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神秘南极深海与气候变化的奥秘 – 译学馆
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神秘南极深海与气候变化的奥秘

The secrets I find on the mysterious ocean floor | Laura Robinson

我是一位海洋化学家
Well, I’m an ocean chemist.
我研究现代海洋的化学特性
I look at the chemistry of the ocean today.
我也研究古代海洋的化学特性
I look at the chemistry of the ocean in the past.
我研究古代海洋的方式
The way I look back in the past
是借助深海珊瑚的化石遗体
is by using the fossilized remains of deepwater corals.
各位可以在我的背后看到这样一张图片
You can see an image of one of these corals behind me.
这是在南极洲附近海平面以下的数千米处采集的
It was collected from close to Antarctica, thousands of meters below the sea,
嗯 这些珊瑚跟其他类珊瑚有很大的不同
so, very different than the kinds of corals
比如说你去热带度假的时候有幸见到的一些
you may have been lucky enough to see if you’ve had a tropical holiday.
我希望这次演讲可以给你带来
So I’m hoping that this talk will give you
一个四维度考察海洋的视角
a four-dimensional view of the ocean.
其中的两个维度 正如这个漂亮的平面图
Two dimensions, such as this beautiful two-dimensional image
描述了海平面的温度
of the sea surface temperature
这张照片是卫星拍摄的 所以有着极高的空间分辨率
is taken using satellite, so it’s got tremendous spatial resolution.
照片的总体特征非常容易理解
The overall features are extremely easy to understand.
赤道地区比较温暖 因为接受的日照很多
The equatorial regions are warm because there’s more sunlight.
极地比较寒冷 因为接受的日照较少
The polar regions are cold because there’s less sunlight.
所以导致了南极洲的土地上 形成巨大的冰盖
And that allows big icecaps to build up on Antarctica
同样的还有北半球
and up on the Northern atmosphere.
如果你深潜入大海里 或者只是让脚趾头碰到海水
If you plunge deep into the sea, or even put your toes in the sea,
你就会知道越深处越寒冷
you know it gets colder as you go down,
这主要是因为填充海底沟壑的深海海水
and that’s mostly because the deep waters that fill the abyss of the ocean
是来自寒冷的极地地区 而那里的水密度更大
come from the cold polar regions where the waters are dense.
如果我们让时光倒流两万年
If we travel back in time 20,000 years ago,
整个地球看上去非常不同
the earth looked very much different.
我刚刚给你们看的是其中一个巨大变化的漫画示意图
And I’ve just given you a cartoon version of one of the major differences
那个时代的景象就像这样
you would have seen if you went back that long.
冰盖要比现在大很多
The icecaps were much bigger.
它们覆盖了大部分陆地 而且延展到各大洋
They covered lots of the continent, they extended out over the ocean.
海平面比现在低了120米
Sea level was 120 meters lower,
二氧化碳水平比现在要低很多
carbon dioxide were very much lower than they are today.
地球上的平均气温比现在大概要低3到5℃
So the earth was probably about three to five degrees colder overall,
而且在极地地区要更加寒冷
and much, much colder in the polar regions.
我想要研究清楚的东西
What I’m trying to understand,
也是我的同事们想要弄明白的东西
and what other colleagues of mine are trying to understand,
是我们地球是如何从寒冷气候条件
is how we moved from that cold climate condition
变成今天适宜我们生存的温暖气候条件的
to the warm climate condition that we enjoy today.
对冰芯的研究告诉我们
We know from ice core research
从寒冷气候到温暖气候的转变 并不是非常平缓的
that the transition from these cold conditions to warm conditions
从日光照射的缓慢增长趋势中可以推论出这一点
wasn’t smooth, as you might predict from the slow increase in solar radiation.
我们能得出这种结论 是因为如果你在冰盖上钻孔
And we know this from ice cores, because if you drill down into ice,
你可以发现按年份分层的冰 就像这幅冰山的图片里
you find annual bands of ice, and you can see this in the iceberg.
你可以看到那些蓝白相间的条纹
You can see those blue-white layers.
气体被封闭在这些冰芯里 所以我们可以据此测定二氧化碳
Gases are trapped in the ice cores, so we can measure CO2 —
因此我们得知以前的二氧化碳水平比现在要低
that’s why we know CO2 was lower in the past —
对冰的化学研究也能显示出
and the chemistry of the ice also tells us about temperature
极地地区的温度情况
in the polar regions.
如果你从两万年前穿越到现代
And if you move in time from 20,000 years ago to the modern day,
你会发现气温出现了增长
you see that temperature increased.
这种增长不是平缓的
It didn’t increase smoothly.
有时候气温上升得非常迅速
Sometimes it increased very rapidly,
然后就稳定一段时间
then there was a plateau,
之后再次迅速上升
then it increased rapidly.
两极地区的气温有些差异
It was different in the two polar regions,
而且二氧化碳水平也以这种跳跃方式增长
and CO2 also increased in jumps.
我们非常确定的是 海洋与这些变化有着密切联系
So we’re pretty sure the ocean has a lot to do with this.
海洋里储存着大量的碳元素
The ocean stores huge amounts of carbon,
是大气中碳含量的大约60倍
about 60 times more than is in the atmosphere.
海洋还有会跨赤道地区输送热量
It also acts to transport heat across the equator,
而且海洋富含养分 它控制着原始生产力
and the ocean is full of nutrients and it controls primary productivity.
如果我们想要研究深海世界里发生了什么
So if we want to find out what’s going on down in the deep sea,
我们就真的需要潜入其中
we really need to get down there,
看看那里有什么
see what’s there
并且开始努力探索
and start to explore.
这是拍摄于海底山峰的一些精彩镜头
This is some spectacular footage coming from a seamount
这个山峰位于赤道地区的公海 而且远离大陆
about a kilometer deep in international waters
大概在大西洋底1000米深处
in the equatorial Atlantic, far from land.
你们和我的研究团队一样
You’re amongst the first people to see this bit of the seafloor,
是第一批欣赏到这片海底的人
along with my research team.
你们可能会看到一些新物种
You’re probably seeing new species.
我们不太了解
We don’t know.
得采集很多样本 然后做非常繁琐的生物学分类才能知道
You’d have to collect the samples and do some very intense taxonomy.
你可以看到这些美丽的泡泡糖珊瑚
You can see beautiful bubblegum corals.
有柔软的海星长在这些珊瑚上
There are brittle stars growing on these corals.
它们看起来就像珊瑚上延伸出的触手一样
Those are things that look like tentacles coming out of corals.
这些珊瑚由不同形式的碳酸钙组成
There are corals made of different forms of calcium carbonate
在这个巨大的海底山峰的玄武岩上茁壮生长
growing off the basalt of this massive undersea mountain,
那些颜色很黑的东西就是变成化石的珊瑚
and the dark sort of stuff, those are fossilized corals,
在我们进行时光旅行时
and we’re going to talk a little more about those
对于那些还得多说几句
as we travel back in time.
首先我们得租一条考察船
To do that, we need to charter a research boat.
这是詹姆斯·库克号 一艘大洋级别的调查船
This is the James Cook, an ocean-class research vessel
停泊在特纳里夫港口
moored up in Tenerife.
看起来很漂亮,对吧?
Looks beautiful, right?
如果你不是个很好的海员 你会觉得确实不错
Great, if you’re not a great mariner.
但是有时她看起来更像这样
Sometimes it looks a little more like this.
我们正在努力确保珍贵的样品不丢失
This is us trying to make sure that we don’t lose precious samples.
每个人都手忙脚乱 然后我也严重晕船
Everyone’s scurrying around, and I get terribly seasick,
所以说这不全是有趣的经历 但是总体还不错
so it’s not always a lot of fun, but overall it is.
我们必须要成为很好的测绘师 才能做这个工作
So we’ve got to become a really good mapper to do this.
你不可能随处都能找到 如此丰富的珊瑚储量
You don’t see that kind of spectacular coral abundance everywhere.
我们得走遍世界 潜入深海寻找
It is global and it is deep,
但是我们必须得找到正确的地方
but we need to really find the right places.
我们刚看到的是一幅全景地图
We just saw a global map, and overlaid was our cruise passage
画的是我们考察船从去年开始走的线路
from last year.
那是一个为期七周的航程
This was a seven-week cruise,
这就是我们自己做的地图
and this is us, having made our own maps
在七周时间里 我们描绘了大约75,000平方公里的海底地图
of about 75,000 square kilometers of the seafloor in seven weeks,
但那也只是整个海底的微小部分
but that’s only a tiny fraction of the seafloor.
我们自西向东航行
We’re traveling from west to east,
穿过一些在地图上毫无特征的海域
over part of the ocean that would look featureless on a big-scale map,
但这里的一些山峰其实可以跟珠峰相提并论
but actually some of these mountains are as big as Everest.
我们在船上制作的地图
So with the maps that we make on board,
大概有100米左右的分辨率
we get about 100-meter resolution,
这已经足够让我们选定地址放置测绘仪器
enough to pick out areas to deploy our equipment,
但是想要看得更清楚就还是不够
but not enough to see very much.
为了使图像更清晰 我们要操纵遥控的深潜器
To do that, we need to fly remotely-operated vehicles
至距离海底5米左右的深处
about five meters off the seafloor.
如果我们这么做 我们可以得到 海平面以下数千米处
And if we do that, we can get maps that are one-meter resolution
分辨率小至1米的高清图像
down thousands of meters.
这就是一台遥控深潜器
Here is a remotely-operated vehicle,
一台科研级别的深潜器
a research-grade vehicle.
你可以在它顶部看到一排大灯
You can see an array of big lights on the top.
上面还有高清摄影机、操纵臂
There are high-definition cameras, manipulator arms,
还有各种小盒子、小零件来收集海底样本
and lots of little boxes and things to put your samples.
这是我们航程的第一次深潜
Here we are on our first dive of this particular cruise,
机器潜到大洋深处
plunging down into the ocean.
我们行进得相当快 以确保这个远程控制的机器
We go pretty fast to make sure the remotely-operated vehicles
不被其他船只影响
are not affected by any other ships.
我们不断下潜
And we go down,
这就是你们可以看到的东西
and these are the kinds of things you see.
这些是大小达到数米的深海海绵
These are deep sea sponges, meter scale.
这是个游动的海参—— 其实是一个小的海蛞蝓
This is a swimming holothurian — it’s a small sea slug, basically.
这是慢镜头
This is slowed down.
我展示的大部分视频资料都是加速播放的
Most of the footage I’m showing you is speeded up,
因为这些过程都耗时很长
because all of this takes a lot of time.
这也是一个漂亮的海参
This is a beautiful holothurian as well.
接下来你们看到的这个动物是一个很大的惊喜
And this animal you’re going to see coming up was a big surprise.
我从没见过这样的东西 我们见了都很吃惊
I’ve never seen anything like this and it took us all a bit surprised.
这是历经15小时的工作才拍到的 我们都很激动
This was after about 15 hours of work and we were all a bit trigger-happy,
突然 这个庞然大物开始滚动
and suddenly this giant sea monster started rolling past.
你可以称它为寄生生物 或者也可以叫它群居尾索动物
as called a parasite or colonial tunicate, if you like.
但这都不是我们要找的东西
This wasn’t what we were looking for.
我们在搜寻珊瑚 深海里的珊瑚
We were looking for corals, deep sea corals.
你们过一会儿就会看到一张珊瑚的照片
You’re going to see a picture of one in a moment.
它很小 只有5厘米高
It’s small, about five centimeters high.
它是由碳酸钙构成的 你们可以看到它的触手
It’s made of calcium carbonate, so you can see its tentacles there,
在洋流之中摆动
moving in the ocean currents.
像这样的有机体一般可以存活100年
An organism like this probably lives for about a hundred years.
在它生长过程中 它从海洋中吸收化学成分
And as it grows, it takes in chemicals from the ocean.
这些化学成分 或是说化学成分的量
And the chemicals, or the amount of chemicals,
取决于海水温度 还有pH值
depends on the temperature; it depends on the pH,
还取决于水中的养分
it depends on the nutrients.
如果我们能弄明白这些化学成分如何进入生物骨架
And if we can understand how these chemicals get into the skeleton,
我们就可以采集样本、回溯历史
we can then go back, collect fossil specimens,
重现古代海洋的图景
and reconstruct what the ocean used to look like in the past.
现在你们可以看到我们在用真空系统收集那个珊瑚样本
And here you can see us collecting that coral with a vacuum system,
然后把样本放在容器里
and we put it into a sampling container.
这里我补充一下 我们做这些时非常仔细
We can do this very carefully, I should add.
这类有机体有些可以活得更久
Some of these organisms live even longer.
这是一个叫做海柳的黑珊瑚 这张图片是我的同事布伦达·劳克
This is a black coral called amtipathes, an image taken by my colleague,
在夏威夷海底500米处拍摄的
Brendan Roark, about 500 meters below Hawaii.
四千年可是很长的时间啊
Four thousand years is a long time.
如果你从这种珊瑚中摘取一段枝条 然后把它打磨
If you take a branch from one of these corals and polish it up,
这张图横向大约有100微米宽
this is about 100 microns across.
布伦达对这个珊瑚做了横切分析
And Brendan took some analyses across this coral —
你们可以看到横向的标记
you can see the marks —
他由此证明了这其实是珊瑚的年轮
and he’s been able to show that these are actual annual bands,
所以说即使在海平面以下500米深处
so even at 500 meters deep in the ocean,
珊瑚可以记录季节的更替
corals can record seasonal changes,
这其实是挺惊人的
which is pretty spectacular.
然而四千年不足以让我们回到最后一个冰川极盛期
But 4,000 years is not enough to get us back to our last glacial maximum.
那么我们怎么办呢?
So what do we do?
我们潜入海中寻找化石样本
We go in for these fossil specimens.
其实这就是为什么我在研究团队里特别不受欢迎
This is what makes me really unpopular with my research team.
要潜到海底
So going along,
到处都是巨大的鲨鱼
there’s giant sharks everywhere,
还有火体虫、游动的海蛞蝓
there are pyrosomes, there are swimming holothurians,
以及巨大的海绵
there’s giant sponges,
但是我要求每个人都潜到这死气沉沉的化石区
but I make everyone go down to these dead fossil areas
然后花很长的时间在海底铲来铲去
and spend ages kind of shoveling around on the seafloor.
我们拾取所有的珊瑚样本 把它们带回来然后做分类
And we pick up all these corals, bring them back, we sort them out.
但是每一个样本都来自不同的时代
But each one of these is a different age,
如果我们可以知道它们有多古老
and if we can find out how old they are
我们就可以测定其中的化学信号
and then we can measure those chemical signals,
这就可以帮助我们
this helps us to find out
研究出古代海洋中发生了怎样的事
what’s been going on in the ocean in the past.
请看左侧的照片
So on the left-hand image here,
我对珊瑚做了一份纵切片 很仔细地打磨
I’ve taken a slice through a coral, polished it very carefully
之后拍摄了光学影像
and taken an optical image.
在右侧的照片中
On the right-hand side,
我们提取了同一片珊瑚 将它放进核反应堆
we’ve taken that same piece of coral, put it in a nuclear reactor,
诱发核裂变反应
induced fission,
每一次都会产生一些衰减
and every time there’s some decay,
你可以在珊瑚中看到一些标记
you can see that marked out in the coral,
我们可以据此判断铀元素的分布情况
so we can see the uranium distribution.
我们为什么要这么做呢?
Why are we doing this?
铀是一种很不被重视的元素
Uranium is a very poorly regarded element,
但是我非常喜欢它
but I love it.
这种衰减能帮助我们了解海洋中发生的事情
The decay helps us find out about the rates and dates
以及它们发生的速率和日期
of what’s going on in the ocean.
如果你们还记得我开头所讲的
And if you remember from the beginning,
这就是我们考虑到气候因素时想要得到的结果
that’s what we want to get at when we’re thinking about climate.
所以我们用激光分析铀元素
So we use a laser to analyze uranium
以及珊瑚中所含的铀的副产物钍元素
and one of its daughter products, thorium, in these corals,
由此我们得知这些化石的精确年龄
and that tells us exactly how old the fossils are.
这是南极洲上的美丽画面
This beautiful animation of the Southern Ocean
我用这个图去阐释我们如何利用这些珊瑚
I’m just going to use illustrate how we’re using these corals
来提取古代海洋的反馈信息
to get at some of the ancient ocean feedbacks.
这个由莱恩·阿伯纳西制作的动画中
You can see the density of the surface water
你们可以看到表面海水的密度分布
in this animation by Ryan Abernathey.
这只是一年的数据
It’s just one year of data,
但是各位已经可以看出南极洲非常动态的变化
but you can see how dynamic the Southern Ocean is.
尤其是方框中的德雷克海峡
The intense mixing, particularly the Drake Passage,
这里洋流交汇非常强烈
which is shown by the box,
其实是世界上最强的洋流之一
is really one of the strongest currents in the world
洋流从西到东穿过海峡
coming through here, flowing from west to east.
洋流在此处汹涌地交汇
It’s very turbulently mixed,
因为它经过了那些巨大的海底山峰
because it’s moving over those great big undersea mountains,
这就让二氧化碳和热量与大气进行交换
and this allows CO2 and heat to exchange with the atmosphere in and out.
本质上海洋系统是通过南极洋进行“呼吸”作用
And essentially, the oceans are breathing through the Southern Ocean.
我们在这个南极的海峡来回穿行 采集珊瑚样本
We’ve collected corals from back and forth across this Antarctic passage,
从我的铀元素年代测定结果 我们得到了很惊人的结论
and we’ve found quite a surprising thing from my uranium dating:
从冰期到间冰期的过渡期
the corals migrated from south to north
这些珊瑚从南方迁移到了北方
during this transition from the glacial to the interglacial.
我们并不知道为什么会这样
We don’t really know why,
但是我们认为这与食物来源有一些关联
but we think it’s something to do with the food source
也或许是因为水中的氧气
and maybe the oxygen in the water.
所以讲到这儿,
So here we are.
我要演示一下我认为我们在南部海域的珊瑚上
I’m going to illustrate what I think we’ve found about climate
发现的关于气候变化的事实
from those corals in the Southern Ocean.
我们在深海山脉里来来回回 收集小的珊瑚化石
We went up and down sea mountains. We collected little fossil corals.
这就是我要演示的内容
This is my illustration of that.
我们回溯到冰河时代
We think back in the glacial,
从我们对珊瑚的分析中发现
from the analysis we’ve made in the corals,
南极海洋深处蕴藏相当丰富的碳元素
that the deep part of the Southern Ocean was very rich in carbon,
并且有一层低密度海水浮在大洋表面
and there was a low-density layer sitting on top.
这就阻止了二氧化碳从海洋中逸出
That stops carbon dioxide coming out of the ocean.
我们之后发现了一些中等年龄的珊瑚
We then found corals that are of an intermediate age,
它们显示 洋流的激烈交汇发生在气候过渡期的中段
and they show us that the ocean mixed partway through that climate transition.
这让深海中的碳元素得以逸出
That allows carbon to come out of the deep ocean.
那么如果我们研究更接近现代的珊瑚
And then if we analyze corals closer to the modern day,
或者我们干脆马上就潜到海里
or indeed if we go down there today anyway
研究珊瑚的化学成分
and measure the chemistry of the corals,
我们可以看到 现在是二氧化碳进入进出交换的时代
we see that we move to a position where carbon can exchange in and out.
所以这就是我们利用珊瑚化石
So this is the way we can use fossil corals
来研究环境演变的方法
to help us learn about the environment.
现在我给大家展示最后一张幻灯片
So I want to leave you with this last slide.
这是从最开始我播放的视频中截取的一张图片
It’s just a still taken out of that first piece of footage that I showed you.
这是一个异常美丽的珊瑚花园
This is a spectacular coral garden.
我们根本没有想象到会发现如此美妙的东西
We didn’t even expect to find things this beautiful.
这里有数千米深
It’s thousands of meters deep.
这里有全新的物种
There are new species.
这就是一个美丽的圣地
It’s just a beautiful place.
这其中有很多化石
There are fossils in amongst,
我已经教大家如何欣赏这些
and now I’ve trained you to appreciate the fossil corals
沉睡在海底深处的珊瑚化石
that are down there.
所以下一次当你有幸飞过大洋时
So next time you’re lucky enough to fly over the ocean
或者是航行在海洋之上
or sail over the ocean,
请记得—— 海底世界有崇山峻岭
just think — there are massive sea mountains down there
无人领略过它的壮美
that nobody’s ever seen before,
海底世界还有美丽的珊瑚
and there are beautiful corals.
谢谢各位
Thank you.
(掌声)
(Applause)

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视频概述

海洋化学家带你领略神秘的南极深海美景,同时告诉你如何通过珊瑚化石发现气候变化的奥秘

听录译者

收集自网络

翻译译者

霜霜

审核员

赖皮

视频来源

https://www.youtube.com/watch?v=6MgDcFlTgVM

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