Big tiny plankton: sailing through diversity

Mr. Lawrence showing an example of a microscope image taken onboard the e-IMPACT cruise (Image font: Sheldon J. Plankton character from SpongeBob SquarePants, spongebob.fandom.com)

Plankton? Who are these bugs?

Maybe you’ve only heard of these organisms because there is a character in the SpongeBob SquarePants cartoons tv show; or maybe you’ve heard these are what whales eat, or maybe even you’ve already seen them if you’ve been enchanted by the famous planktonic drawings of Mr. Ernst Haeckel (and if you don’t know who this is, I recommend you googling his name and have a scroll through his drawings). Any of these are partly showing who these are but, they are way more complex than just that…

In reality, plankton includes all the microscopic organisms of the ocean and freshwater that are carried by currents and tides. There are many sizes, shapes and types of them, and can be found at all sorts of temperature and depth ranges. They are important mostly because they are the essential food source for the rest of the marine organisms (from shellfish to whales), maintaining the health of our oceans.

During this expedition, nets are deployed daily to understand the planktonic population hidden in the upper 200 m. It’s incredible to see how many living bugs are in one litre of seawater. It also makes you think on the huge number of living organisms that may still be unexplored around the globe…

Interestingly, as we traverse the eddy, station by station, we appreciate changes in diversity, showing different group niches. It is fascinating to think how physical and biogeochemical conditions may modulate these changes, to which we do not have explanations yet…

Here are few pictures of the tiny creatures we have been able to observe. Radiolarians, foraminifera, tintinnids, pteropods, copepods, crustacean larvae, some jellyfish… Can you recognise any? Which one is your favourite?

Examples of organisms collected from the plankton nets observed under the microscope