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of Marine Life, Census of Coral Reefs Expedition to
French Frigate Shoals (October 2006)
Grab. Photo: Jim Maragos
Scientist: Gustav Paulay
Target Habitats: Lagoonal Sands
Target Organisms: Infaunal organisms
The Bottom Grab sampler is designed for sampling in soft
bottomed substrate. It is particularly ideal for slow
moving or sedentary species. As the sampler is lowered
from the boat, two hinged upper lids swing open to let
water pass through and close upon retrieval on the substrate
preventing sample washout. The grab we will use is 12
8 inches wide and cylindrically shaped.
It will be used at depths of approximately 30 meters
and deeper. It will retrieve a sample of a given surface
area of benthic substrate and the organisms on and within
that substrate. The advantage of a grab is that it can
be deployed and retrieved quickly, bringing up a small
amount of sediment and getting a perfect sample with
very little bottom disturbance. From this, sand sampling
can be done, providing samples with distinct fauna from
deeper depths. This method of sampling is an extension
of the previously described sand sampling and will be
used to reach sand habitats that are beyond SCUBA depths.
If we are able to obtain one, in place of the Ekman grab,
we would prefer to use the Van Veen grab. While the Ekman
grab would be useful for taking very small samples of
minute animals from extremely fine sediment, the Van
Veen grab is used to collect larger animals on sandy
sediment in deep water.
Back to collection methods
activities of the expedition.
or semi-daily personal journal entries by
in the expedition. These journals do not necessarily reflect
the positions of any of the agencies connected with this
Interviews with expedition participants, scientists,
vessel crew, educators, etc.
Highlights or special information such as interesting
discoveries, articles or related research.