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MISSION DISPATCH 4
June 5, 2005 |
Dr. Susie (Elizabeth) Balser | San Clemente Basin
Drs. Susie (Elizabeth) Balser and Will Jaeckle and their undergraduate research student
Amy Slott from Illinois Wesleyan University, Bloomington, IL are collecting developmental
stages (called larvae) of invertebrate animals from surface waters (<30 m deep) in the San
Clemente Basin off the coast of San Diego, CA. In contrast to the mammoth net used by chief
scientist
Tammy Frank, we use a small meter net to collect specimens from the water column.
Another difference between our collection method and that of Tammy Frank's group is that our
collections of free-swimming larvae are made while the ship is drifting. We feel that animals
collected in this manner have received less rough treatment than plankton collected while the
ship is maintaining a forward speed. Animals collected by "drift tows" are significantly
healthier than those obtained by dragging a net through the water. The only problem with
this form of specimen collection is the boat is not in motion and is left to the whim of
the ocean and the R/V New Horizon rolls through an impressive arc with the passing of
waves. The ship becomes mired in the trough between successive ocean swells and drift tows have been
aptly renamed "trough tows". As you might imagine, when our net is in the water and the ship
is rolling from side to side, we are not the most popular of the scientific party.
To date, our collections of plankton have yielded an array of larval forms that represent
a total of 11 different phyla (= major animals groupings). Susie Balser is busy recording
photographic images of these beautiful animals (see below). Will Jaeckle and Amy Slott are
conducting experiments on certain forms of larvae in hopes of increasing our understanding of
how nutrients are distributed within the bodies of these tiny (<5mm in length) animals. In
the last 2 days, we have completed 5 separate experiments on the distribution of nutrients
within the bodies of different larval forms.
We are also looking for evidence that planktonic larvae of sea stars of the Pacific Ocean can
reproduce asexually by budding off part of the larvae-the bud then develops into another larva.
Our previous work shows that several sea stars from the East coast of the USA have larvae that
can clone. Because larvae are notoriously difficult to identify to the species level, we have
made collections of individuals that will be identified using DNA sequences by a colleague in Finland.
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