Glyphosate is the most widely used herbicide in the United States with applications ranging between 250 and 300 million pounds per year during the past 10 years, largely on corn and soybean in the Midwest. The producers of glyphosate strongly defend it as safe and effective, whereas a wide variety of environmental advocacy groups strongly oppose its use and its fugitive escape to nature. Their argument is bolstered by recent evidence that glyphosate causes Non-Hodgkin Lymphoma in rodents. To date, the U.S. Environmental Protection Agency has maintained that glyphosate is safe and set a water q ..read more

“Boys, I may not know much, but I know chicken shit from chicken salad.” – Lyndon B. Johnson   North Carolina, long known for embracing concentrated animal feeding operations (CAFOs), especially for hogs, has welcomed the burgeoning industrialized production of chickens.  Of course, we all embrace chicken—the meat is healthier than beef and produces less impact on the climate.  Something on the order of a billion chickens are now housed in North Carolina.  With each bird responsible for about 0.10 lbs of nitrogen in chicken waste each year, that amounts to a lot of nitrogen ..read more

Humans extract minerals from the Earth’s crust to enhance the availability of these materials in our economy and often in the environment. For many metals, the mobilization from mining greatly exceeds the natural release of the elements from the weathering and breakdown of rocks. For arsenic, lead, mercury, and vanadium more metal circulates through the atmosphere from human activities than from the sum of all natural processes. This is the science of global biogeochemistry—an evaluation of human impacts on the chemical environment of planet Earth. With its toxic properties, arsenic was once u ..read more

(Title from Canterbury Tales, Geoffrey Chaucer, circa 1385 Most of the human body that is not bone is composed of protein, each built with an array of amino acids that contain nitrogen.  Reflecting the homogenization of our diets in the modern world, most of the nitrogen in those amino acids can be traced, isotopically, to the use of industrial nitrogen fertilizer to grow the grains we eat or to feed the animals that we eat. The advent of synthetic nitrogen fertilizer is often credited with allowing the world population to grow to its present level of about 8 billion, without mass starvat ..read more

Each time an accidental spill coats thousands of seabirds with oil, worldwide opinion is galvanized against off-shore oil production.  Witness the wreck of the Exxon Valdez tanker in Alaska and British Petroleum’s blowout at its Deepwater Horizon platform. Yet, anyone who has walked the beach at Santa Barbara knows about natural oil seepage. Natural sources of oil in the ocean include slow leakage from cracks in the sea floor that connect to oil reservoirs in the underlying sediments. Often the oil companies argue that the oil released to the ocean from natural sources dwarfs the emission ..read more

In the developed world, humans enjoy the benefits of a wide variety of pharmaceuticals that can regulate almost any aspect of our physiology—blood pressure, blood sugar, blood cholesterol, ovulation, anxiety, and headache.  Last night, I even saw a television ad for a pill to reduce anxiety in house cats. Many have said that we are over-medicated, but increasing longevity speaks otherwise.  Antibiotics have saved millions of lives, even though their efficacy is now threatened by the selection of resistant bacteria. Some of these drugs are degraded by our liver, while others pass thro ..read more

Legacy pollution occurs when emissions of a pollutant from long ago persist in the environment and return to impact us at a later time.  About 8 months ago, I blogged about the legacy of phosphorus pollution that is retained in agricultural soils after they are fertilized.  See: Legacy Phosphorus – Translational Ecology (duke.edu).  Today, I want to talk about the legacies of mercury deposited from the atmosphere, where it is derived from the burning of fossil fuels and the smelting associated with the extraction of gold, using mercury as a carrier. Mercury is carried globally i ..read more

I found a glimmer of good news last month amongst the scientific literature that I follow regularly.  Jien Zhang and his colleagues at Iowa State University use a large database to find that the nutrient-use efficiency of some key agricultural crops (corn, rice, cotton and sorghum) in the Mississippi Basin has increased from an average of 0.55 kg of nitrogen taken up per kg of N applied as fertilizer during the 1970s to 0.65 kgN/kgN during the last decade.  That indicates that through crop breeding and better agricultural practices, including more judicious use of fertilizer, a great ..read more

In the South of Georgia, the land of Pogo, lies Okefenokee Swamp, its waters held back from drainage to the sea by the presence of a ridge of sandy deposits known as Trail Ridge that extends from South Georgia into Florida.  The Swamp harbors dense cypress forest and open water habitats with submerged aquatic vegetation. It is a popular recreation area for fishing, canoeing, and birdwatching, which contribute much to the economy of the region. Okefenokee is known as a blackwater swamp, inasmuch as its waters have a rich brown color derived from dissolved organic acids.  The shallow w ..read more

For years, doctors have used an analysis of urine, including its color, to help recognize and diagnose certain diseases in humans. Similarly, ecosystem scientists can recognize subtle changes in ecosystems by shifts in the chemical composition and the color of rivers draining them. In both cases, the effluent from a complex system says a lot about how that system is functioning. For example, when you clear-cut a forest, the stream water draining from it often has much higher concentrations of nitrate and other plant nutrients that would be retained if the forest was still growing. Thus, it is ..read more