ecosystem processes (7-13)

Question 1

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

Answer 1

• 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

Question 2

how much do flood damage costs in England each year?

Answer 2

£1.1bn

Question 3

what are the main water pollutants?

Answer 3

• inorganic soil particles
• organic sediments or particulate matter
• plant nutrients
• pesticides

Question 4

what areas are salination associated with?

Answer 4

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

Question 5

what can lead to local salination?

Answer 5

de-icing of roads with salt

Question 6

what are the aims of the EU water framework?

Answer 6

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

Question 7

how can flooding be regulated?

Answer 7

• provide vegetative cover
• manage drainage
• maintain rivers by increasing channel flow and restoring meanders
• install infiltration devices
• dry basins to promote infiltration
• implement ponds

Question 8

what is artificial recharge?

Answer 8

the practise of increasing water entering aquifers by artificial means

Question 9

what does the nitrate directive require states to do?

Answer 9

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

Question 10

what are wetlands?

Answer 10

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

Question 11

what weather patterns are impacted by temperature trends?

Answer 11

• precipitation trends
• increased occurrence of extreme weather events

Question 12

what environmental changes are linked to temperature trends?

Answer 12

• retreat of land ice and loss of sea ice
• thawing of permafrost, chemical cycling

Question 13

what ecological changes are impacted by temperature trends?

Answer 13

• shifting habitat ranges
• phenological shifts

Question 14

when is radiative equilibrium achieved?

Answer 14

when solar energy input = radiation output

Question 15

what is radiative forcing?

Answer 15

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

Question 16

what are climate feedback loops?

Answer 16

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

Question 17

what are some examples of climate feedback loops?

Answer 17

• precipitation
• clouds
• greening of forests
• desertification
• ice albedo

Question 18

what are climate tipping points?

Answer 18

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

Question 19

what are milankovitch cycles?

Answer 19

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

Question 20

what are sunspots?

Answer 20

explosions on the sun’s surface which cause warmer periods

Question 21

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

Answer 21

a fall

Question 22

what are the 2 fractions that contribute to anthropogenic emissions?

Answer 22

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

Question 23

what did early microbial metabolism probably include?

Answer 23

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

Question 24

what are stromatolites?

Answer 24

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

Question 25

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

Answer 25

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

Question 26

how is methane geologically produced?

Answer 26

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

Question 27

how is methane chemically produced?

Answer 27

• 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

Question 28

how is nitrogen microbially cycled?

Answer 28

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

Question 29

what is putrefaction?

Answer 29

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

Question 30

what is nitrification?

Answer 30

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

Question 31

what microbes carry out ammonia oxidation?

Answer 31

• nitrosomonas (bacteria)
• thaumarchaeota (archaea)

Question 32

what bacteria carry out nitrile oxidation?

Answer 32

• nitrobacter
• nitrospina
• nitrococcus

Question 33

what is eutrophication?

Answer 33

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

Question 34

what is denitrification?

Answer 34

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

Question 35

what bacteria carries out denitrification

Answer 35

pseudomonas

Question 36

how can microbial communities be counted

Answer 36

using UV-fluorescent stains

Question 37

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

Answer 37

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

-> rRNA fulfills this

Question 38

how are microbial communities analysed?

Answer 38

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

Question 39

how is shotgun sequencing carried out?

Answer 39

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

Question 40

what is an operational taxonomic unit?

Answer 40

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