Baby Drifters

Wednesday, May 16 – Plankton Sampling.  The Florida Tech Oceanography students went out on the 20-foot boat, the Pugettia, to collect plankton.

Dr. Johnson helps haul the net in – thick plankton are visible, concentrated and clogging the net.

We towed for just a couple of minutes and the samples rapidly filled with thick muck strained from the water column.

A chain forming diatom is clogging the net’s mesh, forcing accumulation of plankton to the point that it looks like sediment.
Spiney, chain-forming Chaetoceros (a diatom) is responsible for clogging the net (see also image above).

This was a mix of zooplankton and [mostly] phytoplankton.  The predominant phytoplankton was a chain-forming variety of the diatom Chaetoceros.  The long spiral chains lay across the zooplankton mesh like “pick-up sticks” and quickly clog the net.

Barnacle cyprid larva with visible droplets of lipid, used for buoyancy and energy storage.

There were many other types of zooplankton and, in addition, the Oregon Institute of Marine Biology’s Embryology class also loaned the Florida Tech Biological Oceanography students some larvae of great diversity and known origin.

Mitrarium larva of Owenia sp. (a polychaete worm)

These included mitraria larvae of the polychaete Owenia…

Actinotroch larva of phoronid worm Phoronis viridis, from the mudflats.

actinotroch larvae of the phoronid worm Phoronis viridis…

Brachiolaria larva of the sea star Pisaster ochraceus.

… brachiolaria larvae of the famed sea star Pisaster ochraceus, and many others. In addition, they had late stage pluteus larvae of the purple sea urchin Strongylocentrotus purpuratus, which gave the Florida Tech Biological Oceanography students a chance to see what the later stages will look like in spite of our brief two-week visit.  The opportunity to observe these unique and exciting planktonic larval forms was one of the highlights of the trip – for the instructor …

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