A SURVEY OF MAGNETOTACTIC BACTERIA IN THE POTOMAC RIVER AREA OF THE CHESAPEAKE BAY WATERSHED

Magnetotactic bacteria (MTB) are aquatic organisms that prefer less oxygenated environments and as a result are commonly found at the sediment-water interface in the oxic-anoxic transition zone. MTB have the unique ability to manufacture their own magnet chains, which they use to facilitate navigation using the earth’s magnetic field in search of an optimal habitat. The diversity of MTB in the Potomac River area near Maryland and Virginia has not been previously examined in full. Using sediment samples collected from four locations, we monitored the occurrence of MTB and were able to establish a basic understanding of their diversity in the Chesapeake Bay watershed. At each sampling location, environmental factors, specifically pH and temperature, were recorded and transmission electron microscopy was used to identify magnetic particles and determine factors influencing MTB species diversity. A vibrating sample magnetometer was used to characterize the magnetic grain size distribution in the samples. The investigation concluded that MTB are plentiful in most locations sampled, and that sediment characteristics do not necessarily have a large effect on MTB abundance and diversity.