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更新时间:2018-4-23 20:32:45 来源:纽约时报中文网 作者:佚名

The quest to map the mysteries of the ocean floor

The oceans’ floors are not a flat, sandy expanse – they are every bit as varied as the landscapes above water, with plunging valleys and huge mountains. Making a map of them has been a challenging task.


Geologists have charted mountain ranges and forests and desert tundras, astronomers the heavens above, yet our planet’s oceans remain largely unexplored; it’s often said that we have a more complete understanding of the Moon or Mars than we do of our own seabed.


The sea’s terrain plays a critical role in our ecosystem. Underwater crests and valleys determine weather patterns and ocean currents; sea topography influences the management of fisheries that feed millions; miles of underwater cable connect billions more to the Internet; seamounts provide protection against coastal hazards such as approaching hurricanes or tsunamis, and may even offer clues to the prehistoric movement of the earth’s southern continents.


In 2017, an international team of experts from around the world, united under the non-profit General Bathymetric Chart of the Oceans (Gebco), launched the first effort to create a comprehensive map of the world’s oceans.

2017年,在非营利组织大洋水深制图委员会(General Bathymetric Chart of the Oceans, Gebco)的召集下,一支由全世界各地的专家组成的团队首次正式展开全球海床图测绘工作。

While the earliest oceanographers trawled waters one painstaking knot at a time, recent advances in sonar technology mean that a single ship can now provide thousands of square kilometers’ worth of high-resolution maps during an expedition.


But the underwater discoveries that await aren’t only of interest to mapmakers or marine researchers. Far below the ocean’s surface lies buried treasure: precious metals, rare earth elements, oil and diamonds – riches that have, until now, remained inaccessible to even the most intrepid of prospectors.


Some ecologists fear that a map of our sea floor will allow extractive industries the chance to profit from these resources, potentially endangering marine habitats and coastal communities in the process. A global bathymetric map – that is, a map of the ocean’s floor – would certainly offer a better understanding of our blue planet, but it also might plunge us into a realm once reserved for science fiction: robot submarines, underwater volcanoes, sea jewels, coral with pharmaceutical properties, Wild West maritime law, toxic sediment plumes, and an ocean-based enterprise curiously devoid of humans or ships. Once the map is made, will it be used as a tool for responsible management and conservation, or wielded like pirate’s bounty, a guidebook to extraction and exploitation?


Only 15% of the Earth’s ocean is mapped. Zoom in on the middle of the Pacific in Google Earth, for example, and you’ll find a representation of the ocean floor based on satellite and gravity-derived bathymetry: low resolution, indirect, often inaccurate. Considering that we’ve plotted our Solar System and charted the human genome, it’s rather astonishing that no map of the seafloor exists. But the reason is simple: our planet’s oceans are vast, deep, and largely impenetrable, and water literally gets in the way.


For centuries, charting the murky depths meant braving the high seas, dangling plumb lines over the side of a ship, then drawing basic contours on cartographic maps. Sailors etched soundings onto maps as early as the 16th Century, but no international standards for terminology or scale existed then, meaning early maps were not only rudimentary wayfaring tools, they were also confusing and contradictory.


It wasn’t until the turn of the 20th Century, an era marked by soaring interest in the natural world, that a group of geographers gathered under the leadership of Prince Albert I of Monaco to produce the first international charts of the ocean (what would eventually become Gebco). Albert was fascinated by the then relatively new science of oceanography, and commissioned four research yachts to survey the Mediterranean. More than 100 years later, Gebco and the Nippon Foundation formally announced Seabed 2030, a project that aims to map the entire sea floor by the year 2030 using data gathered from vessels around the world – including soundings from those early expeditions.

直到19世纪末20世纪初,那个颇具划时代意义的年代,人类对于自然界的兴趣大增,一群地理学者在摩纳哥王子阿尔伯特一世(Prince Albert I)的召集与领导下,才制作了第一幅世界海洋地图("世界大洋水深图"的雏形)。阿尔伯特一世对于当时新兴科学领域"海洋学"非常感兴趣,组建了四艘艇的研究人员前往勘测地中海。一百多年后,全球大洋水深制图委员会与日本财团基金会(The Nippon Foundation)正式发布"海床2030"计划(Seabed 2030),该计划意图在2030年前利用从世界各管道搜集的数据(也包括早期的一些海洋探测图)绘制出一幅完整的全球海床图。

Modern ships like the kind used in Seabed 2030 are now outfitted with multibeam bathymetry, sonar systems that emit sound waves in a fan shape beneath a ship’s hull. Each sonar ping measures the time it takes for a signal to reach the seafloor and return to the surface, a calculation of the water’s depth that can be marked as a coordinate on a grid.


“Multibeam extends the map area and gives us extended coverage,” explains Vicki Ferrini, the chair of Gebco’s subcommittee for undersea mapping. Most ships already rely on sonar for obstacle avoidance and navigation, but vessels with multibeam dramatically increase the area of seafloor that researchers can ensonify – that is, the underwater footprint or track line they can capture with sonar. “The process is a little like mowing a lawn with a riding mower versus a push mower.”

委员会海底绘制分部的主任费里尼(Vicki Ferrini)解释道,"多波束声纳大大扩展了测算的范围,测绘覆盖的区域更广了。"现绝大部分船只是依靠声纳系统避开障碍及导航。但是多束波声纳则大大增加了研究船只进行声波传播测算(指的是研究人员能够通过声纳捕捉到的海底面积或地势)的海底区域。费里尼说,"多束波声纳与一般船只使用的声纳系统的差别有点类似大型车驾式剪草机相对于小型手推式剪草机。"

Part of the problem, however, is that ocean track lines are a lot like highways: certain parts of our oceans are heavily trafficked, while others may have no roads at all. Continent-sized swathes of our planet’s seas are not regularly plied by ships. One ship’s crossing between Hawaii and Japan, for instance, offers valuable track line data, but planned missions to more remote waters are equally important.


“A bathymetric survey done with modern multibeam is more than just driving a ship around the ocean,” says Rear Admiral Shepard Smith, director of the United States Office of Coast Survey at the National Oceanic and Atmospheric Administration (NOAA), a contributor to Seabed 2030. “Sonar data is valuable, however; particularly in areas where we don’t have anything,” he says. “In the Pacific or the Arctic, for example, individual track lines can be quite helpful to better understand poorly mapped areas.”

任美国国家海洋与大气管理局(National Oceanic and Atmospheric Administration, NOAA)海岸研究部负责人的海军上将史密斯(Shepard Smith)本人也是参与"海床2030"计划的研究人员。他说:"现代多波束声纳的海床测绘工作并不是派一艘船航行于海洋就能够完成的。航船收集的声纳数据非常宝贵,在一些我们几乎未曾踏足的海域更是如此。像是在太平洋或是北冰洋里,单是一艘航船绘制的海底地势线就能帮助我们更好地了解目前测绘还不足的海域。"

Gebco hopes to mitigate this problem by encouraging cargo ships, fishing boats and pleasure craft to participate in the project and transmit their data in real time, effectively crowdsourcing the underwater map. The organisation also offers a “cook book”: a technical reference manual on building bathymetric grids, which can help developing nations make use of shared expertise. Marine enthusiasts are even invited to submit name proposals for various underwater features – knolls, aprons, ridges, reefs, calderas, trenches, saddles, sills and salt domes, to name a few – by sending a letter to the International Hydrographic Organisation in Monaco.

因此,全球大洋水深制图委员会号召更多货船、渔船和游轮等商用或民用船只加入这个计划,并将实时数据传输给委员会,以利用"众包"的形式解决当前数据不足的问题,共同将海床地图绘制出来。委员会还制定了一个"绘图指南":针对大洋水深网格坐标系给出详尽的技术指导,以期帮助发展中国家也可使用。他们还邀请全世界的海洋爱好者提交新发现的各类海底地形地貌特征,如小型土丘、小型海脊、礁石、喷火山口、 沟渠、岩床、盐丘等)的命名方案。海洋爱好者们可以给位于摩纳哥的国际海道测量组织(International Hydrographic Organisation, IHO)写信提交方案。

The actual map is assembled at the British Oceanographic Data Centre in the UK. Helen Snaith, the Global Centre lead for SeaBed2030, notes that “everyone from ocean modellers and researchers to policy makers and the general public can access the current data” via a marine iOS app.

最终的海床地图会在英国海洋数据中心汇总拼成。"海床2030"计划全球中心负责人斯奈思(Helen Snaith)说:"数据是公开的。不论你是海洋模型专家、研究者、政府机关工作人员还是一般公众,都可以在"海洋"这款应用程序上获取现有的数据。"

Perhaps no single modern expedition reveals the complexity of deep-sea ocean mapping more strikingly than the search for the missing Malaysian Airlines Flight 370 (MH370). Investigators suspected that the plane, which vanished in 2014 en-route to Beijing, had crashed in a remote area of the Indian Ocean. The area was so poorly mapped, however, that search teams had to do basic mapping of the search area before they could draw up a more precise map with enough resolution to spot wreckage.


In fact, the search area was too deep to explore with ship-based mapping. In shallower water, sonar-equipped towboats trail behind a manned vessel, but the Indian Ocean’s depth, monsoon climate and powerful currents made navigation of towed vehicles nearly impossible; instead, investigators dispatched a fleet of autonomous underwater vehicles, or AUVs.

事实是这个搜索区域的海水相当深,依靠航船勘探绘图术行不通。在水深稍浅的海域,人工驾驶的航船可以拖上一艘装备声纳的拖船。但是以印度洋的海水深度,季风气候和强劲的洋流,拖船几乎无法在海中按既定航向行驶测量。调查人员只能在海中放置一组自动水下载具(Autonomous Underwater Vehicle, AUV)。

Though underwater robotics is in its infancy, deep sea surveys have come to rely increasingly on submarines to scour the seabed for more detailed mapping. “There are many advantages to AUVs,” explains James Bellingham, director of the Woods Hole Center for Marine Robotics in Massachusetts, USA. “They are faster, they provide higher-resolution seafloor surveys, including hazard assessment, they lower upfront capital costs, and provide increased access to the ocean.” A proper multi-beam bathymetry system costs several million dollars and requires trained operators to sort the data, because ships, by definition, float on the ocean’s surface – not below it.

水下机器人尚处于发展初期,深海测绘越来越依赖潜艇作更详尽的测量。美国麻省伍兹霍尔海洋研究所(Woods Hole Center)海洋机器人实验室主任贝灵汉(James Bellingham)说: "自动水下载具有很多优势。他们速度很快,能够提供包括危险系数评估等在内的高像数海床勘探,并能降低前期投资成本,探索的海域也更广。"一套正规的多波束声纳水深勘测系统要花费几百万美元,且需要专业的操作员来分析数据。因为航船,顾名思义,是航行于洋面,而非潜入水中。

An AUV, by contrast, is less expensive and ideally suited to lonely, open stretches of water: researchers are currently designing new models that can be launched from land, and need to be powered only by batteries. Of course, these assets can quickly turn into hazards: batteries need to be recharged, navigation systems must be tracked from nearby ships, and an AUV that breaks down must be brought back to port for service.


“In the future,” says Bellingham, “an autonomous surface vehicle might tow out underwater vehicles,” thus eliminating human beings from the at-sea aspects of mapping altogether.


The Indian Ocean is known in ancient Sanskrit as Ratnakara, “the mine of gems”. The name is indeed prophetic: hidden in the subsea mountains and valleys of that remote ocean are vast pools of resources, including rare metal alloys, oil, hydrothermal vents, even diamonds. These aquatic riches are already on commercial radar, and a handful of ocean prospectors have begun to make their own high-resolution maps of the sea floor. That data can be of value to researchers, Ferrini explains: oil, mineral and seismic companies might elect to contribute decimated, or lower resolution data, to Gebco’s map, thereby protecting their commercial interests while adding important information to the 2030 project.


Consider that De Beers Group, an international corporation and household name in diamond mining and retail, formed a partnership with the Namibian government over 20 years ago in pursuit of diamonds off the coast of that mineral-rich country. More recently, De Beers added to its naval fleet several AUVs – part of a drill and crawler mining system that can scour the surface of the seafloor, loosen deep seabed sediment for rough diamonds and haul their cache hundreds of metres to the surface.

以世界钻石业中家喻户晓的名字,主宰了全球四成以上的钻石开采和贸易的戴比尔斯(De Beers)为例。这家公司二十年前在钻石矿产丰富的纳米比亚,与该国政府达成了合作,获权开采纳米比亚沿海的钻石。近期,戴比尔斯新引进了一批自动水下载具,它们能够潜入水中勘探海床,开采钻石,挖起海床上含有毛胚钻石的海底沉积物,然后运送到几百米高的海面上。

While shallow-water mining for sand, gold, tin, and diamonds is a decades-old enterprise, commercial deep sea mining is a new industry, its environmental impact yet unknown. Scientists predict habitat degradation, slow and uncertain recovery, toxic plumes from surface ore, undersea noise, chemical spills in transport, and species extinctions.


A De Beers spokesperson confirms that the company “does not mine in areas considered to have high diversity of marine life,” and stated that, post-mining, “seabed recovery occurs naturally over a period of time and is assisted by the sediment that we return to the seabed.”


Still, the industry’s economic incentives often outweigh environmental safety concerns. Rare earth metals found in deep sea alloys are used in everything from cell phones and DVDs to rechargeable batteries, magnets, computer memory and fluorescent lighting; and terrestrial oil reserves are being swiftly depleted, making the switch to deep sea wells an ever more tempting prospect. “This is a race,” explains Bellingham. “A race to get a baseline understanding of our ocean, before we change it dramatically. We’ve lost that race already in the Arctic: life that used to live in sea ice no longer survives.”


Aside from the obvious effects of climate change, many of our shared waters have also become prey to urban ocean: seafloors riddled with pipelines, router cables and aquaculture, a trend that suggests we are all too eager to exploit our oceans before we properly understand them.

除了一些气候变化带来的显著影响外,地球上许多公共水域已成为 "城市化海洋"的牺牲品:海床上充斥着各式管道、路由电缆和水产养殖等等。这些现象表明,人类还没充分认识海洋,就已经迫不及待地滥用海洋资源。

Map or no map, international maritime laws currently restrict deep sea mining more than 200 miles offshore – the point at which countries no longer have jurisdiction over their waters. The United Nations Convention for the Law of the Sea is the legal framework that sets out the rights and duties of States in the use and exploitation of the oceans. Article 76 of the convention repeatedly refers to the “continental margin,” the boundary between crustal provinces (that is, the physical outer edge of a country’s land) and the deep ocean basins beyond them; the law states that deep-sea life must be protected, and that revenue made from any mining venture there must be shared with the international community.


The deep ocean constitutes the largest and least understood biological habitat on Earth. Two-thirds of our planet contains a marine wonderland of beauty and mystery. These regions, characterised by extreme pressure, cold temperatures, and near-constant darkness are nonetheless home to an astonishingly diverse menagerie of creatures – the Dumbo octopus, the vampire squid, the ghost shark, spider crabs, coral and electric eels – bizarre organisms that display striking evolutionary adaptations. Though these underwater denizens have changed little since the time of the dinosaurs, they are not terribly resilient, being slow to reproduce and highly sensitive to disturbance.


An international underwater atlas requires cooperation between stakeholders with various, sometimes competing interests, from government officials and oceanographers to military submarine operators, fishermen and offshore miners. Once detailed bathymetric information is made available to the public, protective measures must be taken to protect both the map and the landscape it describes.


“A high-resolution map is an investment in responsible management of the seabed in the coming centuries,” says Rear Admiral Smith. Indeed, we have but one planetary ocean, and its preservation depends on conscientious stewardship – particularly as we turn to its depths for the resources we can no longer find on dry land. An underwater map might be the very sea change we need.