Scientists are investigating whether the loss of green spaces is linked to asthma among Kiwi kids, in a new study that could have global implications.
A team of researchers from Massey and Otago universities are taking a deeper look at the connection, following earlier work that followed tens of thousands of children.
New Zealand has amongst the highest rates of asthma and allergy in the world, with Māori and Pasifika disproportionately affected.
Because scientists don’t yet have a clear understanding of what triggers asthma development, there’s still no cure in sight for sufferers.
Studying a group of 50,000 children, the research team previously discovered that children exposed to more green space were less likely to develop asthma – and that effect was even stronger in places with plenty of native trees and plants about.
“We followed these children for 18 years and looked at where they are living at different stages of their lives, and then we used satellite data to look at how green the neighbourhoods were that they grew up in – and how diverse those green spaces were,” Massey’s Professor Jeroen Douwes said.
“We found an inverse relationship with green spaces and asthma – children who grew up in areas that were greener had a lesser likelihood of developing it.
“When we started digging a little bit deeper, we found having a more diverse green space was more protective.
“So, just having an area near your house that’s green – it could be grass or trees – may give you some protection. But the biggest factor we found was being exposed to multiple sources of green space.”
Douwes said the overall reduction in asthma risk that came with this likely buffer was 15 per cent.
“To put that into perspective, globally, there’s about 300 million people who suffer from asthma. If you reduce that by 15 per cent, we’re talking quite a substantial proportion.”
The explanation could potentially be found in kids’ gut microbiota, given the growing evidence that the mix of microorganisms living within us play critical roles in maintaining our health.
Their next project will investigate whether changes in gut microorganisms over time are associated with loss of biodiversity, or less access to green spaces.
They’ll also compare samples from asthmatic and non-asthmatic kids here, and also in Ecuador, Brazil and Uganda, to see whether there are differences in human microbiota.
“The exciting bit for me is, if we can replicate those earlier findings, and we do find out what actually confers protection, then we can start applying it to the general population,” he said.
“There are various options here – and one is working with city councils to start making more high-quality green spaces that are more available to people, which would have a number of other benefits as well.”
The three-year, $3m study is among 134 new research projects awarded more than $84m under this year’s Marsden Fund, administered by Royal Society Te Apārangi.
“New Zealanders are world leaders in many research areas and the Marsden Fund plays a critical role in ensuring that we continue to have expertise available in these fields,” Marsden Fund Council chair Professor David Bilkey said.
“Furthermore, Marsden Fund support enhances connectivity between researchers, both nationally and internationally whilst also facilitating the engagement between researchers and their communities.”
Five other fascinating projects
Why are fewer Kiwis smoking, drinking and taking drugs?
Another just-funded study will explore a dramatic decline of substance use among Kiwi adolescents.
In what’s been dubbed a “megatrend”, rates of smoking, drinking and alcohol use has dropped over the past 15 to 20 years.
This large unprecedented decline was youth-specific and sat alongside almost universal declines in teen pregnancy, juvenile crime and dangerous driving.
But researchers still aren’t sure what’s driven it, leaving policymakers and researchers struggling to influence further positive change.
In her project, Otago University’s Dr Jude Ball will work with Māori adviser Anaru Waa and a Māori Masters student to investigate why substance use might have changed in adolescents’ lives, for both Māori and non-Māori.
It will involve comparing archival interview data collected at the peak of adolescent substance use 20 years ago, with contemporary data collected for this study.
The researchers also aim to tackle questions such as whether other practices like social media and gaming are fulfilling the social functions that substance use once did, such as projecting a “cool” or “grown up” identity.
Will climate change hurt hearts?
Climate change means rising temperatures – and with it, an organism’s metabolic rate and oxygen consumption must also increase.
In particular, an animal’s heart must work harder with increasing temperature to meet the body’s growing demand for oxygen.
Ultimately, there’s a certain critical temperature limit, nearing which an animal will experience heart failure and die.
This limit varies between species, and for some it is only 2C higher than habitat temperatures, a change which is alarmingly well within global warming predictions.
The key to understanding this future threat could be in mitochondria – the tiny but essential powerhouses of cells, including those of the heart.
University of Auckland Associate Professor Tony Hickey and Dr David Crossman have already discovered that, near the temperature limit, heart mitochondria fail to produce sufficient energy for survival, effectively dictating the upper-temperature limit of animals.
The precise mechanisms leading to mitochondrial failure, however, are not understood – and cold-blooded animals like fish have evolved to live at specific temperatures.
Using temperate and tropical fish, the team will study the effects of increasing temperature on heart mitochondria.
Using specifically developed equipment and advanced microscopy, they will define the causes of mitochondrial failure, and why the critical temperature limit differs between species.
Their study will prove the most comprehensive analysis ever carried out on the effects of temperature on mitochondrial function, and will yield crucial insights into biological impacts of a warming world.
Why were female moa larger than males?
When it comes to birds and mammals, males are typically bigger – and more colourful – than females.
Male southern elephant seals, for instance, are up to four times the size of females, and peacocks have brilliantly coloured feathers compared to peahens.
These intriguing differences are thought to result from competition between males for mating rights with females.
In contrast, among Aotearoa’s nine species of extinct moa, females were more than twice the size of males.
The phenomenon, known as “reverse sexual dimorphism” is rare and its causes and consequences are hotly debated.
This size reversal is also seen to a lesser extent in some living flightless birds closely related to moa – such as kiwi, emu and cassowary – but not in others, such as rhea and ostriches.
This diversity in size makes moa and their relatives an ideal system for studying reverse sexual dimorphism.
In his study, Otago University’s Dr Kieran Mitchell will isolate ancient DNA from moa bones found in university and museum collections held by New Zealand universities.
He proposes that female moa competed for territory and access to males – a reversal of the usual situation, and will determine if this atypical mating behaviour has left a genetic legacy within moa ancient DNA.
His study will develop moa as a globally significant model system for studying the evolution of mating systems and provide new insight into the biology of these vanished giants.
Are Australian bushfires melting our glaciers?
Our picture-postcard glaciers are extremely sensitive to changes in temperature and precipitation, which has led to an alarming retreat over recent decades.
Fresh snow and ice have high albedo – a measure of how much solar radiation is reflected from the surface of a material without being absorbed.
However, when top layers of snow and ice become contaminated with impurities, the albedo is significantly reduced, leading to greater absorption of the sun’s energy and increased ice melting.
There are two important sources of impurities: wind-blown dust and airborne particles containing smoke and ash; and the growth of microbial populations, such as algae, on the surface of the ice and snow.
Importantly, there appears to be a relationship between growth of these microbial communities and increased deposition of airborne particles.
The devastating Australian bushfires in 2019-2020 produced substantial quantities of black carbon and airborne contaminants over New Zealand, dramatically changing the colour of snowfields and glaciers in the Southern Alps.
Glacial microbial communities also darken glacier surfaces.
A combination of these factors could reduce albedo of our glaciers and increase melt rates.
However, the magnitude of these effects, as well as the interaction between microbial growth and black carbon deposition, are not well known, and current models for glacier melting do not take them into account.
In their study, Dr Phil Novis from Manaaki Whenua Landcare Research and Dr Lynda Petherick from Victoria University will determine the effect of airborne particles on snow algae, along with the effect of both on snow and glacier melting.
Their project will provide the basis for future work on these effects, in a fast-warming world.
The hormone that makes good dads
Like human fathers, male mice make a significant contribution to rearing their offspring.
For male mice this involves a dramatic change in behaviour towards infant mice.
This transition is triggered by the act of mating, but after this there is a delay of about two weeks before behavioural changes are seen.
By three weeks, when up to 10 new babies arrive, male mice are ready to be good fathers – yet the mechanisms that drive this behavioural shift are not known.
Otago University’s Dr Kristina Smiley has recently shown that the hormone prolactin, known best for its role in milk production, is essential for good parental behaviour in male mice.
In female mice, prolactin stimulates the generation of new neurons in a specific region of the brain.
The timing of the appearance of these new brain cells, about two weeks, is associated with the onset of maternal care behaviour.
In her study, Smiley will determine if similar changes occur within the male mouse brain following mating, and whether these changes are required for good paternal care behaviour.
Determining the basis of normal parental care is essential to understanding the causes of postnatal mood disorders, which occur in both men and women.
Smiley hopes to eventually provide a greater insight into mood disorders associated with fatherhood – something which could even help address issues relating to child abuse or neglect.
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