通过分析130年来的海鸟羽毛，研究者们确定，在太平洋中食物网的复杂程度降低，这意味着生态环境的可塑性降低。

撰文/播音：克里斯托弗·因塔格里亚塔

翻译：张心茹

审校：杨枭

Today we have sophisticated buoys packed with instruments, and robotic underwater drones. But a more than a century ago the seas were surveyed by different types of autonomous data-gathering instruments. Which also happened to be alive:

"We just call them sea otters and white sharks and bluefin tuna." Kyle Van Houtan is director of science at the Monterey Bay Aquarium. And what he means is that marine mammals and fish and seabirds concentrate unique chemical clues about the ocean and what lives in it, within their tissues. "In their bones, in their feathers, in their vertebrae, in their earwax."

今天我们有装载仪器的精密浮标，有水下机器人。但一个多世纪前，海洋由多种不同的自动收集数据的“仪器”调查，这些仪器还是活的：“我们称他们为海胆、白鲨和蓝鳍金枪鱼”。吉勒·凡·霍坦（Kyle Van Houtan）是蒙特利海岸水族馆科学主管。他认为，海洋哺乳动物、鱼和海鸟在各自的生理组织中，集中反映了海洋和海洋生物的化学特性。“生理组织包括他们的骨骼、羽毛、脊椎和耳垢。”

For his most recent study, Van Houtan needed to locate feathers from some long-dead birds.

至于他最近的研究，凡·霍坦需要从死亡已久的鸟中获得羽毛。

"Let's see, so I'm just looking here, that was a Bulwer's petrel, from French Frigate Shoals--I have the database open in front of me here…." Molly Hagemann, who describes herself as 'a librarian for dead animals' at Honolulu's Bishop Museum, was able to help.

“我们一起来看看，我正在看的内容，这是来自弗伦奇弗里盖特沙州的纯褐鹱，我已将数据库在我前方打开”莫利·哈格曼（Molly Hagemann）说，她自称檀香山主教博物馆死亡动物的管理员，可以帮助（凡·霍坦）。

"So that one was collected in May 1891. And then we also had a brown noddy from 1895…"

“这一只采集于1891年五月，接下来我们还有一只采集于1895年的白顶玄鸥”

The scientists analyzed the ratios of heavy to light nitrogen isotopes in those old feathers, compared to ratios in modern-day specimens. And they found that Pacific seabirds of yore ate diets dominated by fish. But the birds of today were fishing farther down in the food web. And seemed to be eating nearly twice as much squid as their ancestors did—maybe due to the combined effects of commercial fishing and climate change. The details are in the journal Science Advances. [Tyler O. Gagne et al., Trophic signatures of seabirds suggest shifts in oceanic ecosystems]

科学家们分析了古老羽毛中轻重氮同位素的比例，并与现代样品中的比例对比。他们发现太平洋中海鸟曾经主要以鱼为食。但食物网中现代鸟吃鱼的比例大大降低。（现代的鸟）似乎比他们的祖先多吃了将近一倍的鱿鱼-可能是商业捕鱼和气候变化的共同作用导致的。研究的相关细节收录于《科学·进展》杂志。

Now, nothing against consuming calamari. But: “KVH: It's a risky business to depend on squid. Because squid go through these boom/bust cycles." So the shift in protein source could one day leave the birds hungry.

现在，还没有什么能让海鸟放弃捕食鱿鱼。但是吉勒·凡·霍斯坦认为，“依赖鱿鱼是一件危险的事，因为鱿鱼经历增殖高峰和锐减的周期”。因此在蛋白质来源上的转变可能在某一天会使鸟类挨饿。

But the bigger picture is that it appears food webs in the central Pacific have lost components and become less complex over the last 130 years—meaning they're less resilient to changes.

但更宏观地考虑，太平洋中部的食物网已经在过去的130年中损失了组成成分，复杂性降低，这意味着它们对环境变化的抵抗力也随之降低。

KVH: "It's more than just climate: It's all the noise we're adding to the ocean. All of the contaminants, the microplastic. It's a warming ocean. It's an ocean with more nutrients. It's an ocean with less oxygen."

吉勒·凡·霍斯坦说：“这一切不仅是因为气候，我们在海洋中产生的噪音、排放的所有的污染物和微塑料都是罪魁祸首。现在的海洋是一个变暖的海洋，是一个营养物过多的海洋，是一个氧气含量过低的海洋。”

And it’s an ocean with less capacity to recover from all those insults.

“如今的海洋也是一片由于以上所有原因而承载力下降的海洋”。