The world’s oceans are darkening: What does this mean for us?
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The world’s oceans are darkening: What does this mean for us?
A significant decrease in the amount of light reaching the ocean surface underwater has been detected between 2003 and 2022. Scientists say this is significant enough to affect the behavior of marine life and the oceans’ relationship to climate.
A new study has found that sunlight is not reaching as deep into the water in a significant part of the world’s oceans. Scientists call this “ocean darkening” and say the consequences could have significant implications for both marine life and humanity.
According to the study conducted by the University of Plymouth, a significant decrease in the ability of sunlight to penetrate underwater was detected in 21% of the oceans between 2003 and 2022. In some areas, this decrease meant that light could reach depths of 100 meters less. Over a large area – an area the size of the African continent – light transmission has decreased by at least 50 meters.
What does it mean that light is not reaching the water?
The upper layers of the ocean play a critical role in transporting sunlight to the deeper layers. However, according to the research, this function is weakening. Light affects not only the appearance of the water, but also the basic cycles of ocean life. In particular, many marine organisms regulate their vital functions such as orientation, feeding, reproduction and migration according to light signals.
Dr. Thomas Davies, one of the research team, states that this decrease in light may limit the areas where some species can survive. In other words, the darkening may cause changes in the behavior and habitats of marine organisms, although not directly.
There is no single reason behind this darkening trend. The researchers state that various factors such as changes in algal blooms, warming of the sea surface, increasing particle content in the water and artificial light pollution on the sea may affect this process. Many of these reasons are directly related to climate change.
People may also be affected
The darkening of the oceans may not only affect the ecosystem, but also indirectly affect humans. Sunlight plays an important role in the oceans' ability to produce oxygen and store carbon. The weakening of these systems may put pressure on the global climate balance.
In addition, as some marine species in search of light retreat to areas closer to the surface, competition for food and space may increase. This could change many sectors that depend on the sea, especially fishing.
Researchers warn that darkening could lead to radical changes in marine ecosystems in the long term. The structure of the ecosystem, energy cycles and interactions between species could be directly affected by this change. At the same time, livelihoods such as fishing and vital functions such as climate regulation could be at risk.
In short, the color of the sea may be changing, but the real change is happening underneath.