科技板块--水产养殖：大规模种植海草(上)

Science and technology - Aquaculture: Seaweed at scale

科技板块--水产养殖：大规模的海草

Floating offshore farms should increase production of a useful crop, and might even help alleviate climate change

漂浮在海上的农场有望增加有益作物的产量，甚至可能有助于缓解气候变化

IN MANY PLACES where seaweed used to thrive, often growing in vast “forests”, it is disappearing.

在许多曾经海草繁盛，往往长成大片“森林”的地方，这些植物正在消失。

The cause is global warming, which, by heating the ocean’s upper layer, reduces its density through thermal expansion—thus making it more buoyant.

因为全球变暖导致海洋表层升温，热膨胀会降低海水密度，从而使其浮力更大。

That extra buoyancy means it is less likely to mix with cooler, denser and more nutrient-rich waters below.

浮力增加意味着它不太可能与下方温度更低、密度更大、营养更丰富的水域相融合。

This is bad for the marine environment in general.

总的来说，这对海洋环境不利。

More specifically, it is bad for commercial seaweed farming, a business with revenues of (depending on whom you ask) between $6bn and $40bn a year.

更具体一点，它对商业海草养殖不利，这一业务每年的收入(视具体情况而定)在60亿至400亿美元之间。

The algae involved, particularly kelp, are popular in Asian cuisine.

其中涉及的藻类，尤其是海带，在亚洲菜肴中很受欢迎。

They are also used as fertiliser, and are processed into carrageenan, a natural binder and emulsifier employed in foods, cosmetics and drugs.

它们还可以用作肥料，并被加工成卡拉胶——一种用于食品、化妆品和药品的天然粘合剂和乳化剂。

Most are grown either on the seabed or on ropes attached to it. But some are cultivated on small floating platforms.

多数海草都是在海床上种植，或者用绳子固定在海床上。但有些海草是在小型浮动平台上培育的。

To counter the effects of surface heating, which are particularly pronounced in the tropics, researchers are trying to improve the floating-platform approach by assisting the upwelling of cooler waters to stimulate algal growth on such platforms.

为了抵消海水表面升温的影响——这在热带地区尤为明显——研究人员正试图让冷水上涌，刺激浮动平台上的海草生长，来改进这种种植方法。

This would also increase the area available for seaweed farms, by allowing them to be located well away from coastlines.

这也会增加海草养殖场的可用面积，在离海岸线较远的地方也可以种植。

An experimental floating farm installed in August, off the coast of the Philippines, by a group led by the Climate Foundation, an American charity, is one of the largest attempts so far to do this.

美国慈善机构气候基金会(Climate Foundation)领导的一个小组于8月在菲律宾海岸安装了一个实验性的浮动农场，这是迄今为止最大的尝试之一。

Artificial stimulation of upwelling is not a new idea.

通过海水上涌进行人工刺激并非新鲜之事。

It has been touted for years as a way to regenerate kelp forests, in particular. And for good reason.

多年来，这种方法一直被吹捧为打造再生海草森林的方法。这是有原因的。

With enough nutrients, fronds of giant kelp, which grow to an average length of about 30 metres, can elongate by more than 50cm a day.

有了足够的营养，这些平均长度约为30米的巨型海草叶，每天可以生长50多厘米。

Only now, however, is upwelling-stimulation being attempted seriously.

然而，直到现在，人们才真正开始尝试海水上涌的刺激措施。

The foundation’s test platform has an area of 100 square metres.

该基金会的测试平台面积为100平方米。

It employs solar-powered turbines to suck water up from a depth of several hundred metres through flexible, cylindrical pipes.

它采用太阳能涡轮机，通过柔性圆柱形管道从几百米的深海中抽取海水。

The foundation plans to experiment with wind-powered and wave-powered turbines, too.

该基金会还打算试验风力涡轮机和海浪涡轮机。

If this works, which early results suggest it does, and can be scaled up, not only could such technology boost seaweed production, it might also help ecosystems that depend on seaweed forests.

早期的研究结果表明，这种方法是可行的，如果它能被推广，这种技术不仅能促进海草的生产，还可能帮助依赖海草森林的生态系统。

And—at least in theory—if part of the harvest were sacrificed by sinking it into the deep ocean, that might act as a novel form of carbon capture and storage which could help slow the warming that caused the problem in the first place.

而且，至少从理论上来说，如果将部分海草收成沉入深海，这可能会成为一种新型的碳捕获和储存方式，有助于减缓最初的升温问题。

According to Brian von Herzen, who runs the foundation, the organisation carried out smaller-scale experiments, using similar technology, in 2020.

该基金会的负责人布莱恩·冯·赫尔岑(Brian von Herzen)表示，该组织在2020年使用类似的技术进行了小规模的实验。

These showed that seaweed grows four times faster on platforms irrigated with upwelled water than on equivalent, unirrigated platforms.

这些研究表明，在用上涌水灌溉的平台上，海草的生长速度是同等条件下没有灌溉上涌水的平台的四倍。

Moreover, it continues to grow during the warmest months of the year, when seaweed not so irrigated actually shrinks.

此外，在一年中最温暖的几个月里，海草还能继续生长，而没有得到充分灌溉的海草其实会萎缩。

Dr von Herzen and his colleagues hope to use experience gathered from their latest rig to develop a platform that would cover an entire hectare of the ocean’s surface—100 times the area of the one just launched.

冯·赫尔岑博士和他的同事们希望利用从他们最新平台上收集的经验来开发一个平台，该平台将覆盖一公顷的海洋表面积——是刚刚启动的平台面积的100倍。

To that end, they are collaborating with the Marine Bioproducts Cooperative Research Centre, a public-private partnership in Australia.

为此，它们正在与澳大利亚的一个公私伙伴关系——海洋生物制品合作研究中心合作。

At this scale, the partners estimate, a seaweed farm could pay for itself within five years.

合作伙伴估计，按照这个规模，一个海草养殖场可以在5年内收回成本。