We know that the industrial activities degrade the environment. Overfishing, pollution, plasticthe global warming… the causes are many. But what is less known is how exactly, and especially what other lesser-known processes also contribute to this degradation of the marine environment. This is what a team wanted to study in a study published in the journal Nature Ecology & Evolutionthanks to an international collaboration with 30 researchers specialized in marine and coastal systems. They only focused on the problems emerging and their future impact in the next five to ten years.
For their research, they began by drawing up a list of 75 possible causes in association with the 30 researchers and their network, which they then separated into three categories: impacts on ecosystems, resource exploitation, and new technologies. They then submitted all their suggestions to votes in order to gradually reduce the list : each person rated each problem from 1 to 1,000 according to different criteria, then a participatory workshop made it possible to isolate the 15 most important among the best rated.
On marine ecosystems: unexpected impacts of human activity
Among the problems denounced, several unexpected ones appeared, such as that of the forest fires. The latter, more and more numerous and more and more serious, “free from aerosolsparticles and large volumes of materials containing soluble forms of nutrientsin particularnitrogenfrom phosphorus and metals heavy such as copperthe lead and the iron », explains the study. All this debris is then transported over long distances, sometimes to the coasts, and therefore to the sea or the ocean. Their direct impact is then hard to assess, but such fires have already triggered a proliferation of phytoplankton, or the death of many fish. Another unexpected hazard: coastal darkening. Coastal ecosystems depend on the light from Sun. However, climate change and human activities are modifying the color water, and therefore, the penetration of light. And then triggers a chain reactionbecause the darkening of the water causes a proliferation ofalgaewhich in turn darken the water.
Added to this darkening is the problem of heavy metals, or pollution in general through the discharge into water of contaminated sediments. An effect that goes hand in hand with climate change: the latter makes the oceans more acidsmaking them more likely to absorb metals and increasing their toxicity. In addition to killing some species, heavy metals can quite simply contaminate them: the authors cite in particular bivalves, such as mussels or oysters. But all other marine species are also impacted by global warming. The researchers discuss in their study the Fatty acids essential, contained in large quantities in fish, but which actually come from the phytoplankton on which they feed. The warming of the oceans prevents them from synthesizing them as efficiently, and this effect could impact all the food chain which depends on them.
Deep-sea fishing: a sure decline if nothing is done
Researchers have pointed to the exploitation of the resources of marine ecosystems, used for industrial purposes. the collagen for example. Those are ” of the proteins structures increasingly used in apps cosmetics, pharmaceuticals, nutraceuticals and biomedical », explains the study. They are contained in various marine organisms, such as the jellyfish or sponges. This desire to extract collagen could aggravate overfishing, which is already one of the main causes of the decline in biodiversity Marine. Added to this is the risk of overfishing in deep waters of mesopelagic species, which live between 200 and 1,000 meters deep. They are “unfit for human consumption but could potentially provide fishmeal for theaquaculture or be used as fertilizer, explains the study.
However, these are essential to maintain the ocean carbon storage. “There are areas where we think immediate changes could prevent huge problems over the next decade, such as overfishing in the mesopelagic zone of the ocean”warns Dr. Ann Thornton, first author of the study, and researcher in the Department of Zoology at the University of Cambridge. “Limiting this would not only stop the overexploitation of these fish stocks, but reduce the disruption of the fish cycle. carbon in the ocean – because these species are an ocean pump that removes carbon from our atmosphere. » Finally, the researchers discuss the demand for battery, which could increase fivefold by 2030. They fear that mining will be diverted to become marine exploitation, in basins of brine which are home to many species endemic (who only live in a specific place).
The primary goal of the researchers: to alert
Another aspect of batteries : their degradation in the environment. They are often buried at the end of their life, but ” some binders battery cells and some chemical electrolytes are toxic to aquatic life or form persistent organic pollutants when combustion incomplete “, warn researchers. They then cite the construction of floating marine cities, which would make it possible to optimize the production ofenergy so that it is renewable and on the spot. But, small problem, such constructions could favor the propagation ofinvasive species. Other green alternatives do not escape researchers either, such as bags biodegradable. Used to replace plastic ones, some have not been sufficiently tested in a marine environment and may prove to be toxic. Those containing polybutylene succinate (PBS), thepolylactic acid (PLA) or materials based on cellulose and D’starch can become marine litter and cause harmful effects similar to conventional plastics”. Note that they are still much less bad than the plastic bags used before.
Finally, the primary goal of this study is to alert and encourage a enhanced ocean monitoringwhile since 2021 we have been in the “United Nations Decade of Ocean Science for Sustainable Development”. “Marine and coastal ecosystems face a wide range of emerging issues that are poorly recognized or misunderstood, each with the potential to impact biodiversity.says Dr James Herbert-Read, co-author of the study and a researcher in the Department of Zoology at the University of Cambridge. By highlighting future issues, we indicate where changes need to be made today – in both monitoring and policy – to protect our marine and coastal environments. »
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