It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, October 24, 2020
RUDN University chemist created a catalyst from orange peel for organic compounds production
IMAGE: N-HETEROCYCLES ARE ORGANIC SUBSTANCES USED IN THE CHEMICAL INDUSTRY AND MEDICINE. TO PRODUCE THEM, EXPENSIVE CATALYSTS MADE FROM NOBLE METALS ARE USED. A CHEMIST FROM RUDN UNIVERSITY DEVELOPED A NANOCATALYST... view more
CREDIT: RUDN UNIVERSITY
N-heterocycles are organic substances used in the chemical industry and medicine. To produce them, expensive catalysts made from noble metals are used. A chemist from RUDN University developed a nanocatalyst for N-heterocycles that consists of zinc oxide and niobium and can be obtained using orange peel without any additional chemical agents. The catalyst makes the reaction almost 100% effective, thus increasing the efficiency and reducing the cost of N-heterocycles production. The results of the study were published in the Catalysis Today journal.
N-heterocycles are used in the production of plastics and medicinal drugs (quinine, morphine, pyramidon) and as dyes. Their synthesis requires the use of catalysts based on expensive noble metals such as gold, palladium, or iridium. All previous attempts to use other elements had been unsuccessful due to low efficiency or instability of the end products. However, a chemist from RUDN University developed a nanocatalyst based on cheaper metals--niobium and zinc. The new catalyst provides for almost 100% efficiency of N-heterocycle synthesis, and its precursor (or platform molecule) is levulinic acid.
"Levulinic acid is one of the top-10 most promising platform molecules that can be easily obtained from biomass. The transformation of levulinic acid into N-heterocycles has recently become a popular topic because N-heterocycles proved to be useful in the pharmaceutical, agrochemical, and polymer industries", said Rafael Luque, PhD, the head of the Molecular Design and Synthesis of Innovative Compounds for Medicine Science Center at RUDN University.
His team used a mechanochemical method to create the nanocatalyst: it means, its components were simply mixed in a special grinder without solvents or other additives. Orange peel served as a template for the catalyst preparation. Ground peel, dry zinc acetate, and 18 1-cm steel balls were put in the grinder and mixed at 350 revolutions per minute for 20 minutes. After that, the mixture was heated at 200? for two hours. As a result, zinc oxide nanoparticles were formed. Orange peel was used to give zinc acetate a surface to concentrate on, and also to help form intermediary compounds. The remains of the peel were partially removed from the mix in the course of heating. After that, zinc oxide nanoparticles were combined in the grinder with niobium-containing particles so that the concentration of the metal in the end product would reach 2.5% to 10%.
To test the new nanocatalyst, the chemists used it to transform levulinic acid into an N-heterocycle. The team selected the most efficient ratio of the catalyst: 10% of niobium to 90% of zinc oxide. In this case, almost all levulinic acid (94.5%) was turned into the end product without byproducts, and N-heterocycles accounted for 97.4% of the yield.
"This work shows that if we play with the catalyst structure, valuable compounds can be developed from biowaste. Using organic waste and eco-friendly methods, we can offer an alternative to the modern-day chemical industry that is extremely dependent on fossil fuels," added Rafael Luque.
ANOTHER POWERFUL DEGREASER, THAT CAN MELT PLASTIC; D-LEMONINE, IS AN EXTRACT OF ORANGE PEEL
D-limonene is one of the most common terpenes in nature. It is a major constituent in several citrus oils (orange, lemon, mandarin, lime, and grapefruit).
IMAGE: KATHRYN CLANCY, RIGHT, AND KATHERINE LEE ARE INTERESTED IN STUDYING HOW DAILY ACTIVITIES INFLUENCE BONE DENSITY. view more
CREDIT: BECKMAN INSTITUTE FOR ADVANCED SCIENCE AND TECHNOLOGY
Researchers at the University of Illinois Urbana-Champaign have studied a population of women in rural Poland for the past four years to understand how their lifestyle affects their bone density. The age group and lifestyle of these women are often overlooked in such studies.
The study "Bone density and frame size in adult women: effects of body size, habitual use, and life history" was published in the American Journal of Human Biology.
"My work focuses on understanding how our activities shape our skeleton and what it means for the modern population," said Katharine Lee, a recent graduate of the Clancy group, which is affiliated with the Beckman Institute for Advanced Science and Technology.
The study focused on a population of farmers whose lifestyles involve substantial farm and domestic labor, such as growing fruits and vegetables, churning butter, beating rugs, washing windows, and caring for children. "We made some basic body measurements and looked at the physical activity patterns of these women," Lee said. "We also used a bone sonometer, which was provided through Beckman's Biomedical Imaging Center. It is a portable device that can be conveniently used to carry out bone density measurements."
Previous studies in the field have looked at bone density measurements in menopausal women. The researchers wanted to focus on women between the ages of 18 and 46, an age group that is not often looked at in bone density studies. "We wondered why there was so little research on premenopausal women, since presumably their bone density and activity predicts postmenopausal osteoporosis," said Kathryn Clancy, an associate professor of anthropology at Illinois and a part-time Beckman faculty member.
"We saw that measures such as grip strength and lean mass are associated with the bone density and frame size of these premenopausal women. We also saw that the bone density of the radius, which is the bone at the base of your thumb, is very high compared to an average white woman of European descent," Lee said. "Interestingly, we don't see this increased bone density in Polish American women. We don't fully understand what factors are causing it."
The researchers believe that this study sheds light on the specific contexts of this lifestyle. "A lot of these measures have looked at large populations and averaged, so they have missed many of these details," Lee said. "It is also important to think about which populations are not represented in the literature and look at lifestyles that are different to the modern, sedentary lifestyle that most people in the U.S. have."
Moving forward, the researchers are interested in understanding whether the childhood environment has helped shape the bone health of the women. "We have interviewed them about the different types of work they did when they were growing up. We asked whether they grew up on a farm, whether they had farm animals, or whether they tended a garden. Those activities, rather than the ones they are doing now, might be associated with the bone health measures," Lee said.
Conventional plastic is made from oil. The production of plastic is not sustainable, and it can contain substances we know are dangerous if ingested.
In recent years, bioplastics have come onto the market as an alternative to conventional plastic. Bioplastic has some apparent advantages: it is usually made from recycled material or plant cellulose, it can be biodegradable - or both.
But a new study shows that it is not non-toxic.
Bioplastics are in fact just as toxic as other plastics, according to an article recently published in Environment International.
"Bio-based and biodegradable plastic are not any safer than other plastics," says Lisa Zimmermann from Goethe Universität in Frankfurt. She is the lead author of the recent article.
Zimmermann points out that products based on cellulose and starch contained the most chemicals. They also triggered stronger toxic reactions under laboratory conditions.
"Three out of four of these plastic products contain substances that we know are dangerous under laboratory conditions, the same as for conventional plastic," says Martin Wagner, associate professor at the Norwegian University of Science and Technology's Department of Biology.
Wagner is one of the collaborators for PlastX, a research group at the Institut für sozial-ökologische Forschung (ISOE) in Frankfurt.
This group has just led the work on the largest survey to date of chemicals in bioplastics and plastics made from plant-based materials.
They have looked at toxic substances in these types of plastic. The substances can be directly toxic to cells in the laboratory, or they can act as hormones that in turn can disturb the body's balance.
The study includes 43 different plastic products, including disposable cutlery, chocolate packaging paper, drink bottles and wine corks.
"Eighty per cent of the products contained more than 1000 different chemicals. Some of them as many as 20 000 chemicals," says Wagner.
It goes without saying that it is almost impossible to keep track of absolutely all the possible harmful effects of so many different materials.
Even seemingly similar products have their own special chemical composition. A plastic bag made of bio-polyethylene can contain completely different substances than a wine cork made of the same material.
"Making general statements about certain materials becomes almost impossible," says Wagner.
At present, the consequences this has for the environment and for people's health are still uncertain. We don't know to what extent the substances in plastic are transferable to humans.
Nor do we know whether the alternatives to bioplastics and conventional plastics are better for us and the environment around us, since so many factors come into play. The alternatives may involve polluting production methods and limited opportunities for recycling, or food production has to give way to obtain the materials for the alternative products. More research is needed.
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Source: Lisa Zimmermann, Andrea Dombrowski, Carolin Völker, Martin Wagner (2020). Are bioplastics and plant-based materials safer than conventional plastics? In vitro toxicity and chemical composition, Environment International. https://doi.org/10.1016/j.envint.2020.106066
War on plastic is distracting from more urgent threats to environment, experts warn
A team of leading environmental experts, spearheaded by the University of Nottingham, have warned that the current war on plastic is detracting from the bigger threats to the environment.
In an article published in the peer-reviewed scientific journal, Wiley Interdisciplinary Reviews (WIREs) Water, the 13 experts* say that while plastic waste is an issue, its prominence in the general public's concern for the environment is overshadowing greater threats, for example, climate change and biodiversity loss.
The interdisciplinary team argue that much of the discourse around plastic waste is based on data that is not always representative of the environments that have been sampled. The aversion to plastic associated with this could encourage the use of alternative materials with potentially greater harmful effects.
The authors warn that plastic pollution dominates the public's concern for the environment and has been exploited politically, after capturing the attention of the world, for example through emotive imagery of wildlife caught in plastic waste and alarmist headlines. They say small political gestures such as legislation banning cosmetic microplastics, taxing plastic bags, and financial incentives for using reusable containers, as well as the promotion of products as 'green' for containing less plastic than alternatives, risks instilling a complacency in society towards other environmental problems that are not as tangible as plastic pollution.
The article's authors call on the media and others to ensure that the realities of plastic pollution are not misrepresented, particularly in the public dissemination of the issue, and urges government to minimise the environmental impact of over-consumption, however inconvenient, through product design, truly circular waste-management, and considered rather than reactionary policy.
Dr Tom Stanton, a co-author who led the work while in the University of Nottingham's School of Geography and Food, Water, Waste Research Group, said: "We are seeing unprecedented engagement with environmental issues, particularly plastic pollution, from the public and we believe this presents a once in a generation opportunity to promote other, potentially greater environmental issues.
"This is a key moment in which to highlight and address areas such as 'throw-away' culture in society and overhaul waste management. However, if there is a continuation in prioritising plastic, this opportunity will be missed - and at great cost to our environment."
The article also highlights that plastics are not the only type of polluting material originating from human activity that contaminates the environment. Other examples include natural textile fibres such as cotton and wool, Spheroidal Carbonaceous Particles (remnants of fossil fuels), and brake-wear particles from vehicles - all of which are present in different places, where they may have adverse environmental effects. The authors note that these materials are often much more abundant than microplastics and some, such as glass, aluminium, paper, and natural fibres, are associated with 'plastic alternatives' that are marketed as solutions to plastic pollution, but in reality side-step the inconvenience of changing the consumption practices at the root of the problem. The eco-toxicological impacts of some of these materials are less well known than plastic and microplastic pollution, yet they could have significant impacts.
The authors conclude that that a behavioural science approach should be taken to assess society's relationship with single-use items and throw-away culture, and to overhaul waste mismanagement.
They say there is an understandable desire to minimise the global plastic debris in the environment which should not be discouraged, but positive action to minimise plastic pollution needs to be well informed and should not exacerbate or overshadow other forms of environmental degradation associated with alternative materials.
The article states that solutions are likely to come from a greater focus on designing materials and products that can be recycled, that have their end-of-life built in, and that markets and facilities exist to recycle all plastic waste.
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Regenerated forests offset 12% of carbon emissions in Brazilian Amazon in 33 years
A study quantified the size and age of the forests that grow naturally in degraded and abandoned areas, creating 131 benchmark maps for Brazil. The Amazon has the most restored forests and the Atlantic Rainforest biome has the oldest.
FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO
IMAGE: A STUDY QUANTIFIED THE SIZE AND AGE OF THE FORESTS THAT GROW NATURALLY IN DEGRADED AND ABANDONED AREAS, CREATING 131 BENCHMARK MAPS FOR BRAZIL. THE AMAZON HAS THE MOST RESTORED... view more
CREDIT: TROPICAL ECOSYSTEMS AND ENVIRONMENTAL SCIENCES LABORATORY - INPE
Secondary forests play an important part in carbon capture because they tend to absorb a larger amount of carbon than they lose to the atmosphere. However, the size and average age of these often abandoned areas where vegetation grows back were unknown until now. In a study recently published in the journal Scientific Data, a group led by two researchers at Brazil’s National Institute for Space Research (INPE) quantified these variables and found that the estimated carbon uptake by secondary forests throughout Brazil offset 12% of the carbon emissions due to deforestation in the Brazilian Amazon alone in a 33-year period.
“The capacity of secondary forests to absorb carbon is known from studies that involve monitoring of areas in the field. Their average net carbon uptake rate in Neotropical regions is 11 times that of old-growth forests. However, the long-term dynamics of secondary forests in Brazil and worldwide is poorly understood,” said Aragão, one of the authors of the study, which was conducted at INPE as part of Celso H. L Silva Júnior’s PhD research.
This knowledge is fundamental to enable Brazil to achieve its Nationally Determined Contribution targets under the 2015 Paris Agreement. These include the restoration and reforestation of 12 million hectares of forest by 2030, he noted.
Age and size of secondary forests in each biome
The study calculated the increment in secondary forests that previously had anthropic cover (plantation, pasture, urban infrastructure, or mining) and their age, biome by biome. According to Aragão, secondary forest growth is not linear and correlates with age, so that it is important to establish the age of a forest in order to estimate its carbon uptake.
The data showed that a total of 262,791 square kilometers (km²) of secondary forests were recovered in Brazil between 1986 and 2018. This corresponds to 59% of the old-growth forest area cleared in the Brazilian Amazon between 1988 and 2019.
“The restored forests were located all over Brazil with the smallest proportion in the Pantanal [wetlands in the Center-West], accounting for 0.43% [1,120 km²] of the total mapped area. The largest proportion was in the Amazon, with 56.61% [148,764 km²]. The Caatinga [the semi-arid biome in the Northeast] accounted for 2.32% [6,106 km²] of the total area and had the youngest secondary forests – over 50% were between one and six years old,” Aragão said.
The Atlantic Rainforest ranked second by size of restored areas, with 70,218 km² (or 26.72% of the total), and had the oldest – over half were between and 12 years old.
Four steps
The researchers used the method implemented by the Google Earth Engine (GEE) and a time series of data from the Brazilian Annual Land-Use and Land-Cover Mapping Project (MapBiomas) starting in 1986. They created 131 reference maps for the 33 years between 1986 and 2018 covering secondary forests divided by biome. The raw material is available at doi.org/10.5281/zenodo.3928660 and github.com/celsohlsj/gee_brazil_sv.
Having excluded wetland areas, they executed the methodology in four steps. First, the 34 maps from MapBiomas were reclassified into binary maps, in which pixels representing forest areas were assigned the value “1” and pixels corresponding to other land uses and types of cover were assigned the value “0”. Mangroves and planted forests were excluded. Each pixel corresponded to an area of 30 meters by 30 meters.
Next, the increment in secondary forest areas was measured using the maps produced in the previous stage, pixel by pixel. “We established that secondary forests occurred when a pixel classified as anthropic cover in a given year was replaced by a pixel corresponding to forest cover in the following year,” Aragão said.
In the third stage, the researchers generated 33 more maps showing the size of secondary forests year by year. “To produce the map for 1987, for example, we added the secondary forest increment map for 1986 obtained in stage 2 to the increment map for 1987. The result was a map containing all secondary forest pixels for 1986 and 1987,” Aragão explained. “Given that the sequential sum of these maps resulted in pixels with values higher than ‘1’, to create binary maps showing the size of secondary forests in each year we reclassified the annual maps by assigning a weight of ‘1’ to pixels with values between 2 and 33, which corresponded to forest area size proper year by year. Pixels with the value ‘0’ were left unchanged.”
Finally, it remained to calculate the age of the secondary forests mapped. To do this they added together the annual secondary forest increment maps obtained in the previous stage. “We added maps in this manner until we obtained a map showing the age of secondary forest areas in 2018,” Aragão said, adding that the next step will be to establish secondary forest growth as a function of age. “We’ve submitted an article in which we describe this quantification.”
Emissions
Potential net carbon uptake by secondary forests in each Brazilian biome between 1986 and 2018 was calculated pixel by pixel, assuming an average linear net carbon uptake rate of 3.05 Mg C ha−1 yr−1 (megagrams per hectare per year) during the first 20 years of secondary forest succession, regardless of age. Zero net uptake was assumed after 20 years.
The Pantanal contributed least, accounting for 0.42% of secondary forest carbon uptake between 1986 and 2018. The Amazon biome contributed most, accounting for 52.21%. The study concluded that the estimated carbon uptake by all secondary forests in Brazil offset 12% of carbon emissions from deforestation in the Brazilian Amazon alone in the period 1988-2018.
For Aragão, however, land use must continue to change, especially in the Amazon. “The aggregate area of secondary forest can be seen not to have increased very much in proportion to the deforested area,” he said. “This is due to land use, especially in the Amazon. We have to change land use. Deforestation means loss of the other benefits of natural forests, which play an indispensable role in the hydrologic cycle and in the maintenance of biodiversity – far more so than secondary forest. They’re also more resilient to climate change.”
The new data can help Brazilian policymakers decide on ways to protect biodiversity and plan the use and protection of secondary forests. “They aren’t protected and provide important services. In fact, they typically suffer the most conversion in the land use cycle in the Amazon. Now we can see why they so urgently deserve to be protected,” Aragão said.
Being highly connected to a strong social network has its benefits. Now a new University of Alberta study is showing the same goes for trees, thanks to their underground neighbours.
The study, published in the Journal of Ecology, is the first to show that the growth of adult trees is linked to their participation in fungal networks living in the forest soil.
Though past research has focused on seedlings, these findings give new insight into the value of fungal networks to older trees--which are more environmentally beneficial for functions like capturing carbon and stabilizing soil erosion.
When they colonize the roots of a tree, fungal networks act as a sort of highway, allowing water, nutrients and even the compounds that send defence signals against insect attacks to flow back and forth among the trees.
The network also helps nutrients flow to resource-limited trees "like family units that support one another in times of stress," Birch noted.
Cores taken from 350 Douglas firs in British Columbia showed that annual tree ring growth was related to the extent of fungal connections a tree had with other trees. "They had much higher growth than trees that had only a few connections."
The research also showed that trees with more connections to many unique fungi had much greater growth than those with only one or two connections.
"We found that the more connected an adult tree is, the more it has significant growth advantages, which means the network could really influence large-scale important interactions in the forest, like carbon storage. If you have this network that is helping trees grow faster, that helps sequester more carbon year after year."
It's also possible that if the trees grow faster, they'd have some ability to better survive drought that is expected to intensify with climate change, he added.
"These networks may help them grow more steadily even as conditions become more stressful, and could even help buffer trees against death."
Birch hopes his findings lead to further studies in different kinds of forests in other geographical areas, because it's likely that the connections among trees change from year to year, he said.
"It's a very dynamic system that is probably being broken apart and re-formed quite a bit, like family relationships, so we don't know how they will change under future climates either. Maybe a dry year or a beetle outbreak impacts the network.
"Knowing whether fungal networks are operating the same way in other tree species could factor into how we reforest areas after harvesting them, and it could inform how we want to plant trees to preserve these networks."
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The research was supported by the Natural Sciences and Engineering Research Council of Canada.
Endangered vaquita remain genetically healthy even in low numbers, new analysis shows
Study found no sign of inbreeding or 'extinction vortex' often linked to small populations
IMAGE: THE FIRST VAQUITA CAUGHT AS PART OF A CONSERVATION EFFORT IN 2017. view more
CREDIT: VAQUITA CPR
The critically endangered vaquita has survived in low numbers in its native Gulf of California for hundreds of thousands of years, a new genetic analysis has found. The study found little sign of inbreeding or other risks often associated with small populations.
Gillnet fisheries have entangled and killed thousands of vaquitas in recent years and scientists believe that fewer than 20 of the small porpoises survive today. The new analysis demonstrates that the species' small numbers do not doom it to extinction, however, and so gives hope for the small remaining population. Vaquitas have long survived and even thrived without falling into an "extinction vortex," the new study showed. That's a scenario in which their limited genetic diversity makes it impossible to recover.
"The species, even now, is probably capable of surviving," said Phil Morin, research geneticist at NOAA Fisheries' Southwest Fisheries Science Center and lead author of the new study published this week in Molecular Ecology Resources. "We can now see that genetic factors are not its downfall. There's a very good chance it could recover fully if we can get the nets out of the water."
Small but Stable Populations
An increasing number of species in addition to the vaquita have maintained small but stable populations for long periods without suffering from inbreeding depression. Other species include the narwhal, mountain gorilla, and native foxes in California's Channel Islands. Long periods of small population sizes may have given them time to purge harmful mutations that might otherwise jeopardize the health of their populations.
"It's appearing to be more common than we thought that species can survive at low numbers over long periods," said Morin, who credited the vaquita findings to genetic experts around the world who contributed to the research.
The idea that vaquitas could sustain themselves in low numbers is not new. Some scientists suspected that more than 20 years ago. Now advanced genetic tools that have emerged with the rapidly increasing power of new computer technology helped them prove the point.
"They've survived like this for at least 250,000 years," said Barbara Taylor, research scientist at the Southwest Fisheries Science Center. "Knowing that gives us a lot more confidence that, in the immediate future, genetic issues are the least of our concerns."
Sequencing the Vaquita Genome
The new analysis examined living tissue from a vaquita captured as part of a last-ditch international 2017 effort to save the fast-disappearing species. The female vaquita tragically died, but its living cells revealed the most complete and high-quality genome sequence of any dolphin, porpoise, or whale to date, generated in collaboration with the Vertebrate Genomes Project. Sequencing was led by Olivier Fedrigo, Jacquelyn Mountcastle, and Erich Jarvis at the Rockefeller University. "We felt it our moral duty to generate a high-quality reference of this species on the brink of extinction", said Jarvis. Only in recent years have advances in sequencing technologies and high-powered computers made such detailed reconstruction possible.
While the vaquita genome is not diverse, the animals are healthy. The most recent field effort in fall 2019 spotted about nine individuals, including three calves, within their core habitat. The robust calves suggest that inbreeding depression is not harming the health of these last vaquita. "These examples and others indicate that, contrary to the paradigm of an 'extinction vortex' that may doom species with low diversity, some species have persisted with low genomic diversity and small population size," scientists wrote in the new study.
The genetic data suggest that the vaquita's isolated habitat in the far northern Gulf of California has sustained roughly 5,000 vaquitas for around 250,000 years. The advent of gillnetting for fish and shrimp only a few decades ago drove vaquitas towards extinction, as they are incidentally caught in the nets.
More recently, Illegal gillnetting for totoaba, a fish about the same size and found in the same habitat as the vaquita, has compounded the losses. The practice has caused a catastrophic decline that is estimated as cutting the remaining population in half each year.
"Small numbers do not necessarily mean the end of a species, if they have the protection they need," Taylor said. "In conservation biology, we're always looking for risk. We shouldn't be so pessimistic. The sight of those three healthy calves in the water with their survivor mothers should inspire the protection they need to truly recover."
Sponges are filter feeders that live on particulate matter - but they can also ingest microscopic fragments of plastics and other pollutants of anthropogenic origin. They can therefore serve as useful bioindicators of the health of marine ecosystems.
Pollution of the world's oceans owing to anthropogenic input of plastics and other industrial wastes represents an increasing threat to the viability of marine ecosystems. - And because such pollutants accumulate in fish, crustaceans and mollusks, they enter the food chain and can be ingested by human consumers. Microparticles with dimensions of less than 5 mm present a particularly insidious problem. This class of pollutants includes microplastics and textile fibers, as well as synthetic chemicals found in consumer products such as household cleansers and cosmetics. It is therefore imperative to develop methods for quantifying the magnitude of the threat in order to develop effective measures to mitigate it. In a new publication in the journal Environmental Pollution, a research team led by Ludwig-Maximilians-Universitaet (LMU) in Munich Professor Gert Wörheide (Department of Earth and Environmental Sciences, and GeoBio-Center) shows that marine sponges have great potential as bioindicators for the monitoring of microscopic pollutants in the seas.
Sponges are sometimes referred to as the ocean's vacuum cleaners. They feed on tiny particles suspended in the currents, by filtering them from the seawater that passes through their highly porous tissues - which are supported by mineralized skeletons in many species. To assess their utility as bioindicators for microparticulate pollutants, Wörheide and colleagues studied 15 samples of a type of mineralized sponges belonging to the class known as 'demosponges' from a coral reef off the coast of the island of Bangka in Northern Sulawesi (Indonesia). "We chose this site because Southeast Asia is a hotspot for plastic pollutants in the oceans", says Elsa B. Girard, lead author of the study. Girard recently graduated from the Master's Program in Geobiology and Paleobiology at LMU, and her contribution to the paper was part of her Master's thesis. "In light of the impact of global warming, and the overexploitation of marine resources, local sponge species could act as useful biomonitors of micropollutants, and help us to develop appropriate measures to reduce the deleterious effects of these substances on reef communities", she explains.
In cooperation with specialists from the SNSB- Mineralogical State Collection in Munich and LMU's Department of Chemistry and Center for Nanoscience (CeNS), the biologists used two innovative methods to examine the samples collected from the reef. With the aid of two-photon excitation microscopy (TPE), they confirmed that sponges indeed incorporate microparticles into their tissues. Then they used Raman spectroscopy to characterize the nature of the particles themselves. The data obtained with the second technique revealed the presence of no less than 34 different types of microparticles in sponge tissues. The spectrum ranged from plastics such as polystyrene to cotton and titanium dioxide (TiO2). TiO2 is used in dyes and paints, as well as being a component of sunscreen lotions. Furthermore, the variation in the composition of microparticles in the different samples appears to reflect spatial variations in particle type in the surrounding water.
The researchers detected between 90 and 600 particles per gram of dried tissue in their sponge samples. "Since sponges can weigh up to several hundred grams, we estimate on the basis of these results that each can accumulate more than 10,000 particles", says Wörheide. "This makes them promising candidates for the task of monitoring the levels of anthropogenic microparticle pollution in the oceans." With the exception of mollusks, few other species have the properties required of marine bioindicators. According to the authors of the study, sponges have several other "qualifications" for the job. They are abundant and are continuously active as filter-feeders. Moreover, measurements of pollution levels can be carried out on tissue samples (biopsies) without affecting the viability of the organisms.
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Elkhorn coral actively fighting off diseases on reef, study finds
Findings showed coral has core immune response regardless of disease type
UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE & ATMOSPHERIC SCIENCE
CREDIT: PHOTO: MARGARET MILLER, SECORE INTERNATIONAL
MIAMI--As the world enters a next wave of the ongoing COVID-19 pandemic, we are aware now more than ever of the importance of a healthy immune system to protect ourselves from disease. This is not only true for humans but corals too, which are in an ongoing battle to ward off deadly diseases spreading on a reef.
A new study led by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science looked at the immune system of elkhorn coral (Acropora palmata), an important reef-building coral in the Caribbean, to better understand its response to diseases such as white band disease and rapid tissue loss.
In the experiment, healthy corals were grafted to diseased ones. After one week, the corals were analyzed to study the coral's overall gene expression in response to disease, if they exhibited an immune response, and whether there were different signatures of gene expression for corals that didn't show signs of disease transmission. The researchers found that A. palmata has a core immune response to disease regardless of the type of disease, indicating that this particular coral species mounts an immune response to disease exposure despite differences in the disease type and virulence.
"Our results show that elkhorn coral is not immunocompromised but instead is actually actively trying to fight off disease," said Nikki Traylor-Knowles, an assistant professor of marine biology and ecology at the UM Rosenstiel School and senior author of the study. "This gives me hope that the corals are fighting back with their immune system."
Based upon these findings, the researchers suggest that corals that did not get disease may have tougher epithelia, a protective layer of cells covering external surfaces of their body. And, that the symbiotic dinoflagellate, Symbiodiniaceae, that live inside corals did not have differences in gene expression in response to disease, but over the course of the two-year study did develop differences.
Coral disease is considered one of the major causes of coral mortality and disease outbreaks are expected to increase in frequency and severity due to climate change and other man-made stressors. The Caribbean branching coral Acropora palmata which has already seen an 80 percent decrease on reefs primarily due to disease, which has resulted in them being classified as threatened under the US Endangered Species Act.
"These corals are keystone species for Florida reefs, so understanding that their immune systems are active is an important component that can be useful for protecting reefs," said Traylor-Knowles.
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The study, titled "Innate immune gene expression in Acropora palmata is consistent despite variance in yearly disease events," was published October 22, 2020 in the journal PLoS One. The study's coauthors include: Ben Young and Nikki Traylor-Knowles of the UM Rosenstiel School; Former UM student Xaymara Serrano from NOAA's Atlantic Oceanographic and Meteorological Laboratory; Stephanie Rosales from NOAA's Cooperative Institute for Marine and Atmospheric Studies; Margaret Miller from SECORE International and Dana Williams from NOAA's Southeast Fisheries Science Center.
Fipronil, a common insecticide, disrupts aquatic communities in the U.S.
IMAGE: ECOLOGIST JANET MILLER COLLECTS ROCK TRAYS IN THE CACHE LA POUDRE RIVER IN COLORADO. view more
CREDIT: PHOTO COURTESY OF JANET MILLER
The presence of insecticides in streams is increasingly a global concern, yet information on safe concentrations for aquatic ecosystems is sometimes sparse. In a new study led by Colorado State University's Janet Miller and researchers at the United States Geological Survey, the team found a common insecticide, fipronil, and related compounds were more toxic to stream communities than previous research has found.
Fipronil is used in the U.S. for insect control on pets, structures, yards and crops. Most of the streams where fipronil compounds were found to exceed toxic levels were in the relatively urbanized Southeast region.
Miller said the insecticide is likely affecting stream insects and impairing aquatic ecosystems across the country at lower levels than previously thought. In addition, fipronil degrades into new compounds, some of which this study found to be more toxic than fipronil itself.
The research team also found delayed or altered timing of when these insects emerged from streams, which has implications for the connections between stream and land-based communities.
"The emerging insects serve as an important food source," Miller explained. "When we see changes, including a drop in emergence rates or delayed emergence, it's worrisome. The effects can reverberate beyond the banks of the stream."
In experimental settings that had a high concentration of fipronil, the researchers also saw a reduced number of insects that scrape or eat algae off the rocks, leading to an increase of algae in those streams.
Mimicking natural habitats
In this study, the research team studied the effects of fipronil compounds on aquatic macroinvertebrates, insects that live on the rocks and sediment of stream bottoms. Examples of these insects include mayflies, stoneflies and caddisflies. These creatures spend the larval life stage in streams as aquatic invertebrates, later emerging from streams as flying insects.
"These macroinvertebrates serve as an important food source for fish and other organisms while also playing an important role in nutrient cycling ," said Miller, an aquatic ecologist with the Colorado Natural Heritage Program, which is part of the Warner College of Natural Resources at Colorado State University.
As one part of the study, the research team built rock trays to mimic the invertebrate's habitat, and placed them in the Cache La Poudre River in northern Colorado. In these habitats, the macroinvertebrates colonized naturally with algae to mimic communities that exist in nature.
Next, the scientists moved the rock trays containing macroinvertebrates into the lab, mimicking a natural environment while also controlling temperature, light and water flow. The team then added a range of concentrations of the insecticide fipronil or one of four associated fipronil degradate compounds - sulfone, sulfide, desulfinyl and amide - and observed the effects on macroinvertebrates.
Scientists found these degradates to be as toxic, if not more so than fipronil. Yet Miller said there is generally a lack of data for the compounds.
Streams in southeast most affected by fipronil
As an additional prong of the research, Miller and the team applied results from the laboratory experiment to data from a large field study conducted by the United States Geological Survey that sampled streams across the U.S. in five major regions.
Miller said fipronil compounds were detected at unsafe concentrations in 16% of streams sampled across the U.S. and were most prevalent in streams of the Southeast region of the country. Scientists found fipronil compounds much less widespread in other regions, suggesting use patterns of the insecticide differ across the country.
"We found that 51% of sampled streams in the southeast revealed the presence of fipronil, while in the Pacific Northwest, we detected only around 9% of streams with the insecticide," she said.
Miller said that while the results are concerning, it's helpful to have this scientific-based evidence to share with the scientific community and regulating agencies.
"We hope our findings provide greater understanding of the prevalence of fipronil compounds across the country and the levels at which these compounds are harmful to stream health," she said.
