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Study: New Kind of Seaweed Is Killing Coral in the Pacific Ocean

Scientists say a recently discovered kind of seaweed plant is killing large numbers of very small but important ocean animals called corals.

A new study from the University of Hawaii says the deadly seaweed is spreading quickly in the Pacific Ocean around the Northeastern Hawaiian islands. The area is one of the most protected environments on earth.

Corals live closely together forming large, hard, ocean structures called reefs. The researchers say the seaweed grows over the reefs, blocking the coral from the sunlight and food it needs to survive.

"This is a highly destructive seaweed," said scientist and seaweed expert Heather Spalding, who helped write the study. She said it could overgrow entire reefs.

In 2016, the United States government researchers were studying the Pearl and Hermes Atoll when they found small amounts of a seaweed they had never seen before. Last summer, they returned to the area and discovered the plant seemed to be everywhere. Spalding said in some places she examined, the seaweed covered "everything, as far as the eye could see," in thicknesses of up to 20 centimeters.

"Everything underneath of it was dead," she said.

The area was almost empty of fish and other sea life that usually populate the area.

Scientists say the seaweed probably covers an even larger area than they were able to document in the study.

Pearl and Hermes Atoll is in the middle of the Pacific Ocean, about 3,200 kilometers from Asia and North America. It is part of the 1.6 million-square-kilometer U.S. Papahanaumokuakea Marine National Monument.

The scientists said that some of the seaweed extended across areas the size of several soccer fields. They also said it threatens the atoll, and could endanger the entire Hawaiian archipelago if it spreads.

"We have not, until now, seen a nuisance species that's come in and made such...changes over a short period of time to the reefs," said the University of Hawaii's Alison Sherwood, who led the study.

The scientists carried out genetic studies that showed the seaweed was a new species. They named it Chondria tumulosa.

The new seaweed might have been carried into the area by a boat, although all boats must be cleaned and inspected in order to enter. The scientists say the species also might have been in the area for a long time, but in small amounts. Sometimes, environmental changes can cause an explosion in growth, they explained.

The study was published in the journal PLOS ONE.

I'm Susan Shand.

参考译文

一种新型海藻正在“吃掉”太平洋珊瑚

科学家表示，最近发现的一种海藻植物正在杀死大量非常小但很重要的海洋动物——珊瑚。

来自夏威夷大学的一项新研究称，这种致命的海藻正在夏威夷群岛东北部的太平洋地区迅速蔓延。

这个地区是地球上环境保护的最好的地区之一。珊瑚紧密地生活在一起，形成巨大的、坚硬的海洋构造，称为珊瑚礁。研究人员说，海藻生长在珊瑚礁上，阻止了珊瑚获得生存所需的阳光和营养。

“这是一种破坏性极强的海藻，”协助撰写该研究报告的科学家、海藻专家希瑟·斯伯丁(Heather Spalding)说道。她说，它可能会覆盖整个珊瑚礁。2016年，美国政府的研究人员在研究珍珠和爱马仕环礁时，发现了少量以前没见过的海藻。

去年夏天，他们再次回到这一地区，发现这种植物似乎已经遍布各处。斯伯丁表示，在她观察的一些地方，海藻覆盖了“肉眼能看到的一切”，其厚度可达20厘米。

她说，“被覆盖住的所有生物无一存活。”

这个地区几乎没有鱼类和其他海洋生物，而这些生物通常都生活在这里。

科学家表示，海藻覆盖的面积可能比他们在研究中记录的还要广泛。

珍珠和爱马仕环礁位于太平洋中部，距离亚洲和北美约3200公里。它是160万平方公里的美国Papahanaumokuakea海洋国家纪念碑的一部分。

科学家们表示，一些海藻蔓延的面积有几座足球场那么大。

他们还指出，海藻威胁到环礁，如果继续蔓延，可能会危及整个夏威夷群岛。

“在此之前，我们从没发现能造成如此威胁的物种入侵珊瑚礁，并在短时间内让珊瑚礁产生这样的变化。”领导这项研究的夏威夷大学的艾莉森·舍伍德（Alison Sherwood）说道。

科学家进行的基因研究表明，这种海藻是一个新物种。他们将其命名为“图穆罗萨”。

虽然所有的船只都必须经过清洁和检查才能进入，但新的海藻可能是由船只带入该地区的。

科学家表示，该物种可能在该地区存在了很长时间，但数量很少。他们解释说，有时，环境变化会导致出现爆炸性繁殖。

这项研究发表在《公共科学图书馆·综合》杂志上。

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