In the brink of extinction - many freshwater fish

Tiistai 12.12.2023 klo 17.23 - Mikko Nikinmaa

When I did my Ph.D. thesis 40-45 years ago, the topic: effects of temperature and hypoxia on respiration of rainbow trout, was hardly noticed by the general public. In 1976 we, biology students arranged a theme evening about the pollution of the Baltic  Sea and invited media. Nobody came, and when I asked a newspaper reporter why that was the case, he answered that the topic had no general interest. I wish the situation were the same today: fish would not suffer from pollution, increased temperature and decreased oxygen level. Unfortunately that is wishful thinking.

IUCN (International Union for the Conservation of Nature) has recently updated its Red List with very worrying information of fish, particularly freshwater fish. A quarter of the freshwater species is in immediate danger of extinction. The most important proximate cause is pollution, but toxicant effects cannot be separated from temperature increases and eutrophication, which causes oxygen lack. All of the previous problems increase parasite loads and cause fish diseases. In addition, overfishing and building of waterways, which has destroyed spawning sites or made it impossible to reach them, decreases fish populations.

Below I give a couple of examples of how all of the above cause the disappearance of specific species. First, eels are critically endangered species, which are characterized by their catadromous way of life and long spawning migrations. They grow and reach maturity in freshwater. Their migration from sea to freshwater feeding sites is critically dependent on smell sensing, which is dramatically disturbed by pesticides and metals. Consequently, those types of pollution may be an important cause of declining eel populations. Second, burbot is a coldwater fish. It spawns in the middle of winter, and it is ice-fished in January-February to get the fish and its eggs for soup. Now that the temperature is increasing, burbot is already living at the high end of its temperature tolerance, and may soon become extinct. Another group of coldwater fish is salmon and its relatives. In addition, it requires clear water with high oxygen content. Since both an increase in temperature and eutrophication decrease the oxygen level, salmon and its relatives may become extinct. Lampreys have succeeded in temperate waters for 500 000 000 years. Many of the species live in sea as adults, but spawn in rivers. Because of building of waterways, e.g. hydroelectric power plants, their long saga may be coming to the end. Finally, aquarium hobby is very popular throughout the world. Many of the ornamental fish do not reproduce in captivity, and are thus fished wild. This has made many species endangered because of overfishing.

Electric cars - there are all sorts of environmental problems

Perjantai 5.5.2023 klo 14.22 - Mikko Nikinmaa

In the name of combatting climate change, car manufacturing is rapidly changing from producing petrol- and diesel-consuming cars to electric cars. It is reasonable to ask, if electric cars are a sustainable solution. There are several problems, which should mean that one cannot increase the number of cars, even if they are electric. Rather, to combat climate and other environmental changes, the number of cars should be drastically reduced. The paragraphs below indicate the reasoning for this.

First, electric cars are fossil fuel-free only if the electricity used in them is produced not using coal and oil. The overall electricity use increases markedly with increasing number of electric cars. Hitherto the proportion of electricity produced using fossil fuels has not really decreased, even though the electricity produced using renewable sources has increased markedly. This is due to the increase in the total electricity use. So, presently an electric car user may increase the use of fossil fuels in electricity production (naturally depending on the country).

Second, production of cars is using a lot of steel. Steel production is currently one of the most important sources of emitted carbon dioxide. For example, out of the total carbon dioxide emitted by Sweden, steel production accounts for more than 10 %. The steel producers are aware of their large carbon footprint, and companies are currently competing to have carbon-free steel production. Carbon-free steel will undoubtedly be eagerly bought by car manufacturers. However, its production requires a lot of electricity, so fossil fuel-free electricity production is the key also here.

Third, present electric cars are on average bigger and heavier than petrol-fuelled cars. As a consequence, their production needs more steel. Also, their batteries use more of the metals, which must be mined with dire consequences to the environment. Some of the needed metals occur only in low concentrations even in the richest ores. Electric cars must thus become smaller and new types of batteries utilizing commonly occurring compounds developed.

Fourth, almost every day news alerts us about the dangers of microplastics. It is hardly ever mentioned that by far the most important source of them is tyrewear. They cannot be removed in sewage treatment, as they are produced wherever cars are driven. The amount of particles released increases with the weight of the car, so the heavier electric cars are a bigger problem than current petrol cars.

All in all, electric cars have several problems, so we should try to reduce the number of automobiles in use. By doing that, some land now taken up by roads would be free for other uses. Doing it may be required for the wellbeing of environment.

An Agreement Reached on Protecting High Seas

Maanantai 6.3.2023 klo 19.32 - Mikko Nikinmaa

Worldwide agreement on the protection of open oceans was reached yesterday. In comparison to climate change and biodiversity protection negotiations, reaching an agreement was easy, and nobody expressed serious dissatisfaction. Not surprisingly, though, the negotiations even in this “easy” case took ten years. The reason for reaching an agreement is, however, not that governments would have become environmentally conscious, but because of the following fact. The open seas are ocean areas, which are not under the control of any nation. The maximal “economic zones” where different nations can restrict the use of the sea area are 200 nautical miles (about 370 km) from the coast. Beyond that point anyone from anywhere can use the resources of the sea and sea bottom. Thus, they belong to no nation state, but because more than 70 % of earth’s surface is ocean, form the majority of sea area.

Protecting the oceans is crucial in order to combat climate change and feed world’s people. It is not generally known that oceanic algae consume about half of the carbon dioxide and produce half of the oxygen in the world. Consequently, the well-being of oceans is as important for preventing global temperature rise as preventing the rain forest loss of Amazonas. Because of aquatic pollution, which should now be decreased as the result of the agreement, oceanic photosynthesis has probably decreased by 10-15 %. People have not really cared about what happens to the open oceans before the huge plastic gyres have caught everyone’s eye. It is clear that not only plastic waste but all sorts of chemicals, including oil components are something that sea organisms encounter all the time. To my mind it is probable that the marked decrease in eel stocks, which has occurred in the last 50 years, is to a large extent caused by oceanic pollution. Because of the very strenuous spawning migration, even slight pollution can overstress the eels so that spawning becomes ineffective.

At present, less than 1 % of the oceans is protected. The agreement states that by 2030 30 % of the high seas would be protected. This would enable many overfished species to recover. However, even though the actual protection of the seas is important, it is even more important that the pollutant discharge to oceans is diminished. Only that can help the high seas to stay healthy or recover.