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Study sheds light on limitations of zooplankton for inactivating pathogen contaminated water

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Study sheds light on limitations of zooplankton for inactivating pathogen contaminated water


UTEP study: Zooplankton go "Eew!" to cleaning feces contaminated water
Scientists were recently surprised to find that the natural community of zooplankton — tiny, aquatic animals known to graze on bacteria — present in freshwater and saltwater do not clean water that is contaminated with fecal microorganisms. Pictured: One of the zooplankton found in the water samples is the adult copepod, a miniature crustacean that is about the size of the period at the end of this sentence. Credit: Lauren Kennedy / UTEP

Scientists at The University of Texas at El Paso and Stanford University were recently surprised to find that the natural community of zooplankton—tiny, aquatic animals known to graze on bacteria—present in freshwater and saltwater do not clean water that is contaminated with fecal microorganisms.

The research, published in the biology journal mSphere, reveals important insights about the limitations of zooplankton in treating bodies of water that have been contaminated with fecal organisms, the team said.

A 2017 U.S. water quality inventory revealed that over 50% of rivers, bays and estuaries were unsafe for at least one use, in many cases because of fecal contamination.

“When sewage is released into clean bodies of water and humans are exposed to it, it can lead to illness in humans,” said Lauren Kennedy, Ph.D., assistant professor of civil engineering at UTEP, who is the corresponding author on the study.

“Our research seeks to understand what factors can render pathogens unable to infect people. In other words, how long does it take for the water to become safe for recreation again without any forms of outside intervention?”

Kennedy explained that water from sewage and septic tanks can accidentally enter bodies of freshwater as a result of accidents, inadequate water treatment or corroded infrastructure.

The authors hypothesized that zooplankton naturally present in water might graze on microorganisms from fecal contamination, inactivating the organisms and effectively “cleaning” the water.

To test this idea, the team added a virus called MS2 and the bacteria E.coli to samples of freshwater and saltwater taken from the San Francisco Bay area of California.

MS2 and E.coli are considered useful proxies for scientific research, Kennedy said, because they are present at high concentrations in sewage and their presence often indicates fecal contamination in the environment. The water samples naturally contained both “large” particles like zooplankton, sand and dirt, and “small” or dissolved particles like salt.

They found that the large particles, including zooplankton, did not have a significant effect on the inactivation of the pathogen proxies. The small particles, however, seemed to have a greater impact. The pathogen proxies were inactivated at higher rates in high-salinity water, for example, ocean water taken from San Pedro Beach.

“I am proud that we were able to provide another perspective to consider for surface water remediation efforts,” Kennedy said.

The research, she added, is an important step forward in understanding the limits of zooplankton as natural “cleaners” of contaminated water. The next phase of the research will focus on the impact of salinity on pathogen survival in contaminated waters.

“I am proud to see this important work coming from our team,” said Carlos Ferregut, Ph.D., chair of the Department of Civil Engineering. “The research by Dr. Kennedy and her team provides valuable insights into the challenges of pathogen inactivation, especially in areas where wastewater can compromise human health.”

More information:
You can bring plankton to fecal indicator organisms, but you cannot make the plankton graze: particle contribution to E. coli and MS2 inactivation in surface waters, mSphere (2024). DOI: 10.1128/msphere.00656-24. journals.asm.org/doi/10.1128/msphere.00656-24

Citation:
Study sheds light on limitations of zooplankton for inactivating pathogen contaminated water (2024, October 3)
retrieved 3 October 2024
from https://phys.org/news/2024-10-limitations-zooplankton-inactivating-pathogen-contaminated.html

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FTC antitrust lawsuit against Amazon will proceed, some claims dropped

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FTC antitrust lawsuit against Amazon will proceed, some claims dropped


amazon
Credit: Unsplash/CC0 Public Domain

The Federal Trade Commission’s antitrust lawsuit against Amazon will proceed, though some claims have been dropped, following a ruling from a federal district judge.

Judge John Chun, from the U.S. District Court in the western district of Washington, partially granted and partially denied Amazon’s motion to dismiss the lawsuit entirely, according to a summary of the filing.

The order is under seal so it’s unclear which parts of the lawsuit will proceed. The FTC has until the end of the month to file a second amended complaint regarding any claims Judge Chun dismissed without prejudice, meaning the claims could resurface.

The FTC and 17 state attorneys general sued Amazon in September 2023, arguing the company unfairly used its position as an ecommerce superstore and fulfillment network provider to keep its rivals from gaining a foothold.

In the sprawling lawsuit, the FTC accused Amazon of promoting its own brands over competitors, preventing third-party sellers from setting discounted prices and forcing merchants to pay steep fees to Amazon itself. For consumers, that meant higher prices, fewer options and a degraded shopping experience, the FTC alleged.

Amazon has denied the allegations, maintaining that the business practices under scrutiny are common across the retail industry and have helped to lower prices for consumers. In a motion asking Chun to dismiss the case in December, Amazon described the lawsuit as an “attack” and an “effort to hobble one of America’s most consumer-focused businesses.”

2024 The Seattle Times. Distributed by Tribune Content Agency, LLC.

Citation:
FTC antitrust lawsuit against Amazon will proceed, some claims dropped (2024, October 3)
retrieved 3 October 2024
from https://techxplore.com/news/2024-10-ftc-antitrust-lawsuit-amazon-proceed.html

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Geological surveys shed light on the formation mystery of Uruguay’s amethyst geodes

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Geological surveys shed light on the formation mystery of Uruguay’s amethyst geodes


Mystery of Uruguay's amethyst geodes
Göttingen University researchers in front of a giant amethyst geode in Uruguay. Geodes like this have been found in cooled lava flows dating from the original breakup of the supercontinent Gondwana around 134 million years ago. Left to right: Dr. Klaus Wemmer, Fiorella Arduin Rode, Dr. Graciela Sosa, Dr. Alfons van den Kerkhof. Credit: Fiorella Arduin Rode

Amethyst is a violet variety of quartz that has been used as a gemstone for many centuries and is a key economic resource in northern Uruguay. Geodes are hollow rock formations often with quartz crystals, such as amethyst, inside.

Amethyst geodes in Uruguay have been found in cooled lava flows, which date from the original breakup of the supercontinent Gondwana around 134 million years ago. However, their formation has remained a mystery. A research team led by the University of Göttingen has now investigated, using cutting-edge techniques. The researchers discovered that the amethyst geodes formed at unexpectedly low crystallization temperatures of just 15 to 60 °C.

Taken with their other results, researchers were able to propose a new model to explain their formation. The research is published in the journal Mineralium Deposita.

Amethyst has been mined for over 150 years in the Los Catalanes District of Uruguay, where the research was carried out. This is an area renowned for the deep violet color and high quality of its gems, as well as magnificent giant geodes sometimes over 5 m high. The deposits here have been recognized as one of the top 100 geological heritage sites in the world, highlighting their scientific and natural value.

Mystery of Uruguay's amethyst geodes
Göttingen University researcher Fiorella Arduin Rode working in open pit mine of the study area, Los Catalanes mining district, northern Uruguay. Along with Ametista do Sul in southern Brazil, these regions are the world’s leading mining districts for gems which come from volcanic lava, such as amethyst and agate geodes. Credit: Santiago Guerrero Cherma

However, limited knowledge of how these geodes formed has made locating them challenging, relying largely on miners’ experience. To address this, researchers conducted extensive geological surveys across more than 30 active mines, analyzing geode minerals, geode-hosted water, and groundwater. Using advanced techniques like nucleation-assisted microthermometry of initial one-phase fluid inclusion and triple-oxygen-isotope geochemistry, the team uncovered new insights into how these prized geodes formed.

As well as finding that the amethyst geodes formed at unexpectedly low crystallization temperatures, the researchers also showed that the mineralizing fluids had low levels of salinity and a proportion of isotopes consistent with water originating from the natural weather cycle, which probably came from groundwater held in nearby rocks.

“The precision and accuracy of these new techniques, allowed us to estimate with confidence the temperature and composition of the mineralizing fluids,” said Fiorella Arduin Rode, lead author and Ph.D. researcher at Göttingen University’s Geoscience Centre. “Our findings support the idea that these amethysts crystallized at low temperatures from groundwater-like fluids.”

Mystery of Uruguay's amethyst geodes
Amethyst-calcite geode from Los Catalanes already processed in the workshop and ready to sell. Credit: Fiorella Arduin Rode

The study proposes a model where mineral phases like amethyst crystallize within volcanic cavities in a dark rock known as basalt, influenced by regional variations in temperature in the Earth’s crust.

Arduin Rode adds, “Understanding the conditions for amethyst formation—such as the temperature and composition of the mineralizing fluid, as well as the silica source, the timing of the mineralization, and its relationship with the host rocks—is crucial for unraveling the process. This could significantly improve exploration techniques and lead to sustainable mining strategies in the future.”

More information:
Fiorella Arduin-Rode et al, World-class amethyst-agate geodes from Los Catalanes, Northern Uruguay: genetic implications from fluid inclusions and stable isotopes, Mineralium Deposita (2024). DOI: 10.1007/s00126-024-01310-2

Citation:
Geological surveys shed light on the formation mystery of Uruguay’s amethyst geodes (2024, October 3)
retrieved 3 October 2024
from https://phys.org/news/2024-10-geological-surveys-formation-mystery-uruguay.html

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part may be reproduced without the written permission. The content is provided for information purposes only.





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Decades-long research reveals new understanding of how climate change may impact caches of Arctic soil carbon

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Decades-long research reveals new understanding of how climate change may impact caches of Arctic soil carbon


Arctic
Credit: Unsplash/CC0 Public Domain

Utilizing one of the longest-running ecosystem experiments in the Arctic, a Colorado State University-led team of researchers has developed a better understanding of the interplay among plants, microbes and soil nutrients—findings that offer new insight into how critical carbon deposits may be released from thawing Arctic permafrost.

Estimates suggest that Arctic soils contain nearly twice the amount of carbon that is currently in the atmosphere. As climate change has caused portions of Earth’s northernmost polar regions to thaw, scientists have long been concerned about significant amounts of carbon being released in the form of greenhouse gases, a process fueled by microbes.

Much of the efforts to study and model this scenario have focused specifically on how rising global temperatures will disrupt the carbon currently locked in Arctic soils. But warming is impacting the region in other ways, too, including changing plant productivity, the overall composition of vegetation across the landscape, and the balance of nutrients in the soil. These changes in plant composition will also affect the way carbon is cycled from the soil into the atmosphere, according to a study published this week in the journal Nature Climate Change.

The work was led by Megan Machmuller, a research scientist in CSU’s Soil and Crop Sciences Department.

“Our work focused on pinpointing the mechanisms that are responsible for controlling the fate of carbon in the Arctic,” Machmuller said. “We know temperature plays a large role, but there are also ecosystem shifts that are co-occurring with climate change in this region.”

In particular, Machmuller said, the region is experiencing a kind of “shrub-ification”—an increase in shrub abundance and growth. And what Machmuller and her co-authors found is that over long periods those shrubs may contribute to keeping more carbon in the ground.

“There’s been a lot of focus on the direct effects of warming on soil carbon,” said co-author Laurel Lynch, assistant professor at the University of Idaho, “but what we’re finding with this work is that it’s more complex. We need to think about this ecosystem as a whole community with many interacting parts and competing mechanisms.”

A surprising finding

For the new work, Machmuller and team tested soil samples from a 35-year ecosystem experiment in the Arctic. In 1981, scientists began adding nutrients to test plots at the Arctic Long-Term Ecological Research site in northern Alaska, situated near Toolik Lake at the base of the Brooks Mountain Range. The original idea was to understand how Arctic vegetation would respond to additional nutrients over time, but the experiment has also allowed scientists to examine how long-term changes to the soil can impact carbon storage.

After 20 years, scientists found that there had been a significant loss of soil carbon when nutrients were added compared to the control plots, an important finding that shaped broad scientific understanding of how the Arctic might respond to climate change. Those experiments continued, and Machmuller and her team tested the plots again after 35 years of continuous nutrient application.

Instead of continued carbon loss, however, they found that the trend had reversed. After 35 years, the amount of carbon stored in the test plots had either recovered or exceeded the amount in the nearby control plots.

“We were really surprised by these results and became curious about the underlying mechanism,” Machmuller said.

Machmuller and her team ran advanced isotope tracing experiments in the lab to learn more about how carbon was moving through the system. What they found was that when the nutrients were first added, they stimulated microbial decomposition—a natural process that involves microbes churning through organic matter in the soil that results in the release of carbon dioxide.

But that changed over time, as nutrients were continuously added to the test plots. “Shrubs conditioned the soil in a way that shifted microbial metabolism, slowing rates of decomposition and allowing soil carbon stocks to rebuild,” Lynch said. “We didn’t expect that.”

“This offers a potential biological mechanism that might explain why we observed a net loss of carbon in the first 20 years but not after 35,” Machmuller said.

The importance of looking long-term

These results, Machmuller said, demonstrate that how the Arctic might respond to climate change is more complicated than previously thought. “It’s a complex puzzle,” she said, “and this study has emphasized for us the importance of using long-term studies to advance our understanding of ecosystem processes.”

Gus Shaver, a research scientist who helped set up the initial Toolik Lake experimental plots in 1981 and is a co-author on the study, also stressed the value of doing this kind of work over longer periods of time.

“We’ve shown that long-term experiments offer frequent surprises as we follow the trajectory of their responses over time,” Shaver said. “What you find in the first few years of an experiment is often not what you learn from the 10th or 15th or 35th year.”

Lynch noted that as this ecosystem changes, there are other factors to consider beyond just carbon. Although an increase in shrub abundance could keep more soil carbon from transferring into the atmosphere, other impacts are not as beneficial, she said.

“When you have one plant species that is massively outcompeting the rest of the community, there are major ecosystem implications,” Lynch said. For example, she said, “habitat and food sources for many animals in the Arctic depend on diverse plant communities, and the loss of this diversity can ripple through the entire ecosystem.”

Lauren Gifford, associate director of CSU’s Soil Carbon Solutions Center, who was not involved with the study, said the work highlights the need for more robust and detailed modeling to better anticipate how climate change will impact the carbon stored in the Arctic.

“This is a remarkable 35-year study of one of Earth’s most vulnerable ecosystems,” Gifford said. “Even with comprehensive long-term studies, the impacts of climate change often remain uncertain. Interventions to help adapt to and mitigate climate change may lead to outcomes that are analogous, contradictory, or produce unintended consequences.”

For her part, Machmuller hopes the work will encourage future research on this topic. “Carbon research in the Arctic has been a hot topic for a long time because of the critical role it plays in regulating our global climate,” she said. “But we still don’t have a handle on what exactly the future carbon balance will look like.”

More information:
Arctic soil carbon trajectories shaped by plant–microbe interactions, Nature Climate Change (2024). DOI: 10.1038/s41558-024-02147-3

Citation:
Decades-long research reveals new understanding of how climate change may impact caches of Arctic soil carbon (2024, October 3)
retrieved 3 October 2024
from https://phys.org/news/2024-10-decades-reveals-climate-impact-caches.html

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part may be reproduced without the written permission. The content is provided for information purposes only.





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Study reveals oyster reefs once thrived along Europe’s coasts—now they’re gone

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Study reveals oyster reefs once thrived along Europe’s coasts—now they’re gone


Oyster reefs once thrived along Europe's coasts – now they're gone
European flat oysters. Credit: Stephane Pouvreau / Ifremer

Oysters once formed extensive reefs along much of Europe’s coastline—but these complex ecosystems were destroyed over a century ago, new research shows. The paper, published in the journal Nature Sustainability, is titled “Records reveal the vast historical extent of European oyster reef ecosystems.”

Based on documents from the 18th and 19th centuries, the study reveals that European flat oysters formed large reefs of both living and dead shells, providing a habitat supporting rich biodiversity.

Today these oysters are mostly found as scattered individuals—but the researchers found evidence of reefs almost everywhere, from Norway to the Mediterranean, covering at least 1.7 million hectares, an area larger than Northern Ireland.

The research was led by the University of Exeter and The University of Edinburgh.

Native oyster reefs created their own ecosystems, full of a diverse range of underwater life—supporting a greater number of species than surrounding areas.

In addition to creating homes for the almost 200 recorded fish and crustacean species, the oysters also played a vital role in stabilizing shorelines, nutrient cycling and water filtration—with a single adult oyster filtering up to 200 liters of water a day.

Restoration projects are under way across Europe—and small-scale habitat restoration, such as The Wild Oyster Project, led by ZSL and partners, are key stepping stones to the return of these vital ecosystems on an international scale.

However, restoration efforts need to be scaled up with support from governments and other decision makers across the continent.

Oyster reefs once thrived along Europe's coasts – now they're gone
Oyster reefs have largely disappeared, but clumps of oysters can still be found. Credit: Stephane Pouvreau / Ifremer

“Human activities have affected the ocean for centuries,” said Dr. Ruth Thurstan, from the University of Exeter and part of the Convex Seascape Survey, an ambitious five-year project examining ocean carbon storage.

“This makes it difficult to discover what our marine ecosystems used to look like, which in turn hampers conservation and recovery.

“Few people in the UK today will have seen a flat oyster, which is our native species. Oysters still exist in these waters but they’re scattered, and the reefs they built are gone.

“We tend to think of our seafloor as a flat, muddy expanse, but in the past many locations were a three-dimensional landscape of complex living reefs—now completely lost from our collective memory.”

Due to their economic and cultural significance, oysters feature in historical records including newspapers, books, travel writing, landing records, nautical charts, early scientific investigations and interviews with fishermen.

“By combining descriptive accounts from a range of historical sources, we can build a picture of our past seas,” said Dr. Thurstan, who is mapping past ocean changes as part of the Convex Seascape Survey.

“The greatest concentration of oyster reefs we found was in the North Sea.”

Records show extensive reefs existed along the coasts of modern France, Denmark, Germany, the Netherlands, the Republic of Ireland and the UK.

Oyster reefs once thrived along Europe's coasts – now they're gone
Whitstable, Kent 1) Boats Going Out 2) Dredge 3) Oyster Bags 4) Dredging 5) Landing Oysters. Credit: Illustrated London News Ltd / Mary Evans

“Oyster reefs are slow to develop, with layers of new oysters building up on the dead shells of their predecessors, but their destruction through overfishing was relatively rapid,” said Dr. Philine zu Ermgassen, honorary researcher at the University of Edinburgh.

“This has caused a fundamental restructuring and ‘flattening’ of our seafloors—removing thriving ecosystems and leaving an expanse of soft sediment behind.

“Thanks to this historical ecology research, we are now able to quantitatively describe what oyster reefs looked like before they were impacted, and the spatial extent of the ecosystems they formed.

“These were huge areas that were thickly crusted with oysters and crawling with other marine life.”

The research team was made up of more than 30 European researchers from the Native Oyster Restoration Alliance.

More information:
Records reveal the vast historical extent of European oyster reef ecosystems, Nature Sustainability (2024). DOI: 10.1038/s41893-024-01441-4

Citation:
Study reveals oyster reefs once thrived along Europe’s coasts—now they’re gone (2024, October 3)
retrieved 3 October 2024
from https://phys.org/news/2024-10-reveals-oyster-reefs-europe-coasts.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.





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