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Recap: our 2024 Advent special on Instagram

In December 2024, the social media team of APECS Germany published a series of posts on Instagram to showcase the vast variety of polar research and get everyone into a festive mood!

We here summarize the main posts again for everyone to enjoy.

(The texts have first been published on instagram, at https://www.instagram.com/apecs_germany/).

Snowflakes

The post was made in cooperation with @cloudy_climate.

❄️Snowflakes have long symbolized Christmas🎄 cheer. In Victorian times, crafting paper snowflakes became a festive tradition, inspired by their intricate and unique natural designs. But is it true that every snowflake is unique?🤔

At cold temperatures🥶, ice crystals can form in the atmosphere from water vapor💨💦. The ice crystal shape strongly depends on the temperature🌡️ and the supersaturation conditions. At around -15°C, ice crystals occur as so-called dendrites. Dendrites are six-branched ice crystals that look like what we commonly think of when picturing a snowflake. However, ice crystals can come in a large variety of different shapes. At around -5°C and high supersaturation, ice crystals look like tiny needles. Snowflakes often consist of multiple – sometimes up to hundreds of – individual ice crystals🌨️. That’s because ice crystals can stick to each other, when they come in contact, forming an “aggregate” snowflake.

Because the snowflake shape is so sensitive to the processes that were active during its formation and growth, every snowflake is truly unique. Next time it’s snowing, try to catch a snowflake on your jacket🧥 or glove 🧤(works best on black wool) and have a good look at it. Maybe you can identify some parts of its history.🤗

Diatoms

This post was made by our board members Emma & Sneha.

Did you know that some of the smallest organisms 🦠 in polar regions play an outsized role in their ecosystems?

Enter ✨diatoms✨ —microscopic algae with complex glass-like “shells” (frustules) made of silica. They can thrive in icy waters, forming a vital base of the food web.

Polar diatoms may be tiny, but they’re like nature’s holiday decorators 🎄! Their silica frustules are intricately patterned with delicate, ornamental designs, showcasing a remarkable diversity of ~200,000 unique species. Whether floating beneath sea ice or in pristine polar lakes, diatoms bring life to the coldest corners of the planet 🧊.

Diatoms provide energy⚡️for everything from zooplankton to whales 🐋! But diatoms don’t just feed the ocean and freshwaters – they help regulate the Earth’s climate. Through photosynthesis, diatoms absorb carbon dioxide and release oxygen, contributing an estimated 20-30% of the oxygen we breathe!

💡Fun fact: some scientists study diatoms preserved in sediment cores to learn about past climate – like unwrapping Earth’s history 🎁! Take a look at the images in this post to explore the contrast between living diatoms and preserved diatom remains.

Penguins

🐧❄️Penguins were actually named after their similarity to another bird and associated genus, the Great Auk (Pinguinus impennis). The Great Auk became extinct in the mid-19th century, which is why many people today do not know about this.

Adelie penguins are the smallest penguins in Antarctica, and have a bit of a feisty reputation. They are really good swimmers, and also walk long distances to reach their breeding areas on rocky beaches and other ice-free areas. Penguins can walk but also are known to slide on their stomach to get from place A to B. Adelie penguins are the most widespread species in the Southern Ocean.

When visiting Antarctica, tourists and researchers alike have to make sure erase as much of their footprints in the snow as possible, otherwise penguins can get stuck in them. There are tight rules for not approaching wildlife in Antarctica. Because many penguins do not have land-based predators, you will often find penguins wandering up to humans.

Scientists can locate penguin colonies on ice or snow from space by searching for red spots on satellite imagery – caused by the red colour of penguin poop. Scientists also study the thermodynamics of penguin colonies – penguins will huddle together in large groups. Those in the middle will eventually overheat and move to the outside of the huddle, and vice versa.

All pictures from this post were from @svenja.halfter

Glaciers

🧊Glaciers are dynamic forces of nature, shaping Earth’s landscapes while storing ~70% of the planet’s freshwater. These frozen giants act as time capsules, preserving detailed records of past climates within their icy layers.

Glaciers form over centuries as layers of ❄️ snow accumulate and compress, gradually transforming into dense ice. As the snow compacts, the snow turns into firn – an intermediate stage between snow and solid ice. When the firn becomes thick enough and the grains compact further, it eventually solidifies into glacier ice, which flows like a frozen river under its own weight.

But glaciers don’t just shape landscapes – they hold the secrets of our planet’s climate. Ice cores extracted from glaciers provide frozen archives, preserving ancient 🫧 air bubbles and chemical signatures that reveal records of past atmospheric conditions spanning hundreds of thousands of years.

💧🦠Beneath some glaciers, subglacial lakes hold liquid water, insulated by the ice above, supporting unique ecosystems in extreme conditions. For example, Antarctica’s Lake Vostok, buried under 4000m of ice, is one of the largest freshwater lakes on Earth.

💡Fun fact: The blue color of glacier ice results from the way it absorbs and scatters light. Dense ice absorbs all colors of the spectrum except blue, which is scattered back to our eyes.

Pictures for this post were contributed by our board member Emma.

The Aurora

Christmas is a contemplative time to calm down and the time for little wonders. What could be more wonderful than colorful lights dancing in the sky? 😍 Exactly, we are talking about the Northern Lights or Aurora Borealis. This natural phenomenon is a spectacular, colorful display of light commonly seen in the night sky in the northern hemisphere. Especially during the long and dark nights in December you have a good chance to see them. There are also auroras in the southern hemisphere which are referred to as the Southern Lights, or Aurora Australis.

Aurora Borealis emerges when charged particles from the sun 🌞 strike atoms in Earth’s atmosphere🌍, they cause electrons in the atoms to move to a higher-energy⬆️ state. When the electrons drop back to a lower energy state⬇️, they release a photon: light☄️. This process creates the beautiful Aurora, or Northern and Southern Lights.

Here are some facts about Aurora Borealis:

  • Did you know that Auroras look like moving curtains of light because the particles of plasma are moving in response to the earth’s magnetic field and thus their shape changes over time? ⏱️
  • The most common colors of Aurora Borealis is red and green. 🎄🎀🕯️
  • Auroras also occur on other planets in our solar system—including Jupiter, Saturn, Uranus, Neptune and Mars. Similar to Earth’s Aurora, the lights have been seen close to other planets’ magnetic poles.

Pictures for this post were contributed by  Florian Gebhardt and our board member Joana Steffens.

Ice-sheet modelling

This post was contributed by our board member Lena.

What’s cooler than ice sheets? Using computer models to understand them! 🧊
Today’s post takes us to Antarctica, for which we can use ice-sheet models to understand and predict the behavior of the planet’s largest ice masses. These tools are critical for studying how Antarctica’s ice sheets are changing in a warming world—and what it means for future sea levels. 🌊

How does it work? Ice-sheet modelling involves creating computer simulations of how massive ice sheets, like those in Antarctica, flow, evolve, and respond to factors like temperature, ocean temperatures, and snowfall.

📷 The first step is to create a mesh or grid. For each grid cell (spot the small triangles on the ice sheet surface) the processes that drive the ice dynamics are simulated.

📷 For some regions, like for the rapidly changing Thwaites and Pine Island Glaciers, we want to refine the grid to give importance to small-scale processes.

📷 How could a typical modelling set-up look like? Have a look at the desk of our co-Chair Lena, who spend the last two months working with the ice-sheet model ISSM in Australia ☀️

If you want to read more about how an ice-sheet model works, check out Lena’s Polarfuchs text from last year: https://polf.copernicus.org/articles/91/105/2023/ ✨

(The shown ice thickness data in the posts was taken from BedMachine Antarctica v3, Morlighem et al 2020).

Reindeers

This post was made by our board member Joana W.

🦌❄️ Arctic Survivors – Svalbard Reindeer
The Svalbard reindeer (Rangifer tarandus platyrhynchus) are not only the smallest reindeer species in the world but also some of the most resilient. This isolated population lives exclusively on the Svalbard archipelago and has adapted to extreme conditions. However, climate change poses new challenges: “Rain-on-snow” events cause rain to fall on the snow cover, forming thick ice layers. This makes access to food nearly impossible, leading to frequent food shortages. Some reindeer have even been spotted along coastal areas, feeding on seaweed – an unusual behavior for deer! 🌊🦌

🐻‍❄️ New Threats from Polar Bears: 
Climate change is not only affecting reindeer. Polar bears, struggling to hunt seals due to declining sea ice, are increasingly preying on reindeer. One particularly clever polar bear mother has perfected this hunting strategy and is now teaching it to her offspring. This dramatic shift highlights how interconnected the fates of Arctic species are. ❄️🥶

Symbiosis and Unique Antler Bearers
: Despite these challenges, Svalbard reindeer have developed fascinating strategies. They use their hooves and noses to dig through the snow for plants – a tough job that also benefits ptarmigans. These birds follow the reindeer, feeding on the exposed areas of vegetation. And did you know that in reindeer, both males and females grow antlers? Males lose theirs in autumn, while females keep theirs nearly year-round. This means Santa’s reindeer are likely female – Donner and Blitzen might actually be Donna and Blitzine! 😄✨

The Svalbard reindeer are a symbol of resilience in a changing world. 🌍❄️ But climate change is disrupting the fragile balance of Arctic ecosystems