AQUATIC CHEM QUIZ 3 Flashcards
What key processes do micro organisms carry out in water chemistry?
Photosynthesis and respiration
What are organic hazardous substances carried through water as?
As emulsions of very small particles suspended in water
Some hazardous materials are deposited in sediments
Autotrophic
Use solar/chemical energy to fix elements from simple non-living inorganic material—>complex life molecules that compose living organisms
PRODUCERS
Heterotrophic
Use organic substances produced by autotrophs as energy sources & as a raw material for the synthesis of their own biomass
Cannot produce its own food
DECOMPOSERS(bacteria, fungi)
The roles of micro organisms in water
- Oxygen production
- breakdown of biomass
- Catalysts of aquatic chemical reactions

Examples of microorganisms in water
- Algae
- fungi
- bacteria
Aerobic
Require molecular oxygen as an electron receptor
Facultative bacteria 
Uses free oxygen and other substances as electron receptors
Ways other than photosynthesis and respiration that microbes are involved in the C cycle
- Degradation of biomass
- Methane production
- Degradation of hydrocarbons
What is Nitrogen fixation
Any natural/ industrial process that causes free nitrogen
What is nitrification?
Reduced nitrogen compounds are oxidised to nitrite & nitrate
The conversion of N(-III) to N(V)
2O2 + NH4+ —> NO3- + 2H+ + H2O
What is Nitrate reduction?
Nitrate used as an electron acceptor in anaerobic conditions
2NO3- + {CH2O} —> 2NO2- + H2O + CO2
What is Denitrification?
A process I converts nitrate to nitrogen gas
End product- N2
What are the four trophic classifications of lakes?
- Oligotrophic - little to no aquatic vegetation
- Mesotrophic- intermediate productivity
- Eutrophic- large quantities of organisms (algal blooms)
- Hypereutrophic- excessive algal growth
OMEH
Liebig’s Law of the Minimum states: 
If one of the essential plant nutrient is deficient, plant growth will be poor even when all other essential nutrients are present
or
The yield of a given species should be limited by the nutrient that was present in the least quantity in the environment relative to its demand for growth
What are the Key variables for eutrophication?
Sunlight
Nitrogen
Phosphorus
TN stands for
TP stands for
Total nitrogen
Total phosphorus
Chl a stands for
SD stands for
Chlorophyll a
Secchi disk transparency
Factors that can influence eutrophication
Dissolved oxygen
Light
Macronutrients (Ca, Mg, K)
Salinity
What is eutrophication?
An enrichment of water by nutrients that cause structural changes to the ecosystem
E.g excessive growth of algae
Depletion of fish species
Deterioration of water quality