As global warming accelerates the melting of sea ice in the Arctic, a recent study reveals a significant shift in the underwater light environment, threatening the base of the Arctic food web [1, 2]. The research, led by marine biologists Monika Soja-Wożniak and Jef Huisman from the University of Amsterdam, highlights how this change impacts photosynthetic organisms like ice algae and phytoplankton [1, 11].
Sea ice allows a wide spectrum of light to penetrate, while open seawater absorbs much of the red and green light, leaving mostly blue light [1]. This shift reduces the ability of some algae to photosynthesize efficiently, potentially favoring species better suited to blue light [2, 3]. This disruption can affect the entire food chain, from fish to whales, and alter the ocean's capacity to absorb carbon dioxide [1, 3].
The study emphasizes the need to include these light-related effects in climate models to better predict the consequences of rapid environmental change in the Arctic [3]. The researchers used models and measurements to demonstrate that the altered light reduces the algae's ability to photosynthesize efficiently [1]. This could also change which species thrive in the Arctic Ocean, with algae better suited to blue light potentially outcompeting others and disrupting the balance of species [1, 2].