of fertilizer

Question 24

Nitrification

Answer 24

converts NH4+ or NH3 –> NO2- –> NO3-
- release potential energy by bacteria
- transforms into usable nitrogen

Question 25

autotrophic river

Answer 25

if primary production exceeds decomposition

Question 26

heterotrophic river

Answer 26

if decomposition exceeds primary production - occurs in most streams

Question 27

Nitrogen Assimilation

Answer 27

producers take up nitrogen and incorporate it into their tissues - Primary consumers eat producers and assimilate and excrete nitrogen

Question 28

Nitrogen Mineralization / ammonification

Answer 28

mineralization: breaking down organic compounds into inorganic compounds ammonification: animals excrete urea, uric acid, or ammonia; decaying plant and animal material is also broken down by ammonifying bacteria into NH3+

Question 29

Denitrification

Answer 29

process of converting nitrates into nitrogen gas, returns nitrogen into the atmosphere; done by bacteria o Highly soluble in water

Question 30

5 major transformations in the nitrogen cycle

Answer 30

nitrogen fixation, nitrification, assimilation, mineralization, and denitrification

Question 31

plants need ___ nutrients

Answer 31

dissolved

Question 32

Human impacts on the nitrogen cycle:

Answer 32

Humans have double nitrogen put into terrestrial ecosystems by: o combustion of fossil fuels o production of nitrogen fertilizers o planting nitrogen-fixing crops

Question 33

__% of all plant matter produced in a year is not consumed by herbivores but it is ultimately decomposed

Answer 33

90

Question 34

leaching removes ____% of soluble substances from organic matter

Answer 34

10-30%

Question 35

phosphorous is used for:

Answer 35

bones, scales, teeth, DNA, RNA, and ATP

Question 36

___ is a common limiting nutrient in aquatic and terrestrial ecosystems

Answer 36

phosphorous

Question 37

plants take up phosphorous from ___ and animals eliminate excess through ___

Answer 37

from soil or water - through urine

Question 38

Eutrophication

Answer 38

increase in productivity of aquatic ecosystems

Question 39

Cultural eutrophication

Answer 39

increase in productivity of aquatic ecosystems caused by human activities

Question 40

4 ways for the breakdown of plant matter in a forest:

Answer 40

soluble minerals leach out of organic matter, detritivores consume organic matter, fungi break down the woody and leafy components, bacteria decompose everything

Question 41

___ of organic matter influences breakdown rate

Answer 41

chemical composition

Question 42

Because weathering is a slow process, primary production relies on regeneration of nutrients from the break down of _____.

Answer 42

detritus

Question 43

what factors influence the rate at which nutrients are exported from ecosystems?

Answer 43

precipitation, plant life levels, decomposition

Question 44

In terrestrial ecosystems, nutrients regenerate close to ___________.

Answer 44

the location where they are taken up by producers

Question 45

In aquatic ecosystems, nutrients regenerate in ________.

Answer 45

the sediments, which are often far from the surface waters where producers live.

Question 46

nutrients that life need (each has a cycle)

Answer 46

CHNOPS- carbon, hydrogen, oxygen, phosphorous, sulfur

Question 47

evapotranspiration

Answer 47

evaporating and moving from liquid to gas through transpriation

Question 48

how do plants get carbon?

Answer 48

photosynthesis

Question 49

how is carbon released into the atmosphere?

Answer 49

respiration releases it as CO2

Question 50

how is carbon stored?

Answer 50

in rocks- extracted for fossil fuels; combustion releases it back into atmosphere

Question 51

how is nitrogen returned to the atmosphere?

Answer 51

denitrification

Question 52

weathering and erosion does...

Answer 52

move phosphorus into soil/water supply

Question 53

how is phosphorous returned?

Answer 53

excretion and decay; returns to rocks - doesn't include atmosphere = slow

Question 54

sulfur cycle

Answer 54

- moves from ocean to atmosphere through conversion by bacteria - assimilated through atmosphere, back to oceans - some also stored in rock

Question 55

reservoirs of CO2

Answer 55

atmosphere, fossil fuels, organic material

Question 56

assimilation of CO2

Answer 56

photosynthesis and animal consumption

Question 57

release of CO2

Answer 57

respiration, decomposition, combustion

Question 58

bacteria assimilate and release __

Answer 58

nitrogen

Question 59

phosphorous cycle

Answer 59

plants take in phosphate through roots, animals eat plants, released by excretion and crop residue

Question 60

___ is lost when crops are harvested

Answer 60

phosphorous and nitrogen (fertilizer)

Question 61

___ is not found in the atmosphere

Answer 61

phosphorus

Question 62

where is phosphorous stored and how is it released?

Answer 62

rocks; released through weathering w/ rain, travels to soil for uptake by plants

Question 63

how is phosphorous returned to the environment?

Answer 63

mineralization

Question 64

In terrestrial ecosystems, nutrients regenerate...(location)

Answer 64

close to the location where they are taken up by producers

Question 65

In aquatic ecosystems, nutrients regenerate/accumulate....(location)

Answer 65

in sediments, often far from the surface waters where producers (e.g., phytoplankton) live

Question 66

Terrestrial ecosystems commonly experience ____ decomposition, whereas aquatic ecosystems commonly experience ___ decomposition.

Answer 66

- aerobic decomposition - anaerobic decomposition (much slower)

Question 67

who's responsible for decomposition in aquatic ecosystems?

Answer 67

bacteria

Question 68

material in which organic matter is made out of effects ____

Answer 68

decomposition rate

Question 69

Stratification occurs when...

Answer 69

- surface waters warm while deep waters remain cold - less dense freshwater from rivers flows over more dense ocean saltwater

Question 70

vertical mixing of water occurs when...

Answer 70

the temp of surface water changes to match the temp of deep water

Question 71

vertical mixing in oceans occurs when

Answer 71

evaporation makes surface waters saltier than deep waters - mixing can bring nutrients up to algae

Question 72

5 major nutrient cycles

Answer 72

water, carbon, nitrogen, phosphorus, sulfur

Question 73

clouds dump their water when...

Answer 73

they get colder

Question 74

what forms sediments?

Answer 74

carbon (calcium carbonate)

Question 75

where is the most accessible carbon (largest reservoir)?

Answer 75

the ocean

Question 76

where is the most stored carbon?

Answer 76

the lithosphere

Question 77

The vast majority of molecular nitrogen (N2) in the atmosphere is unavailable to plants bc...

Answer 77

they can use nitrogen only in the form of (NO3) or nitrates

Question 78

Rhizobium (Rhizobia)

Answer 78

associate w/ legumes (form nodules on roots) to provide the plant w/ nitrogen

Question 79

phosphorus does not have a ____ phase

Answer 79

gas (only dust form- PO4^3-)

Question 80

in oxygenated waters, phosphorous precipitates after binding w/ _____

Answer 80

calcium and iron

Question 81

in low oxygen conditions, irons binds with ___ instead of phosphorous.

Answer 81

sulfur (makes phosphorous more available)

Question 82

2 factors responsible for the human impacts on ecosystems

Answer 82

1. the rapid increase in human population 2. the rapid increase in human resource use