Questions With Verified Answers 2024
Most profound nutrients being added to ecosystems by humans - Correct Answer
Nitrogen and phosphorus
Nitrogen facts - Correct Answer makes up 78% of Earths atmosphere and many
enzymes and proteins that humans need
Phosphorus cycle - Correct Answer Necessary for ATP in cellular energy
rare and is most often the limiting factor in ecosystems
Phosphorus sources - Correct Answer All natural phosphorus is from the weathering
of rocks uplifted from the ocean
Most phosphorus used by humans comes from mining
Recycled between biota
Phosphorus is limited - Correct Answer Stocks could increase in 2030 with the peak
of phosphorus extraction but then slowly decrease over time
Morocco, China, and USA have 85% of global Phosphorus reserves
Phosphorus became scarce in 2007 and the price went up by 700% resulting in a
food crisis and political unrest
Phosphorus Sinks - Correct Answer Overall movement of P from land to rivers
causes P to develop on the floor of water bodies
Ocean floor is the biggest sink
,Phosphorus cycle: Phosphate - Correct Answer Only Phosphate (PO3) is available
to plants
Phosphate is assimilated to turn it into organic forms such as ATP
Phosphorus cycle: immobilization - Correct Answer Phosphorous can become
immobilized when bound to rocks and other insolubles
Phosphorus cycle: human disturbances - Correct Answer Inefficient: only 15-30% of
P is taken up by crops and the rest is runoff
Wastefulness of food loses 55% more of phosphorus
Human sewage inputs 3 MT of P into cycles per year
Detergents also used to contain P
biome recycling time - Correct Answer Nitrogen always cycles faster than
Phosphorus and Tropical rainforests have the fastest cycling times, above
Temperate deciduous and Boreal forest.
Big algae debate - Correct Answer was carbon, nitrogen, or phosphorus responsible
for algal blooms
using experimental lakes it was found that carbon and nitrogen could be added with
little to no effect while phosphorus caused major blooms
Cyanobacteria - Correct Answer Typical type of algae that bloom during phosphorus
additions
They are photosynthetic bacteria, some of which are N-fixing
when P/N ratio of elements is high they are favored over other types of algae
, Nitrogen cycle: Fixation - Correct Answer Fixation of N2 gas is done by
microorganisms using energy to break down the gas into organic NOx
compounds(Nitrate and Nitrite)
1/3rd of free-living bacteria(cyanobacteria) conduct fixation
2/3rds of plant-associated bacteria do this as well
Nitrogen cycle: Mineralization - Correct Answer NOx compounds are converted into
NH4+ (ammonium)
Organic Nitrogen compounds (NOx) are inaccessible to plants
Process done by fungi and bacteria in the soil
Nitrogen cycle: Nitrification - Correct Answer NH4+ (ammonium) is turn into NOx
compounds
performed by bacteria to create energy
byproduct of the process is the creation of N2O which is a greenhouse gas that is
300x more effective at warming the earth than carbon dioxide
Nitrogen cycle: Denitrification - Correct Answer NOx compounds are turned back into
nitrogen gas (N2)
performed by microbes
Anammox Process - Correct Answer NH4 + NO2 --> N2
makes up 30-50% of N2 in oceans
Fertilizer and Nitrogen - Correct Answer The nitrogen necessary for fertilizer used to
be harvested from guano and bird poop