Biogeochemistry
What are the 6 bioessential elements (elements essential for life on Earth)?
CHNOPS
What are the two major processes that control 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 causes Earth’s seasons?
The tilt of Earth’s axis as Earth orbits the Sun.
What are the 4 major 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)
Approximately how much incoming solar energy is absorbed by Earth, and how much is reflected into space?
About 70% is absorbed and 30% is reflected.
Humans are part of which 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)
What reservoir is sulfur primarily stored in?
Lithosphere
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 is the difference between weather and climate?
Weather describes short-term atmospheric conditions, while climate describes long-term patterns and averages.
Extra 100 points for the ~years we consider climatological conditions!
What is the average amount of time an element remains in a reservoir called?
Residence time
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
Phosphorous is the __________ nutrient in many ecosystems, meaning its abundance controls the productivity of that ecosystem (hence its use in fertilizer).
Limiting
Approximately how much more CO₂ do human activities release each year compared with volcanoes?
Volcanoes emit ~ 130 -380 million metric tons of CO2/year. Humans emit ~ 30 billion tons of CO2/year by burning fossil fuels.
(100–300 times more)
What is the difference between a positive and a negative climate feedback?
A positive feedback strengthens an initial climate change, while a negative feedback reduces or counteracts it.
What happens to a reservoir when its input fluxes are greater than its output fluxes, making the cycle unbalanced or unstable?
The amount stored in the reservoir increases or accumulates.
Which processes move C through the fast C cycle, and which processes move it through the slow C cycle?
The fast C cycle: photosynthesis, respiration, and decomposition.
The slow C cycle: weathering, burial, rock formation, and volcanism.
Extra points if you tell me the timescales?
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 _________ _________.
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.
What global system of ocean currents transports heat around Earth and is driven by differences in water temperature and salinity?
The global ocean conveyor belt, also called thermohaline circulation.