phosphorous

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

A New “Wonder Material” | Earth Wise

February 11, 2022 By EarthWise Leave a Comment

Graphene is a form of carbon made of single-atom-thick layers. It has many remarkable properties and researchers around the world continue to investigate its use in multiple applications.

In 2019, a new material composed of single-atom-thick layers was produced for the first time. It is phosphorene nanoribbons or PNRs, which are ribbon-like strands of two-dimensional phosphorous. These materials are tiny ribbons that can be a single atomic layer thick and less than 100 atoms wide but millions of atoms long. They are comparable in aspect ratio to the cables that span the Golden Gate Bridge. Theoretical studies have predicted how PNR properties could benefit all sorts of devices, including batteries, biomedical sensors, thermoelectric devices, nanoelectronics, and quantum computers.

As an example, nanoribbons have great potential to create faster-charging batteries because they can hold more ions than can be stored in conventional battery materials.

Recently, for the first time, a team of researchers led by Imperial College London and University College London researchers has used PNRs to significantly improve the efficiency of a device. The device is a new kind of solar cell, and it represents the first demonstration that this new wonder material might actually live up to its hype.

The researchers incorporated PNRs into solar cells made from perovskites. The resultant devices had an efficiency above 21%, which is comparable to traditional silicon solar cells. Apart from the measured results, the team was able to experimentally verify the mechanism by which the PNRs enhanced the improved efficiency.

Further studies using PNRs in devices will allow researchers to discover more mechanisms for how they can improve performance.

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‘Wonder material’ phosphorene nanoribbons live up to hype in first demonstration

Photo, posted October 6, 2010, courtesy of Alexander AlUS / CORE-Materials via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saharan Dust And The Amazon | Earth Wise

October 23, 2020 By EarthWise Leave a Comment

We talk about globalization primarily in the context of how human activities connect up distant parts of the world. But there are natural processes that are global in scope as well. One of these is the transportation of mineral-rich dust from the Sahara Desert in North Africa to the Amazon Basin in South America.

Every year, this dust is lifted into the atmosphere by winds and carried on a 5,000-mile journey across the North Atlantic. It turns out that this dust plays a critical role in the Amazon basin ecosystem. The Amazon Basin in turn plays a major role in global climate. Its trees and plants remove huge quantities of carbon dioxide from the atmosphere and stores the carbon in vegetation.

The transcontinental journey of dust is important because of what is in the dust. The dust picked up from ancient lake beds in Chad comes from rock minerals formed by dead microorganisms and is loaded with phosphorus. Phosphorus is an essential nutrient for plant growth and is in short supply in Amazonian soils. Local nutrients like phosphorus in the Amazon mostly come from fallen, decomposing leaves and organic matter but tend to be washed away by rainfall into streams and rivers.

Studies have shown that the phosphorus that reaches Amazon soils from Saharan dust is essential to replace the amounts lost to rain and flooding.

Recent research has found that the quantities of dust transported to South America are inversely linked to rainfall in North Africa and is likely to be affected by climate change. Changes in dust transport could affect plant growth in the Amazon and the amount of CO₂ removed from the atmosphere. The forces that affect the climate are truly global in nature.

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Study quantifies Saharan dust reaching Amazon

Earth Wise is a production of WAMC Northeast Public Radio.

A Powerful Case For Protecting Whales

October 24, 2019 By EarthWise Leave a Comment

Efforts to mitigate climate change typically face two major challenges. One is to find effective ways to reduce the amount of atmospheric carbon dioxide. The other is how to raise enough money to implement climate mitigation strategies.

Many proposed solutions to climate change, like carbon capture and storage, are complex, expensive, and in some cases, untested. What if there was a low-tech solution that was effective and economical?

Well, it turns out there is one, and it comes from a surprisingly simple, “no-tech” strategy to capture CO2: increase global whale populations.

According to a recent analysis by economists with the International Monetary Fund, whales help fight climate change by sequestering CO2 in the ocean.

Whales sequester carbon in a few ways. They hoard it in their fat and protein-rich bodies, stockpiling tons of carbon apiece. When whales die, they turn into literal carbon sinks on the ocean floor. While alive, whales dive to feed on tiny marine organisms like krill and plankton before surfacing to breathe and excrete. Those latter activities release an enormous plume of nutrients, including nitrogen, iron, and phosphorous, into the water. These so-called “poo-namis” stimulate the growth of phytoplankton, microscopic marine algae that pull CO2 out of the air and return oxygen to the air via photosynthesis. Phytoplankton are responsible for every other breath we take, contributing at least 50% of all oxygen to the atmosphere and capturing approximately 40% of all CO2 produced.

With other economic benefits like ecotourism factored in, economists estimate that each whale is worth $2 million over its lifetime, making the entire global population possibly a one trillion dollar asset to humanity.

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How much is a whale worth?

Photo, posted June 12, 2013, courtesy of Gregory Smith via Flickr.

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The Ecology Of Dust

January 19, 2018 By EarthWise Leave a Comment

It isn’t something we think about very often, but dust is a connector of ecosystems around the world. Dust carries various minerals and nutrients to places where such things are in very scarce supply. This includes the oceans of the world as well as many forests and other ecosystems. For example, phosphorus-bearing dust carried from the Gobi Desert is essential to the growth of giant redwoods in California’s Sierra Mountains.

[Read more…] about The Ecology Of Dust

Preventing Toxic Algal Blooms

May 12, 2016 By WAMC WEB

We have talked about the growing problem of toxic algal blooms on a number of occasions. The increasing occurrence of these blooms has been associated with rising temperatures and carbon dioxide levels as well as the presence of wastewater nutrients and agricultural fertilizers in rivers, lakes and reservoirs. The most notable incident occurred in the summer of 2014, when algae contamination in Lake Erie left 400,000 residents in Ohio and Michigan without water for 72 hours.