Oceans globally darken, threatening marine ecosystems

The ocean's sunlit photic zone is darkening, a trend scientists call "a genuine cause for concern" due to potential ecosystem impacts. This darkening reduces light penetration, affecting marine life. A recent study found that 21% of the global sea surface has darkened between 2003 and 2022. Coastal areas are affected by runoff, while open oceans show changes in algal blooms and rising temperatures. The photic zone, home to most marine life, is crucial for photosynthesis. Reduced light could impact the marine food chain and even deep-sea ecosystems that rely on organic material from the surface.