Oceans worldwide have darkened over the past two decades, raising concerns about the impact on marine life and ecosystems, according to a recent study published in the journal Global Change Biology.
Oceans around the globe have experienced a significant darkening over the last two decades, prompting alarm among researchers regarding the potential consequences for marine life. A study led by Professor Thomas Davies from the University of Plymouth highlights these concerns, revealing that satellite data indicates 21% of the planet’s oceans have darkened between 2003 and 2022.
The research, published in the journal Global Change Biology, emphasizes the importance of photic zones—areas of the ocean where light penetrates sufficiently to support vital photobiological processes. According to Davies, the majority of marine organisms inhabit these zones, which extend to depths of approximately 200 meters.
The photic zone plays a crucial role in sustaining global nutrients and carbon budgets, which are essential for the health of the planet’s fish markets. Marine species that dwell in these upper layers depend on both moonlight and sunlight for critical activities such as hunting, mating, and reproduction.
As the oceans darken, creatures that rely on light may be forced to migrate closer to the surface, potentially leading to overcrowding in these vital habitats. The study utilized satellite data and an algorithm to assess light attenuation in seawater, allowing researchers to determine the depth of photic zones across the globe.
Among the darker regions of the ocean, the study found that 9% of photic zones are now 50 meters shallower, while 3% have become 100 meters shallower. The reasons for the darkening of oceans, particularly in offshore areas, remain unclear. However, the study suggests that global warming and alterations in ocean currents may be contributing factors.
Interestingly, despite the overall trend of darkening, approximately 10% of the oceans, covering around 37 million square kilometers, have become lighter over the past two decades. Coastal areas, in particular, have experienced an increase in light. However, this increase does not correspond to a net reduction in photic zone depth near shorelines.
Davies warns that the implications of ocean darkening could be severe, affecting marine food webs, global fisheries, and the balance of carbon and nutrient budgets. The study underscores the urgent need for further research to understand the full impact of these changes on marine ecosystems.
As scientists continue to monitor these shifts, the findings serve as a reminder of the delicate balance within oceanic environments and the potential risks posed by ongoing climate change.
These insights into ocean darkening highlight the critical need for conservation efforts and sustainable practices to protect marine life and ensure the health of our oceans for future generations, according to Fox News.