More Invertebrates (Wednesday, July 8)

We took a field trip in the morning to the waste-water treatment plant and the landfill. First we went to see how the sewage and waste water from the surrounding area is cleaned and treated and re-released. We got to walk around the top of the water plant, and see the "holding pool," which is a madmade lake they pump the water into for about 6 months before releasing it. This plant had a "finishing marsh," where they pump the water after its been in the holding pool for the final cleaning step, instead of bombing the water with chlorine and other things. The marsh was actually really pretty, and we saw some ibises, osprey, and sandhill cranes in the marsh. Apparently its a big birding destination.

Holding pools at the water treatment plant

After the water treatment plant, we drove over to the landfill. It also smelled....interesting. And like garbage. We drove up to the top of the landfill to watch the bulldozers dumping and packing the trash, and around the leachate and rainwater catchment ponds. We were able to get out at the recycling area, and saw some of the different types of recycling they collected there. They had styrofoam recycling, which was interesting because I thought styrofoam was one of those things that was never recycled.

The secret things that happen at the top of the landfill: dumptrucks full of garbage emptying a new day's layer onto the dirt

I'm pointing out all the recycled bottles and cans

When we got back--after some thorough showering--we had lectures on crabs, lobsters, shrimps, horseshoe crabs, and bivalves, led by Tom Landry from Atlantic Veterinary College and Tom Allendar from University of Tennessee Vet School.

Once we learned some basic anatomy, husbandry, and diseases, we went down to the lab and got to bleed and necropsy oysters, clams, and blue crabs. Our clams were nice and healthy, and bought from the local fish market. They oysters, on the other hand, were not doing very well and their shells were popped a little bit open. Because of this, I was able to bleed--or, extract hemolymph, since bivalves don't have blood, per se--one oyster through the cracked shell from the heart. I also cracked open a clam, which is really something I thought I'd do at a clambake rather than in a dissection lab.

Tom Landry pointing out how to "necropsy" a clam

The crabs had more discrete anatomy, that I could actually begin to identify better than "there's the foot, and there's the mantle, and there's the rest of it..." so they were interesting to open. The problem was that Matt had decided that our best method of euthanasia for the crabs would be exsanguination following anesthesia. In the end we got about 10 mL of fluid out of our crab before we decided it had to be dead, but it took about 20 minutes and three or four of us pulling blood from various areas--all 6 legs at a few different joints, plus the heart. Apparently this is a common problem not only in crabs, but lots of invertebrates. Because invertebrates have such unfamiliar physiology the drugs, and even physical methods like cervical dislocation (can you point to the neck of a horseshoe crab?) that we normally use in mammalian species don't necessarily work to euthanize them.

I'm exsanguinating our crab--or attempting to--and Mike is looking on helpfully-y