Life in Death Valley

What’s behind this desert’s springtime ‘super bloom’ floral phenomenon?

Deep within the Mojave Desert sits one of the hottest environments on our planet. The hostile Death Valley is over 13,500 square kilometres of sunken bedrock at 86 metres below sea level. With the scorched earth and golden sand dunes walled in by mountain ranges, the heat is trapped within the basin, causing the temperature to soar beyond a sweltering 46 degrees Celsius. The average rainfall over one year is just five centimetres, though some years there is no rain at all.

In this extreme climate it seems impossible that any life could survive. Yet just under the surface of the soil there are millions of heat- and drought-resistant seeds that wait for years, sometimes decades, for the perfect conditions to spring into life.

Very rarely, for just a few weeks over summer, the barren, cracked dirt bursts into a kaleidoscopic floral display with fields of vibrant yellow desert sunflowers and rich orange Californian poppies. This natural wonder is set in motion first by rainfall over winter, which erodes the protective wax or protein layer encapsulating the seed. They need desert showers to continue in bursts of around half an inch over the remainder of winter, but without their protective layer, any extreme temperature or too much water (or not enough) will kill them before they have a chance to sprout from the ground and bloom.

This ‘super bloom’ phenomena extends far beyond the usual spring bloom and is key to the desert flowers’ secret to survival in the hostile desert. Rather than struggle year-round, they bloom at just the right time to complete a swift reproductive cycle, having first waited for enough rainfall to support them.

This beautiful mass blooming attracts vast amounts of pollinators to Death Valley, including hummingbirds and butterflies, starting the cycle all over again.

Other desert survivors…

Kangaroo rat

A kangaroo rat (Dipodomys deserti) can survive its entire life without drinking a single drop of water! They have evolved to metabolize water from the starch and fat in the seeds they eat. They also shelter from the day’s intense heat in underground burrows, surfacing mainly at night.

Devil’s Hole pupfish

These tiny, heat-tolerant fish live only within a geothermal pool in Death Valley. Stuck in the same place since the last ice age (when the valley was home to a glacial lake) the Devil’s Hole pupfish (Cyprinodon diabolis) survive in the high salinity by drinking bountiful quantities of water and excreting the salt.

Desert tortoise

This ingenious herbivorous tortoise spends 90 per cent of its life hibernating and relies on its bladder to stay hydrated. The organ acts as a storage tank, and the tortoise reabsorbs the water back into its body. It can go an entire year without drinking any fresh water at all!

Image credit Robb Hannawacker

Creosote bush

A medium-sized evergreen shrub, the creosote’s small, waxy, pointed leaves conserve water by preventing moisture from being evaporated. It’s known as the ‘governess’ in Mexico due to its ability to secure water by inhibiting the growth of surrounding plants.

Image credit Krzysztof Ziarnek, Kenraiz

Golden barrel cactus

This cactus acts like a sponge. When there are periods of rainfall the plant expands to accommodate the newly available moisture and will survive on the stored water during dry spells while gradually shrinking to its original size

This article was originally published in How It Works issue 101, written by Charlie Evans 

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