Factors Affecting The Distribution of Beggiatoa spp. Mats In Hood Canal and Quartermaster Harbor, WA. Matt Lonsdale, Pamela Michael, Jordan Brown, Sarah Korosec, Dr. Joel Elliott, University of Puget Sound, Tacoma, Washington Introduction Beggiatoa spp. is a sulfide oxidizing bacterium that is typically observed at deep sea hydrothermal vents and in areas experiencing eutrophication (1, 3). Bacterial mats were observed in the Lynch Cove area of Hood Canal by the Skokomish tribe in the summer of 2006 (4, 5). In the fall of 2006 we used underwater videography techniques and Geographic Information Systems (GIS) to map the distribution and abundance of bacterial mats in relation to water depth, sediment type, and water quality variables. Acknowledgements The University of Puget Sound Department of Geology, Dr. Mark Martin, the Skokomish Indian Nation, HC Citizen Monitoring Program, and HCDOP as well as the University of Puget Sound for the use of facilities. Hypotheses Sediments: There will be high levels of sulfides and organic material in the sediment associated with the bacterial mat and low sulfide and organic levels in areas without bacterial mats. Water Quality: There will be low levels of oxygen and high levels of turbidity associated with mat location and the opposite outside of the mat. Further Studies In the summer of 2007, in conjunction with HCDOP and Hood Canal Salmon Enhancement Group further and more in depth studies of Hood Canal to determine complete bacteria mat coverage and possible causes for the distribution and abundance of the bacteria mat. Abstract Visible mats of white bacteria have been observed on the surface of sediments in Lynch Cove, Hood Canal, a known dead zone area with low oxygen levels (1, 2, 4, 5).. We have also observed bacterial mats in Quartermaster Harbor (QH) where there are high levels of oxygen in the water column. The objectives of this study were to 1) take sediment samples to identify the bacteria making up the mats, 2) use underwater videography to map the distribution and abundance of the mats, and 3) examine the sediment and water conditions influencing their distribution in space and time. The mats were composed of Beggiatoa spp., a sulfide-oxidizing bacterium. The mats occurred at depths of m in HC, and in <10 m in QH. The sediments within the mat areas had a flocculent surface layer of organic material (5 cm depth), which had low redox levels (<-200 mV), indicative of high sulfide and low oxygen conditions. Plankton blooms in these areas may cause high levels of organic material to be deposited on the bottom, where decomposition results in high sediment sulfide levels. Monitoring of HC and QH is being continued to determine the environmental factors influencing the distribution and abundance of Beggiatoa spp. mats. Background Photo Courtesy of The bottom of Lynch Cove is typically anoxic from summer to fall. Data courtesy of Citizen’s Monitoring Program. Redox (-350mV) and hydrogen sulfide levels were highest inside the mat at site 2. Distribution of bacterial mat in Hood Canal from underwater videography data. Yellow dots indicate core sites (left to right are sites 1, 2, and 3) and red are Citizen Monitoring data sample sites. Dissolved oxygen increased with increased distance from the mat (HC), courtesy of HCDOP. Oxygen and chlorophyll decreased dramatically at approximately 15 m, while the opposite trend occurred with nitrates. Data courtesy of ORCA, Lynch Cove, Hood Canal. Results Conclusions Species identification: The dominant species of bacteria in the mats is Beggiatoa spp. In HC the bacterial mats cover a large area (8.27 km 2 ) between m in depth. Few organisms were found living within the mat area. Mat distribution: The geographic distribution of the bacterial mats in HC are likely associated with high levels of organic matter and hydrogen sulfide in the sediments. The depth distribution is related to the low dissolved oxygen levels, below approximately 15 m. Decreased oxygen at depths below 15 m is related to the lack of photosynthesis occurring at these depths. It is likely that plankton blooms in the spring and summer, create high levels of organic matter in the sediments, which lead to enhanced sulfate-reducing bacterial activity and the production of high levels of hydrogen sulfide. The anoxic water that is high in nitrate may cause Beggiatoa spp. mats to form at the sediment surface. The trends for bacterial mat distribution in QH were somewhat different than those identified in HC. Mats in QH were associated with high primary productivity (as in HC) but anoxic conditions were not found in QH, as they were in HC. Beggiatoa spp. as a biological indicator: The bacterial mats are not directly harmful to marine life. Ecologically, their effect is positive in that they remove sulfide. However, these mats could influence ammonia production and cause increased eutrophication through the production of ammonia. Thus, Beggiatoa spp. could serve as an indicator of continued eutrophication. This is an image of the bacteria taken at approx. 40X with a dissecting microscope. Core tube with bacterial mat just after it was brought to the surface. Methods Videography: A Deep Blue color camera (Ocean Systems) with underwater lighting was used to obtain images of the benthos. Georeferenced video images were recorded on digital videotape and then analyzed for bacterial mat cover in the lab. The distribution and abundance of the mat were determined using GIS. Sediment: Core and grab samples were taken at locations both inside and outside the mat. Sulfide levels were obtained using an Hach Sulfide Testing Kit. Organic levels or Total Volatile Solids were obtained by burning the sediment at C until a stable weight was obtained. Water Quality: We collected water quality data using a Hydrolab Datasonde 4a, and used the data from the Hood Canal Dissolved Oxygen Project (HCDOP) and Citizens Monitoring Program data. Species Identification: We are working with Dr. Mark Martin, microbiologist at The University of Puget Sound, to identify the bacteria. Matt driving video camera ROV. The bacteria were present in core samples from site 2, which had a 5 cm layer of dark black material that gave off a strong odor of hydrogen sulfide. Percent organic was high( 10-14%) but did not very significantly among sites. 123