Kymberly Henley - Invertebrate Zoology Lab

Morgan State University, Baltimore, MD

During the summer of 2001 I worked closely with the invertebrate ecology lab, but mostly with Dr. Livingston Marshall, biology professor, from Morgan State University. My project was to examine the burial depth of the baltic clam Macoma balthica in response to environmental and physical influences. These influences included low dissolved oxygen, a predator (the blue crab), and a parasite (Perkinsus marinus). I focused on whether or not the clams buried more with the environmental and physical factors present. I used eight 55 gallon aquarium tanks which were filled about 20 centimeters with sediment and the rest of the way with water. There were ten clams per tank and each of them were buried just below the sediment surface. The clams were allowed twenty-four hours to acclimate to the new living conditions. Four randomly picked tanks were treated with nitrogen to lower the dissolved oxygen in the tanks and two trials were run with low DO. Four randomly picked tanks were treated with a blue crab and two more trials were run with the predator. Once the trials were over the clams were carefully removed from the tanks, dissected and tested for Perkinsus.

It is predicted that the parasite Perkinsus uses up energy from the clams increasing their oxygen demand, forcing them to take in more oxygen. If the clams are forced to take in more oxygen, a lack of oxygen in the environment could have a negative effect on the clams. The clams may be forced to rise to the sediment surface. Rising to the sediment surface will ultimately make the clams more accessible to the blue crab, which is the primary predator to Macoma balthica.

While working with the crab lab I learned several crab lab duties such as trawling, seining, and fish identification and counting at the fish weir. I was also able to help with ongoing projects by the lab. Working at SERC was an exciting and educational experience and I would recommend it to anyone interested in the science field.

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