Tuesday, February 27, 2001

Finding Evidence of Life in the Solar System

by Maryann Ashworth and Amanda O’Connor

Why would we want to build an instrument that can detect traces of life on other planets? An “in situ” instrument has numerous advantages. The most important being that we know we can analyze a sample that is brought back from outer space.  This extremely cautious procedure presents many problems.  The most important being whether or not the sample will actually be in good condition to analyze. There have been two major crashes of Mars explorations in the last five years leading to the belief that “in situ” would pose no difficulty.  We are guaranteed that the sample can at least be analyzed by stabilizing its condition from the first impact. Since it is more feasible to analyze the sample “in situ,” Dr. Fogel began to think about how to build such an instrument.
Obviously, the first step in building an instrument that can determine if there is life on another planet begins right here on Earth. Earth environments such as hydrothermal springs and vents are homes for Archae. It has been hypothesized that the creation of Archae and Eubacteria were most likely how life started on Earth.  This is also a clue as to how life could have been started or is started on other planets.  Scientists can also use current-day landscapes to scientifically work backwards. Dr Fogel discussed taking a modern environment and analyzing the relationships within that environment that have survived geologic time to indicate the time period when there were first signs of life.
Scientific data such as chemical clues that exist as biochemical remains and inorganic remains were discussed. Biochemical remains range from large molecules (living cells) to isotopic patterns formed by living organisms.  One important fact was that organic remains are present as biominerals (calcium carbonate, for example) or gases such as oxygen and methane that are produced in quantity solely by living organisms.
The next question that was posed was if biosignatures survive the geologic record. If they do not, then what does and how would we recognize it? Dr. Fogel performed a number of experiments observing the rate of carbon and nitrogen decay and concluded that bacterial signatures overprinted plant signatures. Fortunately, the microbial record will survive.

Tuesday, January 30, 2001

The Toxic Pfiesteria Complex: A Story of Water Pollution, Fish Kills and Human Health at the Science/Policy Border

Dr. Burkholder presented her work to an audience of approximately 130 members of the campus community in Illick 5.  She began her talk outlining the many people with whom she has worked and expressed gratitude to her co-workers and graduate students for their help and expertise.  After her introduction, she chronologically traced her work, from investigating the causes of several large estuarine fish kills in the Mid-Atlantic states to the identification of Pfiesteria as the causative agent.  She also discussed the impacts of Pfiesteria on human health and how it can compromise the immune system of humans. While Dr. Burkholder’s lab has done many studies on Pfiesteria, they are still working to understand what triggers the organism to become toxic in the presence of fresh fish.  She outlined the numerous safety measures they use in their laboratory, the difficulty of working with an organism that has a 27-stage lifecycle and how the timing of her analyses is critical to her work.

Dr Burkholder also spoke of the controversy surrounding her research.  She related receiving personal threats from swine industries when she discovered that effluent from their operations was linked to toxic Pfiesteria blooms.  She also described attempts by other scientists and interests to discredit and suppress her research.  Only when a large fish kill occurred in Chesapeake Bay and the governor of Maryland publicly called for further investigation, was Pfiesteria identified as the causative agent.  As a result of the controversy surrounding her research, Dr. Burkholder uses an extremely conservative approach when trying to determine the cause of a fish kill.  She outlined her methodology used to determine whether Pfiesteria is the causative agent, and described how all her lab results are verified by another independent laboratory.

Overall, Dr. Burkholder’s talk was quite fascinating the way science and policy became inextricably linked while studying an organism that no one can see.  Her slides contained an appropriate amount of text and contained numerous electrographs of microbes.  She also had slides containing newspaper text that outlined the relevance of her research.  Dr. Burkholder also interjected her personal experiences into the talk making the lecture filled with science, policy and interesting stories.