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Extremophile

Organism that lives in extreme pH, temperature, or salinity.

Archaea

Microorganisms commonly found as extremophiles.

Extremozyme

Enzyme enabling survival in extreme environments.

Symbiosis

Relationship between organisms benefiting one or both partners.

Rumen

Fermentation chamber in ruminants housing cellulose-digesting microbes.

Mycorrhiza

Fungal relationship with plant roots to enhance nutrient uptake.

Endomycorrhizae

Fungi that penetrate plant root cells.

Ectomycorrhizae

Fungi that surround but do not enter root cells.

Biogeochemical cycle

Cycle of chemicals like C, N, S, and P through ecosystems.

Carbon cycle

Microbial and plant processes converting carbon between forms.

CO2 fixation

Conversion of carbon dioxide to organic carbon by autotrophs.

Chemoheterotroph

Organism that uses organic molecules for carbon and energy.

Decomposer

Organism that breaks down dead matter and releases nutrients.

Nitrogen cycle

Microbial process converting nitrogen between usable forms.

Ammonification

Conversion of organic nitrogen to ammonia.

Deamination

Removal of amino groups from amino acids.

Nitrification

Oxidation of ammonium to nitrite and nitrate by bacteria.

Nitrosomonas

Bacteria converting ammonium to nitrite.

Nitrobacter

Bacteria converting nitrite to nitrate.

Denitrification

Reduction of nitrate to nitrogen gas.

Nitrogen fixation

Conversion of atmospheric nitrogen (N2) to ammonia.

Rhizobium

Symbiotic bacteria forming root nodules for nitrogen fixation.

Root nodule

Plant structure housing nitrogen-fixing bacteria.

Azotobacter

Free-living nitrogen-fixing bacterium.

Cyanobacteria

Nitrogen-fixing microbes with heterocysts.

Heterocyst

Specialized cyanobacterial cell for nitrogen fixation.

Sulfur cycle

Microbial oxidation and reduction of sulfur compounds.

Hydrogen sulfide

Reduced sulfur compound used by sulfur-oxidizing bacteria.

Dissimilation

Release of H2S during protein decomposition.

Phosphorus cycle

Cycle involving phosphate between soluble and insoluble forms.

Acidithiobacillus

Bacterium that solubilizes phosphate by producing acid.

Xenobiotic

Man-made chemical resistant to microbial degradation.

Bioremediation

Use of microbes to degrade pollutants.

Bioaugmentation

Addition of microbes to speed pollutant degradation.

Composting

Microbial degradation of organic waste into humus.

Freshwater microbiota

Microbial communities in freshwater ecosystems.

Littoral zone

Shallow shoreline freshwater region.

Limnetic zone

Sunlit open-water freshwater region.

Profundal zone

Deep freshwater region with low oxygen.

Benthic zone

Bottom region containing anaerobic microbes.

Phytoplankton

Microscopic photosynthetic organisms in water.

Bioluminescence

Light emission by microbes using luciferase.

Indicator organisms

Microbes used to detect contamination, especially fecal.

Coliform

Gram-negative rod that ferments lactose with gas.

MPN method

Statistical test used to estimate coliform numbers in water.

Membrane filtration

Water test concentrating microbes on a filter.

ONPG test

Test for lactose-fermenting bacteria.

Water treatment

Process of cleaning water for safe drinking.

Coagulation

Initial step where particles clump together.

Filtration

Removal of microbes by passing water through sand or coal.

Chlorination

Adding chlorine to disinfect water.

Primary sewage treatment

Removal of solids from sewage by settling.

BOD (biochemical oxygen demand)

Measure of biodegradable organic matter.

Activated sludge

Aerated wastewater containing degrading microbes.

Trickling filter

Bed of rocks/plastic where biofilms degrade sewage.

Sludge digestion

Anaerobic process producing methane gas.

Septic tank

Household system for sewage settling and breakdown.

Tertiary treatment

Advanced sewage treatment removing nutrients.

Microbial ecology

Study of microbes in their natural environments.

Microhabitat

Small, specific environment where microbes thrive.

Biofilm

Surface-attached community of microorganisms.

Holdfast

Attachment structure used by aquatic bacteria.

Thermophile

Organism thriving at high temperatures above 45°C.

Halophile

Organism requiring high salt concentrations.

Acidophile

Organism thriving in acidic environments (low pH).

Alkaliphile

Organism thriving in basic environments (high pH).

Cryophile

Psychrophile that grows in cold temperatures near or below 0°C.

Metagenomics

Study of microbial DNA directly from environmental samples.

Topsoil layer

Region with the highest soil microbial diversity.

Chemoautotroph

Organism using inorganic molecules to produce organic matter.

Endolith

Microbe living inside rock pores or mineral grains.

Hydrothermal vent

Deep-sea location with chemical-rich hot water supporting chemoautotrophs.

Eutrophication cause

Excess nitrogen or phosphorus added to water ecosystems.

Algal bloom

Rapid growth of algae due to nutrient overabundance.

Bioindicator

Organism used to assess environmental health or pollution.

Trichodesmium

Marine cyanobacterium important in nitrogen fixation.

Prochlorococcus

Most abundant photosynthetic organism in the ocean.

Synechococcus

Marine cyanobacterium contributing significantly to carbon fixation.