Metal pollution in British waters may be threatening scallops, study reveals

Metal pollution from historic mining appears to be weakening scallop shells and threatening marine ecosystems in an area off the coast of the Isle of Man, a major new study suggests.

UNIVERSITY OF YORK

Research News

 

IMAGE: A DAMAGED SCALLOP view more 

CREDIT: DR BRYCE STEWART, UNIVERSITY OF YORK.

Metal pollution from historic mining appears to be weakening scallop shells and threatening marine ecosystems in an area off the coast of the Isle of Man, a major new study suggests.

The research, led by an interdisciplinary team at the University of York, suggests that the contamination of seabed sediments with zinc, lead and copper from the mining of these metals, which peaked on the island in the late 19th century, is causing the shells of king scallops to become significantly more brittle.

The thinning and weakening of shells threatens the species by leaving them more exposed to the crushing claws of crabs and lobsters, and, in turn, threatens the marine ecosystem because of the important functions, such as water filtration, that molluscs like scallops carry out.

Given that metal contamination is common in many coastal areas around the world, the researchers are concerned that other species of marine mollusc like mussels, oysters and clams, which together provide more than a quarter of the world's seafood, may be similarly affected.

The current consensus on acceptable levels of metal pollution should be revised, the researchers say, as evidence of damage to scallop shells was present even in areas with metal contamination levels currently not thought to cause significant damage to the marine environment.

Lead author of the study, Dr Bryce Stewart from the Department of Environment and Geography at the University of York, said: "The fact that comparably low levels of heavy metal contaminations appear to affect shell structure and strength in such a potent way represents a challenge to marine species management and conservation strategies. This is particularly true given that the effects we observed are likely to be amplified in the future by ongoing human activities and climate change.

"The potential long-term impact of anthropogenic metal pollution on marine organisms, as shown in our work, is remarkable since the last major mine on the Isle of Man closed in 1908."

Over a period of over 13 years, the researchers compared scallops collected from six areas of the Irish Sea around the Isle of Man. Most scallops exhibited perfectly normal shell growth and strength. However, in one area off Laxey - known to be contaminated with metal pollution, the shells were significantly weaker.

Structural analysis of shells by physicists at the University of York revealed that Laxey scallops had significantly weaker shells and a disrupted shell structure. Lethal damage rates in scallop catches from Laxey were twice as high as those at uncontaminated areas.

Joint corresponding author Professor Roland Kröger, from the Department of Physics at the University of York, said: "We analysed the shell structure of the scallops with cutting-edge microscopy techniques and discovered that shells from Laxey were thinner and exhibited a pronounced mineralisation disruption parallel to the shell surface within the central region of both the top and bottom valves.

"Our data suggest that these disruptions caused reduced fracture strength and therefore could increase mortality.

"It is not clear exactly how metal bearing sediments may be affecting the shell formation process. Metals could be incorporated into shells replacing calcium during the biomineralization process or they may modify the activity of proteins during the crystallisation process and disrupt shell growth."

The researchers looked at a wide range of alternative explanations for the impact on scallop shells but found no other environmental factors that could explain their results.

Dr Stewart added: "While the scallops are still perfectly safe to eat, we believe our results provide a compelling case that metal contamination is playing an important role in the development of thinner and weaker shells at Laxey, and therefore the observed high damage rates.

"The shell characteristics of bivalve molluscs such as clams, oysters, mussels and scallops could potentially function as a good bellwether for the scientific community in assessments of how pollutants are affecting biological organisms."

###

Metal pollution as a potential threat to shell strength and survival in marine bivalves is published in the journal Science of the Total Environment.

The research was carried out in collaboration with: Bangor University, the Department of Environment, Food and Agriculture, Isle of Man and the University of Liverpool. The project was funded by the European Union, the Isle of Man Government, a Nuffield Vacation Research Bursary and the UK Engineering and Physical Sciences Research Council (EPSRC).

 

How parental involvement affects children's performance in school

For scholastic success, support is better than control

NATIONAL RESEARCH UNIVERSITY HIGHER SCHOOL OF ECONOMICS

Research News

 

IMAGE: THE INFLUENCE OF FORMAL AND INFORMAL EDUCATIONAL INSTITUTIONS AND THEIR CONNECTING LINK - PI - IS SHOWN SCHEMATICALLY. view more 

CREDIT: ILYAPRAKHOV ET. AL.

Family Success

Using data from the HSE University longitudinal study Trajectories in Education and Careers (TrEC), Ilya Prakhov https://www.hse.ru/en/staff/prakhov, Olga Kotomina and Alexandra Sazhina determined which forms of family engagement in the school are useful and which are harmful to the student.

This study makes it possible to monitor students' entire educational path (for example, their complete secondary education plus university, or their first nine grades plus a college or technical school). The students surveyed for this study were in the ninth grade in 2012 and by 2015 were in universities and colleges or on the labour market. The TrEC contains data on the students' academic performance and their parents' SES (with cultural capital traditionally measured by the number of books in the family's home library).

In this study, the dependent variables were students' educational achievements, measured primarily as scores on the BSE and U.S.E., and their educational trajectories, while the constants were the different forms of parental engagement in their children's education (controlling for students' gender and the characteristics of their family and school).

The researchers identified four main factors that describe patterns of parental engagement. The first is parental control, such as checking that homework is completed and calling teachers about grades. The second factor is total engagement (the full spectrum of parental activity, from ensuring that homework is completed and hiring tutors to participating in school board meetings). The third factor is when parents are reasonably engaged by, for example, giving their children additional literature and attending parent-teacher meetings. The fourth factor is organizational: family members join the parents' committee and organize extracurricular events.

It turned out that when parents take an active part in school meetings, hire tutors and provide auxiliary literature to their children, the students score higher on the BSE and U.S.E. These forms of assistance increase the likelihood that children will finish out their high school education and go on to university. Membership in the parents' committee, however, has no effect.

As Ilya Prakhov explains, participation in such activities as school meetings lowers the risk of receiving inaccurate information. 'Being properly informed is an important element in choosing an educational trajectory and succeeding in it,' the researcher said. 'At parent-teacher meetings for upperclassmen, parents can receive information on the correct approach for taking the U.S.E., whether additional exam prep classes are available, possible cooperation between the school and universities, and Academic Olympics competitions.'

However, recruiting tutors and supplying additional literature does not help in every school subject. It has a positive correlation with U.S.E. results in Russian, but the connection for math is not as clear. Here, the type of school plays a significant role, with formal education trumping the role of tutoring.

Excessive Control

The new study shows that a family can also be overly engaged. The child needs 'a certain degree of independence in decision-making. This will favourably affect the incentives to study at school and choose a future path,' Mr Prakhov said.

A measured amount of family engagement -- as well as helping with, but not strictly controlling homework -- also has a positive correlation to students' educational success and whether they go on to study at university. On the other hand, the habit that, 'helicopter parents' have of 'hovering' over their children to check on homework and grades is definitely harmful and leads to lower U.S.E. scores. Excessive parental control has a particularly harmful influence on exam scores for ninth graders.

'Here, we are probably seeing the opposite effect: the child is studying poorly and so the parents are forced to take matters in hand,' the researcher said. 'However, exercising total control over a high school student's homework can cause them to protest or rebel, decreasing the motivation to improve academic performance. This can adversely affect U.S.E. results and, as a result, limit the choice of universities that will admit the student.'

Meanwhile, parental engagement depends on the type of family -- its educational level, income and cultural interests. As mentioned above, in families with a high SES, parents devote greater attention to their child's studies, but their engagement is more likely to be reasonable and measured. The type of high school also has a bearing on U.S.E. results, with those offering advanced courses and schools of higher status being the most effective.

Delayed Effect

The study also found that girls score higher on the BSE than boys do and family characteristics have a positive correlation to ninth-graders' final grades. At the same time, the type of school has little influence at this stage. In other words, the family -- in terms of both its characteristics and its level of engagement in the child's studies -- plays the greatest role in middle schoolers' academic performance.

It was also found that attending parent-teacher meetings, hiring tutors and supplying additional literature helps students entering high school grades 10 and 11. However, researchers also noted that a stable progression from the ninth to the eleventh grades was the most important factor behind the strong Russian and math scores on the U.S.E. that are so crucial to university admissions.

Thus, family support at the earlier stages of education can influence academic success in the final year of study, even if the nature of this influence has changed. In other words, a family's investment of time, effort and money in the child's education has a long-term positive effect.

###

 

New technology allows cameras to capture colors invisible to the human eye

Tel Aviv University breakthrough has applications in cancer detection, security and even gaming

AMERICAN FRIENDS OF TEL AVIV UNIVERSITY

Research News

 

New research from Tel Aviv University will allow cameras to recognize colors that the human eye and even ordinary cameras are unable to perceive.

The technology makes it possible to image gases and substances such as hydrogen, carbon and sodium, each of which has a unique color in the infrared spectrum, as well as biological compounds that are found in nature but are "invisible" to the naked eye or ordinary cameras. It has groundbreaking applications in a variety of fields from computer gaming and photography as well as the disciplines of security, medicine and astronomy.

The research was conducted by Dr. Michael Mrejen, Yoni Erlich, Dr. Assaf Levanon and Prof. Haim Suchowski of TAU's Department of Physics of Condensed Material. The results of the study were published in the October 2020 issue of Laser & Photonics Reviews.

"The human eye picks up photons at wavelengths between 400 nanometers and 700 nanometers -- between the wavelengths of blue and red," explains Dr. Mrejen. "But that's only a tiny part of the electromagnetic spectrum, which also includes radio waves, microwaves, X-rays and more. Below 400 nanometers there is ultraviolet or UV radiation, and above 700 nanometers there is infrared radiation, which itself is divided into near-, mid- and far-infrared.

"In each of these parts of the electromagnetic spectrum, there is a great deal of information on materials encoded as 'colors' that has until now been hidden from view."

The researchers explain that colors in these parts of the spectrum are of great importance, since many materials have a unique signature expressed as a color, especially in the mid-infrared range. For example, cancer cells could be easily detected as they have a higher concentration of molecules of a certain type.

Existing infrared detection technologies are expensive and mostly unable to render those "colors." In medical imaging, experiments have been performed in which infrared images are converted into visible light to identify the cancer cells by the molecules. To date, this conversion required very sophisticated and expensive cameras, which were not necessarily accessible for general use.

But in their study, TAU researchers were able to develop cheap and efficient technology that could mount on a standard camera and allows, for the first time, the conversion of photons of light from the entire mid-infrared region to the visible region, at frequencies that the human eye and the standard camera can pick up.

"We humans can see between red and blue. If we could see in the infrared realm, we would see that elements like hydrogen, carbon and sodium have a unique color," explains Prof. Suchowski. "So an environmental monitoring satellite could 'see' a pollutant being emitted from a plant, or a spy satellite would see where explosives or uranium are being hidden. In addition, since every object emits heat in the infrared, all this information could be seen even at night."

After registering a patent for their invention, the researchers are developing the technology through a grant from the Innovation Authority's KAMIN project, and they have already met with a number of both Israel-based and international companies.

###

Species more likely to die out with rapid climate changes

Species are resilient -- to a point. But when things change too quickly things can go badly

NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Research News

 

The climate seems to be getting warmer. This could be bad news for species that depend on stable and abundant access to food at certain times of the year.

"If the changes happen too fast, species can become extinct," says Emily Simmonds, an associate professor at the Norwegian University of Science and Technology's (NTNU) Department of Biology.

She is the first author of an article in Ecology Letters that addresses how great tits can be affected if the supply of larvae changes in the spring.

Several bird species depend on the abundance of larvae while their young are small. If the larvae supply peaks earlier in the spring than normal, there may simply be too little food for the hatchlings.

The warming climate can bring about changes like this. An earlier spring causes trees to leaf out earlier, which in turn causes the larvae that feed on the plants to hatch out earlier.

"When the climate changes, the interactions between different species changes too," Simmonds says.

She and a team of researchers at the University of Oxford used population models to calculate the consequences of different climate scenarios. They wanted to see at what point the changes would happen too fast for the great tit to modify its behaviour quickly enough to keep up with the larvae.

Great tits have genetic variations and varying abilities to adapt to different conditions. This means that they can evolve in tandem with their prey up to a point.

An earlier larvae hatch can be advantageous for the great tits that also hatch their young earlier in the spring. This advantage can be transferred to the next generation of birds, which can in turn become early birds. And so on.

For this advantage to last, the great tits have to evolve fast enough and be flexible enough to keep up with the genetic variation in their prey.

"Given conditions with big greenhouse gas emissions, the great tits won't always be able to keep up with the changes in the larvae supply," says Simmonds.

In the worst case scenario, whole populations of great tits will simply disappear by the year 2100 because they aren't able to procure enough food for their young.

"This could happen even if the great tits are also modifying their behaviour faster in a rapidly changing environment. The larvae might be changing even faster than the great tits," Simmonds says.

The researchers found that populations of great tits would be guaranteed to become extinct by the year 2100 if the larvae appeared about 24 days earlier than the current norm in 2020. This also applies to populations that appear to be completely stable now.

"It could be that the apparent stability today is hiding a future collapse," says Simmonds.

The reason is that we might reach a kind of threshold where the great tits aren't keeping up. The rubber band gets stretched too far, you could say.

"The good news is that the populations will be able to survive scenarios with lower or medium warming trends," Simmonds says.

###

Simmonds collaborated with Dr. Ella Cole, Professor Ben Sheldon and Professor Tim Coulson at the University of Oxford on the project, which was part of Simmonds' doctoral dissertation at the British university.

Source: Ecology Letters. Phenological asynchrony: a ticking time-bomb for seemingly stable populations?

 

How does the brain process fear?

COLD SPRING HARBOR LABORATORY

Research News

 

IMAGE: SCIENTISTS KNOW THAT FEAR MEMORIES FOR MICE ARE MADE IN THE AMYGDALA, AN ALMOND-SHAPED STRUCTURE DEEP IN THE BRAIN. NEW RESEARCH SHOWS THAT THE FEAR CIRCUIT EXTENDS FAR BEYOND THE... view more 

CREDIT: LI LAB/CSHL, 2020

When a frightful creature startles you, your brain may activate its fear-processing circuitry, sending your heart racing to help you escape the threat. It's also the job of the brain's fear-processing circuits to help you learn from experience to recognize which situations are truly dangerous and to respond appropriately--so if the scare comes from a costumed goblin, you'll probably recover quickly.

In more dire circumstances, however, the brain's fear response can be critical for survival. "Being able to fear is the ability to sense the danger and is the driving force to figure out a way to escape or fight back," said Cold Spring Harbor Laboratory Professor Bo Li.

[VIDEO: Watching a mouse think about fear and pleasure - https://www.youtube.com/watch?v=B7MujP-Z0ds]

Li's team is probing the brain circuits that underlie fear, using sophisticated neuroscience tools to map their connections and tease out how specific components contribute to learning fear. A deeper understanding of these circuits could lead to better ways to control the overactive or inappropriate fear responses experienced by people with anxiety disorders.

Many of their studies begin with the amygdala, an almond-shaped structure that is considered the hub for fear processing in the brain. While the amygdala was once thought to be devoted exclusively to processing fear, researchers are now broadening their understanding of its role. Li's team has found that the amygdala is also important for reward-based learning, and as they trace its connections to other parts of the brain, they are uncovering additional complexity. Li said:

"It is important for formation of fearful memory, but it's also important for interacting with other brain systems in a different behavior context. We think that this circuit that we discovered that plays a role in regulating fearful memory is only a tip of the iceberg. It is indeed important for regulating fearful memory, but probably is also involved in more complex behavior."

Li and his colleagues were surprised recently to find that the amygdala communicates with a part of the brain best known for its role in controlling movement. The structure, called the globus pallidus, was not known to be involved in fear processing or memory formation. But when the researchers interfered with signaling between the amygdala and the globus pallidus in the brains of mice, they found that the animals failed to learn that a particular sound cue signaled an unpleasant sensation. Based on their experiments, this component of the fear-processing circuitry might be important for alerting the brain "which situations are worth learning from," Li said.

Li's team and collaborators at Stanford University reported recent findings in the Journal of Neuroscience. For more of Li's research on how fear is processed in the brain, check out this video of his talk at "Life Science Across the Globe".

###

 Climate - Ice breaker data

IMAGE: THE ICEBREAKER R/V POLARSTERN CARRIED MORE THAN 60 ARM INSTRUMENTS FOR THE MOSAIC EXPEDITION. view more 

CREDIT: U.S. DEPT. OF ENERGY ARM USER FACILITY

With the conclusion of an unprecedented yearlong expedition to the North Pole called MOSAiC, data from instruments installed on an Arctic ice floe are available to the scientific community to improve models that predict the environmental future of the planet.

Researchers at Oak Ridge National Laboratory were part of an international team that collected a treasure trove of data measuring precipitation, air particles, cloud patterns and the exchange of energy between the atmosphere and the sea ice. The data were captured by a suite of 63 instruments from the Department of Energy's Atmospheric Radiation Measurement User Facility. ORNL has processed these measurements and made massive amounts of observational data easily accessible and usable for climate modelers.

"We've never had this type of data for the northernmost reaches of the Arctic before," said Giri Prakash, director of the ARM Data Center at ORNL. "These data will be an invaluable resource for scientists to improve predictions of global environmental changes."

Media Contact: Kim Askey, 865.576.2841, askeyka@ornl.gov

Image: https://www.ornl.gov/sites/default/files/2020-11/49464987002_20dab0acb6_o.jpg

Caption: Researchers set up ARM instruments on the ice floe near the ship that served as home during the MOSAiC expedition. Credit: U.S. Dept. of Energy ARM User Facility

Image: https://www.ornl.gov/sites/default/files/2020-11/49464270498_a1ff680b23_o.jpg

Caption: Radiometer instruments collect data on the Arctic ice. Credit: U.S. Dept. of Energy ARM User Facility

Image: https://www.ornl.gov/sites/default/files/2020-11/50192950163_44318b4fe9_o.jpg

Caption: The icebreaker R/V Polarstern carried more than 60 ARM instruments for the MOSAiC expedition. Credit: U.S. Dept. of Energy ARM User Facility

#MYTHBUSTERS

USask researchers find face masks don't hinder breathing during exercise

UNIVERSITY OF SASKATCHEWAN

Research News

 

IMAGE: A NEW USASK STUDY HAS FOUND THAT FACE MASKS DO NOT HINDER BREATHING FOR HEALTHY INDIVIDUALS DURING EXERCISE. view more 

CREDIT: JOHN KO

SASKATOON - A new University of Saskatchewan (USask) study has found that exercise performance and blood and muscle oxygen levels are not affected for healthy individuals wearing a face mask during strenuous workouts.

Questions have been raised as to whether mask wearing during vigorous exercise might compromise oxygen uptake or increase the rebreathing of carbon dioxide, leading to a condition (hypercapnic hypoxia) whereby increased carbon dioxide displaces oxygen in the blood.

But the study, published Nov. 3 in the research journal International Journal of Environmental Research and Public Health, did not find evidence to support these concerns.

"Our findings are of importance because they indicate that people can wear face masks during intense exercise with no detrimental effects on performance and minimal impact on blood and muscle oxygenation," the researchers state.

"This is important when fitness centers open up during COVID-19 since respiratory droplets may be propelled further with heavy breathing during vigorous exercise and because of reports of COVID-19 clusters in crowded enclosed exercise facilities."

The study evaluated use of a three-layer cloth face mask--the type recommended recently by Dr. Theresa Tam, Canada's Chief Public Health Officer. "Results using a single-layer cloth mask may differ," the researchers note.

The study, involving 14 physically active and healthy men and women, controlled for the effects of diet, previous physical activity, and sleep during the 24 hours prior to the test.

"If people wear face masks during indoor exercise, it might make the sessions safer and allow gyms to stay open during COVID," said Phil Chilibeck, a professor in the USask College of Kinesiology, who was a co-author of the study. "It might also allow sports to continue, including hockey, where transmission of COVID-19 appears to be high."

Participants were required to do a brief warm-up on a stationary bike. The exercise test involved a progressive increase in the intensity on the bike while they maintained a required pedal rate. Once they could not sustain the pedal rate the test was over.

"Usually a participant reaches exhaustion on this test in six to 12 minutes depending on their fitness level," said Chilibeck.

The team assessed the participants, who did the test three times each, once wearing a surgical face mask, once wearing a cloth face mask and once with no face mask. The team recorded the participants' blood oxygen levels and muscle oxygen levels throughout the test using non-invasive measurement tools.

Chilibeck notes the study is timely, as Saskatchewan has recently issued new public health orders that go into effect this week making masks mandatory in indoor public spaces in Regina, Saskatoon and Prince Albert to help curb the spread of COVID-19.

While the new provincial mask rules state that persons working out in a gym, ice rink or other recreational space are exempt, Chilibeck recommends that people wear masks in these facilities to keep safe, especially in these areas where people may be breathing harder due to vigorous exercise.

###

The USask research team also included kinesiology alumni Keely Shaw and John Ko, Scotty Butcher from the School of Rehabilitation Medicine, and Gordon Zello from the College of Pharmacy and Nutrition.

The study can be found here: https://www.mdpi.com/1660-4601/17/21/8110

 

Corn and other crops are not adapted to benefit from elevated carbon dioxide levels

CARL R. WOESE INSTITUTE FOR GENOMIC BIOLOGY, UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN

Research News

 

IMAGE: IN THEIR RECENT PAPER, SCIENTISTS ANALYZED 49 SPECIES OF GRASS CROPS AND FOUND THAT BY REBALANCING THE LEAVES' RESOURCES, PLANTS WOULD BETTER THRIVE IN TODAY'S CLIMATE. PICTURED: THE WEST PROJECT... view more 

CREDIT: WEST PROJECT

The U.S. backs out of the Paris climate agreement even as carbon dioxide (CO2) levels continue to rise. Through photosynthesis, plants are able to turn CO2 into yield. Logic tells us that more CO2 should boost crop production, but a new review from the University of Illinois shows that some crops, including corn, are adapted to a pre-industrial environment and cannot distribute their resources effectively to take advantage of extra CO2.

Most plants (including soybeans, rice, canola, and all trees) are C3 because they fix CO2 first into a carbohydrate containing three carbon atoms. Corn, sorghum, and sugarcane belong to a special group of plants known as C4, so-called because they first fix CO2 into a four-carbon carbohydrate during photosynthesis. On average, C4 crops are 60 percent more productive than C3 crops.

When crops are grown in elevated CO2 that mimic future atmospheric conditions, research shows that C3 crops can become more productive while some experiments suggest that C4 crops would be no more productive in a higher CO2 world.

"As scientists, we need to think several steps ahead to anticipate what the Earth will look like five to 30 years from now, and how we can design crops to perform well under those conditions," said Charles Pignon, a former postdoctoral researcher at Illinois. "We decided that a literature review and a retrospective analysis of biochemical limitations in photosynthesis would be able to give us some insight into why C4 crops might not respond and how we might alter this."

The literature review, published in Plant, Cell & Environment, was supported by Water Efficient Sorghum Technologies (WEST), a research project that aimed to develop bioenergy crops that produce more biomass with less water, with funding from the Advanced Research Projects Agency-Energy (ARPA-E).

The team assembled a dataset of photosynthesis measurements from 49 C4 species, including the crops that could reveal photosynthetic limitations. The consistent pattern that emerged was that at low CO2--well below what plants would have experienced before the industrial revolution--C4 photosynthesis was limited by the activity of the enzyme that fixes CO2. However, at today's CO2 levels, C4 photosynthesis was limited by the capacity to provide the three-carbon molecule that accepts the fourth CO2.

"This finding is analogous to a car assembly line where the supply of engines is outpacing the supply of chassis to accept them," said co-author Stephen Long, the Stanley O. Ikenberry Chair Professor of Plant Biology and Crop Sciences. "We need to engineer these plants to better balance their resources in one or both of two-ways."

First, the authors suggest that C4 crops need to cut back on the amount of the enzyme used to fix CO2 and re-invest the saved resources into making more of the CO2 acceptor molecule.

Secondly, they need to restrict the supply of CO2 into the leaf by reducing the number of pores (stomata) on the leaf surface. "Lowering the CO2 within the leaf would re-optimize the biochemistry, without lowering the rate of photosynthesis, and with fewer stomata, less water would be lost so we are increasing the crop's water use efficiency," Long said.

The WEST project concluded in 2019. These proposed changes to C4 crops are now being pursued through the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), which is supported by the Department of Energy.

###

Water Efficient Sorghum Technologies (WEST) was a research project that helped develop bioenergy crops that require less water per acre to ensure a sustainable source of biofuel. The project was supported by the Advanced Research Projects Agency-Energy and led by the University of Illinois in partnership with Cornell University, University of Nebraska-Lincoln, University of Wisconsin-Madison, and the USDA Agricultural Research Service.

 

Soil carbon changes in transition areas suggest conservation for Amazon, scientists say

University of Oregon-led project establishes a 1,600-year baseline for understanding how human impacts and climate affect the Amazon-Cerrado transition

UNIVERSITY OF OREGON

Research News

 

EUGENE, Ore. -- Nov. 5, 2020 -- Conservation efforts on the edges of the Amazon forest, especially in light of recent deforestation by human disturbance, could help the region weather the storm of climate change, researchers say.

That assessment comes from an analysis of vegetation changes and carbon isotope signatures in the soil at 83 sites. The project, led by University of Oregon doctoral student Jamie Wright, established a record of soil changes associated with both climate and human activity over the last 1,600 years based on radiocarbon dating.

The study was published online Oct. 30 ahead of print in Global Change Biology.

Woody vegetation expansion into savannas, the research team found, had continued amid increasing moisture levels regardless of human impacts until only recently, mostly from rapid deforestation in the last decade. Climate modeling previously has suggested that local water and carbon cycles, as well as global climate patterns, are at risk.

"The past, like most things, leaves a trace behind and with it a rich history left to be told," said Wright, a member of the UO's Soil Plant Atmosphere Lab headed by co-author Lucas Silva, a professor in the Environmental Studies Program.

The forest-savanna borderlands, known as the Amazon-Cerrado transition, experience broad climatic and ecological influences. The study helped address uncertainties of those influences in the tropical ecosystem.

"Through the use of soil science, specifically with carbon isotopes, we unearthed a history of forest expansion over several millennia. This region is at the epicenter of deforestation and socio-ecological transformations that cause and drive climate change," Wright said.

Previous studies had suggested that forest expansion was primarily driven by increased precipitation, but that work, Silva noted, did not fully consider the impacts of local influences, such as fire frequency and intensity or whether it was occurring because of climate dynamics in the region. Focusing on soil changes, he said, allowed for these factors to be examined.

"Carbon storage in woody savannas and forests plants at this large of scale can be a significant carbon sink," Wright said. "Increasing tree cover also can ameliorate adverse climatic change impacts, such as droughts, by influencing the hydrological cycle and generating rain clouds."

In total, 742 soil samples were taken from forests, savannas and transition zones across a large swath of north-central Brazil, between latitudes 4 to 16 degrees south and longitudes 46 to 56 degrees west -- an area where precipitation and distribution vary significantly.

The research team also measured the leaf index of the ecosystem's cover, mostly the forest canopy, to understand changes in carbon isotope signatures in the soil. Such changes reflect land usage. To determine changes over time, radiocarbon activity and isotopic ratios were profiled in 43 selected depths that represented the different sites.

While the research affirmed that forest expansion has occurred in most of the past 1,600 years, the researchers found a trend of decreasing woody vegetation in the study area's easternmost sites. The decline, they said, may reflect the prevalence of dry deciduous or semi-deciduous tree species in those areas.

The observed incremental expansion into savannas, they wrote, could have significant impacts on carbon-water relations, potentially affecting the balance between precipitation and evapotranspiration as seen in previous research. However, they noted, they did not see a clear effect of changes in vegetation on soil carbon stocks.

Future studies, they said, are needed to focus on the mechanisms that drive the permanence of carbon derived from woody vegetation expansion, especially because of recent documentation of hotter and longer dry seasons, as well as rising mortality rates of wet climate species.

The next phase of understanding, they said, will come from integrating plant, soil and atmospheric data to understand the influence of human activity on ecosystem-climate feedbacks as a path towards improving carbon sequestration and water conservation.

"Our data indicate a regional increase in tree cover prior to modern deforestation, which could help inform conservation and management for climate change mitigation," said Silva, who also is a professor of geography and member of the Institute of Ecology and Evolution. "We hope that our research will lead to a greater appreciation of ecological processes in the region and their importance for global climatic stability."

In addition to Silva and Wright, the study's co-authors are Barbara Bomfim, a former postdoctoral researcher in Silva's lab who is now at the Lawrence Berkeley National Laboratory, Corrine Wong of Boston College, and Ben Hur Marimon-Junior and Beatriz Marimon, both of the State University of Mato Grosso in Nova Xavantina, Brazil.

The research team is continuing to work closely with collaborators in the Amazon region in an effort to secure funding to launch a reforestation project, Silva said.

###

The National Science Foundation and Brazil's National Council for Scientific and Technological Development funded the research. Additional support came from a 2019 Resilience Initiative Interdisciplinary Seed Funding award given by the UO's Office of the Vice President for Research and Innovation.

Links:

About Lucas Silva:
https://geography.uoregon.edu/profile/lsilva7/

Soil Plant Atmosphere Research Lab:
https://soilplantatmosphere.com/

Department of Geography:
https://geography.uoregon.edu/

Institute of Ecology and Evolution:
https://ie2.uoregon.edu/

Ants are skilled farmers: They have solved a problem that we humans have yet to

UNIVERSITY OF COPENHAGEN

Research News

 

Fungus-farming ants are an insect lineage that relies on farmed fungus for their survival. In return for tending to their fungal crops--protecting them against pests and pathogens, providing them with stable growth conditions in underground nests, and provisioning them with nutritional 'fertilizers'--the ants gain a stable food supply.

These fungus farming systems are an expression of striking collective organization honed over 60 million years of fungus crop domestication. The farming systems of humans thus pale in comparison, since they emerged only ca. 10,000 years ago.

A new study from the University of Copenhagen, and funded by an ERC Starting Grant, demonstrates that these ants might be one up on us as far as farming skills go. Long ago, they managed to appear to have overcome key domestication challenges that we have yet to solve.

"Ants have managed to retain a farming lifestyle across 60 million years of climate change, and Leafcutter ants appear able to grow a single cultivar species across diverse habitats, from grasslands to tropical rainforest" explains Jonathan Z. Shik, one of the study's authors and an assistant professor at the University of Copenhagen's Department of Biology.

Through fieldwork in the rainforests of Panama, he and researchers from the Smithsonian Tropical Research Institute studied how fungus-farming ants use nutrition to manage a tradeoff between the cultivar's increasingly specialized production benefits, and it's rising vulnerability to environmental variation.

Ants as clever farmers

We humans have bred certain characteristics -- whether a taste or texture -- into our crops.

But these benefits of crop domestication can also result in greater sensitivity to environmental threats from weather and pests, requiring increasing pesticide use and irrigation. Simply put, we weaken plants in exchange for the right taste and yield. Jonathan Z. Shik explains:

"The ants appear to have faced a similar yield-vulnerability tradeoff as their crops became more specialized, but have also evolved plenty of clever ways to persist over millions of years. For example, they became impressive architects, often excavating sophisticated and climate-controlled subterranean growth chambers where they can protect their fungus from the elements," he says.

Furthermore, these little creatures also appear able to carefully regulate the nutrients used to grow their crops.

To study how, Shik and his team spent over a hundred hours lying on rainforest floor on trash bags next to ant nests. Armed only with forceps, they stole tiny pieces of leaves and other substrates from the jaws of ants as they returned from foraging trips.

They did this while snakes slithered through the leaf litter and monkeys peered down at him from the treetops.

"For instance, our nutritional analyses of the plant substrates foraged by leafcutter ants show that they collect leaves, fruit, and flowers from hundreds of different rainforest trees. These plant substrates contain a rich blend of protein, carbohydrates and other nutrients such as sodium, zinc and magnesium," explains Shik. "This nutritional blend can target the specific nutritional requirements of their fungal crop."

What can we learn from ants?

Over the years, the ants have adapted their leaf collecting to the needs of the fungus -- a kind of organic farming, without the benefits of the technological advances that have helped human farmers over the millenia, one might say.

One might wonder, is it possible to simply copy their ingenious methods?

"Because our plant crops require sunlight and must thus be grown above ground, we can't directly transfer the ants' methods to our own agricultural practices. But it's interesting that at some point in history, both humans and ants have gone from being hunter-gatherers to discovering the advantages of cultivation. It will be fascinating to see what farming systems of humans look like in 60 million years," concludes Jonathan Z. Shik.