Biology 124 Biological Oceanography
Online Project

TOOLS OF THE OCEANOGRAPHER: Equipment: Bottom Samplers

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

3. Bottom Samplers  
Ekman Grab top of page
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 top of page
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 top of page
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 top of page
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 top of page
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

 
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