This could indicate that a riptide is churning up sand, sediment and seaweed.

这种现象表明激流可能正在搅动着沙子、沉积物和海藻。

Other animals drilled into the substrate after those bacteria, churning up the sediment, driving nutrients even further down, and so the cycle continued.

其他动物在这些细菌之后钻入基质，搅动沉积物， 将营养物质进一步向下推，如此循环继续。

If we're doing a boat going through waves, we would use the big tub that we have to get that slapping sound or churning up the water a lot in the tub with our hands.

如果要创造船只破浪前进的声音，我们会用我们有的这个大缸盆来制造海浪拍打的声响，或用手大量翻搅缸盆里的水。