Have any summer vacation plans that include swimming, fishing, or walks on the beach? If so, lucky you. But, if you’re headed to the East Coast, Great Lakes, Gulf of Mexico, or any number of our nation’s lovely ocean or lake escapes around late July, plan carefully and watch out for toxic and dead zones!
Lake Needwood, in Maryland, is just one of many lakes that has been negatively impacted by algal blooms. Photo: R Salvador.
April showers (+ fertilizer) bring May flowers—and summer dead zones
Almost like clockwork, algal blooms in some of America’s most valuable lakes and bays start popping up every year around late July. Unfortunately, these algae aren’t the kind that you’ll find in miso soup or snack mix. Rather, they can be toxic, and – in runaway quantities – they frequently lead to oxygen depletion in waterways and create dead zones (areas where marine life cannot survive). You may remember hearing about the algal bloom in Lake Erie last August that left 400,000 people in Toledo without water, as just one example.
So, what is going on? Well, as farmers plant their fields every spring, they also apply fertilizers. While crops do need those nutrients to grow, not all of what is applied makes its way to the plants. Instead, much of the excess nitrogen and phosphorus in these fertilizers can easily be washed away with the rains into lakes and rivers, combining with other sources of pollution such as runoff from concentrated livestock facilities to cause a real problem. The exact amount of excess nutrients depends on several factors, but boils down to the timing and amount of fertilizer, rainfall, and crop growth. Excess nutrients in water resources have become nearly guaranteed each summer, but it doesn’t have to be that way.
The Gulf of Mexico dead zone is older than I am and bigger than Connecticut
Algal blooms can be huge, persistent, and devastating. The second-largest dead zone in the world is in the Gulf of Mexico, and has recently extended over 5000 square miles. When the dead zone appears again this year (NOAA has predicted it will be about the same size this year), it will be celebrating its 43rd birthday (the first one was recorded in 1972). Moreover, the impact of this phenomenon is not just aesthetic – a recent estimate suggested that costs add up to about $82 million per year for just the US seafood and tourism industries. While there are goals in place to reduce the size of this problem, the EPA has indicated that we can’t expect to see things change very fast.
New problems heating up in the Pacific
You may have heard the news that scientists have recently surveyed an algal bloom on the West coast that is estimated to be the largest ever in that region. In this case, a few toxins affecting fish and shellfish are dangerous to humans and are therefore wreaking havoc on harvests. Scientists think that higher than average temperatures might be the biggest culprit for the sudden change in this case, but we’ll have to stay tuned.
I’ll take a glass half-full, but please hold the fertilizer
Algae problems seem to be on the rise, but the good news is that there are ways to reduce them. For one thing, we can incentivize different farming practices—ones that include cover crops, perennials, diversified farms, slow-release fertilizers, and more—to limit the growth of toxic blooms and dead zones. By improving the nutrient balance on farmland soils, matching inputs with the actual needs of crops, significant nutrient loss can be avoided. For example, research in Iowa has found that by adding perennials to just 10% of corn stands, nitrogen and phosphorus losses were reduced by 84% and 90%, respectively.
When farms and ranches are considered a part of the broader landscape and ecosystem, it becomes possible to identify solutions that minimize consequences near and far. This is just another reason why many scientists agree that investments in agroecology need to be enhanced. Now, go plan your vacation!