PLANET EARTH Shallow Seas

The jawfish hides underground. The wonderous octopus on the other hand has such a powerful bite that it has a special warning display to tell others to keep out of its way. Here and there, plants manage to take root and they're cropped by green turtles. Seagrasses are the only flowering plants that have managed to grow in the sea although they put out a few ribbon like leaves they produce very extended networks of fleshy stems, rhizomes（根茎）, that are buried in the sand.



At their lushest（最葱郁的） they can transform the sea bed into an underwater meadow. The largest expanse grows in the shallow waters of Shark Bay, in Western Australia. These vast aquatic grasslands stretch for fifteen hundred square miles and, like terrestrial prairies, they support herds of grazers. Dugongs（海牛）. Dugongs are the largest herbivores in the sea. They can be three meters long and weigh half a ton and they eat nothing but seagrass, mostly the fleshy rhizomes, which they excavate（挖掘） with their mobile lips. A herd can clear a patch of seagrass the size of a football pitch in a single day.



Food is not evenly distributed in the tropical shallow seas and it can take a lot of finding but bottlenose dolphins（宽吻海豚） are inquisitive, energetic, and very intelligent and they have discovered a shoal of baitfish（钓饵鱼）. Together, they ride a wave, using it to carry them into the shallows and there, it will be easier to make the catch.