“Every breath you take you need to thank the ocean for generating oxygen and capturing carbon. We should respect the photosynthesis that feeds small animals, that then provide sustenance for the large animals.”
– Sylvia Earle
In our oceans there are tiny plant-like organisms called phytoplankton which are eaten by tiny animals called zooplankton. And so the food chain moves up.
These phytoplankton float along at the mercy of the sea’s tides and currents and indeed, the word plankton comes from the greek for wandering.
Despite their size, some are invisible to the human eye, the entire* ocean ecosystem is reliant on phytoplankton. As photosynthesisers, they introduce the sun’s energy to organisms which live below the waves, and many organisms who live above the waves as well such as humans.
*there are some very deep sea creatures which live off vents which aren’t but there always has to be a rule breaker!
It’s not just their role in food production that we should be thanking phytoplankton for though. They have a huge impact on the air we breathe and the climate we live in.
As part of photosynthesis, phytoplankton release oxygen into the water. This oxygen is estimated to make up between 50 and 80% of the earth’s oxygen. So as you breathe in, don’t forget to thank this overlooked little plant.
But it’s hard work isn’t over, it has the job of controlling atmospheric carbon dioxide to do as well. By holding on to carbon, they reduce the amount that is in the atmosphere, storing it even after they die; they sink to the bottom of the sea where they accumulate and eventually turn into oil. So that’s another thing we need to thank the humble phytoplankton for!
But some phytoplankton have a darker side… There are over 5000 species worldwide and about 2% of those are harmful or toxic. They produce these toxins as a strategy for dealing with predators, competitors and parasites.
When these phytoplankton bloom, the chemicals are are released. A lot of these blooms are red, creating phenomena which has led to the name of the red sea, the vermilion sea and a term called the red tide. These blooms can have harmful affects on fish and other marine life. For example, causing harmful changes to development, affecting reproduction and impacting on the immune system. In 2004, 107 bottlenose dolphins died in Florida because they had ingested affected fish. Other more direct ways of being affected are through ingesting the toxin itself or through inhalation.
The summertime feeding grounds of the Right Whale coincide with seasonal blooms from one of the toxic phytoplanktons. Zooplankton eat the phytoplankton, become contaminated with neurotoxins and are then eaten by the whales who experience altered feeding behaviour and altered respiratory capabilities. This then impacts on the overall population of a whale which is already endangered.
Sea turtles may feel the impact of toxic exposure as lethargy and muscle weakness which can lead to them being washed off course or washed ashore.
Humans are also affected if we eat contaminated fish and because of this, blooms are carefully monitored.
11.30.18 Edited to add: I stumbled across a phytoplankton poem and had to share it!