Final answer:
An ecosystem with high nutrients and high biodiversity suggests an upwelling ecosystem with no light limitation, as the upwelling brings nutrient-rich deep waters to the surface, promoting a diverse and productive food web.
Step-by-step explanation:
The circumstance that will suggest an upwelling ecosystem with no light limitation is an ecosystem with high nutrients with high biodiversity. In marine environments, upwelling brings nutrient-rich deep waters to the sunlit surface, providing the essential nutrients needed for primary production. This nutrient influx leads to increased growth of phytoplankton and the subsequent support of a diverse food web. Sunlight in these upwelling zones is ample for photosynthesis to take place throughout the water column that receives light, hence there is usually no light limitation in this scenario. High nutrients also often correlate with a higher rate of photosynthesis and primary production, leading to high biodiversity due to the availability of resources to support a wide variety of life.