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Maritime Forum

Map of the Week – Global Ocean Chlorophyll (monthly-mean)

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


This week, the United Nations released the new Ocean Observing System Report Card – a high-level annual report providing a deep insight on the state, capacity and value of the Global Ocean Observing System (GOOS). [1] The 2022 Report Card focuses on several key areas:

  • Global view of the state of the Global Ocean Observing System;
  • Monitoring ocean carbon uptake to allow more accurate climate model projections;
  • Advancing coastal inundation forecasts and early warnings;
  • Phytoplankton observations – vital for understanding changes in food webs and shifts in marine life;
  • Involvement of new communities through the GOOS Ocean Decade Programmes.

Phytoplankton are microscopic single-celled algae. Marine phytoplankton form the base of marine food webs and support other forms of life, including commercial fish valued at around US$401 billion/year. [2] GOOS aims to improve forecasting of the ecosystem services provided by phytoplankton that support the Blue Economy by gathering continued global phytoplankton observations. Currently, a large set of satellite measurements provide information on phytoplankton distribution in the upper layers of the ocean at all times of the day and through the year. Complementary to satellites, in situ observing instruments provide information about the composition of species of phytoplankton, the pigments they contain, and their distribution. [2]

Did you know there is a map layer on global Ocean Chlorophyll (monthly-mean) in the European Atlas of the Seas? It shows the average Chlorophyll-a concentration (in mg per cubic meter) at the ocean surface during the last month in regions which were not covered by clouds. Chlorophyll is an indicator for the abundance of phytoplankton. Phytoplankton contain the green pigment chlorophyll, which allows them to use the energy of sunlight to transform CO2 to sugars and oxygen. 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 our oceans. Dive in and explore the Map of the Week!

Access the map

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