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)
Tuesday, April 25, 2023
Paul Hessburg receives Distinguished Landscape Ecologist Award
Hessburg is a senior research ecologist with the USDA Forest Service's Pacific Northwest Research Station based at the Wenatchee Forestry Sciences Laboratory. He was honored for a highly diverse career that has "greatly enhanced the capacity of landscape practitioners to develop strategies and tactics to restore landscapes and adapt them to climate change." His contributions to major landscape assessment projects, including the Northwest Forest Plan science synthesis and Interior Columbia River Basin Ecosystem Management Project, also were noted.
Hessburg—who holds a Ph.D. from Oregon State University in forest entomology and pathology—has authored more than 230 publications, amassing more than 12,000 citations. He also has given more than 800 scientific and professional talks and more than 150 presentations to the public on the importance of fire in western ecosystems.
He received the award at the annual conference of the International Association for Landscape Ecology-North America chapter held in Riverside, California, in March.
The USDA Forest Service's Pacific Northwest Research Station--headquartered in Portland, Ore.--generates and communicates scientific knowledge that helps people make informed choices about natural resources and the environment. The station has 11 laboratories and centers located in Alaska, Washington, and Oregon and about 300 employees. Learn more online at https://www.fs.usda.gov/research/pnw.
Recycling lake sediments for crop production: A sustainable solution for closing the phosphorus cycle
IMAGE: AERIAL VIEW OF THE EXCAVATION PROCESS AT EUTROPHIC LAKE MUSTIJÄRV, LOCATED IN VILJANDI, ESTONIA, TAKEN IN AUGUST 2016.view more
CREDIT: KRISTJAN LUST
A four-year field experiment conducted on the shores of restored Lake Mustijärv in Viljandi, Estonia, has revealed that recycling phosphorus-rich lake sediments back to agriculture could have positive impacts on crop production.
The study was conducted by doctoral researcher Mina Kiani and the AgriChar research group, and it is globally the first of its kind to cover the environmental aspects of recycling lake sediments to agriculture over several years. Kiani defends her thesis on 21 April at the University of Helsinki Faculty of Agriculture and Forestry.
The study aimed to find a sustainable solution for closing the leaking agricultural phosphorus (P) cycle by recycling P-rich lake sediments back to agriculture and helping the restoration of the eutrophic lake by sediment removal. The experiment involved excavating all 7500 m3 of sediment from the 1-hectare shallow eutrophic Lake Mustijärv, which was then used as a growing medium for grass production. The sediment was also analysed for various essential nutrients, including P, sulphur (S), calcium (Ca), magnesium (Mg), boron (B), zinc (Zn), and copper (Cu).
The results showed that sediment-based growing media sustained the grass biomass yield in the field condition, with the sediment being rich in organic matter and a good source of several essential nutrients. Additionally, the sediment continuously provided a moderate supply of N to the plants over the four-year field experiment.
The study also investigated the environmental impacts of various sediment application methods, including greenhouse gas emissions, N and P leaching, aggregate stability, and soil biota. Sediment-based growing media had different bacterial and fungal community compositions compared with soil, and it increased the risk of P and mineral N leaching. Biochar application increased the amount of N taken up by the plants but did not significantly reduce emissions or leaching.
The sediment application rate should be adjusted to match crop requirements, similar to how fertilizers are applied. This can help minimize nutrient leaching back into the lake and further help mitigate eutrophication of the lake.
Furthermore, in this project, the changes in P dynamics at the sediment–water interface in the restored lake were examined during a two-year follow-up period. Theoretically, no markable sediment P release could appear after complete sediment removal. Nevertheless, a large pool of releasable P was rebuilt soon after sediment removal due to an exceptionally high nutrient flow from the catchment. Particularly large quantities of sediment, most likely originating from the stream bed cleaning upstream of the lake, concentrated into the sediment accumulation basins, i.e. deeper parts of the lake created as a part of the lake restoration project. Regularly emptying such sediment accumulation basins may help to efficiently entrap point source nutrient inputs and facilitate future lake restoration efforts.
Mina Kiani and Olga Tammeorg are collecting sediment samples from the Lake Mustjärv to evaluate its condition after being restored through complete sediment removal.
IMAGE: RED JUNGLEFOWL, THE SPECIES FROM WHICH THE CHICKEN WAS DOMESTICATED (PHOTO: MASAKI EDA).view more
CREDIT: MASAKI EDA
Conclusive evidence of chicken breeding in the Yayoi period of Japan has been discovered from the Karako-Kagi site.
The chicken is one of the most common domesticated animals, with a current estimated population of over 33 billion individuals. They are reared for their meat and eggs, and may be kept as pets.
The chicken is believed to have been domesticated in Southeast Asia about 3500 years ago, following which they were carried to all corners of the world. The exact date of introduction of chicken breeding to Japan is under debate, as there are no historical records and archeological evidence is inconclusive.
Professor Masaki Eda at the Hokkaido University Museum led a team to uncover the earliest conclusive evidence of chicken breeding in Japan. The findings, which show chickens were bred in the Karako-Kagi site, a settlement from the Yayoi period [5th century BCE to around 2nd century BCE], were published in the journal Frontiers in Earth Sciences.
“Chickens and their wild relatives belong to a family of birds called Phasianids, which includes pheasants, turkeys and quail,” explains Eda. “Bones of juvenile phasianids recovered from archeological sites could not indisputably be identified as belonging to chickens or to similarly sized wild pheasants. Identification of juveniles is important, as it would indicate that breeding of chickens took place.”
The Karako-Kagi site, in what is now Tawaramoto Town, Nara Prefecture, is considered to be a settlement that played the role of a leader of the Kinki region during the Yayoi period. There are multiple archeological digs in the area; one such dig, at the 58th research point, yielded ten phasianid bones, four of which belonged to juvenile birds.
The team used a technique called Zooarchaeology by Mass Spectrometry (ZooMS) to analyze the collagen in two of the juvenile phasianid bones. Previous work by Eda had shown that domestic chicken and Japanese wild pheasants had different ZooMS fingerprints; ZooMS revealed that both the two bones belonged to chickens. The collagen from one of the bones was also carbon dated to 381–204 BCE, corresponding to the middle Yayoi period.
“Ten of the eleven previously-discovered bones of adult chickens from this period have all belonged to males; hence, it was thought chicken breeding could not have occurred on the Japanese archipelago,” Eda elaborated. “By identifying bones from juvenile chickens, we provide clear evidence that breeding did occur in that time period—which is also the earliest time chickens could have been introduced to Japan. In addition, Karako-Kagi is considered an important trade hub of the Yayoi period, so there is a possibility that this status is a factor in chicken breeding during the period.”
The archeological discoveries of chickens in Japan show that the human-chicken relationship was very different from that revealed by archeological studies in China and in Europe. Future research will focus on understanding these differences.
The bones examined in this study were discovered at the 58th research point in the Karako-Kagi site (Masaki Eda, et al. Frontiers in Earth Science. April 20, 2023).
The two bones from the Karako-Kagi site identified as belonging to juvenile chickens by the Zooarchaeology by Mass Spectrometry technique (Masaki Eda, et al. Frontiers in Earth Science. April 20, 2023).
CREDIT
Masaki Eda, et al. Frontiers in Earth Science. April 20, 2023
The earliest evidence of domestic chickens in the Japanese Archipelago
ARTICLE PUBLICATION DATE
20-Apr-2023
African penguins: climate refugees from a distant past?
A new study on the paleo-historical geographic range of the endangered African penguin since the last Ice Age paints a grave picture of a species in steep decline
IMAGE: THIS IS THE PALEO-HISTORICAL PICTURE OF THE GEOGRAPHICAL RANGE OF AFRICAN PENGUINS OVER THE PAST 22 000 YEARS. SCIENTISTS AT STELLENBOSCH UNIVERSITY’S (SU) SCHOOL FOR CLIMATE STUDIES HOPE TO PROVIDE NEW INSIGHT INTO THE CURRENT VULNERABILITY OF THE LAST REMAINING PENGUIN SPECIES IN AFRICA. THE STUDY, TITLED “A NATURAL TERMINAL PLEISTOCENE DECLINE OF AFRICAN PENGUIN POPULATIONS ENHANCES THEIR ANTHROPOGENIC EXTINCTION RISK” WAS PUBLISHED IN THE AFRICAN JOURNAL OF MARINE SCIENCE ON 20 APRIL 2023.view more
CREDIT: INFOGRAPHIC: JENNY FROST
Imagine the view from the western coastline of southern Africa during the Last Glacial Maximum (LGM) over twenty thousand years ago: in the distance you would see at least fifteen large islands – the largest 300 square kilometres in area – swarming with hundreds of millions of marine birds and penguin colonies.
Now imagine sea levels rising up to a hundred metres between fifteen to seven thousand years ago, gradually covering these large islands until only small hill tops and outcrops remained above water. Over the past 22 000 years this resulted in a tenfold reduction in suitable nesting habitat for African penguins, sending their population numbers into steep decline.
This is the paleo-historical picture of the geographical range of African penguins, created by scientists in the evolutionary genomics research group in the Department of Botany and Zoology and the School for Climate Studies at Stellenbosch University (SU). With this effort, they hope to provide new insight into the current vulnerability of the last remaining penguin species in Africa.
Dr Heath Beckett, first author of the article and postdoctoral fellow at SU’s School for Climate Studies, says this paleo-historical image of multiple millions stands in stark contrast to the current reality of a post-1900 collapse of the African penguin population.
In 1910, Dassen Island (an island off the West Coast, about three square kilometres in area) was teeming with an estimated 1.45 million penguins. However, by 2011 South Africa’s entire African penguin population collapsed to 21 000 breeding pairs, and by 2019 they further declined to only 13 600. Approximately 97% of the current population in South Africa is supported by only seven breeding colonies.
In May 2005 the International Union for the Conservation of Nature classified the African penguin as endangered.
Paleo-historical estimates of penguin population sizes
So how did the southern and western coastlines of southern Africa look like during the last Ice Age? And what can it tell us about penguin population numbers?
As penguins prefer to breed on islands to escape mainland predators, the researchers used topographic maps of the ocean floor off the coast of southern Africa to identify potential historical islands lying at ten to 130 metres below current sea levels.
For islands to qualify as suitable for penguins they needed to offer protection from land-based predators and had to be surrounded by suitable foraging grounds for sardine and anchovy within a 20 kilometre radius.
Today the five largest islands off the West Coast of Southern Africa are Robben Island (~5 km2), Dassen Island (~3 km2), Possession Island (~ 1.8 km2) and Seal Island and Penguin Island (both below 1 km2). Possession, Seal and Penguin Island are all off the coast of Namibia.
Based on the earliest available population density estimates, they then calculated penguin population estimates based on available island area, assuming that penguins usually nest at most 500 metres from the shore.
Following this approach, they estimate that between 6.4 million and 18.8 million individuals could have occupied the southern Cape waters during the Last Glacial Maximum. Due to rising sea levels, however, 15 000 to seven thousand years ago, the habitat for the African penguins to nest on, went into a steep decline.
According to Dr Beckett, the main objective of the study is to show that there have been major changes in habitat availability over the last 22 000 years: “This could have had a massive effect on penguin populations. These populations are now experiencing additional human pressures on top of this in the form of climate change, habitat destruction and competition for food,” he explains.
Implications for conservation management
While this finding raises grave concerns, the researchers argue that it also highlights the potential for a reserve of resilience in African penguins that may be leveraged for its conservation and management in an uncertain future.
Dr Beckett explains: “Changing sea levels would have necessitated the need for multiple relocations of breeding colonies of African penguins on time-scales of centuries, if not even shorter time-scales, and intense competition for breeding space as island habitat became greatly reduced in size. This historical flexibility of response provides some leeway for conservation managers to make available suitable breeding space, even in mainland sites, as long as appropriate nesting sites are made available”.
According to Prof. Guy Midgley, interim director of SU’s School for Climate Studies and a co-author, this millennial-scale set of selection pressures would have favoured strong colonisation ability in the species: “It’s a total survivor and given half a chance, they will hang on. Island hopping saved it in the past, they know how to do this,” he emphasised.
But even given the chance of relocation, how much more will it take to persist given the rise of modern human pressures? When competing against the commercial fishing industry and humanity in general for the same food source, penguins – and other marine life – may not stand a chance.
Therefore, “for any relocation measures to be successful,” they warn, “sufficient access to marine food resources remain a vital element of a coordinated response to prevent extinction of the species”.
A natural terminal Pleistocene decline of African penguin populations enhances their anthropogenic extinction risk
ARTICLE PUBLICATION DATE
20-Apr-2023
Polar ice sheet melting records have toppled during the past decade
The seven worst years for polar ice sheets melting and losing ice have occurred during the past decade, according to new research, with 2019 being the worst year on record.
IMAGE: GRAPH FROM IMBIE SATELLITE DATA RESEARCH SHOWING THE INCREASING CONTRIBUTION OF ICE SHEETS TO GLOBAL SEA LEVEL FROM 1992 TO 2020.view more
CREDIT: IMBIE / CPOM AT NORTHUMBRIA UNIVERSITY
The seven worst years for polar ice sheets melting and losing ice have occurred during the past decade, according to new research, with 2019 being the worst year on record.
The melting ice sheets now account for a quarter of all sea level rise – a fivefold increase since the 1990’s – according to IMBIE, an international team of researchers who have combined 50 satellite surveys of Antarctica and Greenland taken between 1992 and 2020.
Global heating is melting the polar ice sheets, driving up sea levels and coastal flooding around our planet. Ice losses from Greenland and Antarctica can now be reliably measured from space by tracking changes in their volume, gravitational pull, or ice flow.
They have found that Earth’s polar ice sheets lost 7,560 billion tonnes of ice between 1992 and 2020 – equivalent to an ice cube that would be 20 kilometres in height.
The polar ice sheets have together lost ice in every year of the satellite record, and the seven highest melting years have occurred in the past decade.
The satellite records show that 2019 was the record melting year when the ice sheets lost a staggering 612 billion tonnes of ice.
This loss was driven by an Arctic summer heatwave, which led to record melting from Greenland peaking at 444 billion tonnes that year. Antarctica lost 168 billion tonnes of ice – the sixth highest on record – due to the continued speedup of glaciers in West Antarctica and record melting from the Antarctic Peninsula. The East Antarctic Ice Sheet remained close to a state of balance, as it has throughout the satellite era.
Melting of the polar ice sheets has caused a 21 mm rise in global sea level since 1992, almost two thirds (13.5 mm) of which has originated from Greenland and one third (7.4 mm) from Antarctica.
In the early 1990s, ice sheet melting accounted for only a small fraction (5.6 %) of sea level rise. However, there has been a fivefold increase in melting since then, and they are now responsible for more than a quarter (25.6 %) of all sea level rise. If the ice sheets continue to lose mass at this pace, the IPCC predicts that they will contribute between 148 and 272 mm to global mean-sea level by the end of the century.
Professor Andrew Shepherd, Head of the Department of Geography and Environmental Sciences at Northumbria University and founder of IMBIE, said: “After a decade of work we are finally at the stage where we can continuously update our assessments of ice sheet mass balance as there are enough satellites in space monitoring them, which means that people can make use of our findings immediately.”
Dr Inès Otosaka from the University of Leeds, who led the study, said: “Ice losses from Greenland and Antarctica have rapidly increased over the satellite record and are now a major contributor to sea level rise. Continuously monitoring the ice sheets is critical to predict their future behaviour in a warming world and adapt for the associated risks that coastal communities around the world will face.”
This is now the third assessment of ice loss produced by the IMBIE team, due to continued cooperation between the space agencies and the scientific community. The first and second assessments were published in 2012 and 2018/19.
Over the past few years, ESA and NASA have made a dedicated effort to launch new satellite missions capable of monitoring the polar regions. The IMBIE project has taken advantage of these to produce more regular updates, and, for the first time, it is now possible to chart polar ice sheet losses every year.
This third assessment from the IMBIE Team, funded by the ESA and NASA, involved a team of 68 polar scientists from 41 international organisations using measurements from 17 satellite missions, including for the first time from the GRACE-FO gravity mission. Importantly, it brings the records of ice loss from Antarctica and Greenland in line, using the same methods and covering the same period in time. The assessment will now be updated annually to make sure that the scientific community has the very latest estimates of polar ice losses.
Dr Diego Fernandez, Head of Research and Development at ESA, said: “This is another milestone in the IMBIE initiative and represent an example of how scientists can coordinate efforts to assess the evolution of ice sheets from space offering unique and timely information on the magnitude and onset of changes.
“The new annual assessments represent a step forward in the way IMBIE will help to monitor these critical regions, where variations have reached a scale where abrupt changes can no longer be excluded.”
There have been several studies pointing to an impairment of the cognitive abilities of pregnant women. A new Tel Aviv University study reveals that bats, too, experience a decline in their ability to hunt and orient in space during pregnancy. This impairment stems from the fact that they produce about 20 percent fewer calls, the sounds that allow them to orient themselves using echolocation, on top of flying at a slower pace and at a lower altitude. The researchers highlight the fact that, to the best of their knowledge, this is the first evidence of pregnancy affecting mammals’ sensory abilities.
The study was led by Mor Taub, a research assistant in the laboratory of Prof. Yossi Yovel, head of Tel Aviv University’s Sagol School of Neuroscience and faculty member of the School of Zoology, Wise Faculty of Life Sciences. The study’s findings were published in the journal BMC Biology.
Mor Taub explains: “At the peak of pregnancy, bats carry about 20 percent more than their normal body weight, and it is clear that this excess weight impacts their flying capacity. In this study, we wanted to check whether and to what extent pregnancy affects bats’ echolocation ability, their sonar. Bats’ sonar is based on the emitting and receiving of strong and frequent sounds in order to map their surroundings. To make these sounds, bats, like us humans, need to transfer high-pressure air from the lungs through the vocal cords, or vocal membranes, which involves many muscles, such as the chest and diaphragm. We wanted to see if the excess weight from pregnancy affects the production of sounds.”
To this end, Prof. Yovel and his colleagues taught bats to search for and land on a small landing pad in a flight room in the bat laboratory at Tel Aviv University’s Garden for Zoological Research. They recorded the echolocation of two groups: pregnant bats and non-pregnant bats. The researchers found that the rate at which the pregnant bats emitted sounds was significantly lower than that of the control group, with 20 percent greater intervals between each sound.
Prof. Yovel: “Bats change the rate of the sounds they make in accordance with the level of difficulty of the task. The average rate is about 10 calls per second, but when the bat lands, this rate can increase to 100 calls per second. The pregnant bats produced sounds at a rate of only about seven per second, and flew a little slower and lower. Obviously, this slowing down is likely to affect their hunting. When a bat makes fewer calls, it gathers less information about the environment, its chance of colliding with objects increases, and its chance of finding food decreases — and this is at a time when the bat needs extra food to sustain the fetus in its womb. In the second phase of the study, we used a computer simulation to simulate the effect of the decreased rate of calls on the bats’ performance, and indeed, we saw that the slowed rate makes it more difficult for the bats to locate prey.”
The bats in the experiment were of the Kuhl's pipistrelle species, tiny bats that weigh only about six grams (when they are not pregnant). These bats are very common in Israel, and feed mainly on mosquitoes. Despite their weight, bats can live for decades, and their pregnancies are therefore also relatively long, lasting about four months. Previous studies conducted on other species of bats have shown that during pregnancy, bats tend to change their diets. To date, the assumption was that this change in diet was due to the bats’ difficulty in flying, but the current study raises the possibility that the change may also be due to their sensory difficulty in detecting certain types of prey.
“This is the only evidence we found in the professional literature showing that pregnancy affects mammals’ sensory abilities,” says Mor Taub. “We assume that there are similar cases in other species as well, but this is the first time that researchers have been able to measure and demonstrate the impairment empirically. Beyond the scientific interest, it is important to preserve mammal species in the wild, especially during pregnancy and newborn care, since animals are particularly vulnerable during this period.”
POHANG UNIVERSITY OF SCIENCE & TECHNOLOGY (POSTECH)
Last summer, metropolitan areas of Korea including Seoul were hit by an unprecedented heavy rainfall, which inundated various locations. Similarly, torrential downpours engulfed about one-third of Pakistan, leading to widespread flooding. New York State was not spared as it experienced heavy snowstorms in December of last year, with snowfall of more than one meter.
These events underscore a multitude of extreme weather phenomena that the world is currently grappling with. Last year was the 5th hottest year on record since modern temperature recordkeeping began in 1850 (according to the EU Commission’s climate change monitoring agency). Unfortunately, environmental pollution remains a key driver of extreme weather patterns. The harmful substances in our daily lives and air pollutants released by factory chimneys continue to afflict the Earth. To mitigate this situation, it has become necessary to promote green renewables. This measure can help to reduce carbon emissions and harmful substances, ultimately fostering a more sustainable coexistence between humanity and the planet.
A research team led by Professor Taiho Park, and PhD candidates Dohyun Kim, Hyuntae Choi, and Wooteak Jung from the Department of Chemical Engineering at POSTECH, Dr. Nam Joong Jeon from Korea Research Institute of Chemical Technology (KRICT), and Professor Seulki Song from the Department of Chemical Engineering and Applied Chemistry at Chungnam National University successfully developed novel additives for perovskite film treatment, which have been found to enable the production of highly efficient and stable perovskite solar cells. The research findings have been published in Energy & Environmental Science, a prestigious journal in the fields of energy and the environment.
The perovskite solar cell (PSC) is a type of solar cell that includes a perovskite-structured compound. Owing to its easy and affordable fabrication process, PSC has garnered significant attention as a next-generation solar cell. However, it is susceptible to moisture and surface defects, which undermines its power conversion efficiency. To improve its stability and efficiency, the removal of surface defects from perovskite film is deemed essential. The conventional approach to surface treatment has involved dissolving the passivating material in a solvent and adding it to the surface. However, this method has presented challenges, such as solvent vapor leading to the solidification of the additive impeding the removal of the surface defects.
The research team introduced a novel engineering approach for the surface treatment of PSCs, using an additive named alkylammonium formats (AAFos). AAFos comprises a cation and a pseudo-halide anion which remain in a liquid state even at relatively low temperatures due to their weak coordination. The team focused on the phase transition of AAFos from solid to liquid, which facilitated the elimination of defects on the perovskite film surface. After undergoing brief thermal treatment, AAFos transformed from a solid to a liquid state, eliminating the defects on the film surface before solidifying back into a stable state at room temperature. The pseudo-halide anion of AAFos has a higher affinity for halide defects, which results in surface defect passivation while the long alkyl chain of the cation improves moisture stability by preventing moisture permeation into the perovskite layer.
The team’s experimental findings confirm that power conversion efficiency can be increased. With the use of AAFos, the team achieved a power conversion efficiency of 25% from a PSC active area and an impressive fill factor3 of 80.77% in the same PSC module, which is the world’s highest level. Furthermore, in a PSC module with a large active area of 23.75cm2, the efficiency was 20.82%, overcoming the limitations of traditional solar cells where a larger active area typically results in lower efficiency and fill factors.
The development of renewable energy, particularly solar cells, seems to have transitioned from being an option to being a mandate of late. The team’s work holds the potential to position perovskite solar cells as the next generation of solar cells and emphasizes their ability in being utilized over large active areas.
This study was conducted with the support from the National Research Foundation of Korea.
