Provided by JAMSTEC
Red and blue patches float across the gray sea. This is a "prediction map" depicting whether phytoplankton abundance will increase or decrease relative to average conditions over the coming six months.
A research team at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has predicted average surface chlorophyll concentrations for the period from November 2026 to January 2027. Chlorophyll is the photosynthetic pigment found in phytoplankton, and its concentration serves as an indicator of phytoplankton abundance. In the prediction map, areas where concentrations are expected to be lower than average are shown in blue, while areas where concentrations are expected to be higher than average are shown in red.
Phytoplankton are so small that they are almost invisible to the naked eye. Yet as they drift through the oceans carrying out photosynthesis, they serve as food for zooplankton and support food chains that extend all the way to fish. In a sense, they form the "small foundation" of the ocean's food web. Changes in their abundance may also affect fish distributions and catch volumes.
The research team asked whether it might be possible to look six months ahead for these tiny but important organisms, just as weather forecasts provide outlooks for rainfall and temperature. To explore this possibility, they combined a climate prediction system developed by JAMSTEC with a marine lower-trophic-level ecosystem model that simulates the dynamics of phytoplankton, zooplankton, and nutrients, and conducted prediction experiments using a supercomputer.
By comparing the results with satellite observations, the researchers found that surface chlorophyll concentrations, an indicator of phytoplankton abundance about six months in the future, can be predicted with high accuracy in the western tropical Pacific. Changes in seawater temperature and other factors alter the distribution of nutrients required for phytoplankton growth. According to the team, this is the first demonstration that it is possible, to some extent, to predict this "small foundation" of the marine ecosystem.
Going forward, JAMSTEC aims to integrate the forecasting system with models that estimate the habitats of species such as skipjack tuna, with the goal of supporting fisheries management and food supply planning.
The findings were published online on August 27 in the Journal of Climate, an international journal published by the American Meteorological Society. JAMSTEC announced the results on the same day.
Original article was provided by the Science Portal and has been translated by Science Japan.