How does plankton affect the weather? How does the biodiversity of these organisms shape our existence? How do the diminishing numbers of diatoms, a type of micro-algae, and the revival of dinoflagellates or archaic cyanobacteria, threaten our health? Why is the severest impact of ocean plastic pollution not even covered by the media? And why is the Iodysseus programme at the heart of the issues faced by the planet’s global ecosystem?

Pierre Mollo – teacher, researcher, marine biologist, and pillar of the Iodysseus scientific committee led by skipper Eric Defert – has the answers. Raised within the walls of Port-Louis in Brittany, France, à la «godaille», the part of the fish left to fishers, he was entitled to a supplement. Mollo learned quickly that plankton was king. The “bread of the sea” as his grandfather and the elders would say. Nothing would prevent "Pierrot" from devoting his life to it. At the age of 21, in 1969, he quit the factory where he was an adjuster after his Certificate of professional competence. Destination Japan via Quiberon. "The Japanese were 20 years ahead of us in marine biology and in micro-algae, phytoplankton, and zooplankton cultivation," he recalls. He implemented what he had learned overseas back in his home country, starting in Houat at the service of fishermen and later of all maritime trades. In the absence of existing teaching materials, he teaches future professionals by using Anita Conti's "Ocean, Beasts and Man" as a course manual. He will cross the path of "The Lady of the Sea" in person.

Mollo’s commitment to the plankton’s cause has driven him to teach, inform, and create awareness about these microorganisms. With conferences, films, and books, he brings light to the “Ecology of the Invisible”, a microscopic universe that plays an essential part in the bio-engineered foundations of our planet. Now a researcher with a master’s degree in ethnology, Mollo is an ambassador to the “little ones of the sea” - these microscopic critters – while humbly presenting himself as a marine biologist and remaining attached to Houat. He is also the founder of the Port-Louis Plankton Observatory in his home port, founded in the spirit of preventing of sanitary risks linked to the already serious degradation of plankton biodiversity. Mollo recently inspired and co-wrote a symphonic suite titled “The Voice of the Oceans,” a hymn to ocean life. He has also inspired the vocation of the Iodysséus programme and that of his skipper Eric Defert. He is a member of the scientific committee of the programme, for which he has become The Voice of the Ocean.

We met Pierre Mollo in the occasion of gatherings at Slow Fish in Genoa, in May 2019, where we discussed a lot about how to strengthen awareness and knowledge of citizens about the ocean. He has then authorised us to reproduce the entire interview with Jean Pierre Pustienne published on the website of Iodysséus.

Q: Amongst the numerous services the ocean and plankton ecosystems provide the planet and its inhabitants with, they absorb 25 to 30% of all CO2 produced. They also create 50% of our oxygen, according to current estimates. You suggest that this percentage is even higher. Why?

R: The phytoplankton, or micro-algae, mostly form transparent prairies in our oceans, but with a surface area infinitely larger than that of all the earth’s terrestrial land combined. Like forests, these vast fields of micro-organisms need three elements to thrive: light, mineral salts, and CO2, which they then transform into oxygen. Given that CO2 is denser than air, it’s only logical to conclude that it descends. Thus, given that CO2 is heavier than air, wouldn't it fall into the oceans two times out of three given that the ocean covers 70% of the planet's surface? Do winds, the importance of which I do not question, divert CO2 only onto the continents? I believe that the ocean and the phytoplankton that inhabit it absorb 70% of CO2 present in our atmosphere, in proportion with the earth’s surface. They may only trap a part of it, or only over time, but that is another matter. If the earth has two lungs – one on land, and one in the oceans – it is the marine lung that is predominant. In short, plankton has been controlling whether it rains or the sun shines on our planet, as Guy Jacques states, for almost 3.5 billion years. We are merely inhabitants on Planet Plankton.

Q: Sunshine or rain? Are you speaking about the effect of plankton on the atmosphere and on the climate?

R: Yes, literally in regard to the climate, but also figuratively in a broader sense. Clouds are not just masses of water vapour. They also contain particles, bacteria and other microorganisms that end up coming back to earth with the rain. Figuratively, this means that every human impact on the ocean ends up falling back down on us eventually. In this sense, studying plankton is like predicting the future for me. I am currently working with students on a programme called Erasmus+ for Likes secondary schools in Quimper. They will be 50 years old in 2050. 50 years ago, I was like them; I had just come back from Japan where I had been studying aquaculture. My question at the time was: How will phytoplankton and zooplankton be sources of protein for humans in the 2000’s? I never strayed from that initial question. When population numbers reach the 9 or 10 billion-mark, terrestrial vegetal resources will no longer be sufficient for lack of available space. We will have to look to the oceans to feed humanity, provided, of course, that responsible fishing practices are enforced. And provided that abhorrent practices like transforming 5 to 10 kilos of wild fish into feed to produce one kilo of tasteless farmed fish are eradicated. Aquaculture can - and should - serve to sustain marine resources, not the other way around. This is the belief that inspired us when a group of friends and I began campaigning for the restocking of lobster populations and a breeding plant of Houat lobster in the 1970’s. At the time, I was paid by the fisher's cooperative to understand how all this works.

Q: So, in summary, how does it work?

R: It’s quite simple. The very first condition is biodiversity in the surface water. It all starts with the richness and variety of phytoplankton. When this diversity decreases, that of the zooplankton which feeds on it as well and therefore that of the larvae and fry, and so on, up to our plate. In short, the resource is depleted. But not only her. In plankton everything is interconnected: biodiversity and resources, but also the complex balances of the Earth system and the climate. Marine biologists today note, almost everywhere, a decline in plankton biodiversity. However, when we refer to the sedimentary archives, we see that planktonic regressions, breaks in biodiversity, are signs of critical phases in the history of our planet. Like for example, in a previous period of intense warming, 56 million years ago, when the Arctic Ocean was no longer frozen at all.

Q: Could this be our future? The answer again depends on the biodiversity of plankton. This biodiversity that you have personally studied for more than half a century. How are things faring here in Brittany?

R: Badly. One recent incident amongst numerous others was the prohibition of swimming last summer (2018) in Southern Finistère due to Harmful Algal Blooms (HAGs) that looked like red tides. I personally cannot recall having witnessed such a phenomenon before in my lifetime. Green tides, yes, but that is another matter. The culprit turned out to be a dinoflagellate, fortunately harmless in itself to humans. Noctiluca scintillans, another possible culprit for such phenomenon, is famous for making bluish, glowing sparks in the wake of boats or waves at night. The sudden proliferation of this species is far from insignificant. 50 years ago, when I was working in Houat, discovering a single dinoflagellate under a microscope was like a surprise. I would call to my friends: “Look, come see, I’ve got something good!” At the time, diatomes dominated the flora. Today, when I return to Houat, I see dinoflagellates all the time, and always in greater numbers. You should know that in this class of archaic phytoplankton (2,400 species), not all of them are confined to photosynthesizing organic matter. Some species take shortcuts by feeding on phytoplancton species. This is the case of the bioluminescent Noctiluca scintillans.

Q: How is this linked to the phenomenon of bioluminescence?

R: Noctiluca does not simply put on light shows – it is an armed predator. Dinoflagellate literally means "terrible whip.” With this weapon, the species captures prey that is attracted to its bioluminescence, what we can consider to be a type of light fishing. Its favorite prey are the fine, crisp diatoms that zooplankton love. A sea that glows at night is a bad sign for fishermen, because it means that micro-crustaceans and copepods are being devoured, leaving nothing for larvae and fry to eat. These hungry species cannot eat Noctiluca in turn, as it is too big for their microscopic mouths. As a result, fishermen must look elsewhere if they wish to bring home a decent catch.

Q: Can this “survival of the fittest” issue get any worse?

R: I’ll get to that soon. Noctiluca scintillans announces via its luminous signals a favorable context to other dinoflagellates that can be toxic: Dinophysis (see right), Alexandrium, or Gonyaulax, for example. In humans, their effects can range from accelerated bowel movements, to paralysis, coma, and even death. On average, Dinophysis makes oysters and other seafood unfit for consumption 15 days after the appearance of noctiluque. Nevertheless, in places far away from us – at least for now – there is something far worse: Karenia brevis. Some say that it is the source of the first of the "Egyptian plagues" cited in the Bible, when the waters of the Nile River turned to blood, resulting in the death of fish. This story has become a real phenomenon, now more than ever before. Only last summer on the west coast of Florida, 100 tons of dead fish and marine mammals washed onto shore following a HAB, all victims of Karenia. This dinoflagellate species spreads deadly neurotoxins directly into water and kills not only marine animals but also humans via respiration or ingestion. It is economic punishment, both for fishing and for tourism. In the United States, losses due to HAB are now close to a billion dollars for the fisheries sector alone, and this number only continues to increase.

Q: Where do these toxic dinoflagellates suddenly come from?

R: They live in cysts in sediments, their favorite ecological niche, and wait in a dormant state for ideal environmental conditions to grow and multiply. Any manipulation of certain marine sediments thus has a role in plankton toxicity. We know this with Dinophysis. This is a compelling reason to firmly oppose sand extraction projects like that of the cement manufacturer Lafarge, in 2007, which had planned to take hundreds of thousands of tons per year from the Etel Bay, between Gâvres and Quiberon (the project was suspended in 2009, editor's note). The more we stir the s... of the sediment, the more the s... will fall back on us, sooner or later.

Q: Why is the decrease of diatoms, among tens of thousands of other species, of such concern?

R: Because they are not just a regular archaic branch of life. Diatoms were a major component of plankton as it fostered, accompanied, and sustained the explosion of life on Earth, notably the very recent development of Homo sapiens. Their services to us are truly exceptional. Alone, they represent at least 25% of the oxygen we breathe, 40% of the CO2 trapped by the ocean and 50% of the primary production of marine organic matter on the global scale. In short, they represent an irreplaceable foundation in the food chain, starting from photosynthesis all the way to our plates. With more than 14,000 species recorded, diatoms constitute the greatest diversity of phytoplankton. Their nutritional value is as diversified as it is rich. Some are bactericidal, others produce proteins, yet others produce Omega 3 fatty acids, and so on. They are simply essential to the existence of all organic life, including that of humans. This is not the case with other archaic branches, at least not to the same extent.

Q: Can a momentary and regional decline of diatoms be linked to cycles, such as the Atlantic Multi-decennial Oscillation (AMO) which happens every 70 years? Are we not merely just in a warmer phase?

R: It’s certainly a contributing factor. Diatoms are very sensitive to water temperature. They tend to prefer the cooler temperatures of polar zones and have trouble surviving in temperatures above 18 to 20°C, a fact that I have verified myself. Nevertheless, their sensitivity to pollution is no less important, to the point that they are often used as bioindicators for ecosystem health. Pesticides, fungicides, Round Up, and synthetic fertilizers, everything that humans spread onto soils, finds its way to the oceans through runoff and estuaries. Two eco-toxicologists, Geneviève Arzul and Françoise Quiniou, signaled the negative impacts of pesticides on coastal waters in 2016. Their conclusion was clear: Diatoms are the principal victims of these agricultural practices. Only an infinitesimal trace of Round Up is enough to cause significant damage. This diagnosis confirms similar studies dating back to the early 1980s, almost 40 years ago. On the other hand, excessive nutrient enrichment – eutrophication – whether it occurs naturally with upwelling or is intensified by agricultural fertilizers like phosphate and nitrogen, induces outbreaks of dinoflagellates and cyanobacteria. The latter cause asphyxiation and death of the environment. Whether it is in ponds, lakes, or an entire ocean, there are areas where aquatic desertification is gaining ground.

Q: If we’ve understood correctly, red tides and toxic tides have existed long before our so-called "Anthropocene" industrial era. To what point is human activity to blame?

R: With pesticides and chemicals like Round Up, it’s clear to see that we are running straight into a brick wall in regard not only to diatoms. If we do not limit, or better yet, stop the mass dumping of nitrates and phosphates into agricultural soils, a catastrophe will be inevitable. Need proof? Now, every year in Brittany and almost everywhere in France, there is a reoccurring need to close of water bodies or prohibit swimming due to HAB’s or cyanobacterial blooms. Everywhere that there is water, there is plankton. We are dealing with an emerging environmental issue all across the country. In the United States, the situation is reaching critical proportions in several large lakes and on the coasts, both East and West combined. Yet again in Florida last August, a brownish tide was deplored. It was later identified as a Trichodesmium bloom, a filamentous and stinging cyanobacterium that had not been reported in centuries. Here in France, during the summer of 2017, numerous people suffered the loss of their pets due to these cyanobacterial blooms. Like dinoflagellates, these can be toxic to humans as well.

Q: Cyanobacteria have provided immense services to the planet. One of them, Spirulina, is regarded as a potential food source for a future population of 10 billion people. Where is the harm?

R: Spirulina is an exception for cyanobacteria. It is an excellent dietary supplement, and I thoroughly recommend it as a healthy addition to a balanced diet. As for other types of cyanobacteria, this is not the case. Spirulina’s bacterial ancestors, improperly called blue algae, are dangerous. Very dangerous, in fact. A good 40 species produce cyanotoxins that are considered to be some of the most potent naturally occurring poisons and none have antidotes. Studies (notably on mice, editor's note) have proven these cyanobacteria to have carcinogenic and teratogenic effects, namely resulting in the malformation of embryos. The current worldwide expansion of cyanobacteria populations in both fresh and saltwater bodies has begun to foster fears of a giant leap back to the past. The ancestors of these microscopic organisms ruled the earth 3.5 billion years ago during a very long period of intense volcanic activity where biodiversity development was not in full swing, to say the least. So yes, we can thank cyanobacteria in large part for the invention of photosynthesis, the trapping of CO2 – then infinitely more abundant in that ancient atmosphere than it is today – and the de-acidification of the primitive ocean, allowing for evolution to begin. These services were nonetheless rendered in a very different context, when cyanobacteria had to employ antioxidants and other impressive strategies that later allowed them to survive five massive extinctions in bio-atmospheric conditions far less comfortable than what we enjoy today – and that’s an understatement.

Q: Today, the media is focusing on plastic pollution in the ocean. What is its effect on plankton?

R: In terms of magnitude, the risks are inversely proportional to the size of large waste particles that can be found on beaches. A greater danger can be found under our microscopes. Today, we can observe plastic microfilaments among the copepods or diatoms that are even present inside the plankton itself. Most are identified as micro-fibers from synthetic textiles, notably "fleeces" created by the plastic recycling industry. These fibers enter the ocean by the billions each time these types of garments are washed.

Q: So, what you’re saying is that a significant part of plastic pollution is sourced from our washing machines without us realising?

R: Exactly. Today, whether it is your washing machine or water treatment plants, nothing exists to stop or filter out invisible microfibers. We need to start demanding washing machine manufacturers to do something (currently, only one initiative of this nature exists, editor's note). These fibers enter the food chain and end up in our bodies. Larger particles can also be present, resulting from the fragmentation of plastics to the order of 500 microns (millionths of a meter, editor's note). These play an unexpected but no less pernicious role.

Q: According to Tara’s works, these can actually promote the production of diatoms! How and why?

R: Weighed down by their frustule, a kind of siliceous shell, diatoms sink to the bottom of the ocean like sediment. As they sink, they attach to everything they encounter on their journey down. This can be anything from the mooring lines of ships, to buoys, but also to fragments of plastic. This is what is happening in fact, on another scale and in another field, with the rafts known as the Fish Aggregation Devices (FAD) used by industrial tuna vessels in the Indian Ocean that contribute to the species’ overexploitation. The concentrations of diatoms under the raft attract copepods, which in turn attract small and large fish, and finally yellowfin tuna. Predators eat the diatoms, but also consume the microplastics that the diatoms use as makeshift floats. This is yet another way that plastic enters the food chain. We can now find these particles in salt from the ocean and in our excrements. What is contested are the traces of the chemical compounds that are contained in plastics which then pass into animals, like nano-residues from heavy metals or phthalates used to soften plastics. They are serious endocrine disruptors that can affect reproductive capacity, including also in humans. Today, we still are not certain of the consequences of their ingestion in terms of public health. I am not one to diminish the dangers of these pollutants. However, the health risk linked to HAB’s of dinoflagellates and cyanobacteria is no less serious to me and is even more pressing.

Q: How does this ecotoxic danger threaten our health?

R: As I said, simply through our respiration. Inhalation of dinoflagellate toxins and cyanobacteria in the form of aerosols is a recognized form of exposure that directly concerns island and coastal populations. This is a very serious issue as 50% of Europeans and soon 80% of humanity live in coastal areas. We are told, and I am the first to repeat it, that breathing the air by the seaside is invigorating and refreshing. Invigorating yes, good for our health as well, but it all depends on the plankton that proliferates in the waters when you breathe in.

Q: How long have we known about this type of danger from marine aerosols, and how can we assess it?

R: A long time ago, when I was still living in Houat, I noticed that at certain times throughout the year, fishermen would suffer from skin or eye irritations that were quite similar to pollen allergies. As early as the 1970s, serious studies began to note a coincidence between dinoflagellate population peaks and severe respiratory problems among the inhabitants of the Aeolian Islands. At the time, dinoflagellates were much less common than they are today, disregarding cyanobacteria. Anita Conti herself, who was called "The Lady of the Sea" by local fishermen, opened my eyes during those years to marine aerosols and the troubles they can cause. We can now anticipate and predict these increasing risks by studying the composition of plankton at a given time (t). This was the root of my inspiration to later create a Plankton Observatory with the same tools and techniques used to monitor air quality in cities. Samples and point analyses over time are not enough: Permanent vigilance that is related to marine weather is essential to be able to alert caution when needed in a suitable manner.

Q: Citizen observation by trained and motivated people could cut costs: this is the concept of plankton observatories. You have alerted the authorities of this new danger, with what results?

R: Not once, but twice. I sent reports to Ségolène Royal and recently to Nicolas Hulot. No response. At least they will not be able to say that they did not know. The people who are really interested in plankton can unfortunately be summed up to a handful of scientists and professionals. We must raise awareness and continue to constantly explain the roles, services, and multiple risks to plankton. Personally, I’ve been paddling against the tide for 30 years for someone to listen to what I’m telling you today. To my surprise, only the Chinese have listened to me so far. They found the Observatory’s website and flew me out to their country. In only six months, we have created a citizen plankton observatory in Tsingtao, a megalopolis of nine million inhabitants located on the Shandong peninsula. In the end, I do not believe that this is merely a coincidence – they are on top of questions like these today, just like the Japanese were when I started my career in aquaculture. I am convinced that the Chinese will be one step ahead of us in that regard as well. That being said, the quality and media coverage of Tara's scientists’ work has given the planktonic cause some beneficial spotlight. Concentrating on ocean aerosols, the Iodysseus programme is being developed to strengthen and complement Tara’s actions and that of the observatories. The more we are, the more we will come together, and the more chances we will have to incite true change.

Q: How do you think Iodysséus can make a significant contribution to “plankton’s cause”, as you call it?

R: By moving across the oceans and carrying a message, by collecting information that is ever more precise on the content and interactions of marine aerosols. The dispersion of plankton on a mass scale in the atmosphere only happens during large storms far too dangerous for humans to brave in order to collect and analyze data. Armed with its speed, the Iodysséus trimaran will be able to create similar conditions to those made by sea storms with the bow of its leeward float. This is extremely exciting, as we have only ever been able to simulate these phenomena in a lab, which causes critical biases. It should be noted that we will never be able to create anything as good as real ocean storms. From a technical standpoint, the Iodysséus will allow aerosol capture tools to develop, as they are currently quite rudimentary. This will hopefully inspire investors and companies to develop them further so that we can eventually establish models and create a real network for monitoring the quality of ocean aerosols. The stakes are high, given that they concern several hundred million human beings. Odysseus is important for us to continue to enjoy clean sea sides and everything that accompanies them, from fishing, to coastal economies and tourism. This does not exclude the contributions of biotechnological developments from the sea, capable of supporting sustainable economic models. The seas contain many solutions – enough, as I say, to fill an ocean with them.

More information on Iodysséus can be found here.