Toxic Algae Blooms and Agriculture: 5 Things to Know About Their Connection

NASA/USGS

EDITOR'S NOTE: On August 2, the National Oceanic and Atmospheric Administration announced that the 2017 Gulf of Mexico "dead zone," an area of low oxygen that can kill fish and marine life, is 8,776 square miles, an area about the size of New Jersey. It is the largest one measured since dead zone mapping began there in 1985.

If you follow environmental or climate news, then you have probably noticed the rise in reporting about harmful algal blooms (aka toxic algae). Over the past few decades, scientists have not only observed an upsurge in the frequency of these blooms around the planet but also an increase in their severity and geographic distribution. According to the US Environmental Protection Agency (EPA), these blooms - known as everything from red tides to blue-green algae or cyanobacteria - have been cropping up across the country; in fact, in all 50 states. Some areas like upstate New York are expected to have a "big bloom year" and a rough summer. And federal scientists are forecasting that this summer's dead zone in the Gulf of Mexico is expected to be the third largest since monitoring began a little over 30 years ago.

Most news stories understandably focus on the negative impact (and sometimes lethal effects) these blooms can have on humans and animals, but give short shrift to what is causing the blooms. While this is a scientifically complex issue and there are a number of factors that have been linked to the blooms and their toxin production, there is a strong linkage between industrial agriculture and toxic algae outbreaks that we must not overlook. So with the 2017 toxic algae season well underway, here are 5 things to know about the link between agriculture and algal blooms:

1. The Link Between Toxic Algae and Our Broken Food System

First and foremost, these blooms are yet another reminder that we need to make significant and lasting changes to the way we farm and produce our food, especially in reducing nutrient pollution. According to the EPA, "animal manure, excess fertilizer applied to crops and fields and soil erosion make agriculture one of the largest sources of nitrogen and phosphorus pollution in the country." It is this nutrient pollution and over-enrichment that is primarily fueling the harmful algal blooms. And thanks to the important work of NOAA and other federal and state agencies, we know a lot more today about the growing threat that these blooms pose to the nation's aquatic ecosystems, public health and local and regional economies.

Pollution associated with industrial animal production or concentrated animal feeding operations (CAFOs) without a doubt contributes to nutrient over-enrichment which can be a factor in harmful algal bloom outbreak frequency and toxin production. North Carolina - home to a large number of industrial poultry and hog farms (third largest producer of poultry products and second largest pork producer in the US) - provides a unique window into this environmental problem. In June of last year, Waterkeeper Alliance, North Carolina Riverkeeper organizations and Environmental Working Group released a first-of-its-kind interactive map that documents the approximate locations of more than 6,500 CAFOs - large swine, poultry and cattle operations - across the state of North Carolina. If you're thinking, "all those CAFOs must generate a lot of poop," you'd be correct. Research associated with this project estimates that these CAFOs annually produce more than 10 billion pounds of wet animal waste and 2 million tons of dry animal waste in North Carolina.

The aerial views of the CAFOs reveal manure lagoons (aka waste ponds) from swine operations and their proximity to rivers, streams and other vital public water sources. These lagoons are often unlined and nutrients can leach out and find their way into nearby waterways. In addition, these farms are often sprayed with nutrients that are easily washed away in heavy rains. But that's not the only way nutrients can get into the waterways. When storms bring heavy rains, like we saw with 2016's Hurricane Matthew, rivers overflow their banks, flooding the lagoons and washing large amounts of animal waste downstream. While this can have an immediate impact on communities that depend on certain rivers - like the Neuse and Cape Fear - for their drinking water, in the longer term, this pollution caused by flooding can also fuel harmful algae blooms that result in drinking water bans (among other negative impacts).

Crop production can also play a role. The harmful algae blooms that recently plagued Lake Erie were in part fueled by fertilizer runoff from industrial corn and soybean farms.

2. The Climate Piece

Just as industrial agriculture is intimately tied to toxic algae blooms, it is also closely connected to climate change... which is inextricably linked to the toxic algae crisis. Confused? I'll explain.

Among the primary sources of greenhouse gas emissions (GHG) in the US is the agriculture sector - in particular, animal agriculture and livestock production. Cows and other ruminant animals produce methane, a powerful GHG gas, during a digestive process known as enteric fermentation. Another source of methane from ruminant animals is the massive amounts of decomposing manure being stored in the lagoons often used by factory farming operations. According to the Food and Agriculture Organization of the United Nations, global livestock production represents 14.5 percent of all anthropogenic GHG emissions. (It doesn't have to be this way; livestock farming that makes use of regenerative agriculture techniques has the potential to absorb more greenhouse gases than it emits - with the added benefit of curtailing nutrient pollution.)

So that is a brief explanation of agriculture's relationship to climate change. What about the link between climate change and toxic algae blooms?

New research, according to the US Environmental Protection Agency, indicates that the "impacts of climate change may promote the growth and dominance of harmful algal blooms through a variety of mechanisms including warmer water temperatures, changes in salinity, increases in atmospheric carbon dioxide concentrations, changes in rainfall patterns, intensifying of coastal upwelling and sea level rise." Indeed there is already evidence of climate change exacerbating the toxic algae problem. For one, toxic algae outbreaks are arriving earlier and staying longer (partly due to warmer water temperatures); a NOAA scientist noted this trend following the 2013 algae outbreak in Lake Erie. Another example is the trend towards more intense storms and precipitation (and the subsequent flooding) and the role they play in harmful algal blooms. Citing North Carolina's experience with two 500-year floods (linked to Hurricanes Matthew and Floyd) in the last 20 years, Cape Fear Riverkeeper Kemp Burdette warned that "as the world continues to experience climate change and rising sea levels, we're going to see more and more and more flooding brought on by these stronger storms."

In groundbreaking research led by Dr. Christopher Gobler, the recent intensification of toxic algae events - along with their distribution and frequency - in the North Atlantic and North Pacific Oceans has been linked directly to warming ocean temperatures (brought about by climate change).

3. The Economic Connection

If we don't rein in agricultural runoff and toxic algae blooms, then communities across the US will continue to experience the negative impacts to the environment, human health and the economy. Some of the economic impacts relate to our fisheries and drinking water supplies. In an article earlier this year, Tom Philpott wrote that the annual damages caused by toxic algae blooms nationwide, "everything from increased [drinking water] filtration costs to declines in fish populations," amounts to about $2 billion in costs to the US economy.

Philpott points to Lake Erie and its surrounding communities as a "stark example" of the threat posed by polluted agricultural runoff and harmful algal blooms. On the other hand, properly funding initiatives that seek to reduce nutrient pollution, including that which originates from agricultural land, and the consequent toxic algae will help to boost the economy including sectors related to our food system.

4. Farms Can Be Part of the Solution

While some farms are a big part of the nutrient pollution problem, all farms can be a big part of the solution. A large majority of farmers are willing (and, in some cases, doing) the right thing and we need to provide the necessary support to help them keep nutrients in the field and out of our waterways. As noted in Scientific American, one way to cut back on nutrient runoff is somewhat simple: "apply only the right amount of fertilizer in a targeted way at the appropriate time exactly where it can do the most good for crops and have the least likelihood of simply running off in the rain."

That said, the bigger picture and more effective approach is regenerative agriculture. Regeneration International describes regenerative agriculture as "farming and grazing practices that, among other benefits, reverse climate change by rebuilding soil organic matter and restoring degraded soil biodiversity - resulting in both carbon drawdown and improving the water cycle." In regards to the latter, regenerative agriculture practices result in increased water percolation and retention and cleaner (and safer) water runoff.

5. Your Food Choices Make a Difference

Among the most important decisions you make every day are your choices about the food you eat. Given the intense focus on climate change - thanks in part to President Trump's views on the topic and his recent decision to withdraw the US from the Paris climate accord - you are probably already thinking more about how to leverage your personal food choices in the fight to reduce greenhouse gas emissions. In addition to the important role that these decisions play in combatting climate change, many of the same food choices can also help tackle the toxic algae problem. For instance, you could eat a little less meat - try Meatless Monday.

While Americans are eating less beef in recent years, the Natural Resources Defense Council observes that we still consume much more than most countries. In fact, the US ranks fourth globally in per capital beef consumption - we're eating twice as much red meat as advised by USDA's dietary guidelines. If you have a hankering for meat, make sure it comes from a sustainable farm. Also, choose sustainably grown produce as much as possible. Both will translate to less nitrogen and phosphorus runoff that pollute our waterways. And the benefits don't end there - some of these food choices can also shrink your individual water footprint and improve animal welfare, public health and labor conditions.