PermeateFree said:
stan101 said:
Am currently listening to an audio book titled “Science Matters” by Robert > Hazen & James Trefil. It is a good listen so far. When listening today the subject of plankton was touched upon. It was stated that “plankton are microscopic organisms that live on the surface of the water.”
Is that true? Do whales and other plankton muching animals need to surface feed? i thought plankton were present throughout the water column.
There are two basic types of plankton the zooplankton consisting of small animals, which does move up and down the water column. The other is the phytoplankton that are plants, these need the sunlight to undergo photosynthesis, therefore this type will spend more time at or near the surface.
That’s what I would have thought. Surprisingly, though, phytoplankton can be found at depths up to and beyond 120 metres, as this chart shows. I suppose that makes sense, sunlight can penetrate 100 or sometimes 200 metres of ocean. Baleen whales do come up to feed, particularly humpbacks.
From https://www.researchgate.net/figure/270893559_fig7_Fig-7-Depth-distribution-of-phytoplankton-groups’-biomass-as-Chl-a-concentration
