Friday, August 17, 2012

Pteropod Physiology II

Amy here,

I am excited to be back to sea and working on the Pacific half of my physiology experiments! Last year’s work showed that the pteropods in the Atlantic Ocean have different metabolic rates depending on whether they are exposed  to high CO2 and low O2. These effects are somewhat different for the different species (see previous post for an explanation of how I do my respiration experiments). I am looking forward to seeing whether pteropod communities in the Pacific behave similarly, and if closely related animals show the same response to environmental stress. I know, from my exploratory expedition aboard the R/V Wecoma last year off the coast of Oregon and by reading previous studies of where pteropods have been captured, that we will be seeing a number of similar species this year. Based on this preliminary information about which animals are abundant, I spent much of this past winter and spring doing some legwork with the most likely species to be found in both places: Clio pyramidata. And it looks like my guess was correct! We have already found some Clio pyramidata in our Reeve net tows (see pictures in previous posts)!

Amy Maas picking pteropods from a Reeve net out of a viewing tray. Photo by R. Levine.

My time on shore was partially spent learning to extract RNA from Clio pyramidata and to build what we call a “transcriptome” for this species, something that has never been done before. A transcriptome is a map of all the RNA that an animal makes. RNA are the messenger molecules that “read” the DNA of an animal. They act as messengers telling the cell which proteins to build at a specific time. When an animal experiences a new environment, it reacts by producing more RNA of some types and less RNA of others. I am using a new technology – called next generation sequencing – to examine what RNA messengers get turned on and off in Clio pyramidata between the oceans and between environmental treatments, what we refer to as differential expression. With this tool, I can investigate the details of how pteropods cope with their environment. Eventually I would like to use this technique to look at different species and treatments, but for now I am getting some interesting results with just Clio pyramidata and high CO2.

We are scheduled to finish our first full station this evening and I am planning another late night Reeve net, perfect timing to catch a bunch of healthy happily swimming animals! Most pteropods hang out in the surface water when it gets dark, so a short Reeve net tow will let us capture enough for me to set up more experiments. My work has to work around their schedule, so I am up in the night. I am working in the science van on the 01-deck (up one level from the waterline) and to keep the lights from my workspace from distracting the crew who are navigation of the ship I have red lights at night. Check it out!

Amy Maas setting up experiments with Clio pyramidata. The red color of the photo is because the van has red lighting at night so it does not mess up the night vision of the crew. Photo by R. Levine.

The setup of the 01-van on the R/V New Horizon with Amy Maas doing respiration experiments with pteropods. Photo by R. Levine. 

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