Climate & Biodiversity Initiative
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28.04.2021 | Corporate philanthropy
Facing global warming and ocean acidification, what is the role of marine phytoplankton, and what are the impacts on marine biology and productivity? Questions the “NOTION” project is trying to answer, supported by the BNP Paribas Foundation through its Climate & Biodiversity Initiative.
Mar Benavides recently introduced her project through one of our Climate & Biodiversity Initiative conference. Have a look at its summary in the following sketch note format, and relive the conference by watching the replay on our YouTube channel (French audio, English subtitles) and by reading the transcript.
The Earth is known as the blue planet for a good reason: oceans cover 71% of its surface. And there is life inside each drop of water – namely in billions upon billions of drops of water: zooplanktons (such as copepods), phytoplankton (e.g. diatoms) or even millions of bacteria and viruses, that either live together or compete.
In addition, oceans absorb about a quarter of the CO2 generated notably generated by human activities, partly thanks to the phytoplankton that capture it.
“ We need to examine the infinitely small to understand certain consequences on a global scale, which can explain the overall functioning of our planet. It is a bit like the butterfly effect: it is the phytoplankton effect! ”
Microbial oceanographer and researcher at the MIO (IRD)
Though phytoplankton are smaller than an ant, they photosynthesise as much as all the terrestrial plants put together while representing less than 1% of their mass. To perform photosynthesis, it takes CO2 and light but also nitrogen.
Just as growing crops on land requires fertiliser, nitrogen provides the nutrient value that phytoplankton need to grow. However, oceans mostly lack of nitrogen.
Nitrogen in its inert form is everywhere, like in the atmosphere (70%). On the other hand, this key molecule for phytoplankton’s energy production – in its form that living organisms can use – mainly concentrates in the water of coastal areas, Polar Regions and the lowest depths of the sea: there is then a very low level of nitrogen in the middle of the ocean and on 60% of its surface.
Furthermore, the difference in temperature between deep and surface waters forms “strata” of water: they do not move in a vertical direction, or minimally, and thus act like a kind of “plug”. Deep waters, rich in nitrogen, cannot reach the phytoplankton. Why there is still life then?
Other planktonic microorganisms, the diazotrophs, are also part of this ecosystem. They are the focus of the “NOTION” research project. Indeed, through a process that requires investing a great deal of energy, diazotrophs are able to transform the nitrogen from the atmosphere and make it available to phytoplankton so they can perform photosynthesis and capture this CO2 responsible of global warming.Yet facing climate disturbances, there is great uncertainty about their future.
These microscopic cells already have their own chemistry and biochemistry, and the water they are in contains varying levels of oxygen, salt, etc. In addition, these drops of water are moving around in the ocean, which complicates the work of the scientist
With this research team, the “NOTION” project work on establishing connections between the tiny and the global. The findings from the lab experiments will be inputs for global ocean models that can help make predictions. Just like a weather forecast for the coming days, but over the longer term, even over decades as in the case of climate change.
The “NOTION” research team is convinced that the more we find out about how the planet works the more responsible our behaviour will be. It is not enough to know that the oceans are essential to climate change; we must understand why, the mechanisms at play, the challenges to overcome and the efforts that need to be made.
"Modeling nitrogen cycle in the ocean-atmosphere interaction is a major issue with regards to climate change and biodiversity albeit it that has received too little attention so far. NOTION is a multidisciplinary approach that should lead to good science."
BNP Paribas Foundation’s scientific committee
NOTION is a multidisciplinary approach that should lead to good science.
Photos: header ©Adobe Stock // Diazotrophs species: rocosphaera ©Mar Benavides - Trichodesmium ©Sophie Bonnet