Surviving the Midnight Sun – The Red Shift of High Arctic Tundra

Despite its stereotypical image as an empty white landscape, the Arctic is replete with colour. In this vivid, almost literary piece, Dr Gomathy Muthukrishnan explores some of the science behind it.

In the high Arctic, Ny Ålesund, Svalbard few weeks can transform the landscape. During the Indian Arctic expedition 2026 I had an excellent opportunity to visit Storholmen Island where the tundra was at the height of its green growing season. To illustrate this striking seasonal transition from July to August photos kindly shared by Professor Martin Loonen reveal the rapid shift of the same landscape from green to deeper red. 

On the small island of Storholmen in Svalbard’s Kongsfjorden, the brief summer triggers a rapid shift in the landscape’s palette, from the hopeful green leaves and pink blooms of early July to a deep, protective red by August.  With the retreat of snow from Storholmen Island, Arctic vegetation enters a brief but highly active growing period. The combination of exposed ground, available moisture and continuous summer daylight provides the conditions for rapid plant growth. Within weeks, the green tundra begins to show visible signs of seasonal transition.

During the first week of July, the tundra is typically characterized by patches of vibrant green mosses dotted with startling bursts of pink and purple flowers. The most iconic of these early summer bloomers is the Purple Saxifrage (Saxifraga oppositifolia). Capable of beginning its growth even under a thin, translucent layer of melting snow, this hardy plant pushes out star shaped pinkish blooms almost the moment the ground is exposed. Against the stark greys and browns of the glacial moraine, these pockets of pink and green signal the peak awakening of the Arctic ecosystem.

But as the calendar flips forward just one month, the visual character of Storholmen shifts dramatically. During the first week of August, the soft pinks and fresh greens give way to a rusty, crimson hue that sweeps across the vegetation.  This change is not the sign of autumn which is still weeks away but rather a fascinating biological response to the extreme conditions of the High Arctic summer. Plants like saxifrages growing in creeping mats becomes deepen into darker, reddish purple tinges.  Similarly the green of Mountain Sorrel (Oxyria digyna) in July turns to rich red tones along the stems and leaves.

To understand this dramatic colour change from green to red, one has to look at the unique extremes of the High Arctic summer. During polar days of Svalbard the sun never sets and bright even in the midnight.  While this 24 hour daylight provides the vital energy needed for explosive early growth, it eventually becomes a source of intense stress.  By early August, the snow has entirely melted, removing the reflective albedo of the landscape. The plants on Storholmen have been left fully exposed to weeks of relentless, accumulated ultraviolet (UV) radiation under the midnight sun and the same combined with chill dry Arctic winds it’s quite common for the plants to go on the defensive mode of survival.

In response to this environmental stress, the plants may begin to synthesize high levels of anthocyanins that are water soluble flavonoid pigments that also contribute to the red colour of berries and the brilliant autumn colours of many deciduous trees.  For this miniature flora of the tundra vegetation of Arctic, these red pigments may serve two critical, lifesaving functions such as a botanical sunscreen and a thermal blanket. The former one acts as a shield over the absorbing harmful UV rays and protects the plant’s delicate cellular machinery and DNA from solar damage through the red pigmentation and the later lifesaver actually absorb slightly more of the sun’s warmth than bright green leaves do.  These type of hostile environments when every second and fraction of degree matters, the warming effect actually helps the plants to survive and also hint the upcoming winter. 

As August proceeds, the green chlorophyll that fuelled during the initial July growth begins to break down and entirely masked by the hue of red pigment. Ultimately its results in an entire view of landscape that looks like plants are simply wearing an armour to get escape of the peak summer of Arctic.  This drastic change of botanical colour is highly linked with the changing climatic condition where the snowfall dictates the plants to choose green or red colour of choice. 

However, when the Arctic temperatures rise and spring snowmelt occurs earlier in places like Kongsfjorden, plants are highly exposed to the intense midnight sun even little bit earlier in their life cycles. This premature exposure can further trigger the defensive reddening much faster than the earlier. When the snowmelt is earlier in a warmer year, the change of green foliage of July to red sun stressed August happens even faster than the blink of an eye.

Eventually, the shifting colours of Storholmen’s vegetation are a testament to survival just like the Arctic fox adapts its fur to blend into the changing seasons, the plants of Svalbard adapt their cellular chemistry to changing upcoming beautiful weather and the midnight sun.

Dr. Gomathy Muthukrishnan
Tamil Nadu Agricultural University, India

With sincere and special thanks to NCPOR, Goa and MoES, GoI for the support, guidance and the opportunity to participate in Indian Arctic Mission.