Benthic Sampling Flashcards
What is benthos?
The community of organisms that live on or near the seabed or on the bottom of freshwater bodies
What are the types of benthic organisms classified by size?
-Macrobenthos : >1mm
-Meiobenthos : 0.1-1mm
-Microbenthos : <0.1mm
Give examples of macrobenthos
- Bivalves
- Corals
-Lobsters - Sponges
-Polychaetes
Give examples of Meiobenthos
-Copepods
-Nematodes
-Ostracods
Give examples of microbenthos
-Diatoms
-Amoeba
-Flagellates
How are mega benthos defined operationally?
Benthos that can be sampled using towed gear of a certain mesh size or recorded on seabed photographs eg: Starfish
What are hyperbenthos organisms?
Organisms that live just above the sediment
What are epibenthos/epi fauna?
Organisms that live on the substrate
What are endobenthos/infauna?
Organisms that live in substrate
What is ex-situ sampling method?
A portion of the sediment and fauna are removed for latter processing and examination.
Give examples of equipment used for ex-situ sampling.
-Trawls
-Dredges
-Cores
-Grabs
-ROV’s
What is in-situ sampling?
Benthos is directly observed and not removed.
Give examples of in-situ sampling methods.
- Onshore observations
- Imaging
- Scuba observations
- ROV’s
What is Quantitative sampling?
Sampling that produces data that can be measured numerically and transformed into usable statistics.
Give an example of a quantitative sampling method
- Quadrats
- Cores can provide density estimates
What is Qualitative sampling?
Descriptive sampling.
Data can be observed but not measured explicitly.
Give examples of Qualitative sampling methods
Trawls and dredges.
Give an example of semi-quantitative sampling.
CPUE allows some measure of numerical data
How is intertidal sampling sampled?
Intertidal is sampled at a series of regular intervals from the high to low water mark with replicates taken at each location. EG- quadrats.
These are quantitative.
Describe the qualitative sampling method ‘Riley Pushnet’
It is a light metal frame seated on two metal skis.
Net of 5-10mm mesh with finer mesh cod end and a weighted foot rope.
Designed to sample benthic macro fauna in shallow intertidal.
What are the disadvantages of subtidal sampling?
-More expensive
-Requires ship time
-Weather dependent
Give an overview of Trawls/Dredges as sampling methods.
-Selective sampling methods(some organisms will escape)
-Skim over the surface of the substrate
-Large swept area (rare epifauna)
-Qualitative but can be used as semi-quantitative
What do grabs sample?
Suitable for mud and sand sampling.
Quantitative for shallow infauna (top
Give examples of grabs used for sampling sand and sediments.
Day grab
Van Veen Grab
Peterson grab
Preservation method for sampling benthic macro fauna
Counter staining
Sortation
Elutriation
What is the taxonomic identification method?
Technological aids- computer based interactive keys
Name all Qualitative sampling equipment used
Riley pushnet
Trawls
Epibenthic sledge
Anchor dredges
Name all quantitative methods (grabs)
Grabs
-Peterson grab
-van veen grab
-day grab
-shipek sediment sampler
-ekman grab
Name all quantitative methods (corers)
Box sampler/corer
Suction sampler
