The extinction of lanternfish due to the ocean’s oxygen crisis could trigger a devastating collapse of marine ecosystems.
Why it matters: Lanternfish are not just a crucial part of marine biodiversity but also play an essential role in the Earth’s climate system by contributing to the ocean’s biological pump, helping sequester carbon. Their loss could lead to cascading effects throughout marine ecosystems, disrupting food chains, carbon storage, and climate regulation.
The details:
- A recent study analyzed over 10,000 years of fossil records from the Aegean Sea, revealing that lanternfish populations drastically declined whenever oxygen levels in the ocean fell below a critical threshold.
- Lanternfish perform a vital role in carbon sequestration, moving roughly four gigatons of carbon downward each year, a process that helps mitigate climate change by reducing the amount of CO2 in the atmosphere.
- With rising temperatures and the expansion of low-oxygen zones in the ocean, lanternfish may no longer be able to thrive in their traditional habitats, leading to a breakdown of the biological pump.
- The repercussions would be profound, with a 25% reduction in the carbon exported to the depths of the ocean, accelerating atmospheric warming and creating a feedback loop that further diminishes ocean oxygen levels.
The ripple effect: The decline of lanternfish would send ripples throughout marine food chains.
- Lanternfish are a key food source for numerous predators, including whales, tuna, squid, and seabirds. If lanternfish populations collapse, the cascading effects could devastate commercial fisheries and disrupt marine ecosystems that humans rely on for food.
- Tuna and other large fish that rely on lanternfish as a primary food source would face significant challenges, which could lead to reduced fish stocks and even the collapse of local fisheries.
“Our findings corroborate expectations that future expansion of midwater deoxygenation could severely deplete mesopelagic fish communities,” noted the study authors.
What’s next: Cutting greenhouse gas emissions remains the fastest lever for stabilizing ocean oxygen. Local steps, like reducing nutrient runoff that fuels coastal dead zones, protect regional fisheries while the planet decarbonizes. Monitoring programs that deploy autonomous sensors now give managers early warning when oxygen starts to fall. Scientists are also testing marine protected areas designed around depth bands rather than coastlines, preserving critical migration corridors.
