Marine biologists have found evidence of a previously unreported open sea migration route more than 4,500 feet below the surface of the Atlantic Ocean, according to a new document.
The deep ocean is a vast and mysterious biome; 80 percent of it remains unmapped to date. Scientists hope to better understand the ecology of this region, especially since oil and gas operations are drilling in deeper waters. A new study by a large international collaboration of universities has found photographic evidence of seasonal changes in deep sea populations, a sign that these fish are migrating elsewhere.
These data come from time-lapse photographs taken between February 2009 and July 2016 from two stations in the long-term environment observation system on the high seas (DELOS), both located off the Angolan coast; one is 164 feet from an oil well. Researchers counted how many fish were in each photograph per day over the 7.5-year period, according to the document published this week in the Journal of Animal Ecology.
The analyzes revealed a seasonal trend in the amount of fish observed in the two observatories. Not only that, but the abundance of fish seemed correlated with the overall chemical energy of organic matter on the ocean surface; deep-sea fish peaked about four months after the peak of biological activity on the ocean surface, the time it takes for carbon to sink to the bottom of the sea.
For now, this study only presents the first evidence of a flyway, and it’s unclear where the fish actually go. But the team still has a lot of work to hope for. The DELOS platforms with the experiments will run for a total of 25 years, and the team wants to gather more information on the link between energy on the surface and the fish below.
It’s important work. “We don’t have a lot of long-term studies in the deep ocean,” Rosanna Milligan, first author of the study and assistant professor at Nova Southeastern University in Florida, told Gizmodo. “This is something that is starting to change, but it is also something that is becoming more and more important. Most human impacts are impacts that have effects for months, even years, or even much longer. , given climate change, over decades or centuries. With this data, we have these longer time series. ”
This knowledge is also important for short-term impacts, particularly with regard to oil and gas operations. Oil and gas companies travel to drill in deeper waters, but scientists do not have data on the impact of their drilling on animals living in the deep. For example, the Deepwater Horizon drilling rig rented by BP was based on 4,100 feet of water when it exploded in 2010, triggering the largest oil spill in history. But scientists still don’t understand the long-term consequences of this ecological disaster.
Knowing that deep-sea fish migrate, and where they migrate, would be crucial to efforts to protect them from destructive human activities.