Climate change may be causing Australian rainforest trees to die faster
Since the 1980s, trees in Australia’s tropical rainforests have been dying at double the previous rate, according to a new international study published in Nature. The research points to the impacts of climate change as the culprit, as global warming increases the atmosphere’s drying power.
Tropical ecologists have analysed a 49-year record of tree dynamics from 24 old-growth forest plots across a broad climate gradient in Australia’s moist tropics. They’ve found that the average tree death rates have doubled over the past four decades and trees are living around half as long – a pattern consistent across species and sites throughout the region.
By examining the climate ranges of the tree species with the highest death rates, the team suggests that as the atmosphere warms, it draws more moisture from plants, resulting in increased water stress in trees and ultimately increased risk of death.
They also showed that the loss of biomass from this mortality increase has not been offset by biomass gains from tree growth and the recruitment of new trees, which may have resulted in a net decrease in the potential of these forests to offset carbon emissions.
Ancient faeces reveal evidence of parasitic worm eggs near Stonehenge
New analysis of ancient human and dog faeces at the site of Durrington Walls, a Neolithic settlement just 2.8 kilometres from Stonehenge, has uncovered evidence of the eggs of parasitic worms.
Archaeologists investigated 19 pieces of ancient faeces, known as coprolite, that had been preserved for over 4500 years and found that five of them – one human and four dog – contained the eggs of capillariid worms, identified in part by their lemon shape.
This indicates that the person had eaten raw or undercooked lungs or liver from an infected animal, probably a cow, resulting in the parasite’s eggs passing straight through the body. The leftovers were likely fed to the person’s dogs.
“The type of parasites we find are compatible with previous evidence for winter feasting on animals during the building of Stonehenge,” says lead author Dr Piers Mitchell from Cambridge University’s Department of Archaeology, UK.
The research is published in the journal Parasitology.
Faster, cheaper and more accurate 3D mapping
3D mapping is a useful tool – from monitoring construction sites, to tracking the effects of climate change on ecosystems, to verifying the safety of roads and bridges – but the current technology used to automate the process is limited, making it a lengthy an expensive undertaking.
It relies on LIDAR laser scanners that beam millions of pulses of laser light onto surfaces to create high-resolution, computer-based replicas of objects or landscapes. But the accuracy of LIDAR is often lost when mounted on drones, especially in places with numerous obstacles, and this results in gaps and misalignments in the datapoints that must be corrected manually.
Now, scientists have reported a new way to make 3D mapping faster, cheaper and more accurate, using artificial intelligence to detect when an object has accidentally been scanned several times from different angles. This resolves the issue directly at the scanner level, where measurements are taken.
“With our method, surveyors can send laser scanners as high as five kilometres and still maintain accuracy,” says Jan Skaloud, a senior scientist at the Swiss Federal Institute of Technology Lausanne and senior author of the new study published in ISPRS Journal of Photogrammetry and Remote Sensing.
Komodo National Park home to some of the world’s largest manta ray aggregations
The waters of Komodo National Park, an Indonesian UNESCO World Heritage Site, host a large number of reef manta rays (Mobula alfredi) and the area may hold the key to regional recovery of this threatened species, according to a new study in PeerJ.
Growing up to five metres, reef mantas tend to live and feed in shallow, coastal habitats. Conservation biologists teamed up with the Komodo National Park dive-operator community to source photographs of mantas and submit them to MantaMatcher.org, a crowdsourced online database for manta and other rays.
They were able to identify over 1000 individual manta rays from more than 4000 photographs by their unique and sometimes striking abdominal patterns, and analyse their movements with statistical models.
The study makes recommendations for enhancing manta ray conservation within the park, which can also serve as guidelines for manta ray habitats elsewhere in the world.
Key mechanism used to transport zinc in all living things identified
All living things need zinc to survive. The trace element helps many proteins fold into the right shapes, and in enzymes it helps to catalyse chemical reactions, including many that are important for providing energy to cells.
Biologists have now discovered a “chaperone” protein (ZNG1) that delivers zinc to where it’s needed, which could be especially important when access to zinc is limited, according to a new study in Cell Reports.
Such a chaperone is long suspected to have existed, but this research provides the first definitive evidence of its existence by identifying a “destination” for its deliveries. This destination is a zinc-dependent protein – methionine aminopeptidase, or MAP1 – that the researchers found can’t function properly without the chaperone protein.
Through a series of experiments, they also demonstrated that ZNG1 needs to be activated by an energy molecule known as GTP to deliver its zinc cargo.
MAP1 exists across species, so these findings are relevant for health in humans where zinc deficiency leads to growth and developmental impairments.
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Imma Perfetto is a science journalist at Cosmos. She has a Bachelor of Science with Honours in Science Communication from the University of Adelaide.
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