Biogeochemical Cycles Flashcards
Nutrients move through ecosystems in ______, also known as ______
nutrient cycles, biogeochemical cycles.
Elements or molecules travel through the atmosphere, hydrosphere, lithosphere, and biosphere in dynamic equilibrium.
Nutrients move from one ____, or ____, to another for varying amounts of time, called the _____.
reservoir, pool, residence time
When a reservoir releases more materials than it accepts, it is called a _____.
source
When a reservoir accepts more materials than it releases, it is called a _____.
sink
_____ is the rate at which materials move between reservoirs.
Flux
The _____ describes the routes that carbon takes through the environment.
carbon cycle,
Carbon is found in all organic molecules—carbohydrates, fats, and proteins, which make up living organisms.
_____ (plants, algae, and cyanobacteria) pull _____ out of the air and use it to produce sugars like _____
Producers, carbon dioxide, glucose (C6H12O6).
____, _____ consume organic molecules and release some of the ____ as carbon dioxide.
Autotrophs, consumers, and decomposers, carbon
As aquatic organisms ____, their remains may settle in _____ in ocean basins or______
die, sediments, freshwater wetlands.
Converted over time to _____ into oil and skeletons into sedimentary rock like ____
soft tissue sediments, limestone
The oceans are the _______ of carbon, dissolving carbon dioxide, _____ and _____.
second-largest reservoir, carbonate ions (C O3 2−), bicarbonate ions (H C O3−).
_____ is the largest reservoir in the carbon cycle.
Sedimentary rock,
Released during uplift, erosion, volcanic eruptions, or the burning of fossil fuels
Today’s _____ reservoir is estimated to be the largest in the past _____
atmospheric carbon dioxide, 800,000 years.
Combustion of fossil fuels (a carbon sink)
Decrease of surface vegetation
Some of the excess ___ is being absorbed by the oceans, causing it to become more ____.
C O2, acidic
About 2.3–2.6 billion metric tons of released fossil fuel C O2 is ____ for.
unaccounted
Nitrogen is an essential ingredient in ____
D N A, R N A, and proteins.
_____ makes up 78% of the atmosphere, but is chemically inert and cannot leave the atmosphere without assistance.
Nitrogen gas (N2)
Under the right conditions, nitrogen can become biologically active and enter the biosphere and lithosphere, a process called _____
the nitrogen cycle.
In _____, inert nitrogen gas becomes biologically available by combining with hydrogen to form _____, whose water-soluble ions of ______ can be taken up by plants.
nitrogen fixation, ammonia (N H3, ammonium (N H4+)
The intense energy of lightning strikes can also fix nitrogen.
_____ convert nitrogen gas into ammonia.
Nitrogen-fixing bacteria
The bacteria form nodules on plant roots, absorbing sugars from the roots in exchange for nitrogen fixation.
Found in legumes, such as soybeans
Other bacteria perform a process called _____, which converts ammonium ions into nitrite ions (N O2−), then into nitrate ions (N O3−), which plants can directly take up.
nitrification
These ions are also added to the soil through the use of fertilizer.
Consumers obtain nitrogen by ingesting plants or other animals, while _____ obtain and release nitrogen from dead and decaying matter.
Consumers, decomposers
______ will then convert nitrates back into nitrogen gas.
Denitrifying bacteria
Nitrogen fixation has historically been a ______, a step that limited the flux of nitrogen out of the atmosphere.
bottleneck
