BBC Knowledge June 2017

PHOTOS: GETTY X

How do

squid survive

the extreme

pressures of

deep water?

A big challenge facing squid in the deep sea is keeping their cells

working. Under high pressure, important molecules like proteins

in cell membranes and enzymes become squashed and bent

out of shape and either work more slowly or not at all.

One way squid counteract this is by loading their bodies with

trimethylamine-N-oxide, or TMAO, which helps large molecules

keep their shape. For many deep sea animals, the deeper they live,

the more TMAO they have in their bodies. TMAO also gives rise

to the distinctive fishy smell of many sea creatures – the deeper

the species lives, the more it smells. HS

The cartilage pads between the joints in your legs and spine

gradually wear away as you get older, and osteoporosis can

cause the vertebrae themselves to shrink slightly. You also lose

muscle as you age and all of these factors mean your skeleton

slumps down a little more. Between the age of 30 and 70,

this adds up to about 3cm height loss for men and 5cm for

women, increasing to 5cm and 8cm by age 80. LV

WHY DO WE

SHRINK AS WE AGE?

Acid snow is produced in exactly the same way as acid rain.

It all starts when sulphur dioxide and nitrogen oxides are emitted

into the atmosphere, typically by power stations burning fossil fuels.

Inside clouds, these molecules react with tiny droplets of water to form

sulphuric and nitric acids. The water eventually falls as drops of acid rain,

or, if it is cold enough, ice crystals form and fall as acid snow. Acid snow

can be particularly damaging since it can accumulate on the ground,

before abruptly releasing a large quantity of acidic water into

the environment when it melts. AC

Is there acid snow

(like acid rain)?

June 2017 15

It was at that point

Dave wished he’d

taken up a nice

desk job instead