Lecture 21 Flashcards
Eutrophication
”is the process by which an entire body of water or parts of it, becomes progressively enriched with nutrients”
The paradox of enrichment
Increasing the availability of resources (usually food) can lead to the decline or instability of a consumer’s population
Components of paradox enrichment (4)
- Increase resources
- Consumer response
- Overexploitation
- Boom and bust
Instability and/or extinction
Green food web
- how producers obtain energy from primary production and
- how this energy moves up the food web when producers are consumed
Brown food web
- how scavengers, detritivores, and decomposers obtain energy from dead organic matter
- how this energy moves up the food web when they are consumed
Habitat coupling
“the linking of discrete habitats are connected through the movement and foraging of mobile consumers”
Biogeochemical cycle
“the movement and transformation of chemical elements and compounds between living organisms and gaseous/solid/liquid forms in the atmosphere, and rocks, soils, and sediment”
Pools
=> represent “the total amount of a particular substance or element within a specific compartment or reservoir in an ecosystem”
* Can include living organisms (plants, animals, and microorganisms) as well as non-living components (soil, water, and the atmosphere)
* Can vary greatly insize
* Can be relatively stable or dynmic
* Measurement units: mass (e.g., in kg)
Examples of major pools
- Living biomass
- Detritus/organic matter/soil
(soil organic matter, dissolved organic matter) - Sediment
- Atmosphere
- Rocks
Residence time
average amount of time energy or biomass remains within a specific compartment or trophic level
* Before it is either transferred to another pool or removed from the system altogether
Equation of biomass residence time(years)
= total biomass in a pool (kg/m^3) / net biomass flux (kg/m^3/year)
Evaporation
involves the conservation of liquid on the Earth’s surface into water vapor through the input of solar energy
- Primarily from the ocean surface but also from other water bodies
Transpiration
release of water vapor from plants through small openings called stomata on their leaves
- Essentially the plant equivalent of evaporation
- Important component of the water cycle, particularly in terrestrial ecosystems
Precipitation
Refers to the release of water from the atmosphere in the form of rain, snow, sleet, and hail
Runoff
the movement of water over the land surface and into bodies of water such as rivers, lakes, and oceans.
- Occurs when precipitation exceeds the infiltration capacity of the soil or when the soil is saturated with water
- Transports water, sediment, and dissolved substances from one location to another
Percolation/infiltration
the process by which water seeps into the soil downward through pores and fractures
- Replenishes soil moisture, recharges groundwater aquifers, and contributes to the storage of water in the subsurface
Uptake
nutrients are taken up by organisms from the environment
Decomposition
Dead organisms are broken down by decomposers
Mineralization
the conversion of organic nutrients into inorganic forms that can e taken up by plants and other organisms
Leaching
nutrients can be lost from ecosystems through leaching, where water carries dissolved nutrients downward through the soil layers
Runoff
nutrients can be washed away from the lands surface into bodies of water
Volatilization
nutrients are released into the atmosphere
Weather
Physical/chemical breakdown of rocks
Sedimentation
Movement of elements back into sediments
Nitrogen fixation
the process by which atmospheric nitrogen gas (N2) is converted into ammonia (NH3) or other nitrogen-containing compounds
- Conversion of atmospheric nitrogen into a biologically usable form
- Nitrogen-fixing organisms (certain bacteria, archaea, and cyanobacteria) that possess the enzyme nitrogenase
Nitrification
the biological oxidation of ammonia (NH3) to nitrite (NO2-) and then to nitrate (NO3-) by specialized bacteria called nitrifying bacteria
- Occurs primarily in aerobic (oxygen-rich) environments
- Nitrifying bacteria
Ammonification
the microbial decomposition of organic nitrogen compounds (e.g., proteins, nucleic acids) into ammonia (NH3) and ammonium ions (NH4+).
- Releases nitrogen in the form of ammonium, making it available for uptake by plants and other organisms
- Carried out by various decomposer organisms, such as bacteria and fungi, during decomposition
Denitrification
the reduction of nitrate (NO3-) and nitrite (NO2-) to nitrogen gas (N2) to nitrous oxide (N2O)
- Returns nitrogen gas to the atmosphere
- Denitrifying bacteria under the anaerobic (oxygen-deprived) conditions
Weathering
the process by which phosphorus-containing minerals, such as apatite, are broken down by physical and chemical weathering processes, releasing phosphorus into the soil and water
Stoichiometry
study of balance of elements and compounds in biological systems and their role in regulating ecological processes.
i.e. the elemental composition of organisms and ecosystems
