Brainscape's Knowledge GenomeTM

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


See full index

Ecol 417 > Quiz 2 Lecture 4 > Flashcards

Quiz 2 Lecture 4 Flashcards

1
Q

What two big issues is phosphorus linked to?

A

Cyanobacteria blooms
Eutrophication

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

What are the forms of phosphorus?

A

Dissolved plus particulate and can be organic/inorganic

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

What are the three diff types of phosphorus in the cycle?

A

Soluble Reactive phosphorus (SRP)
- involves both Orthophosphate (PO43-) (MAIN)= Dissolved Inorganic Phosphorus (DIP)
and Dissolved Organic Phosphorus (DOP)
Algae can uptake

Particulate organic phosphorus
(POP)

Particulate inorganic phosphorus

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

Where is particulate organic phosphorus coming from?

A

living/dead organisms

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

Where is particulate inorganic carbon bound?

A

most bound to clay minerals

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

How is most of the phosphorus trapped?

A

in particle form in living organisms

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

What is the ratios of SRP, POP, PIP?

A

POP<PIP<SRP

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

How does external loading happen in a system? What forms enter?

A

phosphate will enter aqautic system from rocks and decomp of organic matter as runoff, some atmospheric deposits. Particulate P in organic detritus and PO4

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

How does internal loading of phosphorus occur?

A

Lake sediments, and some decaying organic matter

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

Is there more phos in the sediments or overlying water?

A

in the sediments

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

How much phos do interstitial waters contain?

A

waters around sediment contain 0.06-10 mg P/L

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

What conditions are vital to see internal loading of phosphorus from sediment?

A

conditions at the sediment-water interface

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

What’s the diff between anoxic sediments and oxygenated sediments in terms of phosphorus release? Why?

A

anoxic relase P 1000 =x faster. This is because in oxygenated sediments phos will ppt with iron and trap the phos in sediments, but in anoxic ones the FePO4 reduces to give more free phos in water column

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

How do inorganic sediments (internal loading) result in more or less PO4?

A

in anoxic conditions relases Po4, but if O2, Fe, or Ca will trap

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

With organic sediments (internal loading) how does that lead to PO4 loading?

A

the organic sediment decay

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

How does phosphorus behave in spring (lake mixing)?

A

the sediment-water interface will be oxygenated so less PO4 and mixing in water column

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

How does phosphorus behave in summer (stratified)?

A

Now have diff layers of water, hypolimnion gets depleted of oxygen, get anoxic sediments and see more phosphorus released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does phosphorus behave in FALL(lake mixing)?

A

phosphorus prior relased, and then phosphorus stuck in hypolimnion gets distributed throughout water column.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the three mechanisms for algae to overcome phosphorus limitation?

A

Luxury consumption
Ability to use P at low levels
Phosphatase production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is luxury consumption?

A

algae will store excess p in granule s in cells

21
Q

How do phyto/algae use P at low levels?

A

some algae do better w less p than others, this impacts their succession as it uses a lot of their energy

22
Q

What is photophase production?

A

small microorganisms break down Phosphorus between organic mlcls by using enzyme phosphatase

23
Q

How does internal recycling occur of Phos in aquatic ecosystems?

A

There’s competition between phytoplankton and bacterioplankton, all bacterio, phyto, zoo, and fish contribute to phos, some p becomes organic solubule P which can go back to free P through phosphotase, some free p becomes partciuplate organic p which can also become free p again, the soluble and particulate phos also switch

24
Q

What are the other two major zones besides sediment water interface?

A

Pelagic zone: uptake and sedimentation through organisms
littoral zone: primary producers when they die bring to bottom and bring phos to sediments, also will uptake phos

25
Q

What are the human inputs of the phos cycle?

A

they input phos through agriculture and sewage.

26
Q

How does phosphorus change with lake productivity?

A

least productive has least amount of p, most productive has most

27
Q

How does Soluble phos and total phos change in vertical profiles of lakes in oligotrophic lakes? eutrophic lakes?

A

In oligotrophic it stays the same the entire time, because not much external loading and therefore not much internal loading, because high oxygen at bottom reduces loading

In eutrophic system, it starts off low due to production using it up but increases fast, this is because as oxygen depleted sediments become anoxic and all productivity dies, so phosphorus increases at bottom.

28
Q

What is the timescale for natural versus cultural eutrophication?

A

natural eutrophication takes thousands of years (will lead to accumulation of sediments), cultural eutrophication takes decades.

29
Q

What causes cultural eutrophication?

A

urban runoff, industrial discharge, fertilizers and pesticides, erosion and sedimentation, nonpoint source pollution

30
Q

Does low N availability limit plant growth?

A

yes

31
Q

What are the forms of dissolved inorganic nitrogen?

A

Ammonium, nitrate, nitrite

32
Q

What are organic nitrogen compounds?

A

amino acids, urea, uric acid

33
Q

is N2 gas included in total nitrogen?

A

no as unusable

34
Q

What is N2 fixations and what’s it for? What are the two conditions it can happen in?

A

Most nitrogen enters aquatic ecosystems as N2, so bacteria fix N2 to NH4
it can happen with nitrogenase enzyme. This requires anaerobic conditions that stop the enzyme from oxygen (via heterocysts)
or just live in anoxic habitats to use enzyme .

35
Q

N fixing varies w what?

A

N availability

36
Q

How does N2 gas become organic N?

A

nitrogen fixation via cyanobacteria

37
Q

What is denitrification? Is it anoxic or oxic?

A

Conversion of inorganic nitrogen (nitrate) to N2 gas, makes nitrogen unusab;e, is anoxic

38
Q

What does dentrification? How efficient is it compared to aerobic respiration?

A

By anaerobic bacteria, is done in zones of lakes w no oxygen, is less efficient than aerobic respiration as less energy is produced.

39
Q

What is nitrification? What are the steps? What conditions does it happen in?

A

creates NO3, happens in oxic conditions
1.ammonium oxidized from bacteria (nitrosomas) into NO2.
2. Nitrite gets oxidized by nitrobacter into NO3

40
Q

Why is this nitrification a dissimilatory process?

A

Because the nitrogen form changes but it is not assimilated.

41
Q

Do nitrifying bacteria compete for ammonium w primary producers?

A

yes

42
Q

What is nitrogen assimilation? What form is easiest to assimilate?

A

primary producers use nitrate, nutrient, and ammonium from water, ammonium is easiest to take up, is an oxic process

43
Q

What enzymes converts nitrate to nitrite? nitrite to ammonium?

A

nitrate reductase

44
Q

What is ammonification? Where does it happen. is it an anoxic or oxic process?

A

Organic compounds are broken down by bacteria/fungi and converted to ammonium, this happens in sediments and upper waters. Is an oxic process.

45
Q

What is the nitrogen pattern in oligotrophic versus eutrophic lakes?

A

In oligotrophic- ammonium consistent and low but NO3 slightly increases towards the bottom. No3 increases because less uptake due to less primary production, Ammonium stays low and consistent because oxygen allows it to be quickly assimilated by plants.

In eutrophic- ammonium is low near surface but increases towards bottom (this is due to anoxic sediments releasing ammonium), no3 starts pretty high (because more eutrophication happening) and lowers, this is because there’s denitrification occurring in the anoxic conditions

46
Q

What is the seasonal patterns of nitrate?

A

Nitrate will be higher in winter, decrease during summer stratification, and them bump back in fall mixing.
Winter is because we see limited phytoplankton activity so no one using it so high, in summer primary producers will use it up and then it will decrease

47
Q

What is the seasonal patterns of ammonium?

A

In eutrophic dimicitc, will have accumulation of ammonium in winter, gets used up during summer
in monomictic eutrophic lake- see bumps related to large inputs and then death of the organisms
See peaks in falls in general, due to resuspension of stuff at bottom after summer.

48
Q
A

Ecol 417 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions