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Maritime Forum

Map of the Week – Global Ocean Chlorophyll

This map shows monthly global surface ocean chlorophyll-a concentration. Chlorophyll is an indicator for the abundance of photosynthetic plankton, the primary producers of the ocean.


On 4 March 2023, global negotiations concluded in New York on the landmark Treaty of the High Seas - the ‘Biodiversity Beyond National Jurisdiction' (BBNJ) Treaty - to protect the ocean, tackle environmental degradation, fight climate change, and prevent biodiversity loss. The new treaty will allow to establish large-scale marine protected areas on the high seas, which are also necessary to meet the global commitment of the Kunming-Montreal Global Biodiversity Agreement concluded last December to protect at least 30% of the ocean by 2030. For the first time, the treaty will also require assessing the impact of economic activities on high seas biodiversity. [1]

Areas beyond national jurisdiction cover nearly two-thirds of the world's ocean, comprising the high seas and the seabed beyond national jurisdiction. [1] Through his Spokesperson, United Nations Secretary-General António Guterres said the treaty is crucial for addressing the triple planetary crisis of climate change, biodiversity loss and pollution. [2]

Speaking of marine life, did you know that because of the distinct green colour of the chlorophyll pigment, optical satellite sensors can be used to visualise the distribution of chlorophyll and thus the phytoplankton in the ocean? Phytoplankton are microscopic single-celled algae that drift at the surface of the ocean. Chlorophyll is essential to photosynthesis, the process by which phytoplankton turns water, sunlight, and carbon dioxide into water, oxygen, and simple sugars. Tiny plankton form the base of the ocean food web, which further supports all other aquatic and terrestrial ecosystems across the planet. [3]

Explore the Map of the Week to learn more!

Access the map

The data in this map are provided by Copernicus Marine Service.