Environmental biosensors for aquatic ecosystems
Dr. Charles Trick, Dr. Norman Hüner
Human activities continue to have a dramatic, negative impact on fresh water and marine aquatic ecosystems. Presently, this impact is assessed and measured on the gross ecosystem-level by the loss of fisheries, the loss of water quality due to increased levels of toxic bacteria in our drinking water supplies and closing of recreational areas with increasing frequency. In contrast to this passive approach, the Biotron Environmental Flow Cytometry Facility coupled to the Algal Culture Facility will develop �early warning� biosensors to assess the impacts of human activity and global climate change on sensitive aquatic ecosystems. These data will be indispensable for an aggressive, proactive approach to environmental protection policy and environmental assessment to avoid impending aquatic ecosystem catastrophes.
Flow cytometry is the application of instrumentation aimed at experimentally looking at cells in a population, one cell at a time and a thousand or more cells per second. The basis of flow cytometry is that cells in a population are analyzed for fluorescent properties by passing single cells through a laser and measuring the reflected light or emitted fluorescence. The questions that can be addressed by flow cytometry depend on the design of the experiment but include the following: How many naturally fluorescent eels are in a water sample? This can be assessed by exploiting natural chlorophyll fluorescence. How fast are the cells growing in the population? This can be assessed by in vivo DNA analysis using a DNA-specific fluorescent probes. How many cells in a population contain specific toxins? This can be exploited by using fluorescently labeled antibodies to the toxin of interest. Are cells in a population being killed by exposure to toxic materials in the water? This can be assessed by fluorescence probes for reactive oxygen species associated with the onset of cell death. An additional advantage of the Biotron Flow Cytometry Facility is its portability. The portable model can be transported easily to specific environment study sites such as onboard ships for ocean studies or taken to a field station for the use in river and lake ecosystems.
Dr. Trick is a national and international leader in the development of flow cytometry for use in aquatic ecology and monitoring ecosystem health. The Biotron Environmental Flow Cytometry Facility will develop state-of-the-art, "early warning" biological markers for analysis of populations in environmentally important and sensitive fresh water and marine ecosystems. In collaboration with Dr. I. Creed (UWO) and the CFI-supported Catchment Research Facility (CRF), Dr. Trick will use flow cytometry to assess the impact of forestry harvesting practices on the algal and microbial food web in the Turkey Lakes Watershed. This research will lead to the discovery of specific species that will represent biological markers sensitive to the impact of forestry practices on the nutrient composition of the associated lakes and rivers.
Associated with the measurement of populations in natural ecosystems is the ability of flow cytometry to seek and detect a "needle in the haystack", that is, the ability to measure very low numbers of important, water-borne, infectious microbes in aquatic systems that have a very complex community structure. Through the merging of modern molecular biology and flow cytometry, Trick's group will develop the highly sensitive procedures for the recognition and detection of these organisms. As a spin-off of this research, this group will develop a smaller scale, less-costly analytical sensor in conjunction with the emerging cell detector industries and highly sensitive sensors that utilize developing nanotechnology. These developments in instrumentation and procedures should be applicable to many applications in the environmental and medical research fields. This research will be integrated with Valvano's research in soil pathogenesis as well as the biogeochemical research program lead by Dr. Southam.
Finally, Dr. Trick's group will exploit flow cytometry to understand the impact of human activity and global climate change on marine coastal and oceanic food webs. In this context, this group will use flow cytometry as part of international scientific effort to measure:
- the complexity of natural phytoplankton populations in different environments of ecological importance such as the Bering Sea, Beaufort Sea, Sargasso Sea, Coastal California upwelling, and the Peru upwelling, and;
- the response of marine microbial communities to environmental changes induced by international iron seeding experiments in the North Pacific.
Thus, the Biotron Flow Cytometry Facility is innovative because it will develop instrumentation of unprecedented sensitivity and flexibility to quantify infectious aquatic microbes as well as the impact of human activity and global climate change on rivers, fresh water lakes and oceans. This facility will be integrated with the Photosynthetic Spectroscopy / Fluorescence Imaging Facility established through a CFI-OIT grant associated with H�ner's CRC in Environmental Stress Biology and his research program on global energy sensing in green algae and cyanobacteria.
