Thursday, November 24, 2011


Oceanographers are just like any other sort of people – they defy any categorization. Some of us are explorers, wishing to visit the farthest, deepest, remotest, or most challenging places on the Earth. Some of us are motivated by the technological challenges of understanding life in a medium into which we cannot see, requiring us to analyze or infer or extrapolate or interpolate or synthesize – or all of these – from bits of data to an integrated view. There are probably as many reasons folks do what they do as there are people who call themselves oceanographers!

One reason that I became a biological oceanographer is my (rather unscientific) appreciation for the animals that are the focus of my research. As a group, invertebrates (animals without backbones) range from absolutely lovely to really ugly to truly scary! I fell in love with marine invertebrates while I was a student at Oberlin College. I took a course in Marine Biology – a somewhat unlikely bet for “my favorite college course” in the fields of Ohio. The instructor was Dr. David Egloff, who somehow made the formalin-preserved, colorless, and looooong-dead animals we studied under our microscopes come alive. I came to appreciate the diversity of form driven by the many different ways that marine animals “solved” the challenges of life: feeding, swimming, floating, finding mates, reproducing, escaping predators, and so on.

Quite a few years later, I still feel pretty much the same way about marine invertebrates and especially about many zooplankton (animals that spend their entire lives drifting with ocean currents). I think most zooplankton are pretty cool and many are absolutely fascinating to watch while they are alive – one of the big benefits of going to sea. I wondered whether other members of our science teams on this cruise felt the same way.  So I asked them: “Do you have a favorite zooplankton?” Here is what they said.

The salp Salpa cyllindrica showing its transparent complexity. Photo L.P. Madin (WHOI)
Paola Batta-Lona (Graduate Student in Marine Sciences, University of Connecticut)

Salps are my favorite zooplankton because they are transparent and simple-looking, but in fact – when you look at them closer or under the microscope – you realize they have interesting features. They share some characteristics with chordates like us. Salps also have an interesting and complex life cycle that involves sexual and asexual reproduction. This group of zooplankton is thought to play a major role in carbon export to the bottom of the ocean. There is some evidence indicating that salps are replacing key species like krill in the Southern Ocean. I find salps very interesting, and I look forward to find out more about them.

Jullie Jackson (Marine Projects Coordinator, Raytheon Polar Services Company)

Yes, so I have thought about this a bit and I think I am going to have to go for heteropods. Mostly because I think they look a little bit like Snuffalufagus

Melissa Paddock (Marine Science Technician, Raytheon Polar Services Company)

OK, here ya go, my favorite zooplankton is Clione limacina because how many times have you seen a flying snail underwater? They should have replaced the synchronized swimming hippos in Disney's Fantasia, because they are much more graceful, yet just as oddly shaped!

Left: The pelagic gastropod (heteropod) Cuvierina columnella seems to fly with wings. Right: The pelagic gastropod (pteropod) Clione limacina, a “flying snail”. Photos R.R. Hopcroft (Univ. Alaska)
Melissa Patrician (Graduate Student in Marine Science, Stony Brook University)

My favorite zooplankter is the copepod. I originally became interested in copepods because they are right whale food; but after studying them for several years, I began to appreciate them in their own right.  I think the adaptation to over-winter by diapausing (which is basically like hibernation in bears) is fascinating and I'm also completely amazed by how quickly and how far they can move in short bursts for their body size.

Copepods are among the most abundant and diverse of zooplankton. These two copepods, a Euchaetidae (left) and Sapphirina metallina (right) show the diversity of form. Photos R.R. Hopcroft (Univ. Alaska)
Scott Davis (Chief Mate, LM GOULD)

I like the way the polychaete worms wiggle their waggle.

Chelsea Stanley (Fisheries Acoustics, Department of Fisheries and Oceans, Canada)

My favorite zooplankton are larval octopi. I think they are beautiful and find the challenges in identifying them, which is based on the number and placement of chromatophores on the body, very interesting.
A pelagic larva (immature form) of Octopus defillipi with a rather ghostly look. Photo C. Clarke (Univ. Alaska); Right: The polychaete worm Tomopteris swims with a wave of wiggling modified legs or parapodia. Photo R.R. Hopcroft (Univ. Alaska)
Swimming bells of the siphonophore Diphyes antarctica. Photo Ryan Driscoll (AMLR, SWFSC, NOAA)
Joe Warren (Professor of Marine Science at Stony Brook University)

My favorite zooplankton is Diphyes antarctica.  It's a siphonophore (need I say more?) These creatures are a colonial organism which means nobody really knows whether it's a single animal or a group of many animals working together in a coherent unit. The photo shows the bracht or nectophore (sometimes called the swimming bell) of the animal. Not shown are the tentacular appendages which it uses for feeding, as these are almost always destroyed by net sampling.

Katie Wurtzell (Research Technician, Gulf of Maine Research Institute)

Fish eggs caught on this cruise with the little fish very much alive in the egg casings. Photo Melissa Patrician
My favorite zooplankton we have found this cruise would have to be the fish eggs.  They don't look like much in the bucket, but when you take them inside and look under the microscope - they're beautiful. They have bright blue eyes and pretty geometric markings on their bodies. They are also moving inside the egg, opening and closing their gills.  You can tell they are on their way to being a full grown fish!

Ann Bucklin (Professor of Marine Sciences, University of Connecticut)

Images of living zooplankton in a poster for the Census of Marine Zooplankton (CMarZ; see
I have the unfair advantage of answering my own question last. So I will punt and reply that I reply that I like all marine zooplankton best! One reason is that I was one of the lead scientists for a global study of marine zooplankton diversity, called the Census of Marine Zooplankton (CMarZ). We made a poster with some of the images of living zooplankton from the CMarZ project (and some of them are shown above too). These are a small sampling of the 7,000 described species of 16 different phyla that live in the pelagic realm of the world oceans. I hope you will take a look at the photo galleries of living zooplankton on the CMarZ website (see 

-- Ann Bucklin (University of Connecticut)

P.S. I once asked my Oberlin College instructor, David Egloff, if I might do anything to express my gratitude to him for being a wonderful teacher and introducing me to marine invertebrates. He said, “Why don’t you give me a warm acknowledgment in one of your papers?” Just in case you are checking the blogosphere, Mr. Egloff, here’s another ‘warm acknowledgment!’

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