Nanoparticles and microplastics - real threats or toxicological fashions

Lauantai 13.1.2024 klo 19.21 - Mikko Nikinmaa

In the beginning of 2000s nanotoxicology became very popular. Before 2004 there were no Web of Science articles, in the 5-year period 2004-2009 175, 2010-2014 slightly above 1000 and between 2015 and 2019 about 2100. The results clearly showed that nanomaterials can be toxic. However, virtually all studies were done with nanomaterial levels which far exceeded environmentally relevant levels. Once it was established that nanoparticles can be toxic, it has become clear that their effects in nature must be demonstrated before they can be considered to be an ecotoxicological problem. Luckily it appears not to be the case as the number of nanotoxicological studies has decreased markedly, to about 900, in the last five years.

One can naturally hope that all the studies which demonstrated the possibility of toxic effects were enough to alert the people responsible for the disposal of nanomaterials about the need to consider how the waste is treated. If that were the case, toxicological research had reached a major goal: preventing a potentially significant environmental problem from developing. In worse case, the situation shows that a lot of scientists eagerly follow the fashion and study something that is popular without considering its importance. What the results have shown is that nanoparticles are probably entering the cells of organisms via, e.g., pinocytotic pathways. Thereafter the effects are probably due to the toxicity of the compound(s) which the particle is made of, and environmental impact depends on the probability of nanoparticle concentration reaching a level which causes malfunction of some organisms.

Thus, nanoparticle toxicity is really the toxicity of the material that the particle is made of, the particle itself is only a means of entering the cells. For example, charged compounds are virtually impermeant, but if they are nanoparticle components, they can be taken up via pinocytosis. If the charged compound thus entering the cell is toxic, it will be harmful. So instead of nanotoxicology addressing all nanomaterials, we should evaluate, which toxic materials are used in nanoparticle formulation. If a material is inert, toxic effects are not likely.

About five years after nanotoxicology became in fashion, the same happened to microplastics. Between 2011 and 2015 there were merely 290 studies about them, but during the past five years close to 14000. Most of the studies are concerned with the distribution and uptake of the microplastics. They have now been found everywhere, from Antarctica to glaciers in the Alps and within virtually all organisms, mothers’ milk etc. Their occurrence everywhere is quite clear, but actually very little is known about their toxicity. In contrast, plastic waste, macroplastics has various harmful effects in addition to fouling the environment. Animals get stuck to plastic waste, plastics can clog their lungs, gills or intestine. To everyone watching news reels the sorry sights of seals and birds having died in nets is familiar. But microplastics, their effects are uncertain.  

If microplastics are made of pure polyethene or polyethylene, I have difficult to see that they could be toxic. They are inert materials which can, in my opinion, best be compared to cellulose or starch, which we and all the herbivores eat and digest all the time. However, as with nanoparticles, microplastics can be toxic, if they are associated with toxic materials. This is possible or even probable, if the environment is polluted with hydrophobic toxicants. They get adsorbed to plastics instead of any aqueous material. The toxic particles can then be taken up via pinocytosis and exert cellular toxicity. However, again as with nanoparticles, microplastics in themselves are not toxics, they are just the means by which hydrophobic toxicants can get in the tissues.

As a conclusion, I must stay that many of the studies on nanoparticles and microplastics have been done because the topics are fashionable. Instead of showing over and over again that nanoparticles can be toxic or that microplastics are found everywhere one should start considering, when their presence causes environmental risk because of their association with the pollutants which are the true problem.

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.

 

From plastic waste to green hydrogen, profitably

Torstai 5.10.2023 klo 14.50 - Mikko Nikinmaa

In recent past, plastics have been only considered as a waste, which one should diminish as much as possible. Most of the everyday plastic is polyethylene, and exciting new avenue for its recycling has recently been reported. Wyss et al. (https://doi.org/10.1002/adma.202306763) have written in Advanced Materials how one can produce hydrogen and graphene by rapid heating of polyethylene without any carbon dioxide emissions. By selling graphene, which is needed in increasing amounts, the production of a major energy source for future, hydrogen, becomes highly profitable.

So, a vision for a hydrogen production emerges which simultaneously nearly abolishes plastic problem. First, consumers are paid a small sum of money per kg of polyethylene returned to recycling stations. This is done, because while environmentally concerned people recycle plastics anyway, many people who are now throwing plastic bags to the environment would probably keep them if they knew that some money is given when the plastic is taken to recycling station. Second, the collected plastic is taken to hydrogen production facility. Hydrogen and graphene are produced, and hydrogen becomes, in fact, an energy source with no cost, as the produced graphene can be sold to any interested party at a price that is below today’s market price.

At the moment, the method for the production of hydrogen and graphene from waste plastics is at the lab scale, so scaling it up to commercial scale needs some time. However, in about five years the vision may become reality. It amounts to combatting climate change and plastic problem simultaneously, and doing it profitably. This shows again, how innovative new solutions can make green shift profitable, opposite to what the conservative, oil-loving populists say.

Russia and environmental protection

Lauantai 20.5.2023 klo 15.21 - Mikko Nikinmaa

Russia has now banned Greenpeace, because it demanded that Russia should take actions to combat environmental pollution, biodiversity loss and climate change. That actually says it all about the environmental policy of the present Russian government. Since Greenpeace dares to say that Russia should do something in terms of environmental protection, it is a hostile entity, and shall be banned. This attitude is typical for the Russian dictatorship. No-one is allowed to say anything that could suggest that Russia is not acting completely right. I suppose that all the talk about environmental pollution and climate change is just Western propaganda and lies. Russia is handling all environmental problems perfectly. To say anything else is hostility against Russia.

It doesn’t matter that Greenpeace is also criticizing environmental actions in Europe and North America. That criticism is founded according to Russian government, since Western countries do not carry out environmental protection admirably as Russia does (according to Russian government). It does not matter that environmental standards of Russian industry are low. It is only Western lies that environmental actions are only done, if a company is acting against agreements it has undersigned. It doesn’t matter that Russia is doing virtually nothing to change from fossil fuel-dependent society to fossil fuel-free one. It doesn’t matter that after Western tankers stopped shipping Russian oil, the standard of tankers has decreased increasing the probability of oil spills in the Baltic Sea.

I am afraid that only a revolution in Russia could change it to a more responsible country. Russian imperialism should end, maybe even the small ethnic areas, which now form Russian federation, should become sovereign nation states to enable fruitful dialogue and actions for environmental protection.

Russia is a problem - also environmentally

Sunnuntai 19.3.2023 klo 15.41 - Mikko Nikinmaa

Massive forest fires, melting permafrost with immense release of subterranean natural gas. No information about the environmental conditions in more than half of the arctic areas. The economy almost totally dependent on the exports of fossil fuels and mining products, which are produced with minimal concern about the environment in order to reduce production expenses. Shelling Ukrainian soil with ammunition; the compounds reaching the ground are known to be highly toxic.

That, in short, is Russia today. We have only read the news about the war Russia has started, but for the world the Russian – or at least Putin government’s – attitude to environmental questions may be even more detrimental. Whereas it is generally accepted that climate change is causing massive devastation of habitable areas, sinking coastal cities and island countries, Putin’s government appears to clap hands, as increasing temperatures will probably enable commercial shipping in the Arctic Ocean North of Siberia through the Northeastern Passage.

In the age of Soviet Union, terrible environmental disasters happened without any information about them in the Western world. For example, hundreds of thousands people died or were relocated when a nuclear arms storage site blew up. Chemical weapons were dumped in sea bottom as unknown sites. Western scientists had no way of checking what happens, because they had no contact with Russian scientists. The situation today is definitely not better, and maybe even worse, than at the time of Soviet Union. Putin’s Russia is closed like North Korea, virtually all the intellectuals which could alert of the existence of environmental problems have either been forced to emigrate or are in prison, and the government is anti-environmental. In view of this, the change of Russian government is needed in addition to stopping the war also for enabling sustainable life on the Earth.

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.

Whale strandings - what causes them?

Keskiviikko 22.2.2023 klo 16.00 - Mikko Nikinmaa

The stranding of whales almost invariably result in the death of the animals before they can be returned to water. This is because when whales start to dry, their temperature increases since the surrounding water is not there to cool the body. The body temperature increases until it is lethal. To limit the temperature rise, stranded whales are flushed with water. During the recent past whale strandings have become more and more common. They are one of the symptoms of disturbances in oceanic environments, and may have various reasons. Regardless of the ultimate reason, it is possible that the whales make a decision to commit suicide because of the environmental stress. This can happen, as whales have very complex brains, and appear capable of conscious choices, as, e.g., commit suicide.

However, many of the strandings take place to injured whales. One of the biggest causes of whale injuries is a collision with ship. Because of the injury, the whale may not be able to swim properly and is washed ashore. Also, whales use sea currents to help them in swimming. As a result of climate change, the direction and strength of the currents may have changed so that when the whale thinks that it is swimming normally using the help of the current, it ends up stranded. By far the most important disturbance to whales is noise pollution. This is because long-distance acoustic communication is a major feature of whale life. If acoustic communication is disturbed enough, the whale may decide to commit suicide.

Sounds travel long distances in water. As a result, whales can communicate with their mates tens of kilometres away. This is the way they find partners for reproduction, inform of good food sources etc. Ships and motorboats make a lot of noise in the oceans. The noise levels may disturb whale communication. And the sea traffic has become more intensive and noisier in the recent past disturbing the whales more and more.

Where have the eels gone

Keskiviikko 18.1.2023 klo 14.51 - Mikko Nikinmaa

Everything was better in the past. That is the slogan of conservative populists throughout the world. It is actually true for some things, but the actions should be completely different from the ones advocated by the populists in order for us getting the good things from the past also in the future.

Here I am focussing on the eel. Smoked eel is a true delicacy. When I was a child, one got eels virtually every time one went fishing. The fish was fatty and had virtually no bones making it tasty and easy to eat. However, eels started disappearing from the shops and waters from 1970’s onwards and now you can rarely find them anywhere.

The life cycle of the eel is the main reason why the species is so vulnerable to environmental contamination. The European eel stocks have decreased more than 90 % from 1970’s to 2010’s. If one starts from the sexually mature eel, it migrates several thousand kilometres from the inland waters, where it matures, to the spawning site in Sargasso Sea. During this months-long migration the fish does not eat, but uses the fat deposits as energy stores. This fact has several consequences. First, the condition of eels reaching the spawning site is poor. Many do not make it to the site at all, and the rest are barely able to make the final effort of the spawning migration. Any lipid-soluble environmental contaminants are released to the circulation when lipid deposits are used for energy production. This further weakens the fish. Also, because of the climate change, the ocean currents may have weakened causing an increase in the energy consumption during swimming from Europe to Sargasso Sea. This also weakens the eel before spawning.

The adult eels die after spawning, but the developed embryos start their long travel towards the European feeding grounds. No specific problems have been found in the early part of the migration in the Atlantic. However, it is possible that the food items of the eel embryos have decreased in abundance and that ocean currents have slowed down. When the eels come to the European coasts, a final strenuous part of the travel awaits. They must go up to suitable growth sites. In selecting where to swim to, eels use, e.g., the lateral line organ. This sensory organ is very sensitive to metal contamination. Thus, the present increases of copper, lead and cadmium levels may disturb the final leg of eel migration.

In short, eels suffer from environmental contamination in most parts of their migration. Further, the studies have shown that the presently occurring contaminant levels are adequate to cause, e.g., sensory problems. Consequently, to be able to go back to the good old days, when smoked eel was a common delicacy, we need to improve water quality.

Fish kill in Oder river - it is what I have feared

Sunnuntai 14.8.2022 klo 15.23

As a background, I have studied temperature responses of fish since 1980 and have written the book “Introduction to Aquatic Toxicology”, which was published by Elsevier in 2014, so both temperature- and pollution-related problems are within my expertise.

This summer has been intolerably warm in Central and Southern Europe. Fish kills are frequent in small, shallow lakes during heat waves in Finland, because of both reduced oxygen levels and increased temperatures. Fish kills don’t usually occur in rivers, because they have higher oxygen levels and remain cooler than small lakes. The species composition of fishes in the rivers also differs from that in the small lakes: rivers have more species, which require cooler water and higher oxygen levels. Thus, in the case of the Oder fish kill, one would need to evaluate, if all species have died equally or if species with lowest thermal maxima are overrepresented among the dead fish. If the latter is the case, then it is likely that we are experiencing the first climate change-related mass mortality of fish in Central Europe.

As the reason for the Oder fish kill, one has almost unequivocally concentrated on chemical pollution, although there have not so far been definitive measurements showing that this would have been the case. This is by all means possible, as dredging has been done in the river, which usually liberates contaminants which have been hidden in the sediment. However, even in this case an equally worrisome problem is that drought has caused the flow of the river to decrease markedly: any liberated pollutants have much higher concentrations than would be the case without drought. Also, virtually all pollutants are more toxic to fish at high than at low temperature. This being the case, even if pollutants are the cause of fish deaths, their level need not have increased. Because of the temperature increase, the toxicant level is lethal, even though it would not have been that at a lower temperature. This could be the case even if contaminant concentrations have increased.

In conclusion, the Oder fish kill is either directly caused by climate change, or temperature increase has contributed to the pollutant-induced fish kill. If serious climate actions are not done soon, I am afraid that similar events are observed regularly throughout the globe.

Decreased oil use influences climate change in two ways

Keskiviikko 8.6.2022 klo 20.22 - Mikko Nikinmaa

Oil spills are among the biggest toxicological problems in marine environments. Although the news pictures invariably show oil-covered birds, which die of heat loss in water, oil components are also very toxic to all aquatic organisms. The decrease in the use of fossil fuels will decrease the tanker transport of oil, oil leaks in the harbours of oil refineries, and accidental or intentional oil spills from ships. The net result is that oil pollution will diminish. Although only the importance of oil burning is usually considered as being important in combatting climate change, the decrease in oil pollution must also be considered. The fact is that marine algae carry out about half of the carbon dioxide removal and oxygen production by photosynthesis. Algal photosynthesis has decreased by 10-20 % because of marine pollution. This decrease is so far greater than what has been caused by deforestation of rainforests. The main pollutant causing algal deaths is oil and its components. Thus, decreasing the oil use will combat climate change not only directly but also as decreased oil pollution enables algal photosynthesis to recover. As a consequence, oil ban will have greater positive effect on climate than expected from decreased carbon dioxide production because of oil burning.

Physiological studies should be in the centre of climate change biology

Tiistai 12.4.2022 klo 15.49 - Mikko Nikinmaa

Climate change, and other environmental changes, affect the functions of organisms. The changes in populations and ecosystems follow these functional changes. If the functions of some organisms are not disturbed, the environmental change does not affect the ecosystem, if immigration and emigration can be accounted for.

These simple facts indicate that functional studies, i.e., physiology, should be in the centre of environmental biology. Indeed, a stone could have exactly the same molecules as an organism, but without functions it would still be a stone. However, physiological studies are marginalized in climate change research and environmental biology – there are less than 1/10^th of published physiological articles as compared to ecological articles within environmental biology. Furthermore, studies on animals account for less than 1/3^rd of the physiological studies.

In short, one carries out extensive ecological surveys and population genetic studies and observes that something has happened. This is the major problem with the research, it shows what has already occurred, but fails to evaluate why and how. With climate change research it is obvious that temperature increase plays a role, but only physiological studies can clarify, what the affected pathways are. Also, physiological investigations can answer in real time, if a disturbance is adequate to cause a perturbation in populations and ecosystems.

Climate change research as well as other environmental biology should be predictive. This requires that physiology becomes a central, not a marginal discipline. Studies require intensive, time-demanding work, which is often technically quite demanding. Because of this, the number of scientists working on physiological questions should be drastically increased. Only this makes it possible to turn environmental and climate change biology to predictive science, which is required to combat environmental problems.

Environmental Pollution Accentuates Problems of Hypoxic Fish: Why?

Maanantai 20.9.2021 klo 14.55 - Mikko Nikinmaa

Hypoxia, i.e., low oxygen concentration, has increased in aquatic environments throughout the world. Hypoxia is mainly caused by eutrophication of waters whereby the oxygen consumption of organisms (but also oxidation of dead materials) increases. The occurrence of hypoxia is either continuous or diurnal. Diurnal changes in oxygen levels occur, if the eutrophication is mainly resulting from the increased biomass of photosynthetising organisms: during the day, when light is available, the increased photosynthesis can cause the environment to become hyperoxic, while at night even those organisms only respire, whereby the oxygen level drops. Continuous hypoxia occurs, when the oxygen demand always exceeds its diffusion (especially from the air) and production.

Fish take up the oxygen they need via the gills. The gills are also the major site of acid-base and ion regulation. This dual function has generated the “osmorespiratory compromise”:   high functional surface area and low diffusion distance favour oxygen uptake, whereas low functional surface area and high diffusion distance favour ion regulation. Aspects of this have been reviewed by Wood and Eom in Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology 2021 Vol. 254 (DOI: 10.1016/j.cbpa.2021.110895). From the environmental pollution point of view, it is important to note that many if not most pollutants have important effects on gills.

Because of the effects of pollutants on gills, it can be expected that the hypoxia responses of fish are affected by pollutants. This is all the more worrisome, as the same sources are the cause of both eutrophicating nutrients and many toxic wastes, i.e., water that has gone through wastewater treatment plants. Lau et al. have studied, how hypoxia responses of fish vary in clean water and in effluent from a modern wastewater treatment plant (Lau et al. Environmental Pollution 2021 Vol. 284, DOI: 10.1016/j.envpol.2021.117373). They observed that the hypoxia tolerance of fish was markedly decreased. This was associated with a reduction in the decrease of the so called intralamellar cell mass. Recently, it has been found that fish increase the functional area of gills in hypoxia largely by decreasing the intralamellar cell mass. If this cannot be done, hypoxia tolerance is impaired. It is not known, why the intralamellar cell mass could not be reduced in the effluent-treated fish. However, the results clearly show that the osmorespiratory compromise of the gills is an important factor to be taken into account when the success of fish in polluted, hypoxic environments is studied.

Carbon taxes first, then environmental taxes

Torstai 15.7.2021 klo 19.23 - Mikko Nikinmaa

Both European Union and USA are planning to introduce carbon taxes on imports from third countries with more lenient standards in coal use in production. Since these two areas are the most important users of, e.g., steel, which is among the products that will be taxed for coal use, also production in third countries will certainly soon fulfill US and European standards to avoid taxation.

This is a first step, which is hopefully followed by taxing all imports to Europe, which do not follow European environmental standards. Such measures will also affect companies having headquarters in Europe, as a lot of production has been relocated to areas with less strict environmental standards and lower wages. Such a change would be beneficial both to the third countries, as the environmental impacts of factories remaining there would be markedly reduced, and to the European countries, as some production would certainly return Europe because the costs in the “cheap countries” would increase towards European costs.

Out of Sight, Out of Mind

Keskiviikko 24.2.2021 klo 16.55 - Mikko Nikinmaa

People throw all kinds of thrash all around the place. As a school boy I did a little survey of  trash in roadsides and swimming strands in South Wales. Already at that time the cigarette ends  were very common. And they are a major source of microplastics. With the tide they are washed to the ocean, and start their long-lasting voyage in the sea.

Similarly, people throw all the wrappings, bags and everything else out of the car windows after they have eaten in the car. The car needs to be tidy, but the roadside doesn't since it is soon out of sight. Similarly, bikes, refridgerators etc are just dumped into rivers and lakes, as they sink to the bottom and are out of sight. All kinds of trash are flowing via short pipes to the ocen as long as they are not visible. When the trash is seen, the length of pipes is increased. Different poison barrels are just sunk from boats to the bottom of lakes and seas - out of sight, out of mind.

Environmental crimes, dumping of toxic material, plastic etc, are hardly ever investigated. It is  commonly considered that environmental contamination is not a crime. This attitude has now resulted in the massive plastic waste gyres in the ocans. What has earlier been out of sight has now become visible. Further, the toxins that have been dumped all around the place, start causing effects on organisms. So, it is not out of sight, out of mind any more, since harmful effects are visible.

What should be done is to start collecting all the trash, and make environmental crimes punishable. If both of those things were done the out of sight, out of mind attitude would soon disappear. That would be important for the sake of the environment. 

Noise in the seas ? another anthropogenic problem which could be solved

Keskiviikko 10.2.2021 klo 14.08 - Mikko Nikinmaa

Sound moves faster and longer in water than in air. Different animals use all sorts of sounds in communication. Dolphins top the list with up to 70000 different sounds. It is probably even higher than human sounds – a person with 20000 words has a good vocabulary. Grey whales’ mating calls travel many kilometers in water in order to reach a suitable mate. Thus, the biogenic sounds are important for the functioning of animal populations in aquatic environment. Notably, when I was a child, and we were angling, one needed to be very quiet so that fish would not hear us, because they would do it a long way away.

With an increase of marine traffic and all sorts of other human endeavours in the seas and their shores, the soundscape of the oceans has changed immensely during the recent decades. Anthropogenic noises have even been suggested to be behind the shoring of whales.  In a recent number of Science (Duarte et al., Science 371, eaba4658 (2021)), Duarte et al. reviewed “The soundscape of the Anthropocene ocean” indicating the many problems for aquatic life. However, it would be possible to modify the anthropogenic sounds so that the soundscape of marine life would be acceptable. Thus, with this human-induced problem it is more or less the same as with climate change: we know what should be done, and we have the technical means to do it. However, we lack the political and economic will to do it.

GREED of the present generation decreases the possibilities for sustainable life of future generations.

Environmental effects are complex; that is the problem

Torstai 15.10.2020 klo 14.19 - Mikko Nikinmaa

In any natural environment all animals, here I am focusing on fish, experience changes in temperature, parasite infections etc. On top of that become all the anthropogenic contaminants, metals, pesticides, flame retardants, pharmaceuticals, personal care products and so on. The complex cocktail can affect organisms directly and indirectly, and a change in any variable can affect the growth, health and survival of them.

Because it is very difficult to study, how the environmental heterogeneity and its changes affect animals, most studies use a defined set of abiotic conditions and one pollutant. While this gives much valuable information, it should be remembered that for example a change in temperature, oxygen level, age of animal, salinity of water and the presence of other contaminants can influence the observed result. Occasionally, one gets the surprising finding that what we think as a pollutant and thus expect a negative effect actually increases the tolerance to an environmental change. For example, when we studied the effects of oil pollution on the thermal tolerance of juvenile fish (rainbow trout and European sea bass), we observed that the oil-exposed fish, if anything, tolerated high temperature better than control specimens (Anttila et al 2017, Environ Sci Pollut Res DOI 10.1007/s11356-017-9609-x). Recently, Petitjean et al (Science of The Total Environment Volume 742, 10 November 2020, 140657) have studied gudgeons in six French rivers, and observed clear interactions between the metal loads and temperatures the fish experience: an increase of metal load at high temperature reduces growth. Naturally, this survey conducted in natural environment cannot differentiate between direct and indirect effects of metals. It remains as a possibility that, e.g., the prey organisms of the fish are affected initially, whereby their availability decreases, decreasing the growth of fish.

Here I have focused on temperature, because we are currently undergoing a giant-scale natural event, climate change. It would be much simpler to evaluate, how temperature increase as such affects living functions, than take into account how temperature change affects responses to the mixture of environmental contaminants. The temperature effects can be completely opposite for different contaminants.

Aquatic microplastics, not necessarily a problem

Tiistai 25.8.2020 klo 18.18 - Mikko Nikinmaa

Indigestible fibers are considered to be good for you. Such fibers enter your alimentary canal and pass through it without any changes, nothing is taken up in the gut. However, they help in the motility of the gut, and some materials, which are indigestible to us, can be utilized by gut microbes. Regardless, if material is going through your gut without anything taken up, it is inert and if its dimensions are such that it is easily transferred through the gut, cannot be considered harmful. The same is true for all animals.

So, fibers are good for you. If I changed the word fiber to microplastic, then people would start screaming about terrible poisons. Headline news almost everywhere in the world feature every once in a while stories about how these terrible microplastics are found in fish and other seafood, and can therefore be transferred to you. But if the dimensions are correct, the microplastics can be just like any other inert material going through the alimentary canal. Many plastics are nowadays made such that they meet foodstuff packaging requirements. If these plastics are broken down or if microbeads are produced from such plastics, they are completely harmless. We have been drinking water and soft drinks in plastic bottles for tens of years without being poisoned by microplastics, although every time we drink, we digest microplastics. So, in principle, microplastics are not a problem, if the material is foodstuff quality.

Microplastics can, however, be a problem. First, there are many types of plastics, some of which contain toxic components. Currently, about half of all the microplastics entering water are particles from tire wear. With the current traffic situation, there is very little one can do to this type of contamination. This is in contrast to microplastics in wastewater treatment plants, where more than 95 % of plastics are retained. The tire plastics have toxic components. Second, most of the toxic compounds are hydrophobic. Therefore, they adsorb on plastic particles, and will easily diffuse to organisms through the hydrophobic lipid gut walls. In this case it is not the microplastics themselves which are toxic, but the toxic compounds that have found their way to the environment. By stopping the release of these toxicants also the toxicity of microplastics would disappear.

The problem is that by focusing on microplastics in the aquatic environment, one is not addressing the real questions: decreasing road traffic (thus decreasing tire wear particles), decreasing toxicant release (thus decreasing toxicant adsorption and transfer into organisms) and completely stopping the use of toxic compounds in plastics.     

Lead Poisoning - a Problem Especially for Children in Poor Areas

Perjantai 31.7.2020 klo 16.55 - Mikko Nikinmaa

The first large-scale lead poisoning dates back to Roman times. Many historians are of the opinion that the downfall of Roman empire was partly due to large-scale lead poisoning. The drinking water was lead to Rome and some other big cities in lead aquaducts, with the consequence that some lead dissolved in water and was drunk. The amount of lead this obtained was enough to cause neurotoxicity.

The second time that concerns of common lead poisoning reached news was when car traffic using leaded fuel increased markedly in industrialized countries. This led to quite rapid phasing-out of lead in petrol in 1989’s. Lead was also an important component of paints in, e.g. kitchenware and toys, whereby everyone but especially children were exposed to toxic lead concentrations. Because of this, also lead-containing paints have been banned. As a result of the bans of lead in fuels and paints the lead levels in the blood of children in industrialized, rich countries has decreased to values which do not cause observable toxicity.

The toxicity of lead is especially harmful to children. Lead is primarily a neurotoxicant. It disturbs brain development. If brain development of a child is disturbed, the disturbance persists for the rest of the life. Lead-poisoning decreases the intelligence, increases aggressiveness and generally makes the affected people lethargic. It also decreases the attention time span; it has been estimated that a quarter of ADHD cases would, in fact, be caused by lead poisoning. There are also associations between lead poisoning an hearing acuity, which suggests that lead exposure may cause speech and language handicaps.

Above the level of 5 micrograms per decilitre (µg/dL), lead causes the intelligence, behaviour and learning problems as estimated by the American CDC (Center of Disease Control and Prevention) and WHO (World Health Organization), although WHO points out that there is no safe level of exposure. If the 5 µg/dL concentration is taken as the limit, a third of world’s children have exposure, which causes life-long effects. As children in industrialized countries do not normally have these high lead levels in their blood, this  is another problem between poor and rich countries.

We in industrialized countries have become aware that resources, such as metals, should be recycled. If this is done responsibly, it helps a lot for making the resource use in the world sustainable. However, many of the recycling companies are not in the business to help the earth but to make money. As a result, the “recycling” is done in poor countries, and no precautions, which would be required in Europe and North America, are followed. Because of this, recycling lead-acid car batteries has become the single most important source of lead exposure for children in poor countries. Thus, one should demand that recycling must be done in the commercial area, where the product is used. In addition to car batteries, lead-containing paints and toys containing lead are still common in poor areas.

A more detailed account of lead problem in children is the report by UNICEF and Pure Earth:  The Toxic Truth: Children’s Exposure to Lead Pollution Undermines a Generation of Future Potential, which is available at https://www.unicef.org/reports/toxic-truth-childrens-exposure-to-lead-pollution-2020

 

Physiological studies add a predictive component to modelling fish stocks

Perjantai 3.7.2020 klo 18.00 - Mikko Nikinmaa

Mirella Kanerva, Kristiina Vuori and us others have recently published a study about the  fitness of salmon during their feeding migration in different parts of the Baltic Sea (Kanerva et al. Environmentally driven changes in Baltic salmon oxidative status during marine migration, Science of the Total Environment, in press, https://doi.org/10.1016/j.scitotenv.2020.140259). The study is extremely difficult, since it tried to evaluate, how the physiological status of a commercially important fish species in natural environment is affected by food, water temperature and environmental pollution. It is noteworthy that we were able to show that factors affecting the oxidative status of the fish affected the fitness and seawater survival of the salmon. It was also possible to show that increased toxicant load, elevated temperature and cyanobacterial blooms already in the present Baltic Sea induce changes, which are measurable with physiological parameters, and are likely to affect recruitment of salmon.

The point about physiological measurements being able to predict changes in fitness and recruitment is revolutionary for fisheries biology. This is because earlier one has based all the models for stock estimations on retrospective observations on catches and spawning success. The findings of our study indicate  that physiological expertise can add a predictive component to recruitment models.

Our results also indicate, which parts of the Baltic Sea are most contaminated affecting the oxidative status of salmon. It is no surprise that effects are observed in the Gulf of Finland. However, these findings show that similar parameters could be used elsewhere to evaluate, if environmental contamination is serious enough to affect preferred fisheries species. Again, this adds a predictive component to earlier estimations based on retrospective data.

Hitherto, fish physiology has remained a small field, but our results indicate that it could play a major role in modelling fish stocks, because it adds a predictive component to models and thereby gives possibilities for more rapid fisheries decisions than are currently possible.

World Seas are in peril: Hypoxia in Baltic Sea as an example

Perjantai 5.6.2020 klo 18.40 - Mikko Nikinmaa

Human activities have affected world seas in various ways. A three-volume book on environmental evaluation of world seas has just been published by Elsevier (World Seas: an Environmental Evaluation). In two volumes it evaluates the environmental statuses of different sea areas and in one volume the major environmental problems affecting marine environments. The book’s aim is both to evaluate the present status and to evaluate the future of the seas. It would be impossible to give a comprehensive review of the book’s contents, so I take one environmental problem, hypoxia, in one sea area, the Baltic Sea as an example.

There have always been virtually anoxic bottom areas in the Baltic Sea, but they have increased markedly because of human actions. For example, the area with low oxygen (less than 2 mg/l) has increased tenfold from preindustrial times. The main reason for hypoxic/anoxic sea bottoms is that for about 50 years paper and pulp mill industry’s wastewater was entered the sea uncleaned. The biological oxygen consumption of the waste is approximately the same as that of 100 million people’s waste. Since the waste of tens of millions of people also entered the sea without treatment, the sea bottom now contains so much organic material and nutrients that even without any further wastewater or fertilizer discharges, the Baltic Sea would remain eutrophicated and have large hypoxic areas for tens of years.

Hypoxia is caused by the consumption of oxygen by organisms or organic material, if it exceeds the diffusion of oxygen from atmosphere and its transport from oxygen-rich waters. In the Baltic Sea the water is stratified, and the high-temperature, low- salinity water which is oxygen-rich does not circulate with the dense oxygen-poor bottom water. The bottoms get oxygenated water only, when pulses of oceanic oxygen-rich waters displace the bottom areas. When this happens, the low-oxygen water, which has high nutrient content, will be transported to lower depths and to  Gulf of Finland and also in small amount to Gulf of Bothnia. Because large amounts of phosphorus and nitrogen are liberated, primary production increases, and generation of hypoxia occurs in new areas. The increase of temperature causes increased oxygen consumption of all poikilothermic animals. Thus, climate change increases the likelihood of hypoxic periods. Also, if the predictions of increased rainfall during winter remain accurate, the phopshorus and nitrogen discharges during natural river flow to the Baltic increase markedly.

Although eutrophication is usually linked only to increased plant, algal and cyanobacterial growth, the end result is always hypoxia. In shallow areas eutrophication leads to intermittent hypoxia.               During the day, when there is enough light for photosynthesis, green plants and algae liberate oxygen, and the water often becomes hyperoxic. At night plants, algae, bacteria and animals all only consume oygen, rendering water hypoxic. The oxygen consumption by animals always consumes oxygen, but probably the most important reason for hypoxia is the oxygen consumption of microbes, which eat up all the dead plants, algae, cyanobacteria and animals entering the bottom. There is a group of bacteria which forms bacterial mats to bottoms with very low oxygen.

If one considers communities, hypoxia generally decreases diversity and changes species composition. As an example, at group level, fish disappear first, and are replaced by jellyfish. Among macrofauna, polychaetes survive at lowest oxygen level. With lowering of oxygen level, microfauna and microbes replace macrofauna. Hypoxia reduces the growth of animals and as a consequence fish catches are reduced. Additionally, hypoxia-tolerant species are usually of reduced commercial value. Thus, the Baltic Sea fisheries are markedly suffering from the spreading of hypoxic areas.