When the right nutrients come together in coastal waters, it can feed a phytoplankton bloom large enough to be visible to…
When the right nutrients come together in coastal waters, it can feed a phytoplankton bloom large enough to be visible to satellites. The phytoplankton themselves are microscopic organisms that are easily carried along by oceanic flows. In fluid dynamics terms, they are passive scalars or seed particles–additives that reveal the structure of the flow without altering it. Here the phytoplankton uncover the large-scale turbulent structure of flow in the Arabian Sea. Check the scale in the lower right. Many of the green eddies and swirls in this satellite image are hundreds of kilometers across. Yet, if we could zoom way in, we would still see turbulence acting on scales down to the millimeter length or below. This incredibly large range of length scales–eight or more orders of magnitude here–is a common characteristic of turbulence and part of what makes it such a challenge to understand or model. (Image credit: NASA Earth Observatory)