Farming the Sea
Farming the Sea
In some cool coastal waters, you can find farms with no fences, no tractors and no soil. The crop is kelp, a large brown seaweed, and the "fields" are long ropes floating just below the surface of the sea.
Kelp farming begins on land. In autumn, workers collect a few ripe pieces of wild kelp and place them in tanks of chilled seawater. The pieces release millions of tiny spores, which settle on spools of thin string. For about six weeks the young kelp grows on the string in the tanks, where it is safe from waves and hungry fish.
In early winter the string is wound around thicker ropes, which are then anchored out at sea between floating buoys. Kelp needs cold water rich in nutrients, and here it gets both. In good conditions the young plants grow quickly. By late spring, before the sea warms up, the ropes hang heavy with brown blades, some of them longer than an adult is tall, and the harvest begins.
Farmers like kelp for several reasons. It needs no fresh water and no fertiliser, and it does not have to be fed. As it grows, it takes in carbon dioxide from the seawater, and the ropes give small fish and crabs a place to shelter. Once harvested, the kelp can be eaten, dried for animal feed or turned into fertiliser for crops on land.
Many of these farms are still small, and storms can tear ropes loose. But some growers believe that the sea could one day help to feed far more people than it does now.
Worked explanation 1
Where does the young kelp grow during its first six weeks?
- AA.
On thick ropes anchored between buoys
- BB.
On string in tanks of chilled seawater
- CC.
On rocks in shallow water near the shore
- DD.
In nets hanging beneath the farm boats
Answer: B
Answer: B (On string in tanks of chilled seawater)
The second paragraph says the spores settle on thin string, and 'for about six weeks the young kelp grows on the string in the tanks'. The tanks hold chilled seawater. The answer is B.
The trap: A is where the kelp goes next, in early winter. Children who remember ropes and buoys but not the order pick it.
Why the other options are wrong
- A (On thick ropes anchored between buoys): The ropes come later, in early winter, after the six weeks.
- C (On rocks in shallow water near the shore): Rocks near the shore are never mentioned.
- D (In nets hanging beneath the farm boats): No nets or farm boats appear in the passage.