Title: CHE2DEV Env Water Qual Quiz 3

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Q: Select the correct statement about phosphorus in environmental waters.
- High levels of dissolved oxygen are responsible for phosphorus mineralisation
- An acidic persulfate digestion of a water sample gives a total measure of all soluble and particulate phosphorus species
- Colloids absorb phosphate at high pH
- Plant uptake of phosphorus does not effect levels of reactive phosphorus in waters
A: An acidic persulfate digestion of a water sample gives a total measure of all soluble and particulate phosphorus species

Q: Select the correct statement about health concerns of nitrate in water
- Mutagenic N-nitrosamines are formed in humans by the reaction of nitrates with organic amines from plant material
- Nitrate (NO_3^-) levels greater than 10 mg/L in potable waters pose no significant health risks
- Oxygen transport ability of haemoglobin is increased by nitrosoyl ions (NO^+) that reduce Fe^3+ to Fe^2+
- Nitrosoyl ions (NO^+) are formed in humans following the action of digestive enzymes that reduce nitrate (NO_3^-) to nitrite (NO_2^-)
A: Nitrosoyl ions (NO^+) are formed in humans following the action of digestive enzymes that reduce nitrate (NO_3^-) to nitrite (NO_2^-)

Q: Select the correct statement about phosphorus in environmental waters.
- The solubility of calcium hydroxyapatite, Ca_5(PO_4)_3OH, in water increases at high pH
- Iron and aluminium phosphates are the main soluble phosphate forms in sediments at high pH
- The availability of dissolved inorganic phosphate in water increases at low pH
- The primary phosphate species in neutral and basic sediment are calcium phosphates
A: The primary phosphate species in neutral and basic sediment are calcium phosphates

Q: Fill in each blank with a single word.
Increased levels of plant nutrients in natural waters is known as [...].
As a result of this condition and with appropriate environmental conditions there can be a substantial [...] in the growth of algae.
The resulting bacterial decomposition of the biomass after all the plant nutrients have been consumed produces a significant oxygen [...] on the water body.
Low levels of dissolved oxygen can have [...] consequences for a healthy aquatic ecosystem.
A: eutrophication; increase; demand; dire

Q: Select the correct statement about phosphorus in environmental waters.
- Levels of reactive phosphorus are typically greater than particulate phosphorus
- Phytoplankton readily consume phosphorus from sediment
- Thermal destratification of a eutrophic water body increases levels of dissolved oxygen at the water-sediment interface
- Phosphorus is released from sediment when macrophyte plant growth reduces phosphorus below the water/sediment equilibrium concentration
A: Phosphorus is released from sediment when macrophyte plant growth reduces phosphorus below the water/sediment equilibrium concentration

Q: Fill in each blank with a single word.
Denitrification describes the process whereby [...] in soil and aquatic sediments are responsible for the [...] of nitrates to nitrogen.
This occurs during cellular [...] where nitrates are used as a source of [...] during the oxidation of organic matter
A: a. bacteria b. microbes; reduction; respiration; oxygen

Q: Select the correct statement about nitrification
- Nitrifying bacteria produce substantial amounts of organic carbon material by the oxidation of carbon dioxide (CO_2)
- Oxidation of ammonia nitrogen to nitrite (NO_2^-) contributes to water alkalinity
- Nitrifying bacteria are responsible for the reduction of ammonia nitrogen to nitrate
- Nitrate is used as source of oxygen under anaerobic conditions by some nitrifying bacteria during the oxidation of ammonium (NH_4^+)
A: Nitrate is used as source of oxygen under anaerobic conditions by some nitrifying bacteria during the oxidation of ammonium (NH_4^+)

Q: Select the correct statement about ammonia nitrogen and mineralisation
- Ammonia nitrogen refers to all forms of inorganic nitrogen including ammonia (NH_3), nitric oxide (NO) and nitrogen dioxide (NO_2)
- High levels of ammonia (NH_3) are beneficial to aquatic organisms
- Mineralisation is the process whereby microbes decompose organic matter to release ammonia nitrogen to the environment
- The availability of ammonium (NH_4^+) in water increases at higher pH
A: Mineralisation is the process whereby microbes decompose organic matter to release ammonia nitrogen to the environment

Q: Select the correct statement about nitrogen fixation
- Industrial production of ammonia (NH_3) by nitrogen fixation requires an increase in the activation energy (E_a) for the reaction between molecular nitrogen and hydrogen
- The covalent bond in molecular nitrogen is chemically very reactive because it requires a small input of energy for bond dissociation
- Atmospheric nitrogen fixation involves a spontaneous reaction between nitrous oxide (NO) and oxygen (O_2) to form nitrates (NO_3^-)
- Biological nitrogen fixation involves bacteria that use complex enzymatic reactions powered by cellular ATP to produce soluble forms of ionic nitrogen for plant growth
A: Biological nitrogen fixation involves bacteria that use complex enzymatic reactions powered by cellular ATP to produce soluble forms of ionic nitrogen for plant growth

Q: Select the correct statement about phosphorus in environmental waters.
- Levels of reactive phosphorus are typically greater than particulate phosphorus
- Phytoplankton readily consume phosphorus from sediment
- Thermal stratification of a eutrophic water body increases levels of dissolved oxygen at the water-sediment interface
- Phosphorus is released from sediment when macrophyte plant growth reduces phosphorus levels below the water/sediment equilibrium concentration
A: Phosphorus is released from sediment when macrophyte plant growth reduces phosphorus levels below the water/sediment equilibrium concentration

Q: Select the correct statement about nitrogen fixation
- The covalent bond in molecular nitrogen is chemically very reactive because it requires a small input of energy for bond dissociation
- Atmospheric nitrogen fixation involves a spontaneous reaction between nitrous oxide (NO) and oxygen (O_2) to form nitrates (NO_3^-)
- Biological nitrogen fixation involves bacteria that use complex enzymatic reactions powered by cellular ATP to produce soluble forms of ionic nitrogen for plant growth
- Industrial production of ammonia (NH_3) by nitrogen fixation requires an increase in the activation energy (E_a) for the reaction between molecular nitrogen and hydrogen
A: Biological nitrogen fixation involves bacteria that use complex enzymatic reactions powered by cellular ATP to produce soluble forms of ionic nitrogen for plant growth

Q: Fill in each blank with a single word.
Aquatic plants increase their [...] by converting soluble inorganic phosphorus to organic phosphorus material.
Organic phosphorus is converted to inorganic phosphorus by the action of bacteria during the [...] of organic matter.
Inorganic phosphorus is strongly adsorbed by [...] as mineral phosphates of iron, aluminium and calcium.
The [...] of water controls the solubility of mineral phosphates.
A: biomass; decomposition; sediment; pH

Q: Fill in each blank with a single word.
Denitrification describes the process whereby [...] in soil and aquatic sediments are responsible for the [...] of nitrates to nitrogen.
This occurs during cellular [...] where nitrates are used as a source of [...] during the oxidation of organic matter
A: bacteria; reduction; respiration; oxygen