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Plankton Manifesto unveils importance of “invisible organisms”
Author: Wiida Fourie-Basson (Media: Faculty of Science)
Published: 25/09/2024

Ongoing disruptions to plankton ecosystems due to human activities in our oceans will inevitably have major impacts on marine life as we presently know it, likely leading to unforeseen and potentially dramatic consequences.

But while the planktonic realm remains one of the richest ecosystems on earth in terms of biodiversity, we have a very limited understanding of the composition, distribution, and dynamics of global plankton communities.

This is the warning underlying the Plankton Manifesto launched at the 79th session of the United Nations General Assembly in New York this week.

According to a media release issued by the United Nations Compact Ocean Stewardship Coalition, the Plankton Manifesto emphasizes the critical role of plankton in addressing the interlinked global crises of climate change, pollution, and biodiversity loss.

Plankton are microscopic organisms that have been foundational to life on Earth for over 3.5 billion years. They generate a significant portion of oxygen, absorb vast amounts of carbon, purify water, and recycle nutrients vital for marine life. As the base of the marine food web, plankton indirectly support the livelihoods of more than 12% of the world's population through fisheries and aquaculture. Plankton growths in freshwater affect drinking water availability for countless millions.

Prof. Thulani Makhalanyane from Stellenbosch University and Dr Emma Rocke from the University of Cape Town (UCT) are two of the 30 internationally recognised plankton experts who initiated the manifesto.

Makhalanyane, from SU's Department of Microbiology and the School for Data Science, says there is increased awareness that there is one global ocean and what happens in other parts of the world can profoundly impact marine food webs in another. However, for too long studies on marine microbiomes have focused on plankton in ecosystems which are thought to be important for countries in the Global North: “There is now an effort to study the much neglected South Atlantic after many years of focus on the North Atlantic. We need more studies on plankton along Africa's coastline. For example, how do pollutants from mining in the Congo influence marine food webs in the global ocean?"

Dr Rocke, from UCT's Marine and Antarctic Research Centre for Innovation and Sustainability (MARIS), also supports the call for building expertise in this study area in Africa: “Plankton represent the base of the food chain and as such are critical to a healthy ocean ecosystem. Without plankton we will have no fisheries. Yet our knowledge of their community dynamics lags way behind our understanding of more charismatic organisms."

The Plankton Manifesto has also drawn support from South African marine biologists and scientists working on biogeochemical processes in the Southern Ocean.

Prof. Alakendra Roychoudhury, an environmental geochemist in SU's Department of Earth Sciences, says his research focuses on trying to understand why phytoplankton cannot grow in major parts of the Southern Ocean: “Plankton in the Southern Ocean are responsible for mitigating the warming effects from a large fraction of human-generated CO2 released in the atmosphere. Yet we know little about the diversity of phytoplankton in the Southern Ocean and how it will adapt to changing climatic conditions. Such understanding is crucial to eke out long-term solutions to ongoing and future climate crisis."

Prof. Sophie von der Heyden, a molecular ecologist in SU's Department of Botany and Zoology, says plankton are at the heart of marine biodiversity: “We have been using environmental DNA metabarcoding to document coastal marine biodiversity, and our findings show that many of these species are planktonic. To date, our findings far exceed what is currently described."

Sanda Ojiambo, assistant secretary-general and CEO of the UN Global Compact, says the Plankton Manifesto represents a vital step forward in our collective response to the triple planetary crisis: “Plankton are not only the foundation of marine ecosystems but also key players in our fight against climate change and pollution. By safeguarding plankton, we are protecting a crucial part of our planet's life support system, ensuring the resilience of our oceans and freshwater ecosystems for future generations."

Key recommendations of the Plankton Manifesto include:

  • Improved knowledge to better monitor plankton biodiversity on a global scale. This includes a call for a global consolidated plankton atlas and developing plankton-based health indices to monitor marine and freshwater ecosystems.
  • Creating awareness by means of a global “plankton literacy" project.
  • Integrating plankton in international discussions on climate and biodiversity.

The Plankton Manifesto is the result of a collaborative effort, led by the United Nations Global Compact, that involved 30 international experts from leading institutions and industries worldwide. It will seek endorsements at key global environmental conferences, including COP29 on Climate, COP16 on Biodiversity, and the United Nations Ocean Conference in Nice, France, in June 2025.​​​​