Harmful algal bloom forecast 2019

This year we are experiencing unusual and disruptive weather patterns resulting in high lake levels highlighting the need to manage our freshwater resources in the Great Lakes.

July 15, 2019 - Author: ,

A representation of how much algal is spreading in Lake Erie
This image shows the harmful algal bloom in the Western Lake Erie Basin in 2017 with a severity of 8.0. This year’s prediction of 7.5. | Photo by NASA Landstat-8

Over the past decade, Lake Erie, as well as 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. Researchers within National Oceanic and Atmospheric Administration (NOAA) as well as Ohio Sea Grant provide early season projections of potential seasonal HABs in western Lake Erie. These bulletins are updated weekly until the seasonal forecast is released in July. Beginning in July, the bulletins will switch to a twice weekly status of the lake and short-term forecasts on bloom location, severity, etc. NOAA has provided these weekly bulletins for HABs in Lake Erie since 2009. 

The Harmful Algal Blooms in Lake Erie 2019 Forecast was announced by Dr. Rick Stumpf of NOAA saying, “Much of the Lake will be fine most of the time,”.  With temperatures in Lake Erie starting out cold this year, though up to normal temperature now, the bloom is expected to start in late July.  While this winter and spring were very wet with high discharge, lower concentrations of bioavailable phosphorus have been observed compared to recent years.  The forecast severity for this year is 7.5, suggesting a significant bloom.  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 Western Basin than average and the Detroit River is flowing at 30% above average providing dilution from the nutrient poor Lake Huron.  Because of the previously mention factors, this may lead to more mild bloom.

DRP and Partic phos
A lot of water has come through Maumee River this spring, 1.2 cubic miles, a little less than 2015. Particulate phosphate was very high due to change in flow, not concentration. DRP was not as high as expected. | Chart by Dr. Laura Johnson

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.

NOAA is actively developing tools to detect and predict how toxic blooms will be.  Millions of dollars have been dedicated to the HABs problem and this research is paying off.  Water managers and users are now able to plan for blooms and adjust accordingly.  Several buoys have been deployed that allow for detection, as well as the use of underwater vehicles and aerial scanning technologies. It is important to remember that the size of the bloom does not indicate toxicity.  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 ultimately its impact to local communities.

Tags: dissolved phosphorus, drp, habs, lake erie, lakes streams & watersheds, maumee river, msu extension, nutrient management, water quality


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