Floating cities, wildfires, overfishing, and lithium mining for electric cars – these topics have made a list of concerns from leading marine experts about the impacts the global ocean will face in the next ten years.
Horizon scanning, conducted by an international team of scientists and policymakers, has culminated in 15 problems facing the deep sea and coastlines. It involved 30 marine and coastal systems experts from 11 countries from the global north and south. The results were published today in the journal Nature Ecology and Evolution.
“Marine and coastal ecosystems face a wide range of emerging problems that are poorly recognized or understood, each of which has the potential to affect biodiversity,” wrote Dr. James Herbert-Read of the Department of Zoology at the University of Cambridge, joint first author of the article.
“By highlighting future issues, we point to where changes need to be made today, both in monitoring and policy, to protect our marine and coastal environments.”
This type of study has been used by the Cambridge Department of Zoology in the past. For example, a 2009 “horizon scan” raised the alarm about microplastics, which have since become a widespread ocean problem.
Some of the problems related to the exploitation of the natural resources of the ocean, including for green technologies such as electric vehicles (EV).
The team predicted further extraction from deep-sea “brine pools,” unique and diverse marine environments, which also have high concentrations of lithium-containing salts, the key component of EV batteries.
While overfishing is an ongoing problem, the horizon scan looked at what could happen next. The authors predicted that there could soon be a shift towards fishing in the mesopelagic zone of the ocean (a depth of 200 to 1,000 meters). In these deeper waters, the fish are not fit for human consumption, but can be sold as food to fish farms.
“Stopping this would not only stop the overexploitation of these fish stocks, but also reduce the disruption of the carbon cycle in the ocean, because these species are an oceanic pump that removes carbon from our atmosphere,” said Dr Ann Thornton. from the Department of Zoology, Cambridge, joint first author member.
Scientists and policymakers also believe that wildfires, which are occurring in many coastal regions on an unprecedented scale and duration, pose a significant risk.
Along with threatening communities and pumping vast amounts of emissions into the already superheated atmosphere, fires release aerosols, particulates, large volumes of materials containing soluble forms of nutrients and trace metals.
Winds and rains can subsequently transport these materials long distances to the ocean. “Australian bushfires, for example, triggered widespread phytoplankton blooms in the Southern Ocean along with fish and invertebrate die-offs in estuaries,” the study notes.
There are also concerns about the effects of new biodegradable materials in the ocean, some of which are more toxic to marine life than traditional plastics.
Dr Herbert-Read said: “Governments are pushing the use of biodegradable materials, but we don’t know what impacts these materials may have on marine life.”
For example, the long-term ocean impacts of biodegradable polymers in clothing and by-products such as microfibers are unknown. “However, some natural microfibers have higher toxicity than plastic microfibers when consumed by aquatic invertebrates,” the researchers wrote.
Also on the list are “floating sea cities,” a concept being discussed by the United Nations on how to deal with the impacts of climate change and homelessness for a growing world population.
The team noted that ocean locations provide benefits from renewable energy from waves and tides and food production supported by hydroponic agriculture.
But they also noted that while floating cities “could act as stepping stones, facilitating the movement of species in response to climate change, this could also increase the spread of invasive species.”
The ocean has absorbed more than 90 percent of the excess heat trapped in the atmosphere, caused in large part by emissions from humanity’s burning of fossil fuels. Higher temperatures are likely to create a “hollow” zone at the equator as species move away from the warming region.
As the climate crisis further increases ocean temperatures, the nutritional content of fish will also be affected, affecting other marine species and the human diet.
It’s mostly cold-water dishes that are packed with essential fatty acids, so as waters warm, production of these molecules slows, the researchers noted.
The team believes that some of the impacts in the next five to ten years will be positive. For example, technological innovations in soft robotics and improved underwater tracking systems mean scientists will be able to collect more information about species and their movements.