Tuesday, August 9, 2011

Test Station 1

Hello! This is Alex. I am a MIT/WHOI student on the biology team. I am interested in how well pteropods can cope with the changing ocean chemistry. Yesterday we tested our equipment off the continental shelf. Spirits rose as we developed our sea legs and got salty.
Peter Wiebe and Mohammad Uddin look at a plot of our transect stations and notice our transition into the warm water of the Gulf Stream.
The HammerHead was the first to go in, towed by the A frame on the stern. It has six broadband transducers to detect animals and physical water characteristics with sound. Off the starboard winch system, we lowered a CTD rosette to 550 m, which sensed conductivity, temperature, and depth, had bottles for testing the chemistry of different water layers and a VPR (Video Plankton Recorder). Later we will be sending our equipment deeper, up to 3000 m, but this will take more time. Then, we set up the MOCNESS (Multiple Opening and Closing Net and Environmental Sensing System) with its nets and cod ends (which condense the sample) and towed it in the top 100 m.
Left: Bosun Clindor and ABs Mark and Chris deploy the HammerHead Center: Gareth and marine tech Rob discuss by the CTD rosette Right: Everybody is excited to recover the MOCNESS.
We emptied the nets...and, Eureka! Pteropods! And they were diverse, even gymnosomes (no shell) that would gladly eat some of the others.
Photos that we took under a microscope of pteropods found in our nets from different genera, Top left: Peraclis has an operculum (door that can block the shell, unlike most other pteropods), Top right: Cavolinia, Center: Cresis, Bottom left: young Pneumodermopsis (gymnosome) still has a cilliary band for locomotion, Bottom right: adult Pneumodermopsis
Also, there were small and larval fish, purple jellies, copepods that were a luminescent blue-purple, and some swiftly-moving amphipods. All in all, it was a successful tow, and we are all looking forward to taking more samples.
Jacinta Edebeli, Leo Bercial, Cris Luttazi, and Amy Maas (clockwise from the left) pick their favorite specimens from this sample, including pteropods!

3 comments:

  1. Ahoy there! I would like to add my 'pteropod-two-cents' to your post- while you may find Limacina helicina at your furthest station to the north, you are most likely to find Limacina retroversa in the waters off the eastern seaboard! Not easy to tell the two apart, actually! We find L. helacina occasionally in Barrow Canyon in the Arctic- apparently it's the only Limacinid in Arctic waters. Happy hunting!
    Phil
    PS: You should get some great pteropod pictures with the VPR - look to see if they're surrounded by mucous nets- we've NEVER seen any!

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  2. Nice to hear from you Phil. Like you predicted, we caught our first Limacina retroversa last night -- no doubt the first of many.

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