A few weeks ago, scientists at Ukraine's Vernadsky Research Base in Antarctica found their usually white surrounds were covered in a shocking blood-red. For such a mess, the culprits behind this horrible scene are tiny.

“Our scientists have identified them under a microscope as Chlamydomonasnivalis(雪地衣藻),” said the National Antarctic Scientific Centre of Ukraine in a Facebook post.

These green algae, a type of seaweed, are common in all icy and snowy regions of Earth, from the Arctic to high mountain regions. They lie still during the freezing winter, but once the sunlight warms enough to soften their world, the algae awake, making use of the melt water and sunlight to rapidly bloom.

“The algae need liquid water in order to bloom,” University of Leeds microbiologist Steffi Lutz told Gizmodo in 2016. “The algal blooms contribute to climate change,” the center stated.

A study in 2016 showed that snow algal blooms can decrease the amount of light reflected from the snow by up to 13 percent across one melt season in the Arctic. “This will surely result in higher melt rates,” the researchers wrote.

In 2017 environmental scientists calculated that microbial communities contributed to over a sixth of the snowmelt where they were present in Alaskan ice fields. Their experiments showed that areas with more melt water led to the growth of 50 percent more algae and places with more algae melted further.

This Antarctic summer has certainly seen a lot more melt water than usual. Temperature records keep changing, leading to rapid melting previously only seen in the Northern Hemisphere.

【小题1】What does the underlined word “culprits” in Paragraph 1 mean?

A．Risks.	B．Chances.
C．Effects.	D．Criminals.

【小题2】What can we know about Chlamydomonasnivalis?

A．They can be found anywhere.	B．They are sensitive to temperature.
C．They grow slower than before.	D．They survive only one melt season.

【小题3】What can be inferred from the last two paragraphs?

A．Ice and snow will soon disappear in the Antarctic.

B．Microbial communities bring about extreme weathers.

C．The Southern Hemisphere is warmer than the other parts.

D．Climate change and algae growth interact with each other.

【小题4】Which can be a suitable title for the text?

A．Why Snow Turned Blood-red.	B．How Algae Began in the Arctic.
C．Why Climate Changes Greatly.	D．How the Snow Reflects Sunlight.