我们未来十年的行为将会决定未来一万年的海洋状况
For most of the year, the Gulf of Mexico is teeming with marine life,
一年中的大部分时间 墨西哥湾都充满了海洋生物
from tiny crustaceans to massive baleen whales.
从微小的甲壳类动物到巨型的须鲸都有
But every summer, disaster strikes.
但每年夏天 灾难都会降临
Around May, animals begin to flee the area.
五月左右 动物们开始逃离这个地区
And soon, creatures that can’t swim or can’t swim fast enough
很快 大量不会游泳或者游得不够快的生物
begin to suffocate and die off in massive numbers.
就会大量窒息而死
From late spring to early autumn,
从晚春到初秋
thousands of square kilometers along the coast become a marine dead zone—
海岸沿线数千平方公里成为海洋死区
unable to support most forms of aquatic life.
大部分海洋生物在这片区域都无法存活
This strange annual curse isn’t unique;
这种奇怪的年度诅咒并非独此一处
dead zones like this one have formed all over the world.
像这样的死亡区域遍布世界各地
But to explore what’s creating these lethal conditions,
但想要探究是什么造成了这样致命的环境
we first need to understand how a healthy marine ecosystem functions.
我们首先要去了解 健康的海洋生态系统是如何运作的
In any body of water that receives sufficient sunlight,
在阳光照射充足的水体中
plant-like organisms such as algae and cyanobacteria thrive.
藻类和蓝藻等植物类生物茁壮成长
Clouds of algae streak the surface of deep waters,
深水域的上层布满了海藻团
and in shallower regions, large seaweeds and seagrass cover the ground.
浅水区则由大型海藻和海草覆盖着海底地面
Not only do these organisms form the foundation of local food chains,
这些生物不仅是当地食物链的基础
their photosynthesis provides the oxygen necessary for aquatic animals to survive.
其光合作用还为水生动物提供了生存所必需的氧气
Besides sunlight and C02,
除了阳光和二氧化碳
algae growth also depends on nutrients like phosphorus and nitrogen.
藻类的生长还依赖于磷和氮等营养物质
While such resources are typically in short supply,
虽然这些物质通常供应不足
sometimes the surrounding watershed can flood coastal waters with these nutrients.
但有的时候 周围分水岭中的一些营养物质会被冲进沿湖水域
For example, a large rainstorm might wash nutrient-rich sediment
例如 一场大暴雨可能会把森林里
from a forest into a lake.
富含营养的沉积物冲到湖里
These additional resources lead to a massive increase in algae growth
这些额外的沉积物导致藻类大量生长
known as eutrophication.
即富营养化
But rather than providing more food and oxygen,
这些藻类的激增不仅没有提供更多的食物和氧气
this surge of growth has deadly consequences.
还带来了致命的后果
As more algae grows on the surface, it blocks sunlight to the plants below.
随着越来越多的藻类在水面生长 它阻挡了阳光照射下层的植物
These light-deprived plants die off and decompose
这些缺乏光照的植物死亡并分解
in a process which uses up the water’s already depleted oxygen supply.
而它们分解的过程耗尽了水中已经所剩无几的氧气
Over time, this can reduce the oxygen content
随着时间的推移 氧气含量会降低到
to less than 2 milligrams of oxygen per liter,
每升水2毫克以下
creating an uninhabitable dead zone.
形成一个无法居住的死亡区域
There are rare bodies of water that rely on natural eutrophication.
有一些罕见的水体依赖于自然富营养化
Regions like the Bay of Bengal are full of bottom-dwelling marine life
像孟加拉湾这样的区域到处都是
that has adapted to low-oxygen conditions.
适应低氧环境的底栖海洋生物
But human activity has made eutrophication a regular and widespread occurrence.
但人类活动已经使富营养化成为一种广泛的常态
Nutrient-rich waste from our sewage systems and industrial processes
我们的污水系统和工业生产过程中产生的
often end up in lakes, estuaries and coastal waters.
过营养化的废物通常会进入湖泊 河口和沿海水域
And the Gulf of Mexico is one of the largest dumping zones on earth
墨西哥湾是地球上
for one particular pollutant: fertilizer.
最大的肥料污染物倾倒区之一
American agriculture relies heavily on
美国农业严重依赖
nitrogen and phosphate-based fertilizers.
氮和磷基肥料
31 states, including America’s top agricultural producers,
31个美国主要的农业生产州
are connected to the Mississippi River Basin,
都与密西西比河流域相连
and all of their runoff drains into the Gulf of Mexico.
且所有的径流都汇入墨西哥湾
Farmers apply most of this fertilizer during the spring planting season,
农民在春播季节使用氮磷肥料
so the nutrient flood occurs shortly after.
很快就会导致养分的泛滥
In the Gulf,
在墨西哥湾
decomposing algae sinks into the band of cold saltwater near the seafloor.
腐烂的藻类沉入海底附近的冷盐水带
Since these dense lower waters don’t mix with the warmer freshwater above,
由于高浓度的下层海水和上层温暖的淡水不相混合
it can take four months for tropical storms
热带风暴需要四个月的时间
to fully circulate oxygenated water back into the gulf.
才能使含氧的海水完全循环回海湾
This dead zone currently costs U.S. seafood and tourism industries
死亡区域给美国海产品和旅游业造成的损失
as much as $82 million a year,
高达8200万美元一年
and that cost will only increase as the dead zone gets bigger.
而随着死亡区域的扩大 这一损失只会增加
On average the gulf dead zone is roughly 15,000 square kilometers,
死亡湾区平均面积约为1.5万平方公里
but in 2019 it grew to over 22,000 square kilometers—
但在2019年 它增长到超过2.2万平方公里
approximately the size of New Jersey.
大约相当于新泽西州的面积
Human activity is similarly responsible for growing dead zones around the world.
人类活动对世界各地死亡区域的扩张也负有同样的责任
So what can be done?
那么我们能够做些什么呢？
In the short term, countries can set tighter regulations on industrial run-off,
在短期内 各国可以对工业排放制定更严格的规定
and ban the dumping of untreated sewage into ocean waters.
禁止向海洋水域倾倒未经处理的污水
On farms, we can plant buffer zones
在农场上 我们可以通过种植
composed of trees and shrubs to absorb runoff.
树木和灌木建立缓冲区来吸收流失的营养物质
However, long term solutions will require radical changes to the way we grow food.
然而 长期的解决方案需要我们彻底改变种植粮食的方式
Farmers are currently incentivized to use techniques
目前农民倾向于使用那些
that reduce the health of the soil
对土壤有害的
and rely heavily on nitrogen-rich fertilizers.
并且严重依赖富氮肥料的技术
But there would be less need for these chemicals
但是 如果我们通过种植不同的作物来
if we restore the soil’s natural nutrients
来控制土壤侵蚀及肥沃程度 从而恢复土壤的
by planting diverse crops that manage soil erosion and fertility.
自然营养 那么对这些化肥的需求就会减少
Hopefully we can make these fundamental changes soon.
希望我们能很快做出这些根本性的改变
Because if we don’t,
因为如果我们不这样做的话
the future of our marine ecosystems may be dead in the water.
海洋生态系统的未来可能会葬于水中
Fish need our help.
鱼类需要我们的帮助
By 2050
到2050年
There will be more plastic and trash in the ocean than fish
海洋上的塑料和垃圾就会比鱼还多了
Could the earth really run out of fish?
鱼类真的会从地球上消失吗？
Find out more about the serious threat of over-fishing
在下一个视频了解更多有关过度捕捞的严重威胁
and what we can do to prevent it in this video.
以及如何阻止威胁的发生吧