duke university

Wildfires And Algal Blooms

October 12, 2021 By EarthWise Leave a Comment

Australia is no stranger to wildfires. But the 2019-2020 season proved to be particularly severe: wildfires destroyed 3,100 homes, displaced 65,000 people, and burned more than 72,000 square miles – roughly the same size as Washington State. The season is colloquially referred to as the Black Summer.

According to a new study recently published in the journal Nature, clouds of smoke and ash from these wildfires triggered widespread algal blooms thousands of miles downwind to the east in the Southern Ocean.

The study, which was led by researchers from Duke University, shows that aerosol particles in the smoke and ash fertilized the water as they fell into it. This provided the nutrients that fueled unprecedented blooms in that region, conclusively linking for the first time a large-scale response in marine life to fertilization by pyrogenic iron aerosols from a wildfire.

This finding raises questions about the role wildfires may play in the growth of phytoplankton, the microscopic marine algae that – through photosynthesis – absorbs large amounts of climate-warming carbon dioxide from Earth’s atmosphere.

According to the research team, the Australian algal blooms were so extensive that the subsequent increase in photosynthesis may have temporarily offset a substantial portion of the wildfires’ CO2 emissions. It remains to be seen how much of the absorbed CO2 remains safely stored in the ocean and how much it has been released back into the atmosphere.

The researchers plan to investigate the fate of the phytoplankton further. They also plan more research to better predict where and when aerosol deposition will boost phytoplankton growth in the future.

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Australian wildfires triggered massive algal blooms in Southern Ocean

Photo, posted January 12, 2020, courtesy of BLM-Idaho via Flickr.

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Artificial Reefs As Havens For Marine Predators | Earth Wise

October 28, 2020 By EarthWise Leave a Comment

Climate change, pollution, development and other stresses have accelerated the decline of reef ecosystems across much of the world’s oceans in recent years. Large predators such as sharks, mackerels, barracudas, jacks and others that formerly fed around reefs have had to venture outside their normal migratory routes in search of suitable alternatives.

According to a new study by Duke University, marine predators have taken up residence at shipwrecks and other artificial reefs. The study surveyed 30 sites along the North Carolina coast and found that predator densities were up to five times larger at the 14 artificial reefs surveyed than at the 16 natural reefs in the survey.

Shipwrecks, particularly those that rose between 4 and 10 meters up into the water column, were a big favorite of the fishes. Some of those sites supported predator densities up to 11 times larger than natural reefs or low-profile artificial reefs. The shipwrecks are basically high-rise timeshares in the sea.

The findings of the survey show that artificial reefs can support large predators, supplementing natural reefs if the design and placement of the artificial reefs are appropriate. In addition, when it comes to designing artificial reefs, there appears to be a height advantage. So, reefs either made from sunken ships or at least made to resemble them would be desirable.

Because undersea predators help maintain healthy and sustainable populations of species lower in the food web, providing suitable habitat for the predators is extremely important. Based on the study, it appears that the strategic use of artificial reefs can be an effective way to help counter the increasing loss of natural habitat on the ocean bottom.

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Artificial Reefs Take on a Towering Presence as Havens for Marine Predators

Photo, posted July 29, 2014, courtesy of NOAA Photo Library via Flickr. Photo credit: Flower Garden Banks National Marine Sanctuary

Earth Wise is a production of WAMC Northeast Public Radio.

Indonesian Deforestation

February 28, 2019 By EarthWise Leave a Comment

Deforestation is defined as the intentional destruction of trees and other vegetation without reforesting or allowing the forest to regenerate itself.

In Indonesia, industrial agriculture, primarily for the production of palm oil, is a major driver of deforestation. But, according to researchers at Duke University, its impact has diminished proportionately in recent years as other natural and human causes have emerged. Their peer-reviewed findings were recently published in the journal Environmental Research Letters.

According to the study’s lead author, large-scale plantations were responsible for more than half of Indonesia’s deforestation in the late 2000s, peaking between 2008-2010 when an average of 1.5 million acres of forest was lost annually. The expansion of the massive plantations was responsible for 57% of the forest loss. Between 2014-2016, an average of more than 2 million acres of forest was lost annually, but plantation expansion only accounted for 25% of this figure. While the overall rate of deforestation continued to grow, other factors were responsible for most of it.

Conversions of forests to grasslands rose sharply in 2015 and 2016 when El Nino caused severe droughts and forest fires. Small-scale farming, often overshadowed by industrial agriculture, was also found to play a bigger role, accounting for 25% of all forest loss.

Indonesia has experienced some of the highest rates of deforestation. Its forests absorb and store vast amounts of climate-warming carbon dioxide, help prevent erosion and flooding, and provide habitat to thousands of species. Understanding the varied causes of Indonesian deforestation should help conservationists and policymakers better address the problem.

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Palm oil not the only driver of forest loss in Indonesia

Photo, posted March 26, 2018, courtesy of Achmad Rabin Taim via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Elephant Losses Imperil Forests

April 20, 2018 By EarthWise Leave a Comment

Poaching and habitat loss have reduced Central African elephant populations by 63% since 2001. These losses not only pose dire consequences for the elephants themselves but also for the forests in which they live.

Air Pollution And Solar Power

July 28, 2017 By EarthWise

We are well-aware of the negative effects of air pollution on human health and on the environment, but a recent study at Duke University has revealed that global solar energy production is taking a major hit due to air pollution and dust.

Coal Plants And Fish

March 20, 2017 By EarthWise

High levels of an element found in coal ash have been detected in fish in two lakes where Duke Energy coal-fired power plants are located, according to a peer-reviewed study at Duke University. The element, selenium, occurs naturally but is concentrated in coal ash.

[Read more…] about Coal Plants And Fish

Hydrogen From The Ocean

August 30, 2016 By WAMC WEB

Hydrogen is the most abundant element in the universe. Estimates are that it comprises 75% of all matter. There is plenty of it here on earth too, but almost none of it is in its elemental form. It is mostly bound up in compounds like water.