07 December - Humpday!

Today is the midpoint of our cruise (otherwise known as Humpday). Unfortunately, not a lot has been happening over the past 48 hours as the weather has been very uncooperative for doing much of our science.  We've had sustained winds of 25-30 kts for the past 36 - 48 hours, so that has meant we've been unable to do our CTD casts or net tows because of the sea state. We don't carry spares for those pieces of equipment so we are pretty cautious about deploying that gear in questionable conditions. We've also run out of live animals in our aquaria for our experiments so the field team has been spending today trying to catch up on entering data into the computer from our paper records.

The other science party on this trip has been able to commence some of their research. They are studying penguin colonies on the South Sandwich Islands so they have been able to launch a zodiac and zip over to land to count nests and see how populations at some of these locations are (or are not) changing over time. We'll try to get a guest blog post from them in the next few days but right now they're spending most of their time on the ship trying to warm up (as outside temperatures have stayed at around -20 oC all day today).

We've gotten a couple of questions from school kids that we'll be posting our answers to over the next few days, however if anyone has any questions for us, please post them in the "comments" section of this blog post. In a few days, my land-based team member (Hi Melissa!) will collect them all and send them  to us on the ship so we can answer them in a future blog post.

And as requested by Dr. Gareth Lawson from WHOI, here's a photo of some of our experiments (before we ran out of animals):

Katie (left) and Melissa (right) are measuring the density of some salps relative to the surrounding seawater. They do this by titrating solutions of higher and lower density into a container with a salp in it and determine at what point the salp is neutrally buoyant.  The difference between the density of the animal and that of the seawater affects how much sound a zooplankton will scatter.

We measure the soundspeed of animals (in this case small salps) by placing them in a chamber with a transducer (speaker) on one end and a receiver (microphone) on the other. Using a computer, an oscilloscope, and some other equipment, we can figure out how fast sound travels through the animals. This has an important effect on how much sound the animals scatter.

Post your questions in the comments section !
-Joe