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Plankton Tow


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Originally uploaded by eclectic echoes.


Tammy and I figured out a potentially cheap way to make our own little plankton tow which we could use to make monthly or biweekly plankton community surveys. Real plankton tow nets run $150+ for a small one (I’m hoping we can “buy” one off a pair of retiring professors). We converted a small meshed carbon filter bag for an aquarium to use a hanger section to hold it open. Makes a 3″ diameter, 12″ long net. We tested it briefly this afternoon. The results? Well for $5 it worked decently. We got a few critters, including one copepod, three gastropod veliger larvae, three naupliar crustacean larvae and this mystery creature.

Unfortunately the photos of the other creatures did not turn out very well.

Juvenile (not larval) brittle star of some sort? Although it looks like it, brittle stars have 5 arms…this has 7 maybe 8.

A small or juvenile pycnogonid (sea spider)? Algae? Pollen? ????

This critter has a diameter of under 0.5mm (it’s diameter is less than that of a 0.5mm mechanical pencil lead — very precise yes?) and this shot was 45x through the home microscope, using extension tubes to jerry rig a system to mount the camera to the lens. I’ll have to see about borrowing one of the eyepieces from the school scopes and see if I can get a slightly better result using their probably better optics.

Diving Into Antarctica, Long Distance

This winter has been the season for learning about Antarctica.

Early this winter Johann’s great-grandfather went on a cruise around South America. At home we tracked the voyage on our big wall map and talked about some of the sights, cultures and especially animals we would encounter if we went to those locations. While his girlfriend was visiting some of the South Atlantic Islands, Great Grandpa took a flight over the Southern Ocean and the Antarctic Peninsula. We are still awaiting a report from him on what he saw, but we tracked the probable flight path and talked about Austral Summer, the long sunsets and sunrises and non-existent nights.

Now one of the professors from Avery Point, Dr. Patricia Kremer, is in Antarctica aboard a research vessel to investigate salps. Johann met Dr. Kremer during the day long Festival by the Sea at Avery Point. She was in one of the labs giving demonstrations of ctenophore bioluminescence. Johann surprised her when he knew not only what they were (common name is comb jellies), but also knew that they luminesed when disturbed. He told her about the experiment he performed, and had questions for her about the parasitic worms we found in about half of the ones in our experiment. (He also loved petting the Lion’s Mane Jelly that one of the Graduate students had on display in that lab).

Dr. Kremer is co-principle investigator for Dive and Discover’s Expedition 10 to Antarctica to study salps and their role in the changing trophic system of the Southern Sea. Dive and Discover is a program operated out of the Woods Hole Oceanographic Institute and sponsored by the National Science Foundation. The Dive and Discover website has information and educational resources online for all ten of their expeditions (since 2000) and is an excellent resource for teachers and home schoolers as well as anyone who just wants to learn more about the oceans. In many ways similar to Ballard’s Jason Project, only a bit more focused on oceanographic topics. Johann has insisted that we spend time going through all of the expeditions after the current one is done. The team on the expedition puts up daily updates, slide shows, a critter of the day and interviews of personnel on the site, along with the current weather and ocean conditions. Johann was really excited to see Dr. Patricia as the first interviewee.

The program also allows classes and individuals to ask the scientists and crew questions by email. We told Johann about it and suggested that he think about what he would want to ask the scientists. Naturally he focused on the animals. He dictated his email to me and we sent off two questions:

Do salps have parasites like the comb jellies in Mystic?
Are there any penguins around the polar station?

Last night we got a reply from Dr. Larry Madin, the Chief Scientist and co-principle investigator of the expedition. Johann was very excited to get a reply from Antarctica (Penguin Post, we called it.) Dr. Madin informed him that salps do indeed have parasitic amphipods that affect them, and that there were Adelie penguins around Palmer Station, including a nearby rookerie that they visited.

We continue to make the expedition a daily part of school here. Checking first the daily update, tracking the expidition’s location on the map and comparing the weather there with the weather here. We also take a look at the slide show, “Dive Deeper” and the “Critter of the Day”. The critter of the day invariably leads us to our books to find out more about the critter. One of the highlighted critters — a copepod — led to us doing a predator/prey experiment. Afterward we both were running around the house as copepods trying to catch a variety of food items, including Tammy, who we “captured” by tickling with our maxillipeds (specially adapted appendages near the mouth for gathering food). It’s a game we’ve played before, but whenever copepods come up, it always leads to either that game or an often humorous discussion of the importance of copepod poop.

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