Despite this year’s unusual and disruptive weather patterns of a very wet winter and spring, resulting in higher discharges to the Western Lake Erie Basin (WLEB), concentrations levels of bioavailable phosphorus is 30% lower than average.
According to Dr. Rick Stumpf of the National Oceanic and Atmospheric Administration (NOAA), the forecast severity for this year is 7.5, which suggests a significant bloom in the agency’s Harmful Algal Blooms (HABs) in the Lake Erie 2019 Forecast.
“Much of the Lake will be fine most of the time,” Stumpf said, adding that with water temperatures in Lake Erie starting out cold this year, the bloom is expected to start in late July.
For context, the 2015 bloom was a 10. Due to the sheer amount of precipitation in the region, there is 10% more water in the WLEB than average, and the Detroit River is flowing at 30% above average providing dilution from the nutrient-poor Lake Huron.
Researchers within National Oceanic and Atmospheric Administration (NOAA) and Ohio Sea Grant provide early season projections of potential seasonal HABs in western Lake Erie, along with bulletins to provide status updates of the lake and short-term forecasts on bloom location and severity. (See image below as of July 26, 2019).
Over the past decade, Lake Erie and many inland lakes have seen an increase of harmful algal blooms (HABs) made up of cyanobacteria, also known as blue-green algae. These blooms are capable of producing toxins that pose a risk to human and animal health, impair coastlines and negatively impact communities and business in the region.
The potential impact of HABs within the western Lake Erie is determined by the input of “bioavailable” phosphorus. Total bioavailable phosphorus (TBP) is comprised of dissolved phosphorus and particulate phosphorus, both of which are available for HAB development. Early season projections are based on TBP loading from the Maumee River during the “loading season” (March 1 through July 31).
For more information on the role that phosphorus plays in Lake Erie check out Michigan State University Extension’s article on “Agriculture's role in protecting Lake Erie.” This year, the Maumee River phosphorus loadings were presented by Dr. Laura Johnson of Heidelberg University.
Total bioavailable phosphorus loads are lower than expected; a substantial 30% decrease from average.
This is attributed to delayed harvest and incomplete fall fertilizer applications. Researchers and retailers in Ohio have reported significant decreases in applied manure and commercial fertilizer in the fall of 2018. It suggests that improvements in DRP quantity in the watershed can be made quicker than expected.
“This extremely wet spring has shed light on the movement of nutrients from the land into Lake Erie,” said Christopher Winslow, Ph.D., director of Ohio Sea Grant and Stone Laboratory.
Several buoys have been deployed that allow for detection and the use of underwater vehicles and aerial scanning technologies. The toxins in a large bloom may not be as concentrated as in a smaller bloom due to the effects of wind and mixing. Each algal bloom is unique in terms of size, toxicity, and its impact to local communities.