The robot performed well in a pressurised chamber in the lab, first swimming in a circle and then free swimming.

该机器人在实验室的加压室内表现良好，先是绕圈游泳，然后自由游泳。

With no light available, there are no plants, and so most of the biomass is in the form of animals  either free swimming, or fixed to the ocean floor.

由于没有光线， 没有植物，因此大部分生物质都是动物的形式， 要么是自由游泳的，要么是固定在海底的。