Antarctica is turning green, but that could be bad news

At present, in the northern hemisphere where my country is located, grass and trees are sprouting, spring is coming, and we are feeling the rising temperature and the recovery of nature. However, at the other end of the earth - Antarctica, a different scene is presented.

my country's 41st Antarctic scientific expedition team is carrying out a series of investigation and monitoring activities here. They are accompanied by ice, snow and strong winds, trying to uncover more secrets of this white continent.

Today, the Antarctic continent looks like a "barren land". However, no matter how harsh the environment is, it still cannot resist the miracle of life. Even in such a cold Antarctica, there are still hundreds of plant species surviving and reproducing here.

However, in this special territory, the presence of plants is not necessarily a good thing, but may be a dangerous signal. Why is this? Before answering this question, let us first look at the interesting stories of Antarctic plants according to the types of organisms!

Algae blooms once covered Antarctica with watermelon-flavored "red snow"

If we have the opportunity to reach Antarctica, we will find that the colors here are not so monotonous. Especially in summer, you can see algae of various colors on the ground or rock surface of the Antarctic land, as well as in seasonal rivers and offshore.

Scientists have discovered more than 700 species of algae in Antarctica, which are important producers in the Antarctic ecosystem. Especially in the waters where penguins live, the water is rich in nutrients such as nitrogen, phosphorus and potassium, which is very suitable for the rapid growth of algae.

In fact, strictly speaking, most algae are not plants, although they all perform photosynthesis. Algae have many different origins and morphological differences. Among the many algae in Antarctica, perhaps the most unique is the polar snow algae (Chlamydomonas nivalis).

In 2020, there was a news story: Scientists stationed at the Wonardsky Station woke up and found that the area around the station had become "blood-stained" and the ice surface had turned red overnight. Curious scientists extracted samples and found that the red snow "smelled like watermelon." This is actually the bloom of polar snow algae.

Antarctic watermelon snow Image source: Screenshot from CCTV News Channel

This algae contains red carotenoids in its cells, which can resist the strong ultraviolet radiation in Antarctica. Because the weather was warming at that time, it was suitable for spore germination, so the polar snow algae that were originally deep in the snow emerged and formed red snow.

The lichen that grows all the way to the South Pole only grows less than 1 cm in height over hundreds of years.

As you head deeper from the coastline of Antarctica, it's easy to observe the presence of lichens as you come across some rocks.

According to statistics, there are about 350 species of lichens in Antarctica. They are distributed in most areas of Antarctica and can even be found near the South Pole. They can be called the "southernmost creatures."

In 1895, when humans first set foot on the Antarctic continent, adventurers discovered lichens here and announced that there were "green plants" in Antarctica. However, people at that time did not realize that lichens were not plants.

(Copyrighted images from the gallery, reprinting may lead to copyright disputes)

Lichens in Antarctica come in all shapes and colors, ranging from 10 to 15 centimeters tall to just a few millimeters. The harsh environment in Antarctica makes the growth of lichens here very slow, often growing less than 1 centimeter in hundreds of years.

The tiny moss has lived for hundreds of years.

With the presence of "pioneer" lichens, rocks will decompose faster, which also gives mosses a chance to survive.

In Antarctica, there are about 150 species of mosses, mainly distributed in the relatively warm coastal areas of the Antarctic continent or where melting ice and snow can provide abundant water sources.

Although mosses are small, they are already true plants and have developed differentiated organs. In Antarctica, mosses are like miniature forests, providing habitats for many other organisms, including fungi, water bears and mites, which form the bottom of the Antarctic food chain.

(Copyrighted images from the gallery, reprinting may lead to copyright disputes)

At Casey Station in Vinson Bay, Antarctica, Australian researchers have been observing a patch of moss around the station for 25 years. The moss, Schistidium antarctici, has been there for at least 400 years, nestling between several rocks.

Although these mosses look ordinary, they can reflect subtle changes in the global climate. Scientists also want to know how these mosses quietly wait for the arrival of sunlight during the dark night.

Flowering plants, from bee pollination to wind pollination

In Antarctica, only about 1% of the land is exposed rock, so it is certainly impossible to see flowers everywhere here.

According to scientists, the southern limit of flowering plants on Earth is about 64 degrees south latitude. In Antarctica, the northern tip of the Antarctic Peninsula and some islands just cross the "flowering plant line". So far, humans have discovered three species of herbaceous plants in Antarctica, none of which are unique to Antarctica, proving that Antarctica has never been isolated from the world.

Antarctic hair grass (copyright image from the gallery, reprinting may cause copyright disputes)

Antarctic hairgrass (Deschampsia antarctica) is a species of the Poaceae family, along with wheat, rice and corn. It is also recognized by the Guinness World Records as the southernmost flowering plant in the world. It is easy to find this plant near the Great Wall Station in my country. Chinese scientists have even cultivated it indoors and successfully produced ears and fruits.

In contrast, the Antarctic Colobanthus quitensis looks much more beautiful. This plant is only about 5 cm tall and grows completely close to the ground, looking more like a moss. In summer, this dicotyledonous caryophyllaceae plant will show a different state. It will bloom yellow flowers in the form of wind chimes from its blanket-like leaves. However, on this continent, the Antarctic Colobanthus quitensis has to make changes. In South America, this plant relies on bees for pollination, but there are no such pollinating insects in Antarctica, so it can only be pollinated by strong winds.

Both plants were already present in Antarctica before humans arrived. But another plant, Poa pratensis, was not. This grass is a low-growing lawn grass that is widely distributed in temperate climates and is also the grass species used to lay many golf courses. In 2012, people discovered this plant, which is native to Europe, outside the Polish research station on King George Island. Obviously, it arrived in Antarctica with the footsteps of humans.

More plants mean a better environment? Except in Antarctica

Antarctica is the most unpolluted ecological region in the world, but it also faces the problem of invasive alien species such as Poa annua, and the "dangers" of Antarctica go far beyond this.

Through long-term observation of Antarctica, scientists have come to an astonishing conclusion: Antarctica is becoming increasingly "green". According to statistics, the distribution area of ​​Antarctic hair grass and Antarctic sedge grass has been increasing from 1960 to 2009; in the decade from 2009 to 2018, these two plants have expanded rapidly at an astonishing annual growth rate of more than 20%. Not only flowering plants, but also in Antarctica, the outbreak areas of green algae continue to increase, and mosses are appearing in more and more places.

For most of the world, the increase in plant life is a sign of a better environment. But in Antarctica, the large-scale appearance of plants is not the case.

Behind the increase in Antarctic plants is the accelerated rise in local temperatures. According to records, the average annual temperature on Antarctica's Sigourney Island rose by only about 0.02°C from 1960 to 2011, but from 2011 to 2014, the annual average temperature began to rise sharply, with an average annual temperature rise of 0.25°C.

In addition to rising temperatures, the expansion of Antarctic plants is also related to another factor. The fur seals on the coast coincide with the areas where flowering plants grow. These sea beasts will trample the plants on the shore, thus limiting their growth and spread. But in recent years, the number of fur seals in Antarctica has declined, giving plants more room to grow.

The changes in Antarctica's vegetation are like a "barometer" of the global climate. As for the impact of the increase in vegetation here on Antarctica, there is actually no consensus.

The biological ecology and environmental monitoring of Antarctica is also an important task of the 41st Chinese Antarctic Expedition. Perhaps when the expedition returns successfully, we will have a deeper understanding of the plants in Antarctica, and more interesting secrets that have a significant impact on humans will be revealed with this scientific expedition.

References:

[1] Deng Qian , Gao Baoyan , Tang Zihan , Zhang Chengwu. Species diversity, low-temperature adaptation, and biotechnology application of Antarctic algae [J]. Chinese Journal of Polar Research, 2023, 35(4): 619-629.

[2] Malenovky, Z., Turnbull, JD, Lucieer, A. & Robinson, SA (2015). Antarctic moss stress assessment based on chlorophyll content and leaf density retrieved from imaging spectroscopy data. New Phytologist, 208 (2), 608-624.

[3] Liu, Shenghao & Fang, Shuo & Cong, Bailin & Li, Tingting & Yi, Dan & Zhang, Zhaohui & Zhao, Linlin & Zhang, Pengying. (2022). The Antarctic Moss Pohlia nutans Genome Provides Insights Into the Evolution of Bryophytes and the Adaptation to Extreme Terrestrial Habitats. Frontiers in Plant Science. 13. 10.3389/fpls.2022.920138.

[4] Cordero, RR, Sepúlveda, E., Feron, S. et al. Black carbon footprint of human presence in Antarctica. Nat Commun 13, 984 (2022). https://doi.org/10.1038/s41467-022-28560-w
[1] Cannone N , Malfasi F , Favero-Longo SE ,et al.Acceleration of climate warming and plant dynamics in Antarctica[J].Current Biology, 2022, 32(7):1599-1606.e2.DOI:10.1016/j.cub.2022.01.074.

[5] Primary society and environment Book F. Australia: RIC Publications. 2001: 96. ISBN 1-74126-127-9.

[6] The Weather Company. Bizarre Phenomenon Causes Bright Pink Snow. https://weather.com/news/trending/video/freak-phenomenon-causes-bright-pink-snow-in-antarctica

[7] Australian Antarctic Division. Researchers return to Antarctic 'rainforest'. https://www.antarctic.gov.au/news/2022/researchers-return-to-antarctic-rainforest/

[8] The Economist. Polar invaders. https://www.economist.com/babbage/2012/03/06/polar-invaders

[9] Jin Weiyin. See how angiosperms survive in the polar wilderness[J]. Knowledge is power[2024-11-12].

[10] Li Haomin, Song Dekang. Several angiosperm fossils from King George Island, Antarctica[J]. Acta Paleontologica Sinica, 1988(04):7-135. DOI:CNKI:SUN:GSWX.0.1988-04-000.

[11] Hu Shunshi. Overview of Antarctic plants and research prospects[J]. Acta Botanica Sinica, 1993, 35(11):9. DOI:CNKI:SUN:ZWXB.0.1993-11-011.

[12] Hu Shunshi. Notes on Antarctic Plant Survey[J]. Life World, 1998(4).

[13] Li Chengsen. Protecting Antarctic plants and lichens[J]. Man and the Biosphere, 2017(1):1. DOI:10.3969/j.issn.1009-1661.2017.01.029.

[14] Zhao Beixing, Carl Zimmer. Antarctic ice shows that plants are growing faster[J]. World Science, 2017(7):2. DOI:CNKI:SUN:SJKE.0.2017-07-008.

[15] Li Xuedong. Overview of vegetation near the Great Wall Station in Antarctica[J]. Botanical Journal, 1992, 19(3):2. DOI:CNKI:SUN:ZWZA.0.1992-03-049.

[16] Li Xuedong, Liu Jiaxi, Hu Dong, Chen Fudong. Morphological characteristics and distribution of Antarctic hair grass at the Great Wall Station and nearby islands in Antarctica[J]. Journal of Polar Research, 1996, 8(3): 64-67.

[17] Chinese Academy of Sciences. [China Science Daily] Setting out to Antarctica to search for lichens. https://www.cas.cn/xw/cmsm/201302/t20130219_3763715.shtml

[18] China Ocean Development Research Center. They are the only ones that can still “grow wildly” on the Antarctic ice sheet. https://aoc.ouc.edu.cn/2023/1212/c15171a451704/pagem.htm

Author: Quasimodo in the Garden, Master of Agronomy, Science Popularizer

Reviewer: Wang Kang, Director of the Science Museum of the National Botanical Garden

Produced by: Science Popularization China