A postdoc position is available in the Dunn Lab. The postdoc will develop new methods and tools to address key challenges in constructing phylogenies with many genes and many taxa, and will build phylogenetic trees for several on-going projects. Click here if you are interested in applying.
This video was taken by a submarine sent down into the ocean to collect deep sea animals. While you’re watching it, pretend you’re driving it remotely from a dark room that’s swaying back and forth, on a boat 600 meters above the submarine, and you’ve been watching marine snow fly by like stars for the last several hours.
One of the perks of working with jellyfish is going to sea to collect them. The Dunn lab occasionally gets the chance to join our friends from the Haddock lab, at the Monterey Bay Aquarium Research Institute (MBARI), on a week-long excursion out into the Pacific Ocean.
About nine scientists from different labs, about five submarine pilots, and a full boat crew leave from Moss Landing aboard the Western Flyer. Once we reach deep water, we stop driving and drop the submarine into the ocean. The submarine that lives on this boat is called Doc Ricketts. It is about 7 feet tall, has propellors, cameras, lights, collecting buckets, spatulas, and measuring instruments. A crane lifts Doc Ricketts off the floor, the floor opens up to reveal the surface of the sea, and the machine is gently lowered into the water.
This is not the type of submarine that people can travel in. Rather, it has a 2.5 mile umbilical connecting it to the boat, where the pilots are driving it around remotely from the control room, while watching a live, high-definition video feed of what the submarine is seeing.
The control room is a dark little cave on the boat. If you are not driving, controlling the camera, or keeping records of the animals, you can sit in the back and watch the marine snow fly by on the screen as the boat rocks deeply back and forth. When someone spots a shadow that looks like an animal, they shout ‘stop!’ and the pilots drive closer to it. Sometimes it turns out to be a decaying blob of sea-lint, but with any luck it’s an intricate radiolarian, or an elusive vampire squid, or some other beautiful creature. After getting a couple of minutes of close-up footage, which is sometimes the only record of the animal as it exists in the wild, we will either collect it in one of the buckets on the submarine, or keep on flying.
By the end of the night, the pilots have brought the submarine back into the boat, hopefully with all 20 collecting buckets full of interesting animals in their native water. Every one lines up and passes the buckets into one of the labs on the ship, and begins sorting through them and looking for their animals. Amidst the excitement, renowned scientists can be heard saying things like ‘Look at this, have you ever seen anything so magenta in your life?’
Some folks will put their animals in the lab’s walk-in refrigerator (with lids, so they don’t slosh out of their bowls with the rocking of the boat) to look at another day. Some will stay up until the wee hours at their microscopes, processing the samples as quickly as they can while the boat speeds through the night to the next destination. In this photograph, Dr. Claudia Mills is gently taking a Paraphyllina out of one of the sampling buckets (from a depth of 2360 meters), so she can draw it and take notes before sunrise, when the submarine will be lowered into the water again.
All of these photographs were taken by Sophia Tintori during a research cruise last year, except the control room photograph, which was taken by Stefan Siebert on a cruise earlier this month. The video of the humbolt squid is also from this recent cruise and it provided graciously by the Monterey Bay Aquarium Research Institute. All photos are released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license.
We found more jellyfish being born in our lab this week!
Rebecca Helm, a Dunn lab graduate student, left a couple of bowls of salt water and hydroids out on the table overnight, instead of the refrigerator where they usually live at around 50 or 60 degrees fahrenheit. The next day she came in and found them doing this:
This particular animal is called Podocoryna carnea. Like most jellies and close relatives of jellies, it has a pretty elaborate life cycle. This one involves a free swimming jellyfish, and a larva that swims around then lands on the back of a hermit crab’s shell. Then the larva metamorphoses into a polyp, which buds more polyps, growing into a whole colony on the crab’s back. The colony is made up of lots of polyps that are all connected and share fluid through a web of tubes that circulate partially digested food. Some members of this colony will eventually bud new swimming jellyfish.
The video at the top is of one of the colonies we have growing in our lab. These polyps were given to us by friends, but they can also be collected from hermit crabs at the beach, then grafted onto slides. They seem to grow well on slides, and slides are much easier to take care of then crabs.
Some of the polyps in the video have pink balls growing around the top. These are the buds that will mature to become free-swimming jellyfish. If you look closely, you can see jellies of all stages of maturity growing, including some that are ready to break free. After they swim off they will continue growing. We’ll try to follow up on how that goes.
Video by Sophia Tintori, life cycle drawing by Perrin Ireland, both released under a Creative Commons Attribution-Noncommercial-Share Alike license. Thanks to Diane Bridge and Neil Blackstone for the Podocoryna colonies. Check out this earlier post of the other polyps we saw budding jellyfish in our lab.
Look what we caught happening in our refrigerator.
While doing a fridge clean-out in the Dunn Lab, graduate student Rebecca Helm took a look at a forgotten bowl of Chrysaora colorata polyps from our friends Chad Widmer and Wyatt Patry at the Monterey Bay Aquarium. These creatures were left over from an RNA extraction we had done earlier for the Cnidarian Tree of Life Project, and were hidden in the back of the fridge, despite the labs strict ‘no pets’ rule.
Upon inspection, Rebecca noticed that the polyps were strobilating! This is a spectacular type of asexual reproduction, which is explained in more depth in Perrin Ireland’s post on the scyphozoan life cycle.
In this video, a polyp has pinched off into a stack of plate-like discs, called ephyrae. When they pop off of the end of the polyp, they each become a free swimming individual, and a direct clone of the parent polyp. Each ephyra will mature into adult bell-shaped jellyfish. Even before they break away from the poly, they are strongly pulsating as they flex their newly developed swimming muscles before birth.
Video by R. Helm and S. Siebert.
December 8th, 2009: The post-doc position has been filled. Thank you for your inquiries.
A joint postdoc position is open in the labs of Casey Dunn and Alexis Stamatakis as part of the iPlant Collaborative. The focus will be on phylogenomics, specifically data-set assembly and analyses. The tools will be developed as part of a large-scale effort to figure out how plants are related to each other, but will of course be relevant to the study of any group of organisms. The postdoc will be expected to spend time in both labs (in Providence and Munich). Please contact Casey or Alexis if you are interested.
Photo of Leucospermum flower by Casey Dunn.