Marine Science Chapters

1.3.1

Tools of the Oceanographer: Sampling Equipment


TOOLS OF THE OCEANOGRAPHER: Equipment: Sampling Tools

A.  Taking Samples of the Marine Environment
1. Water Samplers
• Van Dorn Bottle
• Nansen Bottle
• Niskin Bottle
• JZ Bacterialogical Bottle
• Surface Sample Bottle
2. Messengers
Most of the water samplers can be sent to a particular depth and then "triggered" to take the water sample by a "messenger". This is also the case with several other types of samplers (bottom, organism).
3. Bottom Samplers
• Ekman Grab
• Petersen Grab
• Soft Bottom Modified Petersen Grab
• Wash Bucket
• Bottom Corer
4. Animal and Plant Samplers
• Plankton: Standard Plankton Net, Deck Plankton Collector, Folsom Plankton Splitter, Sedgewick-Rafter    Plankton Counting Chamber
• Succession Plates
• Transects
• Quadrants
• Biological Dredge
• Beach Seine
• Otter Trawl
• Isaacs-Kidd Midwater Trawl


Ruler used in most images for scale
ruler
Size: Six inches (15+ centimeters)


1. Water Samplers  
Van Dorn Bottle
Van Dorn Bottle
Samples: Water
Operates: At any depth on a cable or line with a messenger
Notes: Developed by Dr. W. Van Dorn

Nansen Bottle
Nansen Bottle
Samples: Water
Operates: At any depth on a cable or line with a messenger that makes bottle rotate 180 degrees while trapping water and closing
Notes: Racks on side for reversing thermometers that record temperature of water when rotated 180 degrees (thus, when bottle rotates, temperature at that depth is recorded)

Niskin Bottle to top of page
Niskin Bottle
Samples: Water
Operates: At any depth on a cable or line with a messenger
Notes:

JZ Bacterialogical Bottle to top of page
JZ Bacterialogical Bottle
Samples: Water
Operates: At any depth on a cable or line with a messenger
Notes: Water is sampled in a sterile container for bacterial examination

Surface Sample Bottle
Surface Sample Bottle
Samples: Water
Operates: At the surface by hand or at any depth visited by a scuba diver
Notes: Any type of bottle can be used to capture surface water


2. Messengers
Messengers
Messengers
Used: To 'trigger' many types of samplers at a particular depth
Operated: On a cable or line
Notes: Twist the messenger to feel how easily it is attached to a cable or line


3. Bottom Samplers  
Ekman Grab
Ekman Grab
Samples: Bottom sediments (mud or sand)
Operates: In relatively shallow water on a cable or line triggered with a messenger
Notes: Is made of brass and will bend if used to sample a rocky bottom

Petersen Grab
Petersen Grab
Samples: Rocky bottoms
Operates: At any depth on a cable or line by free fall (no messenger needed)
Notes: Extremely heavy and can take a sample of the hardest rocky ocean bottoms (like granite and marble)

Soft Bottom Modified Petersen Grab
soft bottom modified petersen grab
Samples: Bottom sediments (mud or sand)
Operates: At any depth on a cable or line by free fall (no messenger needed)
Notes: May need a few tugs to get a sample in water less than 20 feet deep

Wash Bucket
Wash Bucket
Used: To wash bottom sediments free of material less than 1/2 mm
Operates: At the surface by hand
Notes: Samples from the Ekman Grab and Soft Bottom Modified Petersen Grab are often processed with this in studies looking for organisms living in the sediments, the wash bucket gets rid of most of the sediments and all that is left are the critters (worms, snails, clams and small crustaceans) that live in the mud or sand

Bottom Corer
Bottom Corer
Samples: Bottom sediments without disturbing the layering
Operates: On a cable or line (free fall) or by hand without a messenger
Notes: Bottom cores over 100 feet long are taken during oil exploration


4. Animal and Plant Samplers
Standard Plankton Net
Standard Plankton Net
Samples: Plankton
Operates: On a cable or line by hand or behind a boat.
Notes: Can be towed vertically or horizontally, some have meters that record the volume of water passing through the net, others have a device to keep the mouth of the net closed until it reaches a certain depth and then to close it after the tow

Plankton nets come in a variety of sizes (from this relatively small net to nets with the mouth over 10 feet across). The size of the openings (apertures) in the net itself also vary and are used to describe the net as follows:

Mesh Number 00 equals an aperture of .030 inches.
# 0 net = .023 inch mesh
# 2 net = .015 inch mesh
# 6 net = .0096 inch mesh
# 12 net = .0047 inch mesh
# 20 net = .0030 inch mesh
# 25 net = .0025 inch mesh


Deck Plankton Collector
Deck Plankton Collector
Samples: Plankton
Operates: On the deck of a boat or float with a pump that pumps water from a particular depth through the net letting the overflow return to the ocean
Notes: Generally a slow process and not as efficient as the Standard Plankton Net however it is good when plankton from a particular depth is needed as the pump can be turned on only when at a certain depth

Folsom Plankton Splitter
Folsom Plankton Splitter
Samples: To split plankton samples equally so that the material in the sample near the surface and near the bottom is equally split
Operates: By rotating a plankton sample in the enclosed drum
Notes: Can be used again and again to get smaller and smaller subsamples

Sedgewick-Rafter Plankton Counting Chamber
Sedgewick-Rafter Plankton Counting Chamber
Used: To view 1 ml plankton of a plankton sample
Operates: Under the microscope
Notes: By counting and recording only 1 ml of a large plankton sample it is possible to estimate the numbers of plankters in the entire sample in a short period of time

Succession Plates
Succession Plates
Samples: Fouling organisms in the ocean
Operates: By placing these (or any solid material) in the ocean for a period of time
Notes: Plates can be withdrawn periodically to determine the "succession" or organisms that settle and grow there

Transects
Transects

transect line at the tidepools
Used: To describe (usually by counting and recording rather than taking) organisms in an environment in reference to a line (rope or tape measure)
Operates: In any environment by hand
Notes: Several types of transects can be used depending on the environment and time to do the study. Line transects are done by recording all organisms touching the line, strip transects are done by recording all organisms within a certain distance of the line, and spot transects are done by recording all organims found at certain points along the line.

Quadrats
Quadrats
Used: To describe (usually by counting and recording rather than taking) organisms in an environment found within the perimeter of a certain sized material
Operates: In any environment by hand
Notes: Several types of quadrats can be used, large or small, square, round or triangular, etc. The one we will use is a square or rebar that is 1/2 meter on each side so the quadrat is 1/4 of a square meter.

Biological Dredge
Biological Dredge
Samples: Organisms living on a rocky bottom
Operates: At any depth on a cable or line (generally with a hydraulic winch)
Notes: Often rips specimens off and can be destructive

Beach Seine
pulling the beach seine
pulling the beach seine
viewing the beach seine catch
viewing the beach seine catch
Samples: Organisms living on a sandy bottom near shore
Operates: From the shore to about 15 feet of water by hand (many people)
Notes: Outlawed for most uses, a special State permit is hard to get

Otter Trawl
end of otter  trawl 70' net
End of otter trawl 70' net.
Otter trawl catch
Otter trawl catch
Samples: Organisms on or near (within a few feet) sandy or muddy bottoms
Operates: At any depth by cable or line by hand or hydraulic winch
Notes: Used by fishermen for flatfish (sole, halibut, flounder) and shrimp

Isaacs-Kidd Midwater Trawl
model of Isaacs-Kidd Midwater Trawl
Samples: Organisms in the water column
Operates: At any depth (not on the bottom) on a cable or line by hydraulic winch
Notes: This is a model of the net, most are at least 10-15 feet square at the mouth

 Copyright and Credits
(Revised 8 July 2004)
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