A recent international study highlights a concerning trend: ocean areas with low biodiversity are expanding, a phenomenon known as ocean desertification. This expansion has nearly doubled in just over 20 years, increasing from 2.4% to 4.5% of the global ocean. This nutrient deficiency threatens ocean health and the global climate.
The research emphasizes changes in phytoplankton, the foundation of the marine food web. These microorganisms play a vital role in mitigating climate change by removing atmospheric CO2 through photosynthesis. Global warming exacerbates this issue, causing warmer, lighter water to remain on the surface, preventing the mixing of nutrient-rich, colder water from the depths.
Impact and Adaptation
Less mixing means less food for phytoplankton, impacting the entire food chain. Researchers analyzed satellite data of chlorophyll and phytoplankton from 1998 to 2022 across five major oceanic gyres. While chlorophyll levels are decreasing, phytoplankton biomass remains relatively stable, suggesting adaptation to changing conditions. This adaptation may involve phytoplankton adjusting to new growth conditions like increasing temperature and reduced nutrient availability.
Call for Action
The UN Ocean Conference in Nice, France, from June 9-13, 2025, aims to address these critical issues. The conference will focus on accelerating action and mobilizing all actors to conserve and sustainably use the ocean. Protecting the high seas, tackling harmful fisheries subsidies, and securing a global plastics treaty are among the key priorities for ocean progress in 2025.