Midterm 3 Content Flashcards

Question

define Water Exchange Vm (in 2 box model)

Answer 1

Vm (mols/year) = Mu (mixing up) + Md (mixing down) Mu = Volume flux rate up X Concentration of Deep Md = Volume flux rate down X Concentration of Surface

Answer 2

F (g/year) = flux of particles X Concentration of particles

Answer 3

Rate of burial of elements through sedimentation (final output) B = sediment mass accumulation rate (grams/yr) X concentration in sediment (moles/gram)

Answer 4

R + Mu = Md + F River Input + Mixing Up = Mixing Down + Flux

Answer 5

Md + F = B + Mu Mixing Down + Flux = Burial Flux + Mixing Up

Answer 6

a net addition of nutrients to the surface water because volume up must EQUAL volume down, and the volume coming up innately has MORE nutrients in it because it's coming from the deep.

Answer 7

at steady state, all inputs = outputs for each box and for the entire system. * make this assumption when doing calculations unless otherwise stated

Answer 8

Forms of N involved: N2 (molecular N gas) Type of environment: ocean surface (where there is light), occurs where there is low nutrient concentration Organisms involved: Cyanobacteria Role of process: fixes N into organic form so it's available for other organisms to use

Answer 9

Forms of N involved: NO3- (nitrate) Type of environment: Anoxic/suboxic zones in deep ocean Organisms involved: Heterotrophs that eat phytoplankton Role of process: provides food & nutrient source for heterotrophs

Answer 10

oxidation of ammonium to organic N Forms of N involved: NH4+ (ammonium) Type of environment: Deep ocean (Aphotic zone) Organisms involved: taken up by phytoplankton Role of process: ammonium is taken up and formed into organic N (organisms).

Answer 11

reduction of organic N to ammonium Forms of N involved: NH4+ (ammonium) Type of environment: Deep ocean (Aphotic zone) Organisms involved: heterotrophs that consumed phytoplankton Role of process: happens from respiration by bacteria, breaking down organic material

Answer 12

conversion of ammonium to nitrate Forms of N involved: NH4+ to NH3 to NO2- to NO3- Type of environment: oxic and suboxic environments Organisms involved: nitrifying bacteria (genus Nitrosomonas and Nitrobacter) Role of process: supplies organic nitrogen to organisms for uptake and nutrients

Answer 13

reduction of nitrate to dinitrogen gas Forms of N involved: NO3- (nitrate) & N2 (nitrogen gas) Type of environment: suboxic/anoxic zone Organisms involved: bacteria Role of process: formation of N2 gas from nitrates and nitrites

Answer 14

Loss of fixed N to N2 gas in in the ocean Forms of N involved: NH4+ and NO2- Type of environment: Suboxic zone Organisms involved: bacteria that use NH4+ and NO2- and form N2 that gets released Role of process: can limit oceanic primary productivity if too much fixed N is lost to N2 gas without being converted back.

Answer 15

Yes, because N2 fixation requires a lot of energy, so if there's already nitrite supply it doesn't make sense to expend energy fixing more N when there's already an organic form available.

Answer 16

a region of very low O2 concentration - tends to be in the deep ocean in the Aphotic zone

Answer 17

a region of zero O2 concentration, so no oxygen is available. - in the deepest parts of the ocean where there is no light.

Answer 18

the nutrient that is completely utilized first (concentration goes to ~0).

Answer 19

the Average elemental composition of phytoplankton for optimally growing, nutrient-replete cells. 106 mol C: 16 mol N: (15 mol Si): 1 mol P - C ratio is usually negligible because it is so abundant in the ocean.

Answer 20

it is an important and useful tool for assessing what the limiting nutrients are in an ecosystem

Answer 21

N:P molar ration = 16 N: 1 P. In general, N & P concentration increases with depth. So the lowest N:P concentrations will be at the surface waters.

Answer 22

N will run out first because when graphed, N reaches zero when P still has a non-zero intercept.

Answer 23

Remineralization includes all the processes that breakdown and return organic matter into their simpler, dissolved, inorganic forms (i.e. respiration, decomposition, nitrification, etc.)

Answer 24

the phytoplankton organic matter is remineralized at depth and in Redfield Ratio proportions

Answer 25

surface waters have LOW nutrient concentrations due to uptake by phytoplankton. As you move deeper, concentrations increase to be HIGH once in the deep where phytoplankton aren't growing and there is nutrient regeneration by bacteria.

Answer 26

stratification of the ocean layers! - when the vertical gradient in the ocean is sharp, there is strong stratification which makes it difficult for the mixing of deep water into the surface waters.

Answer 27

in winter months, there is no thermocline because the ocean is well-mixed due to cold temperatures and strong winds. As spring warms in temperature, the thermocline steepens and results in very stratified water column by the summer months and LITTLE MIXING.

Answer 28

1. Turbulent diffusion - wind mixing 2. Advection - upwelling from the deep

Answer 29

Fall blooms are not as large as the spring bloom. - Caused by the increased mixing as winds pick up and temperatures drop after the summer months when there was high stratification. More nutrients get brought up from the deep, causing an increase in phytoplankton biomass.

Answer 30

N* is essentially the slope on a graph of nitrate vs phosphate concentration in the ocean. N* = [NO3-] - 16[PO4] - At the Redfield Ratio, N* = 0 ( when N = 16P), which is when there's normal photosynthesis and remineralization occurring.

Answer 31

indicates that there is extra N supply or P loss (steeper slope)

Answer 32

indicates that there is N loss. (less steep slope)

Answer 33

Decrease so N* < 0 Lowers only N value, not P

Answer 34

Decrease so N* < 0 Lowers both N and P value

Answer 35

the suboxic zone of the ocean, right below the photic zone. where denitrification tends to happen high nutrient concentration! (even with relative N "deficit" to P)

Answer 36

N* is very (-) in the OMZ N* < 0

Answer 37

N* = 0 (normal nutrient conditions) N* > 0 (if N-fixation is occurring) N* < 0 (if strong upwelling region from OMZ)

Answer 38

N* < 0 (denitrification and/or anammox)

Answer 39

N* = 0 (remineralization) N* > 0 (N2 fixation regions)

Answer 40

- stress on the water, creating waves that cause turbulence and mixing. - puts surface waters into motion creating wind-driven circulation

Answer 41

Tw = paCW^2 where pa = air density C = drag coefficient (normally 2 x 10^-3) W = speed of the wind Tw given in units of N/m^2 (force/unit area)

Answer 42

winds are caused by the differential heating at varying latitudes that lead to differences in air temperature between the equator and poles. Creates regions of high and low density, resulting in movement of the air.

Answer 43

a thermally driven circulation pattern caused by the rising of warm air near the equator & moving toward the poles and sinking of cold air near the poles & moving toward the equator. - typically found near the equator due to the rotation of the earth.

Answer 44

1. Hadley Cell - next to the equator 2. Polar Cell - at the poles 3. Ferrel Cell - around the temperate regions between the other two cells, where the circulation goes the opposite direction

Answer 45

In the northern hemisphere, winds are deflected to the right. in the southern hemisphere, winds are deflected to the left. So, the flow is never directed straight from the poles to the equator.

Answer 46

winds that come from the west and are directed to the east.

Answer 47

winds that come from the east and are directed to the west.

Answer 48

high pressure regions

Answer 49

low pressure regions

Answer 50

in the Northern hemisphere, high pressure will be kept to the right of flow. In the Southern hemisphere, high pressure will be kept to the left of flow.

Answer 51

continents tend to break up the wind cell pattern into more 3D patterns that are less regular, but they still maintain the latitudinal bands of high and low pressure and the westerly/easterly flows.

Answer 52

high pressure is from sinking, warm air. warm air can hold more water vapour so the descending air becomes relatively drier

Answer 53

low pressure is from rising, cold air. cool air holds less water vapour. so the water vapour leaves the air as rain.

Answer 54

high precipitation occurs near the equator and near 45-60 degree latitudes. low precipitation occurs between these near 30 degree latitudes and at the poles.

Answer 55

- wind causes stress/net force on the ocean surface, causing the water to accelerate in the direction of the applied stress - the water gets deflected to the right due to Coriolis effect - this causes stress on the water below due to friction forces - water below gets dragged and continuously shifted to the right until the energy dissipates at depth of the "Ekman layer"

Answer 56

how the velocity vectors spiral and decrease exponentially with depth (after wind force is applied to the surface waters) = Ekman Spiral due to Coriolis effect, the surface current flow is moving 45 degrees to the right of the wind direction (N hemisphere)

Answer 57

the depth average (net) flow of water in the direction of 90 degrees to the right of wind direction also known as geostrophic velocity/flow

Answer 58

volume of water transported given by units ___ Ekman Volume flux = Tw/pf * do not need to know Ekman layer depth for this.

Answer 59

there is clockwise circulating winds (N hemisphere) and vice versa in the S hemisphere i.e. high pressure in the centre

Answer 60

there is counter-clockwise circulating winds (N hemisphere) and vice versa in the S hemisphere i.e. low pressure in the centre

Answer 61

1. the 'eddy velocity' is constant with depth 2. the ocean is homogenous (not stratified) but NET FLUX IS ALWAYS 90 DEG TO THE WIND (not an assumption)

Answer 62

the vertical region near the ocean surface that is affected by wind forces on the surface of the ocean. i.e. goes to the depth where the Ekman spirals would end Ekman layer IS NOT the mixed layer though.

Midterm 3 Content Flashcards

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