SouthernWorldwide.com – A recent study has revealed a concerning trend: the world’s oceans are becoming darker, posing a significant threat to marine life.
Professor Thomas Davies from the University of Plymouth, in a study published in the journal Global Change Biology, expressed growing apprehension for the health of marine ecosystems.
Analysis of satellite data from NASA’s Ocean Color Web data portal indicates that a substantial portion of the planet’s oceans, specifically 21%, have darkened between the years 2003 and 2022.
Davies highlighted that the majority of marine organisms reside in the photic zones of the ocean. These are the upper layers where sufficient sunlight penetrates to support essential photobiological processes.
The photic zone, extending down to approximately 200 meters, plays a critical role in sustaining global nutrient and carbon cycles, which in turn support planetary fish markets.
Read more : AI Brain Enables Human-Like Robot Movement
This illuminated region is where marine life, particularly those closer to the ocean’s surface, thrives.
These ocean dwellers depend on both sunlight and moonlight for vital activities such as hunting, mating, and reproduction, among other crucial life events.
The upper levels of the ocean are also home to microscopic organisms and various types of plankton, forming the base of many marine food webs.
As the oceans darken, creatures reliant on light may be forced to move closer to the surface. This migration could lead to overcrowding and increased competition for resources in these already limited spaces.
By employing satellite data and an algorithm to measure light attenuation in seawater, Davies was able to determine the depth of photic zones across the globe.
The study found that in darker ocean areas, 9% of their photic zones had become shallower by at least 50 meters, and in 3% of these oceans, the photic zones were up to 100 meters shallower.
The exact reasons behind the darkening of oceans in offshore regions remain less clear.
However, the study suggests that global warming and alterations in ocean currents are likely contributing factors to this phenomenon.
Despite the overall trend of darkening, the research also indicated that approximately 10% of the oceans, covering about 37 million square kilometers, have actually become lighter over the past two decades.
Furthermore, the study observed an increase in light in most coastal areas. However, this brightening near shorelines does not necessarily translate to a net increase in photic zone depth.
Professor Davies predicts that the implications of ocean darkening could be severe, impacting marine food webs, global fisheries, and the crucial carbon and nutrient budgets that support oceanic life.
