|Photo credit: NOAA|
I sort of feel like we're in our own environmental version of Independence Day, except that the "green shit" is in Lake Erie and its being fired, not from alien ship, but from farm runoff and industrial and municipal waste. Have you seen this stuff? It's nasty!
Due to the persistence of what is termed a confirmed Microcystis bloom, the National Oceanographic and Atmospheric Administration (NOAA) has issued an updated Harmful Algal Bloom Bulletin for western Lake Erie. We saw the first one of these just a week ago.
The NOAA bulletin reads in part: A large Microcystis bloom remains in Western Lake Erie. Models indicate an east-southeast transport that is likely to affect the Bass and Pelee Islands. Windy conditions over the past three days have likely caused subsurface mixing of the bloom. Water temperatures remain high and conducive to bloom intensification. Due to cloudy weather this week, the nowcast and forecast imagery do not represent the full possible extent of the bloom.
There are many species of single-celled organisms living in the Great Lakes, including algae. When certain conditions are present, such as high nutrient or light levels, these organisms can reproduce rapidly. This dense population of algae is called a bloom. Some of these blooms are harmless, but when the blooming organisms contain toxins, other noxious chemicals, or pathogens, it is known as a harmful algal bloom, or HAB. HAB's can cause the death of nearby fish and foul up nearby coastlines, and produce harmful conditions to aquatic life as well as humans.The focus of this research project is to determine the factors controlling microcystin production and to develop methods for determining cyanobacteria blooms from satellite imagery. Imagery is currently available, but we do not know how to discriminate toxic Microcystis blooms from other algal blooms within the images. The combined field data and satellite image data produced from the initial efforts of this project are critical first steps in the characterization of bloom dynamics and development of future bloom forecasting tools.
There is no single factor which causes an algal bloom. A combination of optimum factors such as the presence of good nutrients, warm temperatures and lots of light all encourage the natural increase in numbers of blue-green algae in our waterways. Nature mostly takes care of the temperature and light, but the increased presence of nutrients such as phosphorous is largely due to poor farming practices such as high use of fertilizers and presence of livestock near water supplies, as well as effluent and run-off from towns and cities near waterways. The ponding of water and reducing river flow rates tends to improve the light and sometimes the nutrient environment for algal growth making water turbulence a major factor in bloom development. Pesticides and other chemicals may affect the natural grazers which would otherwise control algal growth and their presence increases the risk of blooms.
An experimental HAB bulletin has been developed to provide a weekly forecast forMicrocystis blooms in western Lake Erie. When a harmful bloom is detected by the experimental system, scientists will issue the forecast bulletin below. The bulletin depicts the HABs’ current location and future movement, as well as categorizes its intensity on a weekly basis.