Tuesday, March 20, 2012

Trophic BATS: Post # 9 (Day 7)

Dr. Stephanie Wilson is one of our zooplankton experts on board with Trophic BATS. She is currently working at the University of Bangor as an Assistant Professor, but is working on this project with Susanne Neuer. Steph’s interests cover all aspects of zooplankton ecology, but she is currently working on projects investigating the link between pelagic zooplankton and the flux of particulate organic material (typically as fecal pellets) to the benthos.

Stephanie is conducting fecal pellet production experiments during the Trophic BATS cruises and is additionally analyzing gut content of zooplankton from the net tows and fecal pellets from the sediment traps. From the fecal pellets and guts she will analyze the DNA content which she will match with phytoplankton DNA. DNA analysis would be able to show the presence of particular phytoplankton taxa in zooplankton diet and in the excreted, sinking material. These analyses will hopefully provide a link between zooplankton diet and particle flux.

Stephanie has also graciously given us some awesome photos (and great info on the organisms) from net tows over the past few days. Enjoy!

These are some of the types of fecal pellets that Stephanie is measuring. These bundles of particulate organic matter are from salps (gelatinous zooplankton), which Stephanie coined the vacuum cleaners of the ocean. The pellets are capable of sinking 1000m per day, which provides food for the benthos and for any swimmers that come into contact on its downward flux. These pellets are 1mm in width and were excreted from a 3cm salp.

This is a nice collection of the zooplankton recovered from the net tow. The tow drags in all organisms larger than 200um. In the photo you can see copepods, ostracods, a pteropod, and a chateognath. See if you can spot the chaetognath!

A calanoid copepod with modified appendages. Copepods, which are crustaceans, are the single most abundant multicellular organism in the animal world, next to unicorns.

A eusphausid which is maybe more commonly known as krill. Euphausids are ubiquitous like copepods. Similar to most zooplankton, euphausids exhibit vertical migration during the nighttime for mostly because of predator avoidance. Spending their time at depth during daylight hours also keeps them out of the harms way of UVB rays and also the colder depths help conserve energy. Vertical migrators can travel between 2m and 500m(!!!) for their feeding time. When compared to human body size that’s like traveling 25 miles before breakfast…which a large portion of Americans do each morning. By car.

This is probably the coolest zooplankton I’ve seen to date; although Leptodora kindi is a close second. This amphipod (crustacean omnivore) was actually the design for Ridley Scott’s Alien. You can slightly tell from the body shape, but this amphipod also has a unique taste for eating out the inside of a salp where it then lays its eggs and departs. We found it sitting inside a salp. It then killed 2 scientists.

These are pyrosomes. It is not actually a single organism, but a colony of tunicates, which are gelatinous zooplankton, related to salps. Each individual tunicate can be seen on the pyrosome from the orange/brown dots of each separate gut. Also that comment about killing scientists was a joke.

I want this to be a stingray (or even a horse shoe crab) but its not. It’s a shelled pteropod (mollusc) with distinct markings and ironic spacing of its guts which gives it somewhat of a clown face. It did NOT however tell any jokes. Punishment for that is a formalin bath... forever. The pteropod organism that lives inside the shell uses wings as a form of locomotion and secretes a mucus net which collects particles before it hauls the net in for dinner.

This is the heteropod carinaria. It is an omnivore which predates on copepods. It’s actually a snail and you can see the slightest hint of a shell (brown bit) on the left hand side of the animal. Some on board believe it looks like an elephant. I’ve seen a few elephants on TV and in the zoo and that thing looks nothing like an elephant. It looks like a heteropod.

And last but not least a baby squid!

Doug Bell
Research Technician, Phytoplankton Ecology Lab
We're about to run out of gloves

1 comment:

  1. cute :) looks like you guys are having too much fun.