nutrient

A hidden cost of climate change

August 25, 2025 By EarthWise Leave a Comment

Climate change is dramatically impacting food production by altering rainfall patterns, increasing temperatures, and triggering more frequent extreme weather events. These changes make crops more vulnerable to droughts, floods, heatwaves, pests, and diseases, leading to lower yields and greater uncertainty for farmers worldwide.

But climate change isn’t just reshaping our planet. It’s also changing what’s on our plates. According to a new study by researchers from Liverpool John Moores University in the UK, rising carbon dioxide levels and warmer temperatures may be making food less nutritious.

The research team focused on popular leafy vegetables, including kale, rocket, and spinach. The researchers simulated future UK climate conditions in growth chambers to study how the crops responded to hotter, CO2-rich environments.

The research team found that elevated CO2 levels help crops grow faster and bigger, but not healthier. Over time, the crops showed a reduction in key minerals like calcium and certain antioxidant compounds. These changes were exacerbated by increases in temperature. In fact, the combination had complex effects. The crops did not grow as big or fast, and the decline in nutritional quality intensified.

This nutritional imbalance poses serious human health implications. Rising CO2 levels can increase sugar in crops while reducing essential nutrients, leading to calorie-rich but nutrient-poor diets. This shift may raise the risk of obesity, diabetes, and nutrient deficiencies, especially in vulnerable populations.

The challenge ahead isn’t just to grow enough food to feed a growing population, but to preserve the quality of that food in a changing climate.

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Bigger crops, fewer nutrients: The hidden cost of climate change

Photo, posted May 25, 2010, courtesy of Jason Bachman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing farm nutrient pollution

December 11, 2024 By EarthWise Leave a Comment

When farmers add nutrients to their fields in excess of their crops’ ability to utilize them, these excess nutrients can enter the surrounding environments and create environmental problems. The primary culprits are nitrogen and phosphorous. These fertilizer components emerge from fields and enter local waterways in surface runoff.

Researchers at the University of Illinois Urbana-Champaign have developed a form of designer biochar that can provide phosphorous in a time-released fashion and reduce the amount that escapes into the environment.

The researchers used sawdust and lime sludge, which are byproducts from milling and water treatment plants, respectively. They mixed the two ingredients and formed pellets which were then slow-burned in low-oxygen conditions to create phosphorous-laden designer biochar. Once the pellets bind all the phosphorous they can hold, they can be spread onto fields where the nutrient is slowly released over time.

They tested the pellets in working field conditions. The pellets are used to remove phosphorous from drainage water and then can be reused in the field to provide the nutrient to the plants.

The results were very encouraging. The biochar proved to be a very effective way to provide phosphorous to crops and then reduce how much phosphorous enters the environment. The cost of producing the biochar pellets was less than half that of alternative substances for phosphorous removal.

There is currently no regulation that requires farmers to remove phosphorous from drainage water but there are a growing number of conservation-minded farmers who want to reduce nitrogen and phosphorous losses from their fields. The idea that the recyclable pellets can both provide and control phosphorous is an attractive one.

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Scientists tackle farm nutrient pollution with sustainable, affordable designer biochar pellets

Photo, posted July 16, 2016, courtesy of Rick Obst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Adirondack lakes becoming inhospitable for trout

February 15, 2024 By EarthWise Leave a Comment

A combination of the warming climate and the phenomenon of lake browning are making the bottom of most lakes in New York’s Adirondack Mountains unlivable for cold water fish – such as trout, salmon, and whitefish – in the summer.

Lake browning occurs when dissolved organic matter from forests turns the water tea-brown. Browning is the legacy of a century of acid rain and subsequently the fact that forest soils have suffered reduced capacity to absorb weak organic acids, leading to more dissolved plant matter flowing into lakes. Climate change has increased the frequency of extreme precipitation events and the length of growing seasons, leading to more runoff of organic matter.

Browner water traps more of the sun’s heat at the top of the lake and blocks the sun’s rays from reaching deeper. The result of the browning is lakes that are either too warm or too deoxygenated to support trout populations.

A study of 1,467 Adirondack lakes by Cornell University researchers found that only about 5% of them may continue to maintain water that is cold and oxygenated enough to support cold-water fish.

Deeper lakes fare much better because they have so much water that their oxygen is hard to deplete, but only 1% of all Adirondack lakes are deeper than 30 meters. Another 4% are very clear because the influx of cold water outpaces the expansion of low-oxygen zones and limits the effects of browning.

The study urges the protection of as many lakes as possible from species invasions, nutrient and salt pollution, and other forms of environmental degradation.

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Most Adirondack lakes will likely become unsuitable for trout

Photo, posted July 17, 2011, courtesy of Lida via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How to reduce pollution from food production

January 17, 2024 By EarthWise Leave a Comment

Present in animal manure and synthetic fertilizers, nitrogen is an essential nutrient for plant growth and is a critical input to enhance agricultural productivity on farms around the world. But excessive and inefficient use of this nutrient is widespread. In fact, up to 80% of it leaks into the environment, mostly in various polluting forms of nitrogen: ammonia and nitrogen oxides (which are harmful air pollutants), nitrous oxide (a potent greenhouse gas), and nitrate (which affects water quality).

A new report prepared for the United Nations has put forth some solutions to greatly reduce nitrogen pollution from agriculture in Europe. A group of researchers coordinated by the U.K. Centre for Ecology & Hydrology, the European Commission, the Copenhagen Business School, and the National Institute for Public Health and the Environment of The Netherlands produced the report.

In it, the research team puts forth its recipe to reduce nitrogen pollution in Europe. The report’s ingredients include:

Reducing by 50% the average European meat and dairy consumption
More efficient fertilizer application and manure storage
Reducing food production demand by reducing food waste by retailers and consumers
Better wastewater treatment to capture nitrogen from sewage
Adopting policies addressing food production and consumption to transition them towards more sustainable systems

Taking action to reduce nitrogen pollution will require a holistic approach involving farmers, policymakers, retailers, water companies, and individuals.

Do Europeans have an appetite for change?

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Scientists provide recipe to halve pollution from food production

Photo, posted March 10, 2022, courtesy of USDA NRCS Montana via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Below-Average Dead Zone In The Gulf of Mexico | Earth Wise

July 20, 2023 By EarthWise Leave a Comment

The Gulf of Mexico dead zone, or hypoxic area, is an area of low oxygen content that can kill fish and other marine life. It occurs every summer and is mostly a result of excess nutrient pollution from human activities in cities and farms throughout the Mississippi River watershed. The nutrients carried by the river into the gulf stimulate an overgrowth of algae, which eventually die and decompose, which depletes oxygen in the water as the algae sink to the bottom.

The resultant low oxygen levels near the bottom of the gulf cannot support most marine life. Fish and shrimp often leave the area seeking better places to be. Animals that can’t swim away – like mussels and crabs – can be stressed by the low oxygen level or even killed.

The National Oceanic and Atmospheric Administration produces a dead zone forecast each year based on a suite of models developed by NOAA and partners at multiple universities.

The latest forecast, completed in May, found that the discharge of nutrients in the rivers was about one-third below the long-term average between 1980 and 2022. Nitrate loads were down 42% and phosphorous levels down 5%.

Based on these measurements, the scientists forecast a summer dead zone that will cover an estimated 4,155 square miles, which is 22% lower than the 36-year average of 5,364 square miles. Ongoing efforts by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force to reduce nutrient levels seem to be paying off.

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NOAA forecasts below-average summer ‘dead zone’ in Gulf of Mexico

Photo, posted September 6, 2013, courtesy of NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Gulf Of Mexico Dead Zone | Earth Wise

July 19, 2021 By EarthWise Leave a Comment

Every summer, a so-called dead zone forms in the Gulf of Mexico. It is primarily caused by excess nutrient pollution from human activities in urban and agricultural areas throughout the Mississippi River watershed.

When these excess nutrients reach the Gulf, they stimulate excess growth of algae, which eventually die and decompose, depleting oxygen as they sink to the bottom. These low oxygen levels near the Gulf bottom cannot support most marine life. Animals that are sufficiently mobile – such as fish, shrimp, and crabs – generally swim out of the area. Those that can’t move away are stressed or killed by the low oxygen.

A team of scientists funded by the National Oceanic and Atmospheric Administration issues an annual forecast for the dead zone based upon a suite of models that incorporate river flow and nutrient data.

The 2021 forecasted area is somewhat smaller than, but close to, the five-year measured average for the dead zone, which is 5,400 square miles, roughly the size of the state of Connecticut. Each year, these forecasts are reported as comparisons to long-term averages, but the problem is that the long-term average is unacceptable.

The Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force has set a goal of reducing the size of the dead zone to a five-year average of 1,900 square miles – about a third of the current average.

Large reductions in nutrient loads have been called for in federal and state action plans for nearly 20 years, but clearly these reductions have not yet been sufficient. The Interagency Task Force continues to provide information for managing nutrient loads in the Mississippi River Basin.

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Average-sized ‘dead zone’ forecast for Gulf of Mexico

Photo, posted October 6, 2020, courtesy of Christine Warner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tracking Down Gluten Sensitivity | Earth Wise

October 6, 2020 By EarthWise Leave a Comment

Celiac disease is a well-documented autoimmune disease triggered by exposure to the dietary proteins found in wheat, rye, and barley. Celiac disease affects less than 1% of Americans yet many more people claim to be sensitive to gluten.

When people with celiac disease eat gluten, their body mounts an immune response that attacks the small intestine. These attacks lead to damage on the villi, the small projections that line the small intestine that promote nutrient absorption. Symptoms range from various digestive problems to fatigue, weight loss, bloating, and anemia. Ultimately, it can lead to a variety of serious health complications.

Until recently, there was a tendency by doctors to dismiss the complaints of people who claimed to be sensitive to gluten but do not have celiac disease. That is starting to change, in part as a result of studies conducted at Columbia University that looked at the biological basis for non-celiac gluten sensitivity.

The new study shows that people with non-celiac gluten sensitivity produce a high level of anti-gluten antibodies but that these antibodies are different from the ones triggered by celiac disease and that the inflammatory responses they instigate are also different. The more restrained inflammatory response is much less likely to be associated with autoimmune activity and intestinal cell damage. In addition, the immune system of people with non-celiac gluten sensitivity appears to be able to gradually reduce its inflammatory response over time.

Discovery of these antibodies could be used in the future to help doctors more readily identify people with non-celiac gluten sensitivity, which now is difficult to diagnose. The researchers also believe that their work could lead to potential new therapies for celiac disease, which is currently treated only with dietary restrictions.

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Unique Antibody Profile Sets Gluten Sensitivity Apart from Celiac Disease

Photo, posted November 27, 2010, courtesy of Francis Storr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shrinking Alaskan Salmon | Earth Wise

September 24, 2020 By EarthWise Leave a Comment

According to a new study published in the journal Nature Communications, salmon returning to Alaskan rivers have become significantly smaller over the past 60 years. As a result of climate change and competition from hatchery fish, wild salmon are spending less time at sea and are returning to spawning grounds at younger ages.

The study, by scientists at the University of Alaska at Fairbanks and the University of California Santa Cruz, examined measurements of over 12 million fish collected by the Alaska Department of Fish and Game from 1957 through 2018. Over that time period, four out of Alaska’s five wild salmon species – Chinook, chum, coho, and sockeye – have shrunk in size. Chinook salmon is the official state fish of Alaska and they used to stay out at sea for seven years before returning to spawn. Many are now returning to rivers at just four years old and are on average 8% smaller than they were 30 years ago.

The shrinking size of Alaskan salmon has consequences for people, the economy, and ecosystems in Alaska. Wild salmon is a staple food for many residents of the state, particularly among indigenous groups. More generally, Alaska produces nearly all of the wild salmon in the U.S. Commercial fishing of over 200 million wild salmon in 2019 resulted in $657 million in income. The fish are also an important food source for bears and other wildlife and the spawning migration of salmon plays an important role in nutrient transportation in Alaskan river ecosystems.

Multiple factors are driving the changes in the salmon population, but the largest effects are the changing climate and the abundance of salmon in the ocean due in part to hatchery production that results in competition for the salmon’s food.

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Alaska’s Salmon Are Significantly Smaller Than They Were 60 Years Ago

Photo, posted September 5, 2019, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Dead Zone In The Gulf Of Mexico | Earth Wise

July 6, 2020 By EarthWise Leave a Comment

The Gulf of Mexico has an area of low to no oxygen in the water that can kill fish and other marine life. It is an annual event that is primarily caused by excess nutrient pollution from human activities in urban and agricultural areas throughout the Mississippi River watershed. When these excess nutrients reach the Gulf, they stimulate the overgrowth of algae, which eventually die and decompose, depleting the oxygen in the water as the algae sink to the bottom.

These low oxygen levels near the bottom of the Gulf cannot support most marine life. Some species – among them many fish, shrimp, and crabs – swim out of the area, but animals that can’t swim or move away are stressed or killed by the low oxygen. The dead zone in the Gulf occurs every summer.

A recent forecast for this summer’s dead zone predicts that the area of low or no oxygen will be approximate 6,700 square miles, which is roughly the size of Connecticut and Delaware combined. This is about 1,100 square miles smaller than last year’s dead zone and much less than the record of 8,776 square miles set in 2017. But it is still larger than the long-term average size of 5,387 square miles.

Making comparisons to the long-term average ignores the fact that the long-term average itself is unacceptable. The dead zone not only hurts marine life, but it also harms commercial and recreational fisheries and the communities they support. The actions that have been taken so far to reduce pollution in the Mississippi watershed are clearly not sufficient to drastically reduce the dead zone in the Gulf.

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Large ‘dead zone’ expected for Gulf of Mexico

Photo, posted October 17, 2017, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disappearing Kelp Forests

January 9, 2018 By EarthWise Leave a Comment

In recent decades, ocean temperatures in many places have warmed by nearly 3 degrees Fahrenheit. An effect of this warmer water is the decimation of what were once luxuriant giant kelp forests in eastern Australia and Tasmania. There used to be thick canopies covering much of the region’s coastal sea surface, but they have wilted in the intolerably warm and nutrient-poor water.