Benthic Sampling

Question 1

What is benthos?

Answer 1

The community of organisms that live on or near the seabed or on the bottom of freshwater bodies

Question 2

What are the types of benthic organisms classified by size?

Answer 2

-Macrobenthos : >1mm
-Meiobenthos : 0.1-1mm
-Microbenthos : <0.1mm

Question 3

Give examples of macrobenthos

Answer 3

• Bivalves
• Corals
  -Lobsters
• Sponges
  -Polychaetes

Question 4

Give examples of Meiobenthos

Answer 4

-Copepods
-Nematodes
-Ostracods

Question 5

Give examples of microbenthos

Answer 5

-Diatoms
-Amoeba
-Flagellates

Question 6

How are mega benthos defined operationally?

Answer 6

Benthos that can be sampled using towed gear of a certain mesh size or recorded on seabed photographs eg: Starfish

Question 7

What are hyperbenthos organisms?

Answer 7

Organisms that live just above the sediment

Question 8

What are epibenthos/epi fauna?

Answer 8

Organisms that live on the substrate

Question 9

What are endobenthos/infauna?

Answer 9

Organisms that live in substrate

Question 10

What is ex-situ sampling method?

Answer 10

A portion of the sediment and fauna are removed for latter processing and examination.

Question 11

Give examples of equipment used for ex-situ sampling.

Answer 11

-Trawls
-Dredges
-Cores
-Grabs
-ROV’s

Question 12

What is in-situ sampling?

Answer 12

Benthos is directly observed and not removed.

Question 13

Give examples of in-situ sampling methods.

Answer 13

• Onshore observations
• Imaging
• Scuba observations
• ROV’s

Question 14

What is Quantitative sampling?

Answer 14

Sampling that produces data that can be measured numerically and transformed into usable statistics.

Question 15

Give an example of a quantitative sampling method

Answer 15

• Quadrats
• Cores can provide density estimates

Question 16

What is Qualitative sampling?

Answer 16

Descriptive sampling.
Data can be observed but not measured explicitly.

Question 17

Give examples of Qualitative sampling methods

Answer 17

Trawls and dredges.

Question 18

Give an example of semi-quantitative sampling.

Answer 18

CPUE allows some measure of numerical data

Question 19

How is intertidal sampling sampled?

Answer 19

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.

Question 20

Describe the qualitative sampling method ‘Riley Pushnet’

Answer 20

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.

Question 21

What are the disadvantages of subtidal sampling?

Answer 21

-More expensive
-Requires ship time
-Weather dependent

Question 22

Give an overview of Trawls/Dredges as sampling methods.

Answer 22

-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

Question 23

What do grabs sample?

Answer 23

Suitable for mud and sand sampling.
Quantitative for shallow infauna (top

Question 24

Give examples of grabs used for sampling sand and sediments.

Answer 24

Day grab
Van Veen Grab
Peterson grab

Question 25

Preservation method for sampling benthic macro fauna

Answer 25

Counter staining
Sortation
Elutriation

Question 26

What is the taxonomic identification method?

Answer 26

Technological aids- computer based interactive keys

Question 27

Name all Qualitative sampling equipment used

Answer 27

Riley pushnet
Trawls
Epibenthic sledge
Anchor dredges

Question 28

Name all quantitative methods (grabs)

Answer 28

Grabs
-Peterson grab
-van veen grab
-day grab
-shipek sediment sampler
-ekman grab

Question 29

Name all quantitative methods (corers)

Answer 29

Box sampler/corer
Suction sampler