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APES Biogeochemical Cycles Test Questions with Verified Answers
biogeochemical cycle - -cycle of matter between
biotic and abiotic things in the environment involving
biological, geologic and chemical interactions; they are
driven by energy and gravity
carbon cycle - -During photosynthesis, plants
remove carbon from the air and store it as chemical
compounds such as sugar, the carbon will be released
back into the atmosphere through cellular respiration.
Sometimes plants or animals with carbon trapped in their
body will get buried before fully decaying; over millions of
years the heat and pressure will turn them into fossil fuels
containing carbon. This carbon is then released back into
the atmosphere through combustion.
nitrogen cycle - -Consists of five steps: nitrogen
fixation, nitrification, assimilaton, ammonification, and
denitrification.
nitrogen fixation - -First step of nitrogen cycle. The
conversion of gaseous nitrogen to ammonia, a form that
organisms can use. Nitrogen fixed bacteria (Rhizobium) is
found in legumes, then this bacteria converts nitrogen gas
to ammonia (NH3) and ammonium (NH4) (NOW
USEABLE FORMS); can be done by lightning,
combustion, volcanic activity and industrially
nitrification - -Second step of the nitrogen cycle.
bacteria change ammonia (animal/plant waste) or
ammonium into nitrate; the plants then absorb it First they
turn it into nitrite, then oxidize it to form nitrate. (ammonia
into poisonous nitrites (by bacteria) and then into nitrates)
assimilation - -3rd step of the nitrogen cycle. Plants
absorb nitrate, ammonia, or ammonium and incorporate
them into plant proteins. (nitrates into protein) animals eat
the plants to make protein. it is used to make DNA, amino
acids and proteins
ammonification - -4th step of the nitrogen cycle.
conversion of animal wastes to ammonium; decomposer
bacteria convert nitrogen containing organic compounds
into simpler nitrogen containing inorganic compounds)
denitrification - -Final step of the nitrogen cycle.
anaerobic bacteria changes nitrates back into nitrogen
gas and returns to the atmosphere
phosphorus cycle - -A sedimentary cycle. Water
erodes phosphorus-containing minerals and releases
phosphorus into soil, where plant roots absorb it and
incorporate it into biological molecules. Dead organisms
decompose and release phosphorus back into the soil to
be reused. Phosphate is often carried by water into the
ocean where it remains on the sea floor for millions of
years until uplift eventually exposes the sea floor
sediments as new land surfaces, where the phosphate will
be eroded again.
sulfur cycle - -Most sulfur is underground in
sedimentary rocks and minerals, which eventually erode
and release sulfur compounds into the ocean. Many
natural abiotic occurrences release sulfur into the
atmosphere, where it combines with oxygen and hydrogen
to form sulfuric acid. Plant roots absorb sulfate from soil
and incorporate it into plant proteins. Dead organisms then
release it back into the soil.
hydrologic cycle - -Water moves from the
atmosphere to the land and ocean through precipitation.
Water evaporates from the ocean, streams, soil, to form
clouds in the atmosphere. Transpiration also adds water to
the atmosphere. Plants and animals absorb or consume
water, then decompose and release it back into the abiotic
environment.
transpiration - -water from plants evaporates into the
atmosphere as water vapor
evapotranspiration - -returns water back to the
atmosphere; faster when the temperature is hotter
infiltration - -downward movement of water through
soil
percolation - -passage of a liquid through spaces of
material (soil)
runoff - -water that flows on the earth's surface into
other bodies of water; opposite of infiltration (lot of runoff..
low infiltration), rate of precipitation exceeds rate of
infiltration, or the ground is saturated (pores are full)
