A Decade-Long Experiment Is Unlocking the Mysteries of the Ocean’s ‘Deep Reefs’

一项长达十年的实验正在揭开海洋“深海珊瑚礁”的神秘面纱

On a bright, sunny day last May, I stood on a boat surrounded by the turquoise waters of the island nation of Palau. I was there in the western Pacific watching scuba divers as they prepared to bring up evidence of a mysterious aquatic world. 去年五月的一个晴朗日子，我站在帕劳群岛国家绿松石般的海水中，身处一艘船上。我当时身处西太平洋，观察着潜水员们准备打捞一个神秘水下世界的证据。

Palau is famous for its spectacular and rich coral reefs. But these divers were planning to descend past those sun-lit marine communities and down into a lesser-known twilight zone known as the “mesophotic coral ecosystem.” 帕劳以其壮观而丰富的珊瑚礁而闻名。但这些潜水员计划穿过那些阳光充足的海洋群落，深入到一个鲜为人知的“暮光区”，即所谓的“中光层珊瑚生态系统”。

Mesophotic essentially means “middle” and “light,” which is where these ecosystems are—not quite in the bright daylight, not quite in the profound darkness, but somewhere in between. For simplicity’s sake, we’ll call these communities, which range from some 30 meters to 150 meters below the surface, the “deep reefs.” “Mesophotic”一词本质上意为“中间”和“光线”，这正是这些生态系统所处的位置——既不在明亮的日光下，也不在深沉的黑暗中，而是介于两者之间。为了简单起见，我们将这些位于海面下约30米至150米处的群落称为“深海珊瑚礁”。

One of the divers on the boat with me was a zoologist and curator at the California Academy of Sciences named Luiz Rocha, who has spent decades studying these deep reefs and their secrets. “Anything between 30 meters and 150 meters is really, really unknown,” he told me. 与我同船的潜水员之一是加州科学院的动物学家兼馆长路易斯·罗查（Luiz Rocha），他花了数十年时间研究这些深海珊瑚礁及其秘密。他告诉我：“30米到150米之间的任何地方都非常、非常陌生。”

Because these deep reefs are so unknown, researchers like Rocha are left with big questions. They want to get a baseline picture of what is going on in these ecosystems—even just who lives there!—so that they can better understand how they function. They’ve also tried to work out whether (or not) these deep reefs might provide a refuge for species living in shallower coral reefs. 由于这些深海珊瑚礁鲜为人知，像罗查这样的研究人员面临着巨大的疑问。他们希望获得这些生态系统运作情况的基准图景——哪怕只是弄清楚谁住在那里！——以便更好地理解它们的功能。他们还试图弄清楚这些深海珊瑚礁是否能为生活在浅水珊瑚礁中的物种提供避难所。

I was in Palau for Vox’s Unexplainable podcast because, in an effort to gather more information about these mysterious places, Rocha left some scientific structures down in these twilight depths back in 2016. Those structures then spent almost a decade becoming encrusted with all kinds of marine life. And now, Rocha was back to retrieve them, hoping that he—along with many other scientists—would be able to open them up, like a box of scientific puzzle pieces, full of clues about this under-understood marine world. 我此次前往帕劳是为了 Vox 的《Unexplainable》播客节目，因为为了收集更多关于这些神秘地方的信息，罗查在2016年将一些科学结构留在了这些暮光深处。这些结构在近十年的时间里被各种海洋生物覆盖。现在，罗查回来回收它们，希望他能与许多其他科学家一起打开这些结构，就像打开一盒科学拼图，里面充满了关于这个未被充分了解的海洋世界的线索。

One thing that’s often acknowledged in papers about mesophotic coral ecosystems is that scientists don’t know as much as they’d like to. A National Oceanic and Atmospheric Administration article about them from 2019 is full of “mays,” as in: They may “serve as essential fish habitat for economically and ecologically important species.” 关于中光层珊瑚生态系统的论文中经常承认的一点是，科学家们了解的还不够多。美国国家海洋和大气管理局（NOAA）2019年的一篇文章中充满了“可能”一词，例如：它们可能“作为具有经济和生态重要性的物种的基本鱼类栖息地”。

Researchers do know some things, of course. They know that these deep reefs can be found in many of the same regions as shallower coral reefs—so mainly the tropical and subtropical parts of the world, like Micronesia, the Caribbean, and even the Gulf of Mexico. They’ve found that there are many species that seem to be unique to these places, and recent research points to their potential susceptibility to climate change. 当然，研究人员确实了解一些情况。他们知道，这些深海珊瑚礁可以在许多与浅水珊瑚礁相同的地区找到——主要是世界的热带和亚热带地区，如密克罗尼西亚、加勒比海，甚至墨西哥湾。他们发现，有许多物种似乎是这些地方独有的，最近的研究也指出它们可能容易受到气候变化的影响。

Researchers have also gotten a sense of some of the key differences between these deep reefs and their shallower coral neighbors. In shallow reefs, hard corals team up with photosynthesizing algae. The algae provide the corals with nutrients, and the corals secrete a calcium-carbonate matrix that helps create the architecture of the reef. 研究人员还了解了这些深海珊瑚礁与其浅水珊瑚邻居之间的一些关键差异。在浅水珊瑚礁中，硬珊瑚与光合藻类共生。藻类为珊瑚提供营养，而珊瑚分泌碳酸钙基质，有助于构建珊瑚礁的结构。

As you go deeper, though, the light begins to fade, and the opportunities for photosynthesis start to fade with it. The temperature also drops. So the animals living down in the deep reefs are ones that can survive in a dimmer, cooler world. 然而，随着深度增加，光线开始减弱，光合作用的机会也随之减少。温度也会下降。因此，生活在深海珊瑚礁中的动物是那些能够在更昏暗、更寒冷的世界中生存的物种。

Scientists can dive into the deep reefs to try to learn more about these understudied places—as Rocha has—but exploring down at 100 meters requires more difficult, riskier technical diving than exploring at shallower depths. The deeper you dive, for example, the faster gases get pushed into your tissues, which imposes limits on these really deep dives. 科学家们可以像罗查那样潜入深海珊瑚礁，试图更多地了解这些未被充分研究的地方，但在100米深处进行探索需要比浅水探索更困难、风险更高的技术潜水。例如，潜得越深，气体进入组织的速度就越快，这限制了这些超深潜水。

“We have a very, very short time,” Rocha says, “And by short time, I mean five minutes. Six, seven minutes.” Scientists can take some pictures in that time, make some measurements, or collect a few samples, but then they have to move back upwards—a process that can take hours, since they must rise slowly to avoid decompression sickness. “我们的时间非常、非常短，”罗查说，“我说的短时间是指五分钟。六、七分钟。”科学家们可以在这段时间内拍一些照片、进行一些测量或收集少量样本，但随后他们必须返回上方——这个过程可能需要数小时，因为他们必须缓慢上升以避免减压病。

It is, obviously, not particularly efficient to study an ecosystem in five- to seven-minute intervals. People have also used remote-operated vehicles and submersibles to explore the deep reefs, but those have their own issues, and cameras can’t always capture all the detail you might want, or photograph more secretive, cryptic animals. So huge gaps remain in scientific knowledge about these ecosystems. 显然，以五到七分钟的间隔来研究一个生态系统并不是特别有效。人们也曾使用遥控潜水器和载人潜水器来探索深海珊瑚礁，但这些设备也有其自身的问题，而且摄像头并不总能捕捉到你想要的所有细节，或者拍摄到更隐秘、更难发现的动物。因此，关于这些生态系统的科学知识仍然存在巨大的空白。

“Whenever we go somewhere,” Rocha says, “the first thing we find is new species. It’s the most basic thing in science you can do.” But this effort goes beyond just cataloging new species of fish, sponges, or sea slugs. “每当我们去某个地方，”罗查说，“我们发现的第一件事就是新物种。这是科学中最基本的事情。”但这项工作不仅仅是编目新的鱼类、海绵或海蛞蝓物种。

Rocha wants to answer fundamental questions like: What is the main energy source for everything down here in the dim light? What does the food chain look like? How have things evolved to live at these depths? How similar are they to the shallow ecosystems, and how different? How are they affected by climate change—and what’s the most efficient way to protect them? 罗查想要回答一些基本问题，例如：在昏暗的光线下，这里所有生物的主要能量来源是什么？食物链是什么样的？生物是如何进化到在这些深度生存的？它们与浅水生态系统有多相似，又有多大不同？它们如何受到气候变化的影响——以及保护它们的最有效方法是什么？

But Rocha says that “in some ways, we don’t even know what questions to ask. We really only know what the crucial questions are when we have a baseline understanding of the ecosystem. And for deep reefs, we don’t have that yet.” 但罗查表示，“在某些方面，我们甚至不知道该问什么问题。只有当我们对生态系统有了基准了解时，我们才能真正知道关键问题是什么。而对于深海珊瑚礁，我们目前还没有做到这一点。”

Rocha is not deterred by the enormous number of question marks that surround these deep reefs. For years now, he has been gathering bits of basic information about them, often via those very short dives. About a decade ago, though, Rocha got interested in another method for sampling the biodiversity of this sort of marine ecosystem—a technique… 罗查并没有被围绕这些深海珊瑚礁的无数问号所吓倒。多年来，他一直通过那些极短的潜水过程，收集关于它们的零星基本信息。然而，大约十年前，罗查开始对另一种采样此类海洋生态系统生物多样性的方法产生兴趣——一种技术……