Biogeochemistry
What are the 6 bioessential elements (elements essential for life on Earth)?
CHNOPS
What are the two major processes that drive the carbon (C) cycle?
Photosynthesis & Respiration
Nitrogen makes up ~ _____ % of the atmosphere.
~80%
Carbon dioxide (CO2) is a _______ _______, and thus, _____ heat in Earth's atmosphere.
Greenhouse gas
Traps
What chemical reservoir is sulfur primarily stored in?
Lithosphere
Extra 200 points to anyone who knows which minerals sulfur is stored in!
What are the 4 major chemical reservoirs on Earth?
Atmosphere (Air), Hydrosphere (Water), Biosphere (Life), & Geosphere/Lithosphere (Rocks)
Carbon is stored in the atmosphere mainly as _______ and in the biosphere (life) as _______.
Carbon dioxide (CO2)
Organic carbon (Corg)
Unlike the carbon cycle, which is controlled largely by photosynthesis & respiration, and thus, plants and animals, the nitrogen & phosphorous cycles are driven by _________.
Microbes
Humans are contributing to global warming by burning _______ ______, which releases ______ to the atmosphere.
Fossil fuels
CO2 (carbon dioxide)
Photosynthesizing organims that produce sulfur instead of oxygen are called ____________ photosynthesizers.
Anoxygenic photosynthesizers.
Humans are part of which chemical reservoir?
The Biosphere (Life)
Plants (& other photosynthesizing organisms) absorb sunlight and take up _______ & _______ to produce ________ & _________.
CO2 (carbon dioxide) & H2O (water)
O2 (molecular oxygen) & Corg (organic carbon)
We, animals, get our nitrogen from plants, but plants can't just 'breathe in' nitrogen from the atmosphere like they do with carbon dioxide. They rely on microbes to convert the atmospheric nitrogen gas (N2) into other forms through a processes called _________ _________.
Nitrogen fixation
Is the greenhouse effect bad for Earth? Why or why not?
No, the greenhouse effect is essential for life on Earth; it is only harmful to life on Earth when its strength changes rapidly.
What are the two main types (end-member compounds) of sulfur involved in the S cycle?
H2S (reduced) & SO42- (oxidized)
Extra 100 points to whoever can say what oxidized reduced mean?
Which of the chemical reservoirs store carbon (in any form)?
Atmosphere, biosphere, hydrosphere (and cryosphere), and geosphere
What do plants (& other photosynthesizing organisms) do at night when there is no sunlight available?
Respire oxygen (they consume O2 and produce CO2 instead of the other way around)
Phosphorous is the __________ nutrient in many ecosystems, meaning its abundance controls the productivity of that ecosystem (hence its use in fertilizer).
Limiting
How does continental weathering cause cooling?
It increases the rate of carbon burial
Extra 100 points for anyone who knows the chemical reaction that occurs during silicate weathering that actually removes C from the atmosphere!
How is the S cycle tied to the O cycle?
H2S in the ocean increases when O2 decreases in oceanic (ocean anoxia).
100 extra points for anyone who knows why H2S increases during anoxic periods!
100 extra points for anyone who knows why this is relevant to modern climate change!
Other than humans, name 2 times in Earth's history when life caused global climate change, and explain how it did so.
1. Photosynthesizing bacteria caused the rise of O2 on Earth ~2.4 billion yrs ago.
2. Formation of soil caused major carbon sequestration & cooling in the Ordovician & Devonian periods as non-vascular plants and trees evolved.
Name 4 processes (other than photosynthesis & respiration) that can heavily affect the carbon cycle.
Volcanos, Impacts, Continental Weathering, Carbonate Rock Formation, Burning Fossil Fuels, Glacial Ice Formation
Why is phosphorous so limited in ecosystems? What chemical reservoir is it stored in?
Majority of phosphorous is stored in the lithosphere (rocks).
Extra 100 points for anyone who can name a P-containing mineral!
Name 2 ways (other than burning fossil fuels) that humans are contributing to global warming.
Deforestation (releases carbon stored by trees & soil in those regions)
Increased wildfires (through poor forest management)
Desertification (drying out soils due to modern agriculture practices which we'll talk more about in future lectures)
Pollution (plastics have been shown to increase beach/sand surface temperatures)
Some not listed in the video: Urban heat island effect (city development, dark surfaces lead to faster warming), habitat desctruction/fragmentation (similar to deforestation- takes away natural, C-storing landscapes), etc.