What is necessary when conducting research in a marine environment?
Sampling and an un-biased estimate of "what is there"
What sampling methods are used to sample the shallow-waterter benthos (< 30m)?
- video and cameras
- very useful for rocky shore habitats
- covers a large area
- problem with position
- qualitative data
- size and shape of sampling unit
- sometimes too small
- sometimes too large -> difficult to sample, reduces number of replicates
good in less then 30 m depth
What sampling methods are used to sample the deep water benthos?
- 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
-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
What sampling methods are used to sample the pelagic environment?
-multiple opening-closing nets
Longhurst-Hardy plankton recorder
Trawls and seines
- 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
-measure vertical fluxes
-high concentration of phytoplankton might attract predators that influence the sample
What are some values and limitations of remote sensing?
- sound waves and frequency
- non-destructive sampling
- requires calibration and data processing
- common in fish stock assessment
-synoptic view (shows chlorophyll a distribution -> to find base of food chain)
-address large-scale variability
-only surface sampling possible, no deep penetration