kills

What happened to the sea stars?

September 11, 2025 By EarthWise Leave a Comment

Billions of sea stars off the Pacific coast of North America from Mexico to Alaska have died from a wasting disease since 2013. This die-off is considered to be the largest ever marine epidemic. Over 90% of the population of sunflower sea stars has succumbed to the disease.

The result has been an explosion in the population of the sea urchins that the sea stars feed on. In turn, the sea urchins have devoured kelp forests that provide habitat for thousands of marine creatures. These kelp forests support a multi-million-dollar economy through fisheries and tourism as well as sequestering carbon dioxide and protecting vulnerable coastlines.

The disease begins with lesions and eventually kills sea stars by seemingly melting their tissues over a period of about two weeks. Sea stars with the disease become contorted and lose their arms.

For years, the definitive cause of the wasting disease has been elusive. But researchers from the University of British Columbia, the Hakai Institute, and the University of Washington have now identified a bacterium that is the disease-causing agent.

A strain of the Vibrio pectenicida bacteria – named FHCF-3 – is responsible. The Vibrio genus of bacteria includes pathogens that infect corals, shellfish, and even humans. Vibrio cholerae is the cause of cholera.

Research is now underway to understand the link between the disease and warming ocean temperatures due to climate change. The hope is that the discovery of the cause of the wasting disease will help guide management and recovery efforts for sea stars and impacted ecosystems.

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‘Disease detectives’ discover cause of sea star wasting disease that wiped out billions of sea stars

Photo, posted April 16, 2011, courtesy of Brian Gratwicke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pollution in downwind states

August 26, 2024 By EarthWise Leave a Comment

Air pollution is a serious health threat. It is associated with asthma and can lead to chronic disease, cancer, and premature death. Globally, air pollution kills 7 to 9 million people, and 200,000 Americans die from it each year.

There are multiple sources of air pollution including automobiles, power plants, and other industrial activities. Exposure to pollutants such as nitrogen oxide, sulfur dioxide, and particulate matter does not require living or working near their sources. Winds can carry pollution great distances including across state lines.

The Clean Air Act included the EPA’s “Good Neighbor Plan”, which requires “upwind” states to implement plans to reduce emissions from power plants and other industrial sources. However, three states – Indiana, Ohio, and West Virginia – along with various industrial companies and trade organizations sued the EPA when it tried to enforce these plans. A recent Supreme Court decision to block a federal rule curbing interstate air pollution further complicates efforts to reduce emissions.

As a result, there is a disproportionate burden on downwind states. They face major challenges in demonstrating and attributing air pollution to sources across state lines and pursuing legal actions to get the EPA to address their problems.

A recent study by the University of Notre Dame looking at all the complex issues related to interstate pollution underscored how the regulatory system continues to be hamstrung when attempting to address a serious threat to human health and the environment.

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Downwind states face disproportionate burden of air pollution

Photo, posted February 19, 2021, courtesy of David Wilson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Controlling Malaria Without Chemicals

August 28, 2019 By EarthWise Leave a Comment

Nearly half of the world’s population lives in areas vulnerable to malaria. The disease kills roughly 450,000 people each year, most of them children and pregnant women. Malaria is spread by Anopheles mosquitoes and, over time, the mosquitoes have been developing resistance to the chemical insecticides that are used to control them. In addition, there is great concern about the toxic side effects of the chemicals used on the mosquitoes.

About 30 years ago, scientists identified a type of bacteria that kills Anopheles, but the mechanism was not understood. As a result, the bacteria could not be replicated or used as an alternative to chemical insecticides.

But now, an international research team, headed by researchers at UC Riverside, has identified the neurotoxin produced by the bacteria and has determined how it kills Anopheles. The work is described in a paper published in Nature Communications.

It took the team 10 years to achieve a breakthrough in understanding the bacteria. Modern gene sequencing techniques were the key.

While many neurotoxins target vertebrates and are highly toxic to humans, the neurotoxin that kills Anopheles mosquitoes does not affect humans, vertebrates, fish, or even other insects. Known as PMP1, the substance is not even toxic to mice when given by direct injection.

The team has applied for a patent on this discovery and hopes to find partners to help them develop the bacteria-based insecticide.

There is a high likelihood that PMP1 actually evolved to kill the Anopheles mosquito. This finding opens the door to new avenues of research into other environmentally friendly insecticides that would be targeted at other disease-spreading pests.

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Controlling deadly malaria without chemicals

Photo, posted June 9, 2018, courtesy of Mario Yardanov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Off-The-Charts Heat

August 9, 2019 By EarthWise Leave a Comment

There have been some blistering heatwaves this summer – in Europe, in the Middle East, and here in the United States. A new report by the Union of Concerned Scientists projects that within the next 20 years, millions of people in the United States could be exposed to dangerous “off-the-charts” heat index conditions of 127 degrees Fahrenheit or more. Within 60 years, over one-third of the population could be exposed to such conditions.

Extreme heat kills hundreds of people every year across the U.S. Our bodies’ natural cooling process is affected by humidity and the combined heat index measures the impact of high temperature and high humidity. When the combined heat index reaches 90 degrees, it is considered to be a “dangerous day”, when many groups of people are at serious risk.

Because of the warming climate, the number of dangerous days has been increasing in many parts of the country. Unless there is success in limiting the effects of climate change, by 2050, even relatively temperate cities like Detroit, Minneapolis, New York, and Chicago will have 50 or more dangerous days a year. Places like Dallas, Houston, Phoenix and Miami will experience dangerous days for half of the year.

The National Weather Service’s heat index goes up to 127 degrees Fahrenheit. But in as soon as 20 years, the Southeast, Southern Great Plains, and Midwest will begin to experience days that are so hot that they are “off the charts.”

These extreme conditions could still be avoided with steep, rapid carbon emission reductions. But however successful we are going forward, the US will still be significantly warmer than today with 85 urban areas exposed to 30 or more days with a heat index above 105 degrees, compared with just three urban areas historically.

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‘Off-the-charts’ heat to affect millions in U.S. in coming decades

Photo, posted August 8, 2008, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.