Biogeochemical Cycling - Chemical 14 Flashcards
Describe the GAIA hypothesis
-J. Lovelock observed how earth is a closed system when it comes to matter –> earth is superorganism with limited resources
from an evolutionary standpoint, what is the contribution of cyanobacteria to primary production today?
- initially produced the available oxygen in the atmosphere
- endosymbiotic theory ( clinical role)
from an evolutionary standpoint, what is the contribution of cyanobacteria to primary production today?
- initially produced the available oxygen in the atmosphere
- endosymbiotic theory ( clinical role)
are humans involved in biogeochemical cycling of nutirent ?
yes…
give an example of the recycling of a nutrient by humans
- ## digestive system ( intake glucose and recycle into mineral CO2 and cell mass)
give an example of the recycling of a nutrient by humans
- digestive system ( intake glucose and recycle into mineral CO2 and cell mass)
- mineralization of amino acids into urea
What examples are there of loss of self-regulation and why ?
-global warming
What examples are there of self-regulation of the superorganism?
-
How has earth maintained conditions favorable for life?
-biogeochemical cycling helps maintain life
what is an example of a unidirectional biogeochemical activity?
- evolution of the carbon cycle
- “ “ oxygen cyle
what are stromatolites?
-microbial mats (layered cyanobacteria that are taken advantage by other evolved microorganisms;symtrophy) fosilized
how did stromatolites form?
- the microbial mats are exposed to conditions that allow fossilisation ( symtrophic environment present)
what might be a limiting factor to microbial growth rate with the evolution of oxygen production ?
-the development of a symtrophic cycles ( important cycles developed so that they can use resources)
How is biomass in the oceans generated?
- accumulation of food chain
- -> phytoplankton< zooplankton< Predatory zooplankton< filter feeders < predatory fish < ect.
what reaction drive biogeochemical cycling?
- physical transformations ( dissolution, precipitation, volatilization, fixation)
ie. pH change, carbon dioxide reabsorption in ocean forming carbonates that are used to form coral, through fixation process the loss of material, nitrogen cycling - chemical transformations ( biosynthesis and biodegradationi)
- sunlight and energy flow through the ecosystems is the driving forces
Spirulina, what is it?
-blue green algae = cyanobacteria, filamentous
what makes microbes good at geochemical reactions?
- they are super adaptable
- -> size and surface area
- ->ubiquity
- ->diversity (the ability to adapt metabolically)
- ->high rates of enzymatic activity (growth rate)
what is the result of carbon fixation?
- net primary productivity of some natural and managed ecosystems
consider evolution and the present day . what is the contribution of cyanobacteria to primary production today ?
-cyanobacterium theory
how does carbon cycle within a habitat?
see slide
what are the major carbon inputs into the environment?
lab 8
- plant materials (through photosynthesis)
- fungal cell walls/arthropods
what role does the nitrogen cycle play in maintaining earths atmosphere?
- ## level of nitrogen is maintain based on the amount of other gases present in the atmosphere
what are we doing in lab 5?
- amminia oxdiation( nitirification)
- nitrite oxidation (nitrification)
- nitrate reduction to ammnonium or nitrogen gas (denitrification)
- nitrate reduction to fixed N compounds like a.a ammonia annd amino groups (assimilation)
- ammonium mineralization (mineralization)
what are we doing in lab 5?
- ammonia oxidation( nitrification)
- nitrite oxidation (nitrification)
- nitrate reduction to ammonium or nitrogen gas (denitrification)
- nitrate reduction to fixed N compounds like a.a ammonia and amino groups (assimilation)
- ammonium mineralization (mineralization)
what kinds of results did we get in lab 5?
- growth is slow because little energy is produced in these reaction
- ## nitrate build up (nitrification)
What does SNGDD indicate?
-nitrite presence
–>SNGDD reagent reactions with NO2-
if no reaction–> add zinc –> NO3–> no reaction indicates : been converted to N2
negative stain and slime bacteria
- slime layer inhibits staining to bac
what is the mienralization of urea important?
-produces forms of nitrogen that can be assimilated
Other than high or low concentrations of ammonia, what other factor may be involved in whether Nitrogen is mineralized or assimilated?
- presence of [ nitrogen ]
- presence of other nutrients ( carbon, ) ie. C:N ratio greater then 20 = mineralization
and less then 20 = assimilation
why might bacteria need such a high c:n ratio to support biosynthetic reactions
you have a certain amount of carbon that does not end up as biomass ( only 40% of carbon is used to generate biomass)
what is the fate of NO3-, following Nitrification ?
- it can accumulate if no leaching takes place
-some will be retained - some will assimilate
and some will disassimilate
