Hexbyte Glen Cove Study reveals more hostile conditions on Earth as life evolved 

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Graphic showing how UV radiation on Earth has changed over the last 2.4 billion years. Credit: Please credit: Gregory Cooke/ Royal Society Open Science

During long portions of the past 2.4 billion years, the Earth may have been more  inhospitable to life than scientists previously thought, according to new computer simulations.

Using a state-of-the-art climate model, researchers now believe the level of ultraviolet (UV) reaching the Earth’s surface could have been underestimated, with UV levels being up to ten times higher.

UV radiation is emitted by the sun and can damage and destroy biologically important molecules such as proteins.

The last 2.4 billion years represents an important chapter in the development of the biosphere. Oxygen levels rose from almost zero to significant amounts in the atmosphere, with concentrations fluctuating but eventually reaching modern day concentrations approximately 400 million years ago.

During this time, more complex multicellular organisms and animals began to colonize land.

Gregory Cooke, a Ph.D. researcher at the University of Leeds who led the study, said the findings raise new questions about the evolutionary impact of UV radiation as many forms of life are known to be negatively affected by intense doses of UV radiation.

He said: “We know that UV radiation can have disastrous effects if life is exposed to too much. For example, it can cause skin cancer in humans. Some organisms have effective defense mechanisms, and many can repair some of the damage UV radiation causes.

“Whilst elevated amounts of UV radiation would not prevent life’s emergence or evolution, it could have acted as a selection pressure, with organisms better able to cope with greater amounts of UV radiation receiving an advantage.”

The research “A revised lower estimate of ozone columns during Earth’s oxygenated history” is published today in the scientific journal Royal Society Open Science.

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Hexbyte Glen Cove California imposes water restrictions as drought drags on

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Water flows down a sidewalk from water sprinklers running at a home Thursday, April 2, 2015, in Rancho Cordova, Calif. The State Water Resources Control Board voted Tuesday, Jan. 4, 2022 to adopt mandatory water use restrictions that prohibit excessive runoff from sprinklers. Credit: AP Photo/Rich Pedroncelli, File

For the second time in a decade, Californians will face mandatory restrictions governing their outdoor water use as the state endures another drought and voluntary conservation efforts have fallen short.

The rules adopted Tuesday by the State Water Resources Control Board are fairly mild—no watering lawns for 48 hours after a rainstorm or letting sprinklers run onto the sidewalk— and could take effect as soon as the end of the month. Scofflaws could face $500 daily fines, though regulators say they expect such fines will be rare, as they were in the last drought.

The action comes as Californians have failed to meet Gov. Gavin Newsom’s call for a voluntary 15% reduction in water use compared to last year. Between July and November, the state’s water usage went down just 6%.

The new restrictions follow an extremely wet December that state officials warned may not continue during the winter months that normally are the state’s wettest. Weather patterns have become more unpredictable due to climate change and state climatologist Michael Anderson said forecasts show January, February and March could be drier than average.

Earlier forecasts didn’t predict such a wet December, which saw record amounts of rain and snow in many areas. In mid-December, about 80% of the state was in extreme or exceptional drought conditions. By the end of the month only about a third was experiencing those conditions, according to the U.S. Drought Monitor that tabulates conditions. Meanwhile, the state Department of Water Resources announced Tuesday that recent storms will allow the resumption of hydropower generation at the Oroville Dam, which was halted in early August due to historically low lake levels.

Despite the rain, significant parts of the state’s water system are still under stress from the extremely dry conditions earlier in 2021 that dropped many of California’s largest reservoirs to record and near-record lows.

“Conserving water and reducing water waste are critical and necessary habits for everyone to adopt as we adjust to these uncertainties and we build resilience to climate change, so adopting emergency regulations now just makes sense,” said Eric Oppenheimer, chief deputy director for the state water board. “We need to be prepared for continued drought.”

Northern California was wetter than Southern California in November and conserved significantly more water.

Anthony Burdock, left, and Sean de Guzman, chief of snow surveys for the California Department of Water Resources, check the depth of the snow pack during the first snow survey of the season at Phillips Station near Echo Summit, Calif., Thursday, Dec. 30, 2021. Despite a wet December The State Water Resources Control Board adopted mandatory water restrictions on Tuesday, Jan. 4, 2022 designed to spur more conservation. Credit: AP Photo/Randall Benton,File

Regions north of the San Joaquin River, including Sacramento and San Francisco, used between 17% and 26% less water than November 2020, while Los Angeles, Orange and San Diego counties that account for 55% of the state’s population used nearly 1% more, according to state data.

Among the water uses that won’t be allowed under the new rules: outdoor watering that results in excessive runoff into the street and sidewalks; using water for landscaping and irrigation during the 48 hours after storms that bring at least .25 inches (.63 centimeters) of rain; washing cars with hoses lacking shut-off nozzles; using potable water to wash driveways, sidewalks, buildings and patios and for street cleaning or to fill decorative fountains or lakes.

There are some exceptions. For example, trees in street medians can be watered, while turf cannot. The rules take effect once an administrative review is completed.

Though much of the U.S. West is in drought, no other western state has adopted statewide restrictions on residential water usage. Instead, it’s local governments and water agencies in places like Denver and Las Vegas setting policies about when people can water their lawns. For example, the Las Vegas region adopted restrictions on planting grass, including banning it in front yards, in an effort to save water.

California adopted similar restrictions during the five-year drought that ended in 2017, and some cities and local water districts made them permanent. Such restrictions were just one piece of the state’s conservation approach, which also included incentives for Californians to rip up water-hungry lawns in favor of drought-resistant landscaping.

Today, California’s overall water use is lower than it was when the last drought began. But that makes conservation trickier this time, because some of the easiest measures have already been adopted. State water board officials were unable to say how many of California’s nearly 40 million people are under such rules or exactly how much water they expect to save.

Though the regulations include an ability to fine violators up to $500 per day, fines were rare last time around. The state has no plans to put “water cops” on the streets, Oppenheimer said, but he noted that during the last drought many local water districts beefed up staff to monitor conservation and compliance.

The state also has a website where individuals can report their neighbors or others they see violating the rules. The complaints will be directed to the relevant local water agency. During California’s last drought, people engaged in so-called ” drought shaming “, the process of publicly outing people who are wasting water by posting videos to social media.



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California adopts water restrictions as drought drags on (2022, January 4)
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Hexbyte Glen Cove Exploring growth within a confined space

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Credit: Pixabay/CC0 Public Domain

Grow a tomato inside a square box, and you’ll end up with a square tomato. It’s an experiment that shows clearly how confinement can influence a body’s evolving shape.

Now, MIT and Yale University researchers have developed a theoretical framework to explain the mechanics of how growing bodies respond to confinement. To test their theory, a research team led by Tal Cohen, MIT associate professor of civil and environmental engineering and of mechanical engineering, grew cholera bacteria inside a soft gel, observing the architecture of the expanding bacterial at single-cell resolution as they grew 10,000 times larger.

Following the theory, the biofilms adopt paths that optimize their shape in response to and to damage in the surrounding gel as it deforms to contain the biofilm, according to the study published in the Journal of the Mechanics and Physics of Solids.

The study of inclusion problems was revolutionized in the 1950s by British scientist John Eshelby, but the work by Cohen and colleagues is a significant step forward, says Pradeep Sharma, the M.D. Anderson Chair Professor of Mechanical Engineering at the University of Houston.

“One of the key limitations of Eshelby’s work is that it is restricted to materials that deform only slightly. However, we routinely encounter contexts where the deformations are hardly ‘slight,'” explains Sharma, who was not part of the MIT-Yale study. “Cohen and co-workers have ingeniously solved the Eshelby’s inclusion problem for large deformations. Inclusion problems in soft matter like gels, elastomers used in soft robotics, biological membranes, how cells interact in tissues are now accessible thanks to Cohen’s paper.”

Researchers would like to learn more about how biofilms grow, since they can contribute to antibiotic resistance and mechanical fouling of boats and water filtration systems. But the findings by Cohen and colleagues also apply to a variety of confined growth scenarios, from a precipitate forming inside a metallic alloy to a tumor growing in the lung.

Smooshed spheres

Scientists have studied the interplay between growth and environmental stress for confined bodies or inclusions for 70 years. These studies use a linear framework to understand the relationship—the more force the growing body placed on its confining boundaries, the more displacement those boundaries experienced.

But the behavior of materials in the real world is much more complicated, Cohen explains. Pushed by a growing body, the confining boundaries might resist displacement, or might break down. The relationship is always evolving as the changing shape of the inclusion interacts with the changing responses of its enclosing material. Cohen’s lab specializes in studying these nonlinear effects in solid materials. The nonlinear inclusion theory developed by the researchers predicted significant differences in inclusion shapes depending on their growing environments. In the case of the biofilms, formed an oblate or “smooshed” sphere instead of a regular sphere when the surrounding material was stiffer.

The biofilm experimental system was important for refining their theory, says Cohen. “Actually observing these enormous deformations happening internally in a material in a very controlled way would have been very hard without it.”

The experiments and theory are a starting point, Cohen adds. For instance, the researchers are also curious about how their theory could account for the way nutrients diffuse in a growing system, and whether “that could explain to us even better the coupling between the and the growth itself,” she says.

Understanding how inclusions grow—and maybe how and why they stop growing, or how they cause damage in their surrounding body—could be important for addressing tumor growth, she suggests. The theory could also be applied to metal processing, to better control the growth and stresses created by a precipitate in metal to create alloys with different features.

Different approach to growth

The extreme example of a bacterial biofilm growing 10,000 times bigger is at the heart of what Cohen’s lab works on. She and her students are interested in what happens to materials when they are pushed to their limits. The push could come from extreme loading, or a shock wave, or the stresses related to growth.

Cohen says her lab looks at growth in a different way than most, however. Most people start with an observation. They see a tree, for example, they hypothesize about how it grows, and then create a theory that reproduces the observation.

Cohen and her colleagues instead begin by examining the basics of growth itself. “We dissect a system and try to understand it microscopically,” she says, “and ask, ‘What are the basic mechanisms that are generating growth here?’ And hopefully we can find the physical principles that induce different morphologies.”

The researchers then ask what a system with these principles could grow into. This open-ended approach, Cohen says, makes their theories useful across a variety of problems in biology and physical systems.

This work required a team effort to combine advanced analytical, computational, and experimental tools. The lead authors, Jian Li and Mrityunjay Kothari, both MIT postdocs, spearheaded the computational and analytical efforts, respectively. MIT Ph.D. students Chockalingam Senthilnathan, Thomas Henzel, and Xuanhe Li contributed to the theoretical effort. The experiments were conducted by Qiuting Zhang, a postdoc at Yale University in the group of Assistant Professor Jing Yan.



More information:
Jian Li et al, Nonlinear inclusion theory with application to the growth and morphogenesis of a confined body, Journal of the Mechanics and Physics of Solids (2021). DOI: 10.1016/j.jmps.2021.104709

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Hexbyte Glen Cove Study finds fertilization affects soil microbial biomass and residue distribution by changing root biomass

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Structural equation model for controls of aggregate-associated fungal residues and their distribution. Credit: Jing Yanli

Increasing nitrogen (N) and phosphorus (P) input is one of the major contributors to anthropogenic climate change, which can regulate the sequestration and storage of soil organic carbon (SOC) by changing microbial communities and their residues, the significant component of stable SOC. However, it remains unclear how N and P fertilization influence aggregate-associated microbial communities and their residues in P-deficient soils. Answering this question is of great significance to reaching a better understanding of soil carbon cycles under carbon neutrality.

A research team led by Wang Qingkui from the Institute of Applied Ecology of the Chinese Academy of Sciences recently conducted a six-year fertilization manipulation experiment to explore the impacts of N and P fertilization on soil and their residues at aggregate scales in subtropical P-deficient plantation soil.

They found that N and/or P fertilization significantly decreased the soil microbial of bulk soils due to a decrease in bacterial biomass in small macroaggregates and microaggregates, and fungi in large macroaggregates. However, there was no significant difference among these fertilization treatments, indicating a non-additive interaction of N and P fertilization.

N/P fertilization redistributed microbial residues from large to small macroaggregates by stimulating fungal residues in small macroaggregates.

Moreover, decrease in root biomass, rather than soil pH, was responsible for the reduction in soil microbial biomass and changes in microbial residue distribution.

These findings highlight that the interactive effect of N and P fertilization and aggregate sizes should be considered to help improve the prediction of carbon dynamics under fertilization.

This study was published in European Journal of Soil Biology and was supported by the National Natural Science Foundation of China and the Key projects of Jiangxi Science and Technology Program.



More information:
Yanli Jing et al, Non-additive effects of nitrogen and phosphorus fertilization on microbial biomass and residue distribution in a subtropical plantation, European Journal of Soil Biology (2021). DOI: 10.1016/j.ejsobi.2021.103376

Citation:
Study finds fertilization affects soil microbial biomass and residue distribution by changing root biomass (2022, January 4)
retrieved 5 January 2022
from https://phys.org/news/2022-01-fertilization-affects-soil-microbial-biomass.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 p

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