Biogeochemical cycles

Question 1

Which biogeochemical cycles require life and which just have it

Answer 1

requires life - oxygen, nitrogen, phosphorous, sulphur, carbon? (it did not originally, now it is debatable)
does not require - water

Question 2

What is biogeochem cycle

Answer 2

is the movt of matter through a syst
As earth is a closed system, all matter on earth actuallly cycles

Question 3

Why do we know biogeochem cycles exist

Answer 3

A - elmnts required in life are in stable amts, we can see consistant molecular structurs in geochem and biogeochem cycl
B - there are diffusion gradients around the world, distribution of elemts varies
C - the biosphere pushes these things but also uses them

Question 4

What are the major bgcycles

Answer 4

water, sulphur, carbon, nitrogen,oxygen, phosphorus

Question 5

What are reservoirs and fluxes

Answer 5

reservoir is location, where elements are stored for period of time
Fluxes are the movt of materials between the reservoirs

Question 6

What is box diagram

Answer 6

reservoirs are boxes, fluxes are arrows, size of arrows shows flux

Question 7

What is the biggest flux and reservoir for carbon cycle

Answer 7

Flux - deforestation, fossil fuels
reservoir - deep ocean

Question 8

Describe water cycle and its drivers

Answer 8

Start at atmos, precipitation
excess is runoff to water bodies like lake, ocean
can also go underground groundwater ends up in water bodies
oceans export water to land by evaporation
evaporation to hydrosphere into atmos
More water falls then goes back up

Drivers
more water falls on land than evaporates
more water evaporates than falls in ocean

Question 9

describe equilibrium of carbon cycle

Answer 9

Resp of biosphere basically at equilibrium
Atmos to ocean is also net even with non human reasons
everything is balanced except fossil fuels which is not.

Question 10

what are major fluxes of carbon cycle (10)

Answer 10

FFB - fossil fuel burning
P - photosynth
PR - primary respiration, photoresp, plants breathing out
DEF - Deforestation
SF - soil formation, when things decompose
SR - soil respiration, when things in soil breath
FFF - fossil fuel formation
E - evaporation
D - deposition
CP - carbonate production

Question 11

Which of the following is the largest flux of carbon dioxide, ocean and plants (HE LIKES THIS QUESION)

Answer 11

Plants? both are the biggest but plants is probably more than ocean

Question 12

Importance of the range at which we view our data and why we should still be scared or carbon increase

Answer 12

How scary it sounds depends on the time you take and the interval you look at
In global context we are in CO2 decline over 600 million years \
The earth has seen CO2 levels before, the rate of change is very high though. That is unusual.

Question 13

Why do we use oxygen as final electron acceptor`

Answer 13

could also use formate, nitrate but ox is best
Ox provides most energy, 90% efficient
has the largest change in free energy from glucose

Question 14

describe ox cycle (fluxes reservoirs), also draw

Answer 14

biosphere is key catalyst to cycle, it mainly sucks in ox, photosynth can increase it over time
greatest reservoir is lithosphere, in the rock
largest fluxes are between plants and atmos (photosynth and respiration)
some ox is generated in upper atmos - photolysis

Question 15

Why is nitrogen the most abundant element in atmos

Answer 15

Volatile in most forms
Not reactive with materials that make up the earth
Very stable in the presence of solar radiation

Question 16

describe nitrogen cycle, fluxes, reseroirs

Answer 16

fluxes mainly down - nitro fixation by bact, also humans
largest res - hydrosphere, ocean
comes down in rain, lighting, fixation by microbes and humans
denitrification by bact, make it accesible to plants they extrete it into atmos

Question 17

example of nitrogen fixation and why important

Answer 17

nitrogen is converted to ammonia by bact and fungi
happens in root nodules of plants
helpful for plant, important to nitrogen cycle
returned when things die
denitrification releases N back to atmos by bact

Question 18

Why are humans important to n cycle

Answer 18

Industrial means
We grow nitrogen fixation crops , nitrogen fertilizer, fossil fuels
Leads to food web outcomes, change in the biosphere and diversity

Question 19

What is eutrophication, how can Nitrogen be bad

Answer 19

We apply ammonia as fertilizer
Gets converted to nitrates
overused and gets taken to hydrosphere,
increases concentration of nitrogen, helps fertilize plants
Grow fast and get algal bloom
When the nitrates get used up algae dies and the decomposition causes the O2 to be sucked out of the water,
Causes dead zone, fish die
Caused by overuse of nitrogen fertilizers
proccess called eutrophication

Question 20

how is phosphorus cycle

Answer 20

like nitrogen cycle, never found as solids
has reservoirs in water and ground

Question 21

describe sulphur cycle

Answer 21

like N cycle
helped through human means
oxidizes in atmos
comes down as precip
goes into ground
goes up through fossil fuel burning, human means

Question 22

does titan have possibility for biogeochem cycle

Answer 22

Given the differential topography and volcanism that is the same things we saw that caused bgchem cycles on earth.
Molecs on titan are diff but all topography and organic compounds are ripe for biocycles,
has clouds, has lakes, winds, precip

Titan has possibility of bgchem cycle