Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Climate Change - Ocean/Terrestial > Dynamics - Nitrogen > Flashcards

Dynamics - Nitrogen Flashcards

1
Q

What are the form of nitrogen in waters?

A

Dissolved molecular N2
Organic compounds
Nitrite, ammonia and nitrate

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

What are the deposition pathways of nitrogen into water?

A

Nitrogen fixation
Precipitation
Deposition of groundwater drainage

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

How is nitrogen lost?

A

Conversion into N2 by denitrification
Permanent sedimentation loss
Outflor from the basin

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

Prominent source of nitrogen…

A

Direct terrestial runoff

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

What is most atmospheric nitrogen in the form of?

A

Ammonia.

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

Where is N2 foudn mostly?

A

Colder waters, not water soluble.

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

Heterocysts

A

Differentiated cyanobacterial cells carrying out nitrogen fixation under aerobic conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do cyanobacteria fixate nitrogen?

A

Heterocysts as filamentous cells with outrgwoths.

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

Denitrogenase Reductase

A

Transfers electrons from an electron donor to denitrogenase which then catalyses nitrogen reduction to ammonium

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

How does filamentous cyanobacteria form heterocysts?

A

Combined nitrogen present like nitrate or ammonium, whilst in absesne, heterocysts form in semi-regular intervals

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

What may destroy Nitrogenase?

A

Oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do nitrogenase prevent oxygen degradation?

A

Protection by microzone formation, redox conditions seperate of the surrounding water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does turbulence reduce fixation?

A

Increasing diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are fixation rates based on lake type?

A

Low in oligo/mesotrophic whilst high in eutrophic (1-10% and 8-% nitrogen input rate for either)

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

What do N2 fixation enzymes requried?

A

Molybdenum and Iron trace elements thus higher fixation rates are dependent on these both

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

Molybdenum in oxygenated conditions…

A

Exist as molybdnate ions, where sulfate ions can competitvely inhibit fixation

17
Q

What trees increase nitrogen levels?

A

Alnus and Myrica of trees bordering wetlands

18
Q

Endophyte

A

An endosymbiont living within a plant for some part of its life cyycle without causing disases

19
Q

Alnus and Myrica nitrogen fixation…

A

Fungi at or just below the soil

20
Q

Where is alnus effective?

A

Glaciated regions in Alaska, where leaf litter nitrogen levels have 4x nitrogen levels

21
Q

When are nitrogen fixation levels higher?

A

When phosphorous fertilization occurs

22
Q

Fixation diurnal changes..

A

Maximises midday with maximum insolation…

23
Q

Seasonal changes of nitrogen fixation…

A

Winters where CB are absent, so is nitrogen fixation

24
Q

Fucntion of Mo in nitrogenase…

A

Cofactor catalysing redox reactions to convert N into ammonium ions.

25
Q

Nitrogens combined forms…

A

Hydroxylamine, Ammonia, Nitrite and Nitrate

26
Q

What is high ntirogen indicated with?

A

High algal productivitiy.

27
Q

How does ammonia form?

A

Deamination of proteins and nucleic acids by heterotrophic bacteria

28
Q

Most energy-efficient nitrogen source for plants?

A

NH4

29
Q

Variability of ammonium distribution…

A

In trophogenic assimilated rapidly by algae being most significant nitrogen source for plankton in lakes.
Oligotrophic water low NH4

30
Q

Nitrificaiton

A

Linking of ammonia oxidation to loss of fixed nitrogen in the form of N2

31
Q

Nitrification processs.

A

Begins with ammonia, then hydroxylamine to pyruvix oxine then nitrous acid.

32
Q

Bacteria capable of nitrification from NH4 to NO2…

A

Mesophilic

33
Q

Bacteria capable of nitrification from NO2 to NO3….

A

Nitrobacter oxidation

34
Q

Denitrfication

A

Nitrate/nitrite is reduced to gaseous nitrogen…

35
Q

What is denitrfication dependen ont…

A

Molybdenum, extremely low in granitic mountain regions.

36
Q

Where are nitrification and denit prominent?

A

Trophogenic zone.

37
Q

What is required with nitrogen reductase?

A

Iron and molybdenum

38
Q

Nutrient transport in rivers/streams…

A

Downstream dissolved substances assimilat, ulttimately released called nutrient spiralling.

Climate Change - Ocean/Terrestial (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions