organisms

What Is Healthy Soil? | Earth Wise

August 30, 2022 By EarthWise Leave a Comment

Soil supports life by providing many critical ecosystem services. For example, soil acts as a water filter, a growing medium, and provides habitat for billions of organisms. Soil is also the foundation of our cities and towns, and the basis of global agroecosystems, which provide humans with feed, fiber, food, and fuel.

For all of these reasons and many more, having healthy soil is vital. But what does soil health mean? And how should it be measured?

According to new analysis by researchers from Cranfield University and Nottingham University in the U.K., how we think about, measure, and study soil must change in order to better understand how to manage this resource effectively.

While the term ‘soil health’ is widely used, it means different things to different people. There is no single agreed upon way to gauge the overall health of soil.

Current approaches to assess soil health measure individual soil properties and use findings to assign a single number giving an overall score. But according to the research team, this does not reflect the wider system perspective that’s needed to fully evaluate the health of soil over time.

Instead, the researchers propose a new system to assess soil health based on a hierarchical framework that takes in several measures, including signs of life, signs of function, signs of complexity, and signs of emergence, which is the extent to which soils recover from multiple stressors.

This new approach, which can be applied to all soils, moves us closer to an interdisciplinary understanding of the whole picture of soil health. After all, healthy soil is fundamental to our survival.

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We need to change how we think about soil

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Progress On Artificial Photosynthesis | Earth Wise

August 8, 2022 By EarthWise Leave a Comment

Photosynthesis is the process by which plants use the energy from sunlight to turn water and carbon dioxide into biomass and ultimately the foods we and other organisms eat. Scientists at the University of California Riverside and the University of Delaware have found a way to create food from water and carbon dioxide without using biological photosynthesis and without needing sunlight.

The research, recently published in the journal Nature Food, uses a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate, which is the primary component of vinegar. Food-producing microorganisms then consume the acetate in order to grow. Solar panels are used to generate the electricity to power the electrocatalysis. The result is a hybrid organic-inorganic system that is far more efficient in converting sunlight into food than biological photosynthesis.

The research showed that a wide range of food-producing organisms can be grown in the dark directly on the acetate output of the electrolyzer. These include green algae, yeast, and the fungal mycelium that produce mushrooms. Producing algae with this technology is about 4 times more energy efficient than growing it with photosynthesis. Yeast production is about 18 times more energy efficient than the typical method of cultivating it using sugar extracted from corn.

Artificial photosynthesis has the potential to liberate agriculture from its complete dependence on the sun, opening the door to a wide range of possibilities for growing food under the increasingly difficult conditions imposed by the changing climate.

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Artificial photosynthesis can produce food without sunshine

Photo, posted September 7, 2016, courtesy of Kevin Doncaster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Environmental DNA | Earth Wise

August 5, 2022 By EarthWise Leave a Comment

Marine protected areas are sections of the ocean where governments place limits on human activity. They are intended to provide long-term protection to important marine and coastal ecosystems. MPAs are important because they can protect depleted, threatened, rare, and endangered species and populations.

In January 2020, the Republic of Palau in the western Pacific Ocean created one of the world’s largest marine protected areas. The Palau National Marine Sanctuary covers 80% of the country’s economic zone and prohibits all extractive activity like fishing and mining over a 183,000 square mile area in order for the island nation to ensure its food security and grow its economy in the face of climate change.

The Marine Sanctuary is an ambitious enterprise. The question is how Palau can evaluate whether and how well it is working?

A team of scientists from Stanford University and Palau-based colleagues are making use of Environmental DNA – or eDNA – technology to monitor the large-scale marine protected area. eDNA is the cells, waste, viruses, and microorganisms that plants and animals leave behind. Samples of marine eDNA effectively provide a fingerprint of the organisms that have recently passed through the water in a given area. This gives scientists a way to assess an ecosystem’s biodiversity and keep track of the types of species inhabiting a specific area. Using eDNA, it is possible to keep track of all the organisms that live below the surface and learn about things we can’t even see.

The team has embarked on a program of periodic sampling of the waters off Palau and hope to be able to monitor the results of establishing the Marine Sanctuary.

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eDNA: Bringing biodiversity to the surface

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

Earth Wise is a production of WAMC Northeast Public Radio.

Less Phytoplankton In The Gulf Of Maine | Earth Wise

July 20, 2022 By EarthWise Leave a Comment

Phytoplankton, also known as microalgae, are the base of the marine food web and also play a key role in removing carbon dioxide from the air. They are eaten by primary consumers like zooplankton, small fish, and crustaceans.

Phytoplankton, like land plants, absorb carbon dioxide from the atmosphere and use photosynthesis to grow. Then they become a food source for other organisms and ultimately for people who depend upon marine ecosystems. If phytoplankton productivity is disrupted, there can be adverse effects on regional fisheries and the communities that depend on them.

The Gulf of Maine is becoming warmer and saltier, because of ocean currents pushing warm water into the gulf from the Northwest Atlantic. These temperature and salinity changes have led to a significant decrease in the productivity of phytoplankton. According to a new paper from scientists at Bigelow Laboratory of Ocean Sciences in Maine, phytoplankton are about 65% less productive in the gulf than they were 20 years ago.

The study’s results come from the analysis of the Gulf of Maine North Atlantic Time Series, a 23-year sampling program of the temperature, salinity, chemical, biological, and optical measurements of the gulf. The scientists refer to what they describe as a giant windmill effect happening in the North Atlantic, which is changing the circulation of water coming into the Gulf of Maine. In the past, inflows from the North Atlantic brought water from the Labrador Current, which made the gulf cooler and fresher. The new circulation is making the water warmer and saltier.

These changes have significant implications for higher marine species, fisheries, the lobster industry, and other activities in the states that border the Gulf of Maine.

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NASA-funded Study: Gulf of Maine’s Phytoplankton Productivity Down 65%

Photo, posted November 15, 2015, courtesy of Paul VanDerWerf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tourism And Invasive Species | Earth Wise

March 7, 2022 By EarthWise Leave a Comment

Tourism has experienced exponential growth during the past 70 years. In 1950, there were 25 million international tourist arrivals. By 1990, it had ballooned to 435 million. Between 1990 and 2018, the numbers more than tripled reaching more than 1.4 billion. And by 2030, the number of international tourist arrivals is expected to reach 1.8 billion.

Tourism is vital to the success of many economies around the world. Tourism can boost revenue, provide jobs, develop infrastructure, protect wildlife, and help preserve heritage sites and cultures. But there can also be many downsides to tourism, one of which is that it can contribute to the introduction and spread of invasive species. Non-native organisms can cause all sorts of social, environmental, and economic damage.

Tourists help spread invasive organisms far and wide. These organisms hitch rides in their luggage and on their shoes and clothing. A 2011 study in New Zealand found that for every gram of soil on the shoes of in-bound international passengers, there were 2.5 plant seeds, 41 roundworms, 0.004 insects and mites, and many microorganisms.

A new study by researchers from the University of Melbourne in Australia and AgResearch New Zealand examined to what degree tourism plays a role in the spread of invasive species. According to the study, which was recently published in the journal NeoBiota, the research team found that the number of nights spent in hotels significantly correlated to the incursion of invasive species during that period.

Creating effective mechanisms to prevent the introduction of invasive species in the first place is the best way to prevent this problem.

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Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species

Number of tourist arrivals

Photo, posted March 27, 2005, courtesy of John via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Butterflies And Moths In A Changing World | Earth Wise

July 20, 2021 By EarthWise Leave a Comment

Extinction is a part of life. Plant and animal species disappear all the time. In fact, approximately 98% of all the organisms that have ever existed on planet earth are now extinct. Earth’s so-called ‘normal’ rate of extinction is thought to be somewhere between 0.1 and 1 species per 10,000 species per 100 years.

But anthropogenic climate change is bringing about rapid change in nature. Put more simply, human activity is killing nature at an unprecedented rate. According to many scientists, the earth’s sixth mass extinction has already begun. Mass extinctions are defined as times when the Earth loses more than 75% of its species in a geologically short interval.

The changing climate puts immense pressure on species for change. According to a new study by researchers from the University of Helsinki and the Finnish Environment Institute, the few butterfly and moth species capable of adjusting to the changing climate by moving up their flight period and moving further north have fared the best.

In Finland, researchers compared temporal shifts in the flight period and spatial shifts in the northern range boundary of 289 moth and butterfly species, as well as changes in abundance over a roughly 20-year period.

They found that about 45% of species that either moved northward or advanced their flight period fared much better than the roughly 40% of species that did not respond in either way. On average, the populations of these poorly responding species declined. But the 15% of species that did both had the largest increase in abundance.

The ability to adapt to a changing climate is going to be vital for species survival.

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Butterflies and moths have difficulty adjusting to a rapidly changing climate

What is mass extinction and are we facing a sixth one?

Photo, posted August 16, 2017, courtesy of Tero Laakso via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Species Moving North | Earth Wise

April 19, 2021 By EarthWise Leave a Comment

Climate change is leading to warmer winter weather throughout the southern U.S., providing opportunities for many tropical plants and animals to move north. A new study by scientists at UC Berkeley looked at the changing distribution of tropical species driven by the warming climate.

Some species are appreciated in their new locations, such as sea turtles and the Florida manatee, which are gradually moving northward along the Atlantic Coast. Others, like the invasive Burmese python are not so welcome. That goes double for many insects, such as the mosquitoes that carry diseases like the West Nile virus, Zika, dengue, and yellow fever, as well as beetles that destroy native trees.

The transition zone, northward of which experiences freezes every winter, has always been a barrier to species native to more temperate places. For most organisms in such places, if they freeze, they die. Cold snaps like the recent one in Texas usually don’t happen for decades and are now likely to be less and less frequent. In the meantime, tropical species can get more and more of a foothold and maybe even develop populations that can tolerate more cold extremes in the future.

The warming climate is leading many plant species to expand their ranges, in some cases pushing out native species. The general story is that the species that do really well are the more generalist species whose host plants or food sources are quite varied or widely distributed and can tolerate a wide range of conditions. By definition, they tend to be the pest species.

We need to prepare for widespread shifts in the distribution of biodiversity as climate, including winter climate, changes.

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Tropical species are moving northward as winters warm

Photo, posted May 7, 2010, courtesy of Jim Reid / USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Microplastic Hotspots In The Ocean | Earth Wise

June 4, 2020 By EarthWise Leave a Comment

Many of us are aware of the infamous ocean “garbage patches” of floating plastic. The Great Pacific Garbage Patch is roughly the size of Texas. But over 10 million tons of plastic waste enter the oceans each year and the floating patches only account for 1% of that total. The remaining 99% of the plastic ends up in the deep ocean, generally in the form of microplastics – tiny fragments of large plastic debris that have broken down as well as manufactured polyethylene beads used in various products.

According to a new study published in the journal Science, there are actually microplastic hotspots on the ocean floor, formed by deep-sea currents that act as conveyer belts moving the tiny plastic fragments around. One of these hotspots – in the Tyrrhenian Sea off the west coast of Italy – contained 1.9 million microplastic pieces in just one square meter of seafloor. This is the highest reported value for any place in the world.

Because of their small size, microplastics can be ingested by organisms across all levels of the marine food chain and eventually find their way into human diets.

The spatial distribution and ultimate fate of ocean microplastics are strongly controlled by near-bed thermohaline currents. These are deep-ocean currents driven by differences in water density, which is controlled by temperature and salinity. Thermohaline currents are known to supply oxygen and nutrients to the flora and fauna found at the ocean bottom. As a result, deep sea biodiversity hotspots are likely to be in same places where there are microplastic hotspots.

The discovery of these deep- sea hotspots is just another reason why we need behavior and policy interventions to limit the flow of plastics into natural environments.

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Seafloor microplastic hotspots controlled by deep-sea circulation

Photo, posted September 6, 2012, courtesy of Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Dolphins

May 27, 2019 By EarthWise Leave a Comment

We don’t think of heatwaves as something that affects the ocean, but increasingly, as the planet warms, there have been instances where ocean water temperatures become much higher than normal for extended periods of time. There has been much discussion of this phenomenon with regard to coral reefs where the catastrophic rise in coral bleaching events has been the result.

Recently, a study at the University of Zurich looked at the effects of ocean heatwaves on marine life higher in the food chain. They studied the well-known dolphin population in Shark Bay, Western Australia.

In early 2011, a heatwave caused water temperatures in Shark Bay to rise more than 4 degrees above the annual average for an extended period. This led to a substantial loss of seagrass, which is a driving factor in the Shark Bay ecosystem.

The researchers investigated how this environmental damage affected survival and reproduction of dolphins, using long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017.

Their analysis showed that dolphins’ survival rate dropped by 12% and female dolphins were giving birth to fewer calves. That phenomenon that began in 2011 lasted at least until 2017.

The researchers were surprised by the extent and the duration of the influence of the heatwave, especially the fact that the reproductive rate of dolphins had not returned to normal even after 6 years.

This study shows for the first time that marine heatwaves not only affect organisms at the lower levels of the food chain, but also might have considerable long-term consequences for the animals at the top, such as dolphins.

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Climate change is a threat to dolphins’ survival

Photo, posted December 14, 2014, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Carbon And The Dark Ocean

January 4, 2018 By EarthWise Leave a Comment

Sunlight entering the water can travel as much as 3,000 feet into the ocean depths under the right conditions, but ordinarily there is no significant light that penetrates beyond about 650 feet down. That upper 650 feet is called the euphotic or “sunlight” zone and is home to most familiar marine life. The “dark ocean”, everything below that depth, makes up 90% of the ocean and remarkably little is known about it.