ecosystem processes (7-13) Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what happens to water once it undergoes infiltration into subsurface soil and rock?

A
  • some will remain in the shallower soil layer where it gradually moves vertically and horizontally through soils and subsurface material
  • eventually it might enter a stream by seeping into stream banks
  • much of the water moves vertically downwards and ends up as groundwater
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how much do flood damage costs in England each year?

A

£1.1bn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the main water pollutants?

A
  • inorganic soil particles
  • organic sediments or particulate matter
  • plant nutrients
  • pesticides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what areas are salination associated with?

A

they are often associated with irrigated areas where low rainfall, high evapotranspiration rates, or soil texture characteristics impede washing out of salts which subsequently build up in soil surface layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what can lead to local salination?

A

de-icing of roads with salt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the aims of the EU water framework?

A

it aims to:
- protect or enhance all waters
- achieve ‘good status for all waters’ by December 2015
- manage water bodies based on river basins or catchments
- involve the public

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how can flooding be regulated?

A
  • provide vegetative cover
  • manage drainage
  • maintain rivers by increasing channel flow and restoring meanders
  • install infiltration devices
  • dry basins to promote infiltration
  • implement ponds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is artificial recharge?

A

the practise of increasing water entering aquifers by artificial means

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the nitrate directive require states to do?

A

they have to:
- designate nitrate vulnerable zones
- establish a voluntary code of good agricultural practices
- establish a mandatory action programme of measures for purposes of lacking nitrate loss from agriculture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are wetlands?

A

areas of marsh, fen, peatland, or water whether natural or artificial, permanent of temporary, with water that is static or flowing, fresh, brackish, or salty, including areas of marine water - the depth at which low tide does not exceed 6m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what weather patterns are impacted by temperature trends?

A
  • precipitation trends
  • increased occurrence of extreme weather events
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what environmental changes are linked to temperature trends?

A
  • retreat of land ice and loss of sea ice
  • thawing of permafrost, chemical cycling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what ecological changes are impacted by temperature trends?

A
  • shifting habitat ranges
  • phenological shifts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

when is radiative equilibrium achieved?

A

when solar energy input = radiation output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is radiative forcing?

A

the change in average net radiation at the top of the troposphere which occurs because the concentration of a greenhouse gas or another change in the overall climate system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are climate feedback loops?

A

processes that can either amplify or diminish the effects of radiative forcing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are some examples of climate feedback loops?

A
  • precipitation
  • clouds
  • greening of forests
  • desertification
  • ice albedo
18
Q

what are climate tipping points?

A

conditions beyond which changes in a part of the climate system become self-perpetuating

19
Q

what are milankovitch cycles?

A

the periodic motions in Earth’s orbit contribute a predictable amount of variation to the Earth’s climate over time frames of tens of thousands to hundreds of thousands of years

20
Q

what are sunspots?

A

explosions on the sun’s surface which cause warmer periods

21
Q

are volcanoes associated with a rise or fall in global temperature?

A

a fall

22
Q

what are the 2 fractions that contribute to anthropogenic emissions?

A

1 - CO2 from fossil fuel burning and cement production
2 - CO2 from deforestation and agricultural development

23
Q

what did early microbial metabolism probably include?

A
  • methanogenesis in early Archaea
  • autogenesis in early bacteria
  • sulfur based metabolism
  • anoxygenic photosynthesis
24
Q

what are stromatolites?

A

they are living fossils thought to contain ancestors or cyanobacteria present in archaeal oceans 3.5bn years ago

25
Q

what are the different pathways that make methane (methanogenesis)?

A

1 - hydrogenotrophic
2 - reduction of methyl groups
3 - oxidation/reduction of acetate

26
Q

how is methane geologically produced?

A
  • it is contained and produced in hydrothermal fluids
  • it is released by volcanoes, at hydrothermal vents, or natural gas seeps
27
Q

how is methane chemically produced?

A
  • it is produced by the reduction of CO2 in H2 rich fluids in the earth’s crust
  • it is degraded by hydroxylation in the atmosphere
28
Q

how is nitrogen microbially cycled?

A
  • nitrogen mineralisation - organic matter decomp
  • nitrogen immobilisation - microbial uptake into cells
  • nitrification - for energy production
  • denitrification - anaerobic respiration
  • dinitrogen fixation - for cell growth
29
Q

what is putrefaction?

A

the anaerobic decomposition of proteins with the production of very foul-smelling intermediates

30
Q

what is nitrification?

A

the chemoautotrophic oxidation of NH3/NH4+ to nitrite (NO2-) and nitrate (NO3-)

31
Q

what microbes carry out ammonia oxidation?

A
  • nitrosomonas (bacteria)
  • thaumarchaeota (archaea)
32
Q

what bacteria carry out nitrile oxidation?

A
  • nitrobacter
  • nitrospina
  • nitrococcus
33
Q

what is eutrophication?

A

the promotion of plant growth in an aquatic ecosystem by rapidly adding substantial amounts of nutrients
- it may trigger explosive algal blooms and fish kills

34
Q

what is denitrification?

A

the microbial reduction of NO3- and NO2- with the intention of gaseous end products such as nitric oxide, nitrous oxide, and dinitrogen

35
Q

what bacteria carries out denitrification

A

pseudomonas

36
Q

how can microbial communities be counted

A

using UV-fluorescent stains

37
Q

what features must molecular sequence data have to be useful for phylogenetic analysis?

A
  • it must be universal
  • ideally contain variable and conserved regions

-> rRNA fulfills this

38
Q

how are microbial communities analysed?

A

1 - retrieval of environmental sample
2 - extraction of nucleic acids
3 - PCR amplification of marker genes
4 - analysis if diversity of marker genes by high throughput sequencing
5 - statistical comparison of communities from different samples, time points etc

39
Q

how is shotgun sequencing carried out?

A

1 - the bacterial chromosome is randomly sheared
2 - size selection occurs
3 - the chromosome piece is inserted into a plasmid vector
4 - clones are picked to create a library

40
Q

what is an operational taxonomic unit?

A

it is a taxonomic level of sampling selected by the user, typically using a percent sequence similarity threshold for classifying microbes within the same or different operational taxonomic unit