Movement of Elements Flashcards
Nutrients
Elements required by organisms for metabolism and growth
Biogeochemistry
Physical, chemical, biological factors that influence the movements and transformation of elements
Elements … among biotic and abiotic ecosystem components
cycle
Assimilation
requires energy. Inorganic to organic.
Dissimilation
releases energy. Organic to inorganic.
Two abiotic sources of nutrients
Minerals and gases
Mechanical Weathering
Physical alteration of rocks. Freezing, wetting/rewetting, otherwise “broken apart”
Chemical Weathering
Minerals subjected to chemical processes. Lichens do both this and mechanical weathering.
Atmospheric Deposition
Precipitation, particles, aerosols, and gases move from the atmosphere to the earths surface
Hydrologic Cycle
The movement of water through ecosystems and atmosphere; driven by evaporation, transpiration, and precipitation
Detritovores
Physically break organic matter into smaller pieces.
Decomposers
Break dead organic matter into inorganic elements. Process called mineralization.
The true decomposers are the … who …
bacteria and fungi, convert organic macromolecules into soluble nutrients
Decomposition proceeds most rapidly at
warm temperatures
Low soil moisture leads to
decreased decomposition.
High soil moisture leads to
low oxygen concentrations which lowers the activity of decomposers.
Moist forests have … rate of decomposition
low, not water logged
High quality detritus has lower … ratios because … is important for decomposition
C:N, nitrogen
Less nitrogen means
slower decomposition
Atmosphere is made of mostly
nitrogen
Nitrogen is required by … organisms
all
Too much nitrogen can cause
toxic plant/algae growth. The amount of fixed nitrogen is increasing.
Nitrogen fixation
The entrance. Converts atmospheric nitrogen into forms consumers can use. Nitrogen to ammonia to ammonium or nitrate
Biotic fixation
A type of nitrogen fixation involving free-living and mutualistic bacteria
Abiotic fixation
A type of nitrogen fixation involving lightning, wildfires, fossil fuel combustion, fertilizer production.
Intermediate Nitrogen Processes
Nitrification, assimilation, ammonification
Nitrification
Conversion of ammonium to nitrate by bacteria. Nitrates more easily used by plants
Assimilation of nitrogen
Incorporation of NH4+ or NO3- into organism tissues
Ammonification
Nitrogen in organic matter (feces, dead organisms) converted to ammonia or ammonium. Fungal and bacterial decomposers. Can then be converted back into nitrates.
Denitrification
The exit. Nitrates are water soluble and are leached from the surface. Nitrates are converted back intro nitrogen gas (N2) by bacteria under anaerobic conditions. NO3 to NO and NO to N2.
Like nitrogen, … is an essential element
phosphorus
Phosphorus moves as …
Phosphate (PO43-). Often limits productivity. Excessive phosphorus can cause toxic plant/algae growth.
Phosphorus only enters the atmosphere as …
dust
Plants assimilate phosphate which then moves to the … and when they die their excretion and decomposition allows it to …
consumers, go back into the soil for future leaching or going into runoff.
Some sedimentary rock from phosphorus is … allowing the phosphorus back into …
uplifted from aquatic systems, terrestrial systems.
Three major processes by humans that have increased N-fixation
Haber bosch, crops, gaseous emissions
Oligotrophic
Low nutrient levels. Low NPP. Healthy, diverse fish and invertebrate communities
Eutrophic
Nutrient rich. High phytoplankton, algae abundance and turnover. Oxygen depleted leads to anaerobic organisms. Accumulation of detritus leads to turbid and cloudy water. Loss of diversity.
Consequences of eutrophication
Hypoxia creates dead zones. Inability for fish to get oxygen.
