Saturday, February 08, 2020

AMAZON RAINFOREST

Secondary forests provide deforestation buffer for old-growth primary forests

Currently, re-growing forests comprise roughly 21% of previously deforested areas in the Brazilian Amazon. However, these forests, referred to as secondary vegetation, have been little studied, despite occupying a total area similar to that of the United Kingdom.

Now, researchers led by the University of Leeds, the Brazilian National Institute for Space Research (INPE), and Brazilian Agricultural Research Corporation (EMBRAPA) have examined 14 years of data on secondary vegetation formation and cutting in the Brazilian Amazon based on the TerraClass Amazon mapping project.

Their study, published in Nature Sustainability, has found that secondary forests account for an increasing proportion of overall forest loss in the Brazilian Amazon, rising from 32% of total deforestation in 2000 to 72% in 2014.

However, while secondary forest cutting has increased in recent years, deforestation of old-growth primary forests in the Brazilian Amazon remained stable. This suggests that secondary forest loss has eased deforestation pressure on primary forests and their irreplaceable biodiversity and carbon storage.

Study lead author Yunxia Wang, from the School of Geography said: "There in an ongoing demand for new pasture and agricultural land in Brazil. Our study shows that this demand has increasingly been met by secondary forests, providing a buffer that has stalled deforestation of primary forests.

"But the strength of this buffer depends on the area of secondary forest available. The limited legal protection means that secondary forest loss is largely unregulated.

"Not only would easing the strain on secondary forests help Brazil meet climate change targets, as they accumulate carbon very rapidly, but future deforestation would likely lead to increased loss of primary forests once easily accessible secondary forests are diminished."

Brazil has committed to restore 120,000 km2 of forest land by 2030 as part of its Nationally Determined Contribution for the Paris Agreement. The authors suggest that a cost-effective way to do this would be to allow part of its existing Amazonian secondary forest area to recover naturally.

Study co-author Dr. David Galbraith, Associate Professor in Earth System Dynamics at Leeds said: "Managing this ecosystem sustainably to maximize the conservation value of these forests, while not intensifying pressure on primary forests, requires an integrated strategy that includes active monitoring of secondary forests in Amazonia and strengthening of their governance in Brazilian law."

Amazon forest regrowth much slower than previously thought

More information: Yunxia Wang et al. Upturn in secondary forest clearing buffers primary forest loss in the Brazilian Amazon, Nature Sustainability (2020). DOI: 10.1038/s41893-019-0470-4

How some of Earth's most breathtaking landscapes are created by glaciers

by Simon Cook, The Conversation

Glaciers have carved some of Earth's most beautiful landscapes by steepening and deepening valleys through erosion. Think of the Scottish Highlands, Yosemite National Park in the US, or the Norwegian Fjords. But big questions remain about how glacial erosion works.

A problem for scientists seeking to understand how glaciers affect the landscape is that the processes of glacial erosion are very complex and not fully understood. For the most part that's because these processes occur under tens, hundreds or even thousands of meters of ice—we simply can't observe them.

One mystery is why glaciers erode at different rates. Some glaciers are only able to strip away a hair's breadth of bedrock each year. Others cut down several centimeters per year, producing huge amounts of sediment that are washed into meltwater streams, lakes or the sea.

Knowing what controls glacial erosion is important because it helps us manage human activity in environments with active glaciers. For example, hydropower schemes can become silted up by the sediment that is spat out of glaciers into meltwater streams. Equally, the safe burial of radioactive waste in countries like Finland, Sweden and Switzerland must consider the possibility that glaciers could grow in the future and dig out any such waste.

On geological timescales, glacial erosion even influences climate because the tiny bits of ground-up rock that are generated by glaciers are more susceptible to chemical weathering. Chemical reactions between the glacial sediment and the air remove CO₂ from the atmosphere, which leads to cooling.

Glacier speed

Our latest research shows that the speed at which glaciers move, and the climate in which glaciers exist, control how quickly they cut downward into bedrock. We often talk about things moving at a glacial pace if they are slow, but actually glaciers can be relatively fast. Some, such as Meserve Glacier in Antarctica, will barely move at all each year, but others, like Jakobshavn Isbrae in Greenland, will move as much as 40m a day.

This huge variability in velocity can explain huge differences in erosion. This makes sense—the faster the glacier moves, the more it drags particles over the bedrock below, wearing and tearing it away. But until now there's been very little evidence to back this up.

Our study has provided that evidence, showing a strong correlation between sliding velocity and erosion rate for many glaciers. This indicates that velocity is a good predictor of how much erosion a glacier can cause.

But then there's a bigger question of whether there is something even more fundamental that controls glacier speed and erosion.

Recent research suggested that temperature was that underlying factor. Some glaciers (such as in Iceland or Alaska) are actually pretty warm, with temperatures hovering around the freezing/melting point. Others (say, in Antarctica) may have temperatures several tens of degrees below freezing. If a glacier is frozen to the bedrock then it won't slide anywhere and can't cause much erosion. Conversely, if it can slide freely over the rock then it will cause lots of erosion.

The role of climate

Until now, nobody had looked at the other really important aspect of climate—precipitation—and its influence on erosion. We gathered information from glaciers all round the world and showed that the most erosive glaciers are those that are in relatively warm climates with lots of snowfall such as Alaska. Glaciers in colder climates with hardly any snowfall, such as Antarctica, cause very little erosion.

This link between climate and glacial erosion has long-lasting effects. Take Scotland—a country with spectacular, but contrasting, landscapes that have been carved by multiple ice sheets and glaciers over the past two million years. In the west are the Scottish Highlands with deep and broad glacier-carved valleys, such as Glen Coe. In the east, there are the Cairngorms, with a broad, high-altitude plateau exhibiting less erosion. The glaciers that sculpted these landscapes probably experienced different climates.

Today, the west of Scotland is wetter because most of the UK's weather systems come in from the west. In the east, it's much drier (and sunnier). At times of glaciation, the glaciers in the west may have experienced a milder climate and higher rates of snowfall. So these glaciers were more dynamic, faster, and were able to cut the beautiful valleys that we see today.

In the Cairngorms, it would have been much colder and drier, so the ice cover was less able to cut deep valleys. In many ways, Scotland owes its beauty to glaciers, variable climate and erosion.

Scientists find formula for rate of glacial erosion

Researchers study elephants' unique interactions with their dead

by Zoological Society of San Diego

Stories of unique and sentient interactions between elephants and their dead are a familiar part of the species' lore, but a comprehensive study of these interactions has been lacking—until now. A recent review of documented field observations of elephants at carcasses reveals patterns of elephants' behavior toward their dead, regardless of the strength of former relationships with the deceased individual.

The findings, published in the journal Primates, indicate that elephants exhibit a generalized interest in their dead, even after bodies have long decayed—and even if the elephants studied were not closely bonded to the dead individual. The most common behaviors observed were approaching the dead, touching and examining the carcass. Elephants also appeared to use their advanced sense of smell to identify dead individuals, and they were observed vocalizing and attempting to lift or pull fallen elephants that had just died.

The research was led by Shifra Goldenberg, Ph.D., from the San Diego Zoo Institute for Conservation Research and the Smithsonian Conservation Biology Institute, and George Wittemyer, Ph.D., from Save the Elephants and the Department of Fish, Wildlife and Conservation Biology at Colorado State University. The project was funded by Save the Elephants, the National Science Foundation and Colorado State University.

The study consisted of a literature review of 32 original observations of wild elephant carcasses from 12 distinct sources across Africa. Despite variability across sources in methodology, some trends were apparent.

"The most commonly recorded behavior of elephants towards their dead included touching, approaching the dead animal and investigating the carcass," said Goldenberg. "The motivations underlying observed behaviors are hard to know, but clearly varied across circumstances and individuals. For example, some elephants made repeated visits to a carcass, and it's possible that temporal gland streaming by a young female at the site of her mother's carcass is associated with heightened emotion."

Elephants form lasting relationships over decades, and individuals maintain different types of relationships across populations. They live in socially complex, fission-fusion societies, in which social groups divide and merge over time. These complex relationships necessitate recognizing and remembering a wide range of individuals in their species. Not surprisingly, elephants have demonstrated notable cognitive abilities, extensive memory and highly sophisticated olfaction.

"Witnessing elephants interact with their dead sends chills up one's spine, as the behavior so clearly indicates advanced feeling," said Wittemyer. "This is one of the many magnificent aspects of elephants that we have observed, but cannot fully comprehend." When greeting each other after separation, elephants engage in prolonged olfactory and tactile investigation, suggesting that they're constantly updating social and spatial information. It is possible that elephant behavior toward a carcass serves the same purpose as who an elephant interacts with and has important implications in an individual's survival.

The researchers said they hope future studies will be performed to better understand elephant memory and further explore the possibility of grief and emotion in elephants' responses to death.

African elephants demonstrate movements that vary in response to ecological change

More information: Shifra Z. Goldenberg et al, Elephant behavior toward the dead: A review and insights from field observations, Primates (2019). DOI: 10.1007/s10329-019-00766-5

Rejuvenate Bio launches to help dogs live longer, healthier lives

by Harvard University

The Wyss Institute for Biologically Inspired Engineering at Harvard University announced today that Rejuvenate Bio has secured an exclusive worldwide license from the Harvard Office of Technology Development to commercialize a gene therapy technology developed at the Wyss Institute and Harvard Medical School (HMS) to prevent and treat several age-related diseases in dogs, extending their overall healthspan. The announcement follows the publication in PNAS of a study led by Harvard researchers detailing the technology's efficacy in mitigating obesity, type II diabetes, heart failure, and renal failure in mice.

"We are very excited to translate our winning gene therapy work from mice to dogs, where there is a dearth of treatment options to combat age-related diseases," said Daniel Oliver, CEO and co-founder of Rejuvenate Bio, who was formerly an Entrepreneur-in-Residence (EIR) at the Wyss Institute and a Blavatnik Fellow at Harvard Business School, and is a co-author of the PNAS publication.

Rejuvenate Bio has secured funding from the Department of Defense's Small Business Innovation Research program, as well as seed funding from investors and a grant from the American Cavalier King Charles Spaniel Club. With this support, the company has launched a pilot study testing its technology's efficacy in halting mitral valve disease, which strikes the majority of Cavalier King Charles Spaniels by age eight and causes heart failure. Following demonstration of efficacy, they hope to expand their treatment to all dog breeds, as more than 7 million dogs in the US suffer from mitral valve disease.

"We are very passionate about and focused on dogs' health, because so many dog owners around the world have to helplessly watch their beloved pets' quality of life deteriorate as they age," said co-author Noah Davidsohn, Ph.D., who is a co-founder and Chief Technology Officer of Rejuvenate Bio and a former Research Scientist at the Wyss Institute and HMS. "We want to get rid of the morbidities associated with aging, so dogs can be as happy and healthy as possible throughout their lives."

Pull quote: "Science hasn't yet found a way to make complex animals like dogs live forever, so the next best thing we can do is find a way to maintain health for as long as possible during the aging process." George Church

Rejuvenate Bio's technology originated in the lab of co-founder George Church, Ph.D., as part of Davidsohn's postdoctoral research into the genetics of aging. Church is the Robert Winthrop Professor of Genetics in the Blavatnik Institute at HMS and a Core Faculty member of the Wyss Institute. Davidsohn, Church, and their co-authors hypothesized that providing three longevity-associated genes (FGF21, sTGF?R2, and ?Klotho) to mice via a combination gene therapy would combat age-related diseases and confer health benefits. Those three genes have previously been shown to impart increased health and lifespan benefits in mice that were genetically engineered to overexpress them, and the team's goal was to produce the same outcome in non-engineered animals. They created separate gene therapy delivery vehicles for each gene using a serotype of adeno-associated virus (AAV8), and then injected the AAV constructs into mouse models of obesity, type II diabetes, heart failure, and renal failure to see if there was a beneficial effect.

FEBRUARY 6, 2020

Rejuvenate Bio launches to help dogs live longer, healthier lives

by Harvard University

FGF21 alone caused complete reversal of weight gain and type II diabetes in obese, diabetic mice following a single gene therapy administration, and its combination with sTGF?R2 also reduced kidney atrophy by 75% in mice with renal fibrosis. The gene sTGF?R2 alone and in combination with either of the other two gene therapies improved the heart function of mice with heart failure, showing that co-administration of FGF21 and sTGF?R2 could successfully treat all four age-related conditions, thereby improving health and survival.

Importantly, the injected genes remain separate from the animals' genomes, do not modify their natural DNA, and cannot be passed to future generations or between living animals.

"Since the treatment works to suppress fibrotic processes, we believe it could also be applied to other heart diseases such as dilated cardiomyopathy, which eventually leads to congestive heart failure and/or sudden death in affected dogs," said Davidsohn. "We are hopeful that our pilot study will allow us to move toward an animal drug trial with the FDA, which generally takes about three years to complete."

The first gene therapies for humans have been approved by the FDA in recent years, including Spark Therapeutics' Luxturna® for inherited retinal disease and Novartis' Zolgensma® for pediatric spinal muscular atrophy, but these treatments target relatively rare diseases. If Rejuvenate's therapy proves to be both safe and effective in dogs, it could pave the way for similar treatments for common, age-related illnesses in humans.

"Science hasn't yet found a way to make complex animals like dogs live forever, so the next best thing we can do is find a way to maintain health for as long as possible during the aging process," said Church.

"The Wyss Institute is extremely proud of the Rejuvenate team for reaching this milestone on the path to commercialization of a truly novel technology, and we are excited to follow the rest of their journey from the lab to the clinic," said Donald Ingber, M.D., Ph.D., who is the Wyss Institute's Founding Director as well as the Judah Folkman Professor of Vascular Biology at HMS and Boston Children's Hospital, and Professor of Bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).

Combination gene therapy treats multiple age-related diseases

Journal information: Proceedings of the National Academy of Sciences

Water-conducting membrane allows carbon dioxide to transform into fuel more efficiently

by Rensselaer Polytechnic Institute

Methanol is a versatile and efficient chemical used as fuel in the production of countless products. Carbon dioxide (CO2), on the other hand, is a greenhouse gas that is the unwanted byproduct of many industrial processes.

Converting CO2 to methanol is one way to put CO2 to good use. In research published today in Science, chemical engineers from Rensselaer Polytechnic Institute demonstrated how to make that conversion process from CO2 to methanol more efficient by using a highly effective separation membrane they produced. This breakthrough, the researchers said, could improve a number of industry processes that depend on chemical reactions where water is a byproduct.

For example, the chemical reaction responsible for the transformation of CO2 into methanol also produces water, which severely restricts the continued reaction. The Rensselaer team set out to find a way to filter out the water as the reaction is happening, without losing other essential gas molecules.

The researchers assembled a membrane made up of sodium ions and zeolite crystals that was able to carefully and quickly permeate water through small pores—known as water-conduction nanochannels—without losing gas molecules.

"The sodium can actually regulate, or tune, gas permeation," said Miao Yu, an endowed chair professor of chemical and biological engineering and a member of the Center for Biotechnology and Interdisciplinary Studies (CBIS) at Rensselaer, who led this research. "It's like the sodium ions are standing at the gate and only allow water to go through. When the inert gas comes in, the ions will block the gas."

In the past, Yu said, this type of membrane was susceptible to defects that would allow other gas molecules to leak out. His team developed a new strategy to optimize the assembly of the crystals, which eliminated those defects.

When water was effectively removed from the process, Yu said, the team found that the chemical reaction was able to happen very quickly.

"When we can remove the water, the equilibrium shifts, which means more CO2 will be converted and more methanol will be produced," said Huazheng Li, a postdoctoral researcher at Rensselaer and first author on the paper.

"This research is a prime example of the significant contributions Professor Yu and his team are making to address interdisciplinary challenges in the area of water, energy, and the environment," said Deepak Vashishth, director of CBIS. "Development and deployment of such tailored membranes by Professor Yu's group promise to be highly effective and practical."

The team is now working to develop a scalable process and a startup company that would allow this membrane to be used commercially to produce high purity methanol.

Yu said this membrane could also be used to improve a number of other reactions.

"In industry there are so many reactions limited by water," Yu said. "This is the only membrane that can work highly efficiently under the harsh reaction conditions."

Scientists create 'artificial leaf' that turns carbon into fuel

Study shows restrictions on wood burning in Utah dramatically improve air quality DUH OH

by Vincent Horiuchi, University of Utah

A new University of Utah study on the impact of wood burning stoves and fireplaces along Utah's Wasatch Front proves that 20-year-old restrictions have had a tremendous impact on the state's air quality.

"This study is showing a reduction in the contributions of wood burning by a factor of four or five," says University of Utah chemical engineering assistant professor Kerry E. Kelly, who heads the study. "Of the strategies people are looking at to reduce air pollution, this is a pretty effective one."

The study led by the U's College of Engineering was conducted by Kelly, chemical engineering research associate Cristina Jaramillo, as well as researchers from the Utah Division of Air Quality and the Pacific Northwest office of the U.S. Environmental Protection Agency (EPA).

According to the EPA, smoke from burning wood creates tiny particulate matter known as PM 2.5 that can get trapped in the lungs and eyes and trigger asthma attacks, even heart attacks, stroke, and heart failure in people at risk for these conditions. The elderly and children with respiratory conditions are more susceptible to the dangers of bad air quality.

Beginning in 1999, restrictions on wood burning were placed in Salt Lake County and parts of Davis and Utah counties. Over time, limits were also placed in Cache County and parts of Weber, Box Elder and Tooele counties. In all of these areas, the main restriction involves banning wood burning during days of inversion, when atmospheric conditions trap air pollution in the valley. Between November 1 and March 1, residents in these counties are prohibited from using wood fireplaces and stoves, pellet stoves and coal-burning stoves on "no-burn" days, when fine particulate matter builds up to unhealthy levels during winter inversions.

The U study looked at air quality data from 2007 to 2017 at three air quality monitoring stations in Salt Lake City, Lindon and Bountiful. The research showed dramatic reductions at all three stations over the 10-year period, specifically from wood burning, as the restrictions were put in place and residents became more educated about the issue.

Researchers analyzed the combination of elements in the filters at these stations such as metals, nitrate, sulphate, and certain organic material. This data could reveal the origins of PM 2.5 and therefore when the air quality worsened due to wood burning. The analysis also considered the atmospheric conditions at the time the readings were taken, such as whether there was an inversion that day that made the air quality worse.

The results of the study are encouraging, Kelly says, proving that such restrictions can be an effective way of improving air quality, particularly in a valley similar to the Wasatch Front where surrounding mountains act like a bowl to trap bad air.

"More people are aware of these restrictions and are following them, and it's reducing community-level exposure to air pollution," she says. "It can benefit all of us because it's a cost-effective way to reduce pollution. And it's a nice example where research from the U helped influence policy in a positive way. It's important to make data-driven decisions about air quality."

Kelly wants to present the findings to various air quality boards and other policy makers to show their decisions are working. Consequently, other important steps can be considered to help clean the air along the Wasatch Front, such as building more natural-gas fireplaces in new homes and converting wood-burning fireplaces in older homes.

"There has been a lot more public attention on public health and air quality, and as a result people are following the bans," she says. "So there may be more incremental opportunities out there that we can take. As the population continues to grow, we're going to have to stay on top of the issue of air quality."

Indoor wood-burning can affect air quality

Proposed hydropower dams pose threat to Gabon's fishes

by Oregon State University

Proposed hydropower dams in Gabon pose a substantial threat to the African nation's most culturally and economically important fishes, according to a new study.

The study, published today in the journal Ecosphere, is the first of its kind to predict the distribution of fishes throughout central African freshwaters by linking museum records to ecological data. That synthesis allowed the study's authors to infer how the nearly 40 dams planned for construction in Gabon might affect its many fish species.

Many of the culturally and economically important fish species in Gabon move from the ocean into rivers, with some known to swim up to 250 miles upstream into pure freshwaters.

Gabon has some of the world's most pristine unimpeded river systems and high freshwater biodiversity. The proposed dams will block access to much of the freshwater habitat that is also suitable for marine species and will impact at least 350 fish species, said Brian Sidlauskas, study co-author and associate professor at Oregon State University.

"Our modeling found that particularly in Gabon's second-largest river, the Nyanga, dam development could cut marine fishes off from 60% of the most suitable freshwater habitats, representing 392 river kilometers," Sidlauskas said.

Previous research shows that freshwater ecosystems are among the most imperiled in the world and approximately 20% of the assessed freshwater fishes are threatened with extinction, and that dams are causing major shifts in species distribution and abundance, including extinctions.

There are three free-flowing rivers at least 500 kilometers in length in Gabon: the Ivindo, the Nyanga, which is currently undammed, and the Ogooué. While the 38 proposed dams in Gabon, including 28 in the Ogooué watershed, can increase energy production, they would fragment and alter relatively pristine river systems, according to the study co-authors.

Potentially impacted fish species include the Giant African threadfin, snappers, croakers, bonga shad, mullets, Atlantic tarpon and tongue soles. Though these fishes are known to enter rivers regularly as adults or as juveniles, most of the 38 potential dam sites have never been scientifically surveyed for their presence, and no previous formal studies of fish movement within Gabon's freshwater ecosystems had been conducted.

For their study, researchers at OSU and University of California, Santa Cruz, compiled records for fresh and brackish water fishes of Gabon and Equatorial Guinea from three databases, and grouped them by guilds. An ecological guild is any group of species that exploits the same resources, or that exploit different resources in similar ways.

The research team used a geographic information system to record river data to create two connectivity scenarios: one under existing dams and one with the proposed dams.

The model used guild data, which included traits and prevalence; topography, including tree canopy cover, waterfalls or steep changes in elevation, and other hydrological information.

The model predicted marine-associated fishes had a high likelihood of occupying the Nyanga and its major tributaries and much of the Ogooué's main channel, as well as portions of its major tributaries.

Construction of all the proposed dams might lead to a loss of access to 7% of highly suitable habitats, or 466 stream kilometers. These losses were largest on the Nyanga, Ogooué, Mvoung, Lolo, Komo and Okano rivers.

Planned hydropower dams threaten fish in the tropics

More information: Joseph S. Cutler et al, Habitat loss due to dam development may affect the distribution of marine‐associated fishes in Gabon, Africa, Ecosphere (2020). DOI: 10.1002/ecs2.3024

Whales coordinate deep dives to evade predators

by Nature Publishing Group

Groups of beaked whales reduce predation risk through extreme diving synchronization, according to a study in Scientific Reports. This behaviour has not been observed in other deep diving whales and the underlying reasons have remained unclear.

Natacha Aguilar de Soto, Mark Johnson and Peter Madsen and colleagues analysed data on 26 beaked whales carrying sensors that tracked the depths they swam to, the steepness of their dives, and the sounds they made.

The authors observed that the whales performed closely coordinated deep dives in order to forage using echolocation (using sounds to search for prey) but limited vocalizations at shallow depths where they are vulnerable to hunting by killer whales. Beaked whales began vocalizations at an average depth of 450 metres before searching for food individually. Whales then reunited as a group at an average depth of 750 metres and ascended silently to the surface at a shallow angle covering an average horizontal distance of one kilometre.

The authors suggest that by limiting vocalizations to depths out of the range of killer whale attacks and surfacing at unpredictable locations, beaked whales prevent killer whales from tracking them. However, the authors note that this strategy is costly; long silent ascents from dives lasting more than one hour reduce foraging time by around 35% compared to the diving strategies used by other toothed whales.

The findings suggest that predation risk may have been a strong evolutionary force driving the unique diving and vocal behaviour of beaked whales.

Echolocation found to be cheap for deep-diving whales

More information: Fear of Killer Whales Drives Extreme Synchrony in Deep Diving Beaked Whales, Scientific Reports (2020). DOI: 10.1038/s41598-019-55911-3

Journal information: Scientific Reports

8 things we do that really confuse our dogs

by Melissa Starling and Paul McGreevy, The Conversation

Dog behaviour is extraordinarily flexible—this is why we can keep them in our homes and take them to cafes with us at the weekend.

Nevertheless, there are ways in which evolution has not equipped dogs for the challenges of living in our world, and puppies must learn how to cope.

These are some of the things we do they struggle to understand.

1. We leave them alone

As born socialites, dogs make friends easily. Puppies are intensely interested in spending time with other dogs, people, and any species willing to interact with them socially. They usually play, rest, explore and travel with company. Yet we often leave dogs alone: at home, in kennels or the vet clinic.

In these situations, naive dogs can't be sure we'll ever return to collect them. Only after experience are they likely to expect a reunion, and even then, their experience depends on the context.

At home, we may try to enforce dog-free zones. Naturally, many dogs protest. How can they stay with their (human) social group when they're separated behind impenetrable barriers (doors)? This explains why dogs so often demand to be let inside when their human family is there, and why those with separation-related distress frequently find some solace in being indoors.

2. We are visually driven

Dogs live in an olfactory world, while ours is chiefly visual. So, while TVs may offer a visual feast for humans, parks and beaches are an olfactory banquet for dogs.

An additional challenge is dogs move while investigating the world, whereas we often sit still. They may not relish the inertia we enjoy in front of a noisy, flashing light-box.

3. We change our shape and smell

Shoes, coats, wallets, briefcases, bags and suitcases: countless smells cling to these items after we take them into shops and workplaces, then back to our dogs. Cleaning products, soaps, deodorants and shampoos also change the scents our dogs are used to.

Towels, hats and bags change our shape when we're using them. And when we're pulling them on, jumpers and coats alter our visual outline and may catch dogs unaware.

Dogs change their coats at least once a year. In contrast, we change our external cladding every day. This means the odours we carry are changing far more than dogs have evolved to expect.

In their olfactory world, it must be puzzling for dogs to encounter our constantly changing smells, especially for a species that uses scent to identify familiar individuals and intruders.

4. We like to hug

How humans use their forelimbs contrasts sharply with how dogs do. We may use them to carry large objects a dog would have to drag, but also to grasp each other and express affection.

Dogs grasp each other loosely when play-wrestling, and also when mating and fighting. Being pinned by another dog hinders a quick escape. How are puppies to know what a hug from a human means, when that behaviour from a dog might be threatening?

5. We don't like to be bitten

Play-fighting is fun for many puppies and helps them bond with other dogs. But they must monitor the behaviour of other dogs in play-fights and know when they've used their tiny, razor-sharp teeth excessively.

Humans are much more susceptible to pain from playful puppy jaws than other dogs are, and so we can react negatively to their attempts to play-fight with us.

Dogs interact with objects almost entirely with their muzzle. And to feed, they use their jaws, teeth and tongue.

Dogs also "mouth" other dogs when playing, expressing affection and communicating everything from "more" to "please don't" to "Back off!". So, naturally, they try to use their mouths when communicating with us, and must be puzzled by how often we take offence.

6. We don't eat food from the bin

Dogs are opportunists who naturally acquire food anywhere they find it. In contrast, we present them with food in dishes of their own.

Puppies must be puzzled by our reaction when we find them snacking from benches and tables, in lunchboxes and kitchen bins. We should not be surprised when dogs unearth food we left somewhere accessible to them.

7. We share territories

We visit the territories of other dogs, bringing back their odours, and allow unfamiliar human and canine visitors to enter our dogs' home. Dogs have not evolved to accept such intrusions and threats to their safety and resources.

We shouldn't be surprised when our dogs treat visitors with suspicion, or when our dogs are treated with hostility when we bring them to the homes of others.

8. We use our hands a lot

Sometimes our hands deliver food, scratches, massages and toys. Other times, they restrain dogs, trim nails, administer ointments or tablets, and groom with brushes and combs that may pull hair.

No wonder some dogs grow to fear the human hand as it moves about them. We can make it easier for dogs to accept many types of hand-related activities if we train them to cooperate with rewards.

But humans often misread their fear and may even greet it with violence which compounds the problem. Hand-shy dogs can easily become defensive and find their way into pounds and shelters, where life expectancy for nippers and biters is poor.

On the whole, dogs show a remarkable ability to adapt to the puzzles we throw at them. Their behavioural flexibility offers us lessons in resilience and how to live simply and socially. Our challenge is to understand the absence of guile and malice in everything they do.

Microplastics sticking to Orkney's seagrass beds

by Heriot-Watt University

Microplastics are accumulating in Orkney's seagrass beds at much higher rates than in the areas surrounding them. Marine scientists from Heriot-Watt surveyed a 100m transect of a seagrass bed in Orkney and found microplastics on all seagrass blades and in over 94% of all samples collected.

Microplastic pollution is now common in marine environments, with areas like rivers and estuaries particularly vulnerable to high levels of pollution.

The scientists measured the presence of microplastics in Orkney's seagrass beds by taking samples of seagrass and the small creatures that live on the blades, like sea snails, shrimp-like amphipods, worms, as well as sediment from the seabed. The team confirmed that the seagrass bed was home to much higher concentrations of microplastics than the adjacent sediment.

Dr. Mark Hartl from Heriot-Watt University in Edinburgh said:

"Seagrasses are very sensitive habitats and perform a number of critical functions. They bind and characterise the shoreline, create habitats for other species and protect them from predators.

"Every blade of seagrass we examined had microplastic flakes, fibres or fragments sticking or adhering to it.

"We did notice that the number of microplastics varied depending on where the blade was along the transect line, but this was likely influenced by slight differences in the density of seagrass canopy cover and reflects the generally patchy nature of microplastics contamination."

Increased exposure to microplastics

The research found that the water above the seagrass beds contained more than double the average amount of microplastics in bare sediment, while seagrass blades were around 20% higher. The seagrass sediment was around 40% higher.

The average number of microplastics found in the sea snails and other grazing creatures matched the average number found on the seagrass blades. This suggests that seagrass grazers may be exposed to more microplastics than sediment-dwelling organisms.

The research, published in the Marine Pollution Bulletin, was undertaken as an MSc project within Heriot-Watt's MSc in Marine Science. It was carried out by Dr. Angela Capper, Dr. Mark Hartl, Dr. Mike Bell and MSc student Katherine Jones.

Follow-up study

Dr. Capper is also looking at this issue on a larger scale along the Central Queensland coast of Australia with the Coastal Marine Ecosystems Research Centre (CMERC) at Central Queensland University, to determine the extent and mechanisms involved in microplastic loading in seagrass canopies and potential impacts to grazing organisms.

Dr. Capper, based at Central Queensland University, Australia said:

"The impact of microplastics on marine creatures and environments isn't fully understood.

"It is concerning, however, that such a sensitive habitat is sequestering such high concentrations of microplastics. The species that live in seagrass beds, and in particular the larval and juvenile fish, will be vulnerable to any negative impacts associated with microplastics.

"A follow-up larger-scale study on the microplastics contamination of Orkney seagrass beds is currently being prepared for publication."

Microplastics from ocean fishing can 'hide' in deep sediments

More information: Katherine L. Jones et al. Microplastic accumulation in a Zostera marina L. bed at Deerness Sound, Orkney, Scotland, Marine Pollution Bulletin (2020). DOI: 10.1016/j.marpolbul.2020.110883

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Saturday, February 08, 2020

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