PAST PAPER 2019

Question 1

What is the purpose of using a CTD rosette to collect water samples?

Answer 1

• obtain a preview of the water column
• can sample specific features (e.g. chlorophyll maximum)
• large volumes can be sampled by using more than one bottle

Question 2

Name 3 different Autonomous underwater vehicles that can be used to study marine processes?

Answer 2

Autosub 6000
Sentry
REMUS 6000
(ABYSS)
(Autosub Long Range)
(Autosub 3)

Question 3

Aside from riverine inputs name 3 other inputs into estuarine & coastal systems?

Answer 3

• Atmospheric inputs
• Submarine groundwater discharge
• Trace gases
• (glacial inputs)
• (benthic sources)

Question 4

What are AUVs?

Answer 4

• autonomous underwater vehicles
• deployed from a ship
• pre-programmed dive sequences
• can carry wide variety of instruments (flow cytometers, ADCPs, chemical sensors etc)
• newest versions can operate down to 6km depth & e.g. under ice shelves

Question 5

Define conservative behaviour in an estuary?

Answer 5

During estuarine mixing phases, if a linear relationship exists between concentration of a particular dissolved constituent and a conservative indicator of mixing between seawater and fresh water (e.g. salinity), then the behaviour of the constituent can be described as conservative.

If constituent plots along the line linking river water endmember to seawater endmember (the theoretical dilution line), the constituent said to show conservative behaviour in the estuary.

Question 6

Describe an experiment whereby you can test the impact of organic matter on oxygen concentrations in estuaries?

Answer 6

Incubate marine sediments w oxygen probes (see slides)

Question 7

Define the term Eutrophication?

Answer 7

The enrichment of the environment with nutrients and associated production of undesirable effects.

Causes an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms and to the water quality concerned.

Question 8

List 3 causes of coastal eutrophication?

Answer 8

Sewage pollution
Fertiliser runoff
Coastal algal blooms

Question 9

Name 3 types of marine pollution?

Answer 9

• degradable wastes e.g. urban sewage, food processing
• fertilisers, contain nitrates and phosphates
• dissipating wastes, e.g. heat, acids/alkalis, cyanide
• (conservative wastes, e.g. heavy metals, radioactivity)
• (solid wastes, e.g. litter)

Question 10

Name 3 different toxicity tests?

Answer 10

Lethal dose (LD50) - acute toxic effects are quantified by controlled experiments to determine the dose causing immediate death of 50% of the population.

Median Lethal Time (LT50) - Time for death of 50% of a sample - depends on concentration

Median Lethal Concentration (LC50) - e.g. 4 day LC50. Short term tests exposure of test aquatic organism to toxin for constant period of time.

Question 11

What are the 3 sources of oil to the ocean?

Answer 11

1. Transportation (tanker operations, tanker accidents, bilge and fuel oils, dry docking, non-tanker accidents)
2. Fixed installations (offshore production, drilling production, coastal refineries, marine terminals)
3. Natural inputs

Other sources: municipal wastes, industrial wastes, urban run off, river run off, atmos fallout, ocean dumping