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Scientists have discovered what may be the oldest fossils of a green plant ever found.
科学家们发现了可能是迄今为止发现的最古老的绿色植物化石。
The fossils were found in rocks from northern China.
这些化石是在中国北方的岩石中发现的。
The plant is thought to be a piece of seaweed that grew on Earth"s seafloor about 1 billion years ago.
该植物被认为是大约10亿年前生长在地球海底的一片海藻。
That would make this seaweed an ancestor of all green plants alive today.
那使得这种海藻成为而今所有绿色植物的祖先。
Researchers in the United States reported on the discovery in the publication Nature Ecology & Evolution.
美国研究人员在《自然生态与进化》杂志上报道了这一发现。
The researchers are with the Virginia Polytechnic Institute and State University in Blacksburg, Virginia.
这些研究人员来自维吉尼亚理工学院和维吉尼亚州布莱克斯堡的州立大学。
The seaweed is a form of green algae called Proterocladus antiquus.
这种海藻是一种被称为古绿藻的绿藻。
It was very small, about the size of a single piece of rice.
它非常小，大约只有米粒大小。
Researchers say the plant was connected to the seafloor with a root-like structure.
研究人员称，这种植物通过根状结构和海底相连。
At the time, the plant was one of the largest life forms in the sea,
当时，这种植物是海洋中最大的生命形式之一，
which contained mostly bacteria and other microorganisms.
海洋中主要是细菌和其它微生物。
The researchers say Proterocladus was able to perform photosynthesis,
研究人员表示，古绿藻能够进行光合作用，
taking energy from the sun to produce life-supporting carbon and oxygen.
吸收太阳的能量来产生维持生命的碳和氧。
They believe the plant also provided food and shelter for many different kinds of sea life.
他们相信这种植物还为许多不同种类的海洋生物提供了食物和庇护。
Shuhai Xiao serves as a Professor of Geobiology at Virginia Tech.
肖树海是弗吉尼亚理工学院地球生物学教授。
He said the fossils were found in rock taken from an area of dry land - formerly ocean - near the city of Dalian in China"s Liaoning Province.
他说这些化石是在中国辽宁省大连市附近一块陆地上的岩石中发现的，这块陆地之前是海洋。
Qing Tang, another Virginia Tech researcher, discovered the micro-fossils in the rock using an electronic microscope in a laboratory.
弗吉尼亚理工学院的另一位研究人员唐青在实验室里用电子显微镜发现了岩石中的微化石。
Xiao said the fossils represent the oldest green seaweed ever found.
肖说，这些化石代表了迄今为止发现的最古老的绿色海藻。
The next oldest fossil of green seaweed was found in rock thought to be about 800 million years old.
第二古老的绿色海藻化石是在岩石中发现的，人们认为大约有8亿年的历史。
The scientists say the seaweed once lived in an ocean that was not very deep.
科学家们说，这种海藻曾经生长在不太深的海洋中。
Once the plants died, they became "cooked" under thick sediment, which created fossils in the shape of the seaweed.
一旦死亡，它们就会在厚厚的沉淀物下“煮熟”，形成海藻状的化石。
Many millions of years later, the dirt was lifted out of the ocean and became the dry land where the examples were collected.
数百万年后，这些淤泥从海洋中露出来，变成了陆地，样本就是在那里收集到的。
These new fossils suggest that green seaweeds were important players in the ocean
这些新发现的化石表明，绿藻在海洋中发挥着重要作用，
long before their land-plant descendants moved and took control of dry land, Xiao said.
早在它们的陆生植物后代迁移并掌控陆地之前就是这样，肖说。
He added that Earth"s biosphere depends heavily on plants for food and oxygen.
他补充说，地球生物圈严重依赖植物来获取食物和氧气。
But the first land plants, believed to be ancestors of green seaweeds, did not appear until about 450 million years ago.
但被认为是绿藻祖先的第一批陆生植物直到大约4.5亿年前才出现。
The Virginia Tech researchers believe that land plants
弗吉尼亚理工学院的研究人员认为，陆生植物
– including trees, grasses, food crops and others
——包括树、草、粮食作物等
– all developed from green seaweeds that lived in the ocean.
——都是由生活在海洋中的绿藻进化而来的。
Then, over millions of years, the seaweed plants moved out of the water and adapted to life on land.
然后，在数百万年的时间里，海藻离开了水，适应了陆地上的生活。
The history of how green plants developed is a subject of debate.
绿色植物的发展历史是一个有争议的话题。
"Some scientists think that green plants started in rivers and lakes,
“一些科学家认为绿色植物起源于河流和湖泊中，
and then conquered the ocean and land later," Xiao said.
后来攻占了海洋和陆地，”肖说。
Proterocladus is believed to be closely related to a modern seaweed, widely eaten by humans today.
古绿藻被认为是和一种现代海藻亲缘关系近的藻类，这种海藻现在被人类广泛食用。
It is called sea lettuce.
它叫做海莴苣。
I"m Bryan Lynn.
布莱恩·林恩为您播报。
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