Marine conservation in response to pandemics

Authors: Auriane Petit, Christelle Noirot

Health crisis and the sidelining of biodiversity

In recent weeks, the Covid-19 crisis, due to its sudden nature and the drastic behavioral changes it has caused, has gained infinitely more media attention than the climate and biodiversity crises. Although news articles still feature photos of wild animals, it is the captive pangolins and bats that have suddenly replaced the marine turtles entangled in plastic in the Mediterranean, the hunted and butchered sharks, as well as the devastated bleached coral reefs. It seems that the perception has shifted from "species to protect" to "species ready to contaminate us" as wildlife is designated as the starting point for highly devastating pandemics.

The world of marine conservation is severely impacted by the Coronavirus crisis and the lockdown measures it entails. Managers of protected marine areas, conservation project leaders, and the entire philanthropic, administrative, public, and private ecosystem surrounding these issues are paralyzed, uncertain about the months to come.

Should we only postpone activities? Will project funding be ensured? Will conservation and environmental protection be relegated to secondary issues in the face of economic recovery?< Many experts such as Valery Masson-Delmotte, François Gemenne, or Bruno Latour anticipate a return to the old economic regime based on fossil fuel exploitation with a strong rebound effect. In this vein, the American administration has already begun distributing pollution permits to companies if they demonstrate that their failures were caused by the coronavirus[1]. Will environmental protection efforts and their growing scope be neglected in the greatest indifference in the name of the health and economic crisis caused by the Coronavirus?

Biodiversity, zoonoses, and marine blind spots

Knowing that 70% of human infectious diseases are zoonotic, meaning transmitted from wild animal carriers, disrupting ecosystems through habitat destruction, marine pollution, and genetic modifications for farming amounts to affecting reservoirs that harbor infectious pathogens. That is why it is necessary to question the link between biodiversity and pandemic<, between destruction of natural habitats and development of pathogenic agents<. If we take a quick look at the news from the past few weeks, we see that it is mainly terrestrial wild animals that are identified as virus vectors, but what about marine animals that represent 70% of the planet's animal biomass[2]?

To date, marine biodiversity remains largely unexplored, and little knowledge has been gained about viruses, bacteria, protozoa, and marine fungi compared to terrestrial biodiversity[3].

To what extent is the destruction of ecosystems by human activities closely linked to the emergence of new viruses such as Covid-19? Can marine ecosystems also be considered as a breeding ground for viruses?

A year ago, in May 2019, a study was published in the renowned scientific journal Cell, conducted by around twenty international research programs such as Tara Oceans in France, focusing on the DNA of marine biodiversity in the poles 4. This study reveals that viruses are abundant in the world's oceans, uncovering a diversity of nearly 200 000 virus genera, which is about 10 to 100 times more than what was previously known. Furthermore, researchers also claim that over 40% of this viral diversity is found in the Arctic Ocean, a surprising fact given the dogma of the "latitudinal biodiversity gradient," which states that diversity is generally much higher in subtropical or equatorial regions and decreases towards the poles. In light of the current health crisis, should we consider this oceanic nursery of viruses as a ticking time bomb?

A healthy ecosystem "carrier"

Infectious diseases originating from wild animals such as avian flu from migratory birds, tuberculosis from cows, whooping cough from pigs, HIV from macaques, and Ebola from bats are not a recent phenomenon. They date back at least to the Neolithic revolution, when human societies began to exploit wild habitats to expand cultivated land and domesticate animals for farming[5]. In reality, most of their microorganisms live naturally within them and in perfect harmony. Ecosystems function like the human body: when they are robust and healthy, meaning they are composed of diverse species that create a balance, they are more resistant to diseases. The necessity for healthy coastal and oceanic ecosystems is even more crucial to avoid this pitfall[6].

Destruction of habitats and emergence of infectious diseases

However, the balances of ecosystems are disrupted (even broken) by damages and destructions (deforestation, urbanization, pollution, oil spills, destruction of seabeds by bottom trawling, etc.). Climate change, with its effects on rainfall and temperatures, leads to species migrations, particularly towards the poles[7] or migrations of southern species in the Mediterranean towards the West and North[8].

These movements significantly increase the chances of encountering other species (including humans), which influences the emergence of new diseases. Indeed, if the species that is moving carries pathogens and comes into contact with humans or other carrier species (mosquitoes, bats), they will become effective transmission vectors for the spread of infectious or viral diseases. This phenomenon is called the crossing of the "species barrier." Does this barrier also exist in the oceans, where ecosystems are more diffuse due to moving water carrying thousands of viruses, bacteria, and microorganisms?

Let’s take deforestation as an example compared to the destruction of posidonia seagrass beds, an emblematic habitat of the Mediterranean. With the disappearance of trees, the layer of dead leaves and roots is also affected. Water and sediments flow more easily over the stripped soil now bathed in sunlight, forming puddles favorable for the reproduction of mosquitoes that carry pathogens. According to a study conducted in twelve countries, species of mosquitoes that carry human pathogens are twice as numerous in deforested areas compared to intact forests.

Similarly, if we apply the process to the marine environment, the degradation of posidonia meadows (habitat and bioindicator of ecosystem status) indirectly leads to the desertification of seabeds, which can have consequences on water quality. On land, habitat loss leads to the extinction of species, some of which could have been poor vectors and reduce transmission.

If these species were still alive, they could have reduced transmission – this is what is called "the dilution effect"[10]. In fact, the destruction of biodiversity promotes the spread of a pathogen and affects potential natural barriers to diffusion.

Today, there is no marine region that is not affected by human activities[11]. However, many signs regarding the impacts of profound changes in land and marine use suggest that the frequency of new infectious agents emerging could increase in the coming decades[12].

Wildlife trade, intensive farming, and viral bio-incubators

The risks of disease emergence are not only exacerbated by habitat loss but also by the way we replace them. Cultural attraction to meat and rare species has developed illegal wildlife trade, which is sold in live animal markets (wet markets) and also through intensive industrial farming.

In the case of wildlife markets<, species that would never have crossed paths in nature are found side by side. They are kept alive in cages, stressed and immunocompromised, allowing microbes to easily pass from one to another. Added to this is a high frequency of a human population of all ages, more or less in good health, coming from different locations, resulting in a bio-incubator for epidemic viruses<. These combined infectious agents are then capable of crossing the species barrier and contaminating humans. Regarding the Covid-19 virus, it seems to have developed from the illegal trade of pangolins, an anteater from Africa and Southeast Asia listed in Appendix I of the CITES Convention[13] which prohibits international trade in endangered species[14]. Similarly, the illegal trafficking of sea turtles, rays, and sharks, stored in aquariums in contact with species from other oceanic regions or domestic species, also acts as a formidable bio-incubator for viruses.

In the case of intensive industrial farming<, hundreds of animals or fish with little genetic diversity are concentrated, creating ideal conditions for microbes to mutate into deadly pathogens[15]. For example, the H5N1 virus (avian flu) from poultry farms in contact with certain wild birds is transmissible to humans and kills more than half of infected individuals[16]. At the same time, industrial salmon farming in aquaculture in the Chiloé region of Chile, in contact with wild species, has developed the AIS virus (infectious salmon anemia), which emerged in July 2007 and has caused massive devastation in Chile's "Salmon Valley"[17]. This virus, which has not yet been transmitted to humans but has triggered several epidemic episodes since, requires heightened surveillance.

These examples of environmental degradation causing the emergence of a virus and its mutation, alongside the case of marine environmental degradations, allow us to draw a preliminary conclusion: viruses develop in both terrestrial and marine environments, and the degradation of ecosystems, disrupting balances, reinforces this trend.

However, their transmission to humans has been demonstrated and experimented in several terrestrial cases but not yet at the marine level. Here, the vectors for spreading the virus are different and can indirectly impact humans, for example, through the spread of a virus in the food chain. The case of the AIS virus in salmon can affect the entire food chain, causing a massive die-off in fish stocks, which can severely undermine food security. The case of the norovirus epidemic affecting oysters on the Atlantic coast in December 2019 and causing gastroenteritis symptoms in humans consuming them 18 is one example of the indirect impact of marine viruses on humans.

Hyper-connectivity as an amplifier of pandemics

The hyperconnectivity[19] of our societies< favors the emergence of new viruses and accelerates their spread to create epidemics and real pandemics like the one we are experiencing today. The global transmission of viruses is not a new phenomenon; it has been observed many times throughout the history of the Great Discoveries and colonization, recently in the case of military interventions and, surprisingly, in the context of humanitarian aid. In Congo, the construction of railways and border towns by Belgian colonizers allowed a lentivirus hosted by local macaques to spread to humans, eventually becoming the infamous HIV[9]. More recently, the intervention of Nepalese peacekeepers following the 2010 earthquake in Haiti triggered a cholera epidemic deadlier than the earthquake itself.

Today, different forms of connectivity present a risk of pathogen spread<. First, the development of new marine trade routes such as the Northern Route connects previously less frequented areas with major global trade hubs.

Furthermore, the passage of container ships promotes microbiological exchanges between different oceanic zones with the discharge of ballast water[20], which also risks connecting new wild species and developing new viruses. Secondly, the weakening of ecosystems coupled with the hyper-connected nature of our societies fosters the establishment and proliferation of invasive species such as the blue crab in the southern Mediterranean or the Caulerpa taxifolia algae. These invasive species can then carry viruses that may be pathogenic to species living in a habitat. Thirdly, plastic, whether micro or macro, also acts as a vector for viruses in the oceans. Researchers from the Med Expedition have demonstrated that around the plastic fragments recovered in the Mediterranean, a film of microorganisms consisting of viruses and potentially dangerous bacteria has developed.

Indeed, these plastics, carried by currents, become concentrated in ocean gyres, creating a bacterial soup that then spreads across the oceans. Researchers from the Med expedition have identified the presence of the bacterial group Vibrio, which can cause gastrointestinal diseases in fish as well as cholera in humans[21].

Remarkably illustrated by the drastic confinement period we are experiencing today, the hyperconnectivity of our societies greatly contributes to the development of pandemics.

Understanding to act: strengthening marine conservation

Given that we are not passive victims of the process of development and diffusion of epidemics, we can act to reduce the risks posed by these microbes:

• First, it is necessary to intensify the protection of marine habitats< to ensure that wild species do not transmit their pathogens. This includes, among other things, the creation of protected areas and particularly their effective and sustainable protection<.
• Secondly, although aware of the consequent cultural barriers, we believe it is urgent to stop creating absurd food circuits<, whether it involves the global trade of exotic and wild species under uncontrolled sanitary conditions or feeding farm animals with inappropriate products, as shown by the mad cow disease with the consumption of animal meal.
• Finally, it is crucial to rethink our relationship with nature, develop more sustainable lifestyles and limit our negative impacts on the environment to preserve biological diversity.<

As epidemiologist Larry Brilliant stated, "the emergence of viruses is inevitable, but epidemics are not"[9]. However, we will only be spared from the latter if we put as much determination into protecting marine ecosystems as we have into disrupting them through transport, resource extraction, mass tourism, and plastic pollution<. It is in this context that BlueSeeds advocates for a systemic approach to marine conservation through integrated management of issues that directly or indirectly influence the ecological health of ecosystems. We place great importance on conducting an integrated diagnosis of a coastal area to understand the ins and outs of this complex system. The health dimension is also taken into account, which is why we are interested in the topic of marine conservation. Finally, we develop an extended theory of change to highlight the interactions between the different identified elements. Conservation lies at the intersection of two complex sets: that of ecosystems and that of human behaviors with their social, economic, and cultural dimensions. This is why the BlueSeeds team works daily on the development and testing of effective and sustainable marine conservation methods<.

References

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Biography

• BAR-ON YINON M., ROB P., RON M., “The biomass distribution on Earth”, PNAS, 2018.
• BILLARD S., "Covid-19 was inevitable, and even predictable" due to our ecological impact", L'Obs<, published on 17.03.2020, accessed on 30.03.2020.
• CARRINGTON D., "Coronavirus: 'Nature is sending us a message', says the UN environment chief", The Guardian, published on 25.03.2020, consulted on 30.03.2020.
• FERAL J.-P., "Indicators of marine biodiversity" in Espaces Naturels, Review of professionals in natural spaces, no. 9, January 2005.
• GARRIC A., "Pangolins, the most poached mammals in the world, are now protected", Le Monde<, published on 29.09.2016, accessed on 30.03.2020.
• GOZLAN R., "How environmental changes give rise to new diseases", The Conversation, published on 12.02.2020, updated on 02.03.2020, consulted on 30.03.2020.
• GLASS R. I., "Norovirus Gastroenteritis", The New England Journal of Medicine, vol. 361, published on 29.10.2009, consulted on 02.04.2020.
• GRANDCOLAS P., JUSTINE J-L., "COVID-19 or the pandemic of a mistreated biodiversity", The Conversation, 25.03.2020, consulted on 30.03.2020.
• GREGORY A. C., ZAYED A. A., CONCEICAO-NETO N., SUNAGAWA S., WINCKER P., SULLIVAN M. B., "Marine DNA Viral Macro- and Micro-diversity from Pole to Pole", Cell, Vol. 177, Issue 5, published on 16.05.2019, consulted on 01.04.2020.
• HALPERN B.S. et al.., « A Global Map of Human Impact on Marine Ecosystems », Science, vol. 319, n^° 5865, 2008.
• LEGRAND C., " In Chile, the second largest salmon producer in the world, 'pink gold' is running out ", Le Monde, published on 08/25/2009, consulted on 03/30/2020.
• MONBIOT G., " There's a population crisis all right. But probably not the one you think ", The Guardian, 11/19/2015, consulted on 03/30/2020.
• PEDROTT ML, PETIT S, ELINEAU A, BRUZAUD S, CREBASSA J-C, DUMONTET B, et al. Changes in the Floating Plastic Pollution of the Mediterranean Sea in Relation to the Distance to Land. PLoS ONE, 11(8), 2016.
• PEREZ T., CHEVALDONNE P., "Marine Biodiversity in the Mediterranean", in EUZEN A., EYMARD L., GAIL F., Second Part – The Environment, a Dynamic Global System, Sustainable Development Uncovered, 2013.
• PRICE P., "Expert: To prevent pandemics like COVID-19, 'take care of nature'", Conservation International, 27.03.2020, consulted on 20.03.2020.
• SCHAUB C., "The coronavirus crisis is an ecological crisis", Libération, published on 25.03.2020, consulted on 30.03.2020.
• SHAH S., "Against pandemics, ecology", Where does the coronavirus come from?, Le Monde diplomatique, published in March 2020, consulted on 27.03.2020.
• SHAH S., "What you get when you mix chickens, China and climate change", The New York Times, 05.02.2016.
• TANNEAU F., "Arctic Ocean: a 'nursery' of marine viruses", Mer et Océan, Sciences et Avenir<, published on 28.04.2019, accessed on 01.04.2020.
• VIDARD M., "Is the coronavirus killing ecology?", L'édito Carré, France Inter, 30.03.2020, accessed on 30.03.2020.
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