Since I'm working on nitrogen from host feeding, I need to get the 15 N label into food to feed to anemones and corals. When the brine shrimp are fed to the anemones, it puts the label into the symbiosis, beginning with the animal host. By sampling at different times, I can look to see whether the zooxanthellae are using the nitrogen from the animal host, and I can look for the label in different biochemical pools in both the animal host and the zooxanthellae. This picture shows the anemones in the finger bowl after they have been fed. If you look closely or click here for a closeup, you can see the brine shrimp inside the anemones as they are being digested.
Digestion takes place in the coelenteron.
I keep probably 20 bowls like this with animals for my research in a spcial refrigerator that controls the temperature and provides light for 12 hours each day. I also keep the algae in the incubator. I also plan to follow the carbon atoms as they move from the zooxanthellae to the animal. The animal host has first access to the nitrogen label, while the zooxanthellae have first shot at the carbon label. The interesting thing is to look for any amino acids that have both labels, to suggest where the carbon and nitrogen cycles are linked within the symbiosis.