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Marine Ecology & Monitoring > Sampling Marine Environments > Flashcards

Flashcards in Sampling Marine Environments Deck (5):
1

What is necessary when conducting research in a marine environment?

Sampling and an un-biased estimate of "what is there"

2

What sampling methods are used to sample the shallow-waterter benthos (< 30m)?

advantages/disadvantages

SCUBA

epibenthic organisms

  • video and cameras
  • transects
  • very useful for rocky shore habitats

Hydroplanes

  • covers a large area
  • problem with position 
  • qualitative data 

cores/quadrats

  • size and shape of sampling unit
  • sometimes too small
  • sometimes too large -> difficult to sample, reduces number of replicates

suction samplers 
good in less then 30 m depth

3

What sampling methods are used to sample the deep water benthos?

advantages/disadvantages

  • ROVs
  • AUVs
  • Manned submersibles 

only a few facilities that can go that deep

grab samplers (box corers)

-to take a piece of seabed

-only small samples possible

benthic dredges

-unprecise (overfill, bounce around, samples escape)

-limited penetration depth

-semi-quantitative rather than qualitative

-take a long time (1/h)

-expensive due to running costs of research vessels

create a lot of material that needs processing

4

What sampling methods are used to sample the pelagic environment?

advantages/disadvantages

MOCNESS

-multiple opening-closing nets

-net minders

Longhurst-Hardy plankton recorder

Trawls and seines

-stock assessments

-quantification

  • difficult
  • consistent methods (depth, speed, time) -> overlap of two years when new vessels are introduced to match methods
  • the patchy distribution of species makes stock assessment difficult

Sediment Traps

-measure vertical fluxes

-swimmers

-high concentration of phytoplankton might attract predators that influence the sample

5

What are some values and limitations of remote sensing?

Acoustics

  • sound waves and frequency
  • non-destructive sampling
  • requires calibration and data processing
  • common in fish stock assessment

Towed sensors

  • optical
  • chemical

Satellites

-synoptic view (shows chlorophyll a distribution -> to find base of food chain)

-address large-scale variability

-only surface sampling possible, no deep penetration