Flashcards
Water Column Sampling
Cards in this deck (21)
- 1What are the key requirements of water bottles?Rapid exchange with surrounding water
Reliable closure and no leaks
Resistant to corrosion
No contamination
Easy to handle, < 10L in size - 2What are the advantages and disadvantages of deploying bottles on a hydroline?+ Simple mechanism
- Line not vertical in the water column
- No knowledge of water properties - 3What are the benefits of deploying bottles on a CTD rosette?Bottles can be closed individually
Large volumes can be obtained
CTD provides preview of water column
Targeted sampling of specific features - 4What is the purpose of filtering samples?To remove particulate matter, including dust, biology and resuspended sediment
- 5What are the requirements of a filter?Mechanically strong
No contamination or adsorption
Uniform particle cut of size - 6How should samples be stored to analyse them for macronutrients?Freeze samples to slow down bacterial processing
Ammonium cannot be stored - 7How should samples be stored to analyse for trace metals?Acidify to pH2 using HCl
- 8What are the advantages of in situ pumps?Rapid deployment
Good for collecting fine particles
Can collect a large mass of particles - 9What are the disadvantages of in situ pumps?Time series not possible
Difficult to estimate flux of falling particles
Not good for collecting large particles - 10What are the different types of sediment traps?Cones and tubes
Eulerian (fixed)
Lagrangian (free drifting) - 11What are the advantages of sediment traps?Time series via array of rotating collectors
Direct flux measurements
Can acquire large mass of material
Collection of rare, large particles - 12What are the disadvantages of sediment traps?Potential for over/under trapping
Swimmers and microbial alteration
Relatively expensive
Not good for fine particles - 13What are the limitations of ship-based sampling?Limited spatial and temporal resolution
Restricted capabilities of ship
Expensive and time consuming
Not good for precise sampling - 14What is the benefit of manned submersibles and ROVs?Precise sampling of small-scale features
- 15What are some of the sensors on the Autosub 6000?CTD, dissolved oxygen, turbidity, sonar, bottom profiler, 2 high resolution cameras, magnetometer, ADCP
- 16What is Boaty McBoatface?Autosub Long Range (ALR)
- 17How are gliders controlled?Buoyancy
Wings for lift
Rudder for direction - 18What sensors do gliders have?Temperature, salinity, oxygen, fluorescence, nutrients, echo sounder
- 19What in situ chemical analyses can be carried out by gliders?Dissolved oxygen, pH, pCO2 and redox potential
- 20What are the advantages of gliders?Operate independently of a ship
High spatial and temporal coverage
Plug and play
Data relayed to shore remotely - 21What are the disadvantages of gliders?Not effective in strong tidal current
High turbidity can reduce photo quality
Possible entanglement or collision
Limited battery life
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- BSc Marine Biology (Coasts and Estuaries) Flashcards on Water Column Sampling, created by Holly Sheridan on 27/05/2024.
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- Holly Sheridan
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