New Scientist - USA (2021-02-06)

20 | New Scientist | 6 February 2021

Materials

Environment Palaeontology

Personality mix is

best for bird health

Wild house sparrows have

distinct “personalities”.

When housed in a cage,

some might sit quietly

while others try to escape.

Researchers housed birds

in small groups and found

they were healthier when

their personalities differed

from those of cagemates

(Proceedings of the Royal

Society, doi.org/fscq).

Some shark species

see massive decline

Most of the 31 open

water “oceanic” species

of sharks and rays are at

risk of extinction following

a drop in their numbers of

at least 71 per cent over

the past 50 years. There

are many more “coastal”

species in shallow waters,

and earlier studies suggest

they are declining too

(Nature, doi.org/fscc).

Poll: climate change

a global emergency

The biggest ever poll of

climate change views has

found that 64 per cent of

people think the issue is

a “global emergency”.

The Peoples’ Climate Vote,

commissioned by the UN

Development Programme,

had 1.4 million responses

in 50 countries. Belief we

face an emergency was

highest in the UK and Italy.

See-through wood:

knotty issue solved

TRANSPARENT wood just got even

better, moving us a step closer

to windows that are far better

insulators than traditional glass.

The standard process for making

wood see-through involves

soaking it in a vat of sodium

chlorite – a chemical compound

used in some bleaches – to remove

a structural component of the

wood called lignin. However, this

takes a lot of chemicals, produces

liquid waste that is tough to recycle

MICROPLASTIC may be as damaging

to soil ecosystems as drought.

Yudi Lozano at the Free

University of Berlin and her team

suspected that microplastic fibres

may affect soil-water interactions,

so they examined the impact of

this pollution on grassland soils.

The researchers collected dry

loam soil and mixed in polyester

microfibres. They planted seven

grassland plant species in the soil,

keeping some well-watered and

others in drought-like conditions.

To simulate a moderately high

level of microplastic pollution, the

fibres were at a concentration of

0.4 grams for 100 grams of dry

soil, less than the 7g per 100g

possible in heavily polluted areas.

The team focused mostly on the

effects on the soil ecosystem, not

plant growth, looking at respiration

in the soil, pH, retention and cycling

of nutrients, soil clumping and

overall soil ecosystem health, or

multifunctionality. Under well-

watered conditions, the presence

of fibres meant multifunctionality

was up to 34 per cent lower (Journal

of Applied Ecology, doi.org/fsjq).

This impact of microfibres in

well-watered soils is of a magnitude

comparable to that caused by

drought in non-polluted soils,

the team says. Donna Lu

and can weaken the wood.

Liangbing Hu at the University

of Maryland and his team came

up with a method that modifies

the lignin instead of removing it

completely. It is quicker, uses fewer

materials than the usual method

and leaves the wood stronger.

The researchers’ method stems

from the recent discovery that

lignin can be made transparent

by removing only the parts of its

molecules that give them their

colour. They brushed hydrogen

peroxide, which is often used as a

disinfectant, over the surface of

the wood and then left it under a

Evolution of thumb

shaped human story

OUR thumbs allow us to use a

variety of tools, from hammers to

smartphones, and a new analysis

suggests they have a long history.

Now, researchers have found that

some hominins were developing

more dexterous thumbs about

2 million years ago, possibly

allowing them to exploit more

resources, eventually leading to

the emergence of human culture.

Katerina Harvati at the

University of Tübingen, Germany,

and her team looked at thumb

efficiency across various human

species. They looked at the shape

of thumb bones and soft tissue

and used 3D models of thumb

samples to work out their torque.

“Levels of dexterity very similar

to what we see in modern humans

were already present 2 million

years ago,” says Harvati.

Previous research suggests that

Australopithecus, an earlier genus

of hominin, may have been the

earliest tool-makers, but the team

found they lacked the dexterity

of Neanderthals and Homo naledi

(Current Biology, doi.org/fsj6).

The researchers suggest that

Australopithecus may have been

a tool user, but the Homo genus

gained dexterous thumbs and

became adapted for more efficient

tool-making. Krista Charles

UV lamp designed to simulate

natural sunlight. After soaking the

wood in ethanol to remove any

remaining gunk, they filled any

pores with clear epoxy, a step that

is also part of making lignin-free

transparent wood.

The end product allows more

than 90 per cent of light to pass

through it and is more than 50

times stronger than if all lignin is

gone (Science Advances, doi.org/

fsj4). The material is lighter and

stronger than glass and could be

used for load-bearing windows

and roofs, says Hu, possibly even

a see-through house. Leah Crane

Plastic in soil has impacts that

are akin to those of drought

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Really brief

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