biochemical cycles Flashcards
What is the rate of water movement within reservoirs in the water cycle and what factors
influence this rate?
- equl deposition and evopration between ocean (non anthropogenic)
- largest fluexes between plants and anmosphere (non anthropogenic)
- even fluxes between resoirs (non anthropogenic)
- anthropogenic factors are extra
- What are the main carbon reservoirs in the carbon cycle and what factors influence the
rate of movement between them?
relative rates of carbon from most to least: ocean> fossil fules> plants> atmosphere
- carbon to the atmosphere: plant respiration, soil resipration, fossil fuel burning, deforestation, ocean exsolving, weathering, total of 231.6 GtC/yr…. compared with from atmosphere: plant photosynthesis and ocean dissolving, total or 227 GtC/yr
- huamns caused fluexes are small but persistant (at least in the last 150 years)
- largest fluxes between land plants and atmosphere, and the cean and the atmosphere
- flux or carbon out of fossil fules is 60,000 times faster than flux into fossil fules
- flux to atmosphere from ofssil fuel and deforestation is greater than accumulation of carbon in the atmosphere bc ocean exchanges works by diffusion
- we burn, ocean stores
- carbon concentration have incresed a lot; we would survive a great increase but life will survive. life other than us can sustain increased carbon
- How are the oxygen, and nitrogen cycles affected by plants and bacteria?
- o2 cycle didnt occur until autotropihc organisms
- there is nitrogen fixing bateria. without them, we have no access to atmospheric nitrogen
- symbiotic microbe and fungi that facililtates n2 fixation so it is accessible to the planet
- How could you utilise biogeochemical cycles (e.g. oxygen or carbon) to investigate Earth
history (e.g. 5 mya)? Would the net movement of these cycles differ?**
- net movement of cycles would differ
- human fluxes make a big impact
- can investigate what organisms lived when nitrogen was high, or whe no oxygen present etc
- we know oxygen and nitogen require living organisms.
What evidence is there for biogeochemical cycles on Mars? What elements would likely
be involved in these cycles?
- we dont know
- mars has season which would drive cycles, like earth
- but also, mars is smaller and has no atmopshere
evidence : - active volanicm (provides reduced chemical species which biota can use for organic synthesis. valcanic carbon dioxide and methan can sereve as greenhouse gases)
- liquid water (life requires water as a substrate and conditions)
- we need to find the golilock zones
- volanism: there are volanoes that we think are dormant but we dont know. similar patterns to earth whihc possibily means active mantle
- water: histroic evidence. early period or precipiation evidence for surface runoff. martian hematit (ironthat can only form with aquoes environment). layered deposits and putative pleolakes (sedimentary rocks which we know need and aquesous environment to form on earth). recurring slope lineae (represent seasonal and saline liquid water)
- Given your knowledge of Earth’s biogeochemical cycles and life’s reliance upon them,
could life exist or have existed on Mars? Why
- yes
- in past
- life doesnt mean humans
- evidence of water and active mantle
- isnt improbable to belive that life was once on mars
- mars no longer has conditions for life
- nitrogen is very stable in solar radiation, ie could have stil been present with little atmopshere
what is a biogeochemical cycle?
cycles of biologically important chemicals. The movement or cycling of matter through a system. Earth can be called a closed system, so all matter cycles
why do biogeochemical cycles exist?
- elements reuired for life are relatively stable (eater, carbon, nitrogen, phosphorus, oxygen)
- distribution of elements varies over the globe
- elements are seqiestered and released by organics
water cycle
- more precipitation falls on land than evaporates or transpires
- excess precipitatipn leaves as runoff and subsurface runoff (back to the ocean)
- Less precipitation falls on the ocean than evaporates or trasnpires (more precipiation on land, more evapration on ocean, less on land)
- ocean exports water to the land VIA THE ATMOSPHERE
- ocean is the largest water supply
anthropogenic
human bases factos
oxygen cycle
- cellular resiration ,anerobic respiration. we have evolved to used oxygen because it provides lost of energy and makes cellular respiration more efficeint
- oxygen cycle did not occur until the existence of autotrophic organisms
- the bioshpere is the key catalysr/ engine of the oxygen cycle
- largest fluxes between plans (land and marine) and atmopshere (photosynthesis)
- greastest resovior of o2 is in the LITHOSPHERE
- small amounts of o2 are generated in the upper atmopshere (photlysis)
nitrogen cycle
- key is nitrogen fixation
- microbedependant
- requires life
- there is n2 fixing bacteria in the lithosphere. some fixing also due to decomposition
why is nitrogen most abundant atmospheric element
- it is highly stable
it is diatomic - it is volatile in most of its forms
- highly unreactive with material that make up the solid earth 9compared with o2)
- very stable in the resence of solar radiation
human imapcts on n2 cycle
- we make so much of our food that we need to facilitate the nitogen avalible to plants
nitogen as a pollutant
- ammonia is used in fertilizer
- plants and soil dwelling bacteria and archea use ammonia. nitrate is byproduct
- nitrate runs into river and causes a huge algae/cynobateria bloom
- whn these bloomed cells die, the ecomposing bateria and archea grow rapid and use up all the o2
- creates an anoxic dead zone
