Oceans and Fisheries

As we’re putting pressure on ecosystems of all kinds, polar, alpine, tropical rain forests, dry-land areas. We’re of course, also putting tremendous pressures on our marine eco systems and the oceans.

We know that we’re changing basic ocean chemistry. We know that we are poisoning the oceans with the pollution of coming from huge oil spills and other disasters and we are also degrading the biodiversity in the oceans through human activities, especially through the over fishing and over harvesting of marine life.

The oceans cover three fourths of the Earth’s surface area. And we know, of course, as we discussed many times that, our huge cities around the world hug the oceans, depend on the oceans for trade, for economic activity, for our food supplies, for our proteins, and, Invaluable, nutrients such as omega-3 fatty acids from, our fish intake. Back in 1950, the estimate is that the total ocean catch measured, in total metric tons was somewhere, around, 20 to 30 million metric tons of fish catch. By 1990, that had become around 90 million metric tons that perhaps a factor of three or four increase globally in how much we were taking from the oceans.

And that is even an under estimate of the true effect, because those numbers, as conventionally reported, don’t measure what we discard and throw back in the oceans. When fishermen catch fish in the nets, they also bring in a lot of bi-catch, or unintended catch, of marine life that they don’t want. And that’s not counted in the, harvesting of the fish, but it is an absolutely core part of the actual, over harvesting of marine ecosystems. You’re looking here at a fascinating graph which has a very important message and reality to it. The blue area shown here is the capture from the oceans, it’s the amount of fish taken, and marine life taken, in metric tons year by year. And it rose sharply, as I said, up to the 1990s. And then more or less leveled off. You might say that’s a good thing. But in a way it was force majeure in the sense that, that leveling of reflects the collapse of many fisheries around the world that had increased the takes so much that they had driven the fisheries to depletion, to crisis.

So that the amount that could be taken out was, was limited, increases were no longer possible and in many cases such as the, near, my former home when I was a professor at Harvard university up in New England. A complete closure of the cod fisheries because of the collapse of the cod fisheries after so much heavy fishing for so many decades. So that leveling off is a reality that came from the enormous pressures being put on ocean fisheries. It doesn’t mean that we’ve reached an equilibrium because many fisheries around the world continue to be driven towards  depletion. And our, in a situation of crisis. Now on top of that is another green area of rising production of aqua-culture. This is going to managed fisheries, not in the open sea catch, as in a traditional fitching, fishing, but in raising fish industrially either on the coasts in many cases or in inland areas that are suitable for growing fish. China is the world champion of aquaculture. And as the limits to the marine catch have intensified, the markets for aquaculture have expanded. And that has permitted a continuing overall rise in the metric tonnage of fish that are consumed. That’s a good thing overall, because, of course, this is, a reflection of the fact that, fish are highly desired in our diets, and highly nutritious as well. But it also poses a whole new chapter of risks, for us, because aquaculture itself has huge impacts on ecosystems. The cultivation of fish in managed locales at the coastline or in fish farms in in the interior Can lead to spread of disease, can lead to excessive nutrient flows of many kinds, can threaten the biodiversity of wild fish through escaped varieties from managed fisheries in aquaculture and so forth.

But what the diagram shows is that we are hitting limits of the open sea catch, and compensating in part and on the whole, in a desirable way, through aquaculture. But only if that aquaculture itself is operated in a responsible matter, and that is a complex challenge given all the things that can go wrong with aquaculture. Now, how did this massive increase of catch occur? It came from a massive increase of fishing activity. Shown here, comparing the intensity of fish fleets in different fisheries around the world in 1950 and in the early years of this new century. And what you see is a massive expansion in the magnitude of the fleet coverage in this period. There were huge technical advances in the use of massive long line nets, which allowed for much greater capture, in the use of all kinds of remote sensing, satellite imagery and other kinds of sensing to identify where the fish are located in the use of ocean bottom trolling. to, that just scrapes up the fish on the ocean floor and other marine life, often completely devastating those highly complex, highly bio diverse marine ecologies as a result of all of this. And so, the consequence is that technological advances, as is often the case, has not been the friend of biodiversity and of ecosystem sustainability.

It has led to a huge depletion of fisheries, a huge loss of biodiversity, and a huge threat to the productivity of these marine ecosystems. One measure of how big the catch is, is an innovative measure that has been developed, that looks at the amount of photosynthesis needed to produce primary food products for the amount of fish take that is being and marine catch that is being harvested from the oceans. And so, one looks at the amount of primary production implied by the fish take as a fraction of the primary production in that fishery area as an indicator of risk. In other words, how much photosynthesis is being appropriated for the fish catch. Just as we looked when Professor Vetusak asked how much of the terrestrial photosynthesis is being appropriated for the human species. And we found the shocking number that it’s 40 to 50% of the net primary production. Well, the same thing is true for the amount of fish that we’re taking, so this is, again, human appropriation. Of net primary production, but indirectly, in the form of the fish take, and what you can see in these red areas, shown on this map are fisheries where the amount of net primary production associated with that amount of fish capture is already an endangered zone. 30% or higher in many cases of the total net primary production being, taken, in fish catch each year, implying that we are harvesting at a rate that is completely unsustainable for these fisheries.

Now, one implication of this is not only are we driving the abundance of fish down to levels that threaten their very survival, but we’re also changing the structure of the ecosystems as well. It’s called fishing down the the trophic chain or fishing down the food chain. Because the first fish to go are the high trophic fish, the large blue fin tuna, and others that are the big prized carnivorous or pacivorous fish that eat other fish, that eat other fish, that eat the plankton. And the net primary producers weigh down the trophic level and what, the fish ecologists, have done is to measure the average trophic level of the fish that are caught. Meaning, are we mostly harvesting fish that are the first, on, on the first line of eating, the photosynthetic output or are we catching fish up the food chain that are the, predators of the fish lower down. And what we find in, from the evidence provided by, the ecologists, is that over time more and more of the catch is lower and lowered down the trophic chain. And the reason is that humanity is very good at eating those prized fish, way up the food chain.

The predators of the predators of the predators and we value those fish, we catch them, we deplete them, they’re smaller in number and they’re highly valued and then, later on, we go to smaller fish and lower down on the food chain. And this is shown by these two downward sloping lines which measure, over the years, the average trophic level of the catch that is brought from the fisheries. The top blue line in this chart is for the marine fisheries and the red line lower down is for fresh water fisheries. And what’s superimposed on this is aquaculture where we’re growing fish that are higher up the trophic level. Now that is also complicated.

When we grow, in agriculture, fish that are high up the fish chain. It means those fish have to be fed smaller fish. Or fish meal and that means that that kind of aquaculture requires massive open sea fishing to provide the fish meal. To feed the, the growing aquaculture, and so, in this way, aquaculture maybe doesn’t substitute for the open, open sea excessive harvesting, but actually can exacerbate it if we are feeding piscivorous fish in the aquaculture. To the extent that the aquaculture is for fish that are that, that eat photosynthetic output rather than other fish, herbivorous fish. Then we don’t have that phenomenon. And, those kinds of aquaculture. For instance, tilapia, us, is a substitute rather than, a, an amplifier, of the, the, pressures on the open sea fishing. Now, the, the basic framework that fisheries ecologists use is a framework that asks how much can be taken sustainably. And they calculate or try to calculate a complicated concept of maximum sustainable yield of a fish type. And the question that they’re asking is, how much tuna can be taken from this fishery or how much anchoveta can be taken from this fishery or how much cod can be taken from this fishery without depleting the fish stock? And the basic question is, at what natural rate is that particular species, for example growing, within this ecosystem?

So that if that amount is harvested, it’s leaving that amount of species, unchanged year to year, and therefore in a stable population. The basic idea of calculating the maximum sustainable yield is to try to determine what is a safe level of fishing. That concept has become more complicated necessarily in recent years, because ecologists came to understand it’s not good enough to ask, for an individual species, how much can be sustained.

We have to take an ecosystem-wide perspective, so now the ecologists are calculating a maximum sustainable yield, based not on a single species framework, but on an ecosystem wide sustainability concept. Now, the most essential point is that humanity continues to fish more than the maximum sustainable yield. And thereby drive more and more of the fisheries into danger of depletion, ultimate collapse, even extinction of, certain, fishes, that are, depleted, and, and then driven to extinction. What can be done about it? Well, the key point is clear. One has to put a limit on how much fish can be taken. And this has led to many kinds of policy innovations, none of which is foolproof by any means, because these market pressures are relentless. But to try to identify the maximum sustainable yield and then assign permits for that amount of fish catch. And in some cases, to allow those permits to be traded, among individual fishermen, in which case their individual fish quotas. Or among groups or companies. But a kind of tradeable permit system, where the total number of permits given is in correspondence with what the ecology tells us is a sustainable amount of fishing is the main policy direction that has been taken. But, with all of the lobbying pressures, more quotas, don’t tell us there are limits, with all of the illegality of unmonitored, and undocumented, and illegal fishing these systems have in some cases shown results. But in other cases have essentially been brushed aside by legal and illegal forces, political and economic that have meant that the depletion has continued despite the attempt to put on these kinds of limits. Well, if the oceans were troubled only by the extent of harvesting of marine life, we’d have trouble enough. But it’s important for us to remember that the kinds of assaults of humanity on marine ecosystems is coming from many, many different directions. This map is showing the corals at risk along the coasts of the world and emphasizing that the reasons for this risk are multiple, as usual. Tourism over fishing, over exploitation of the coral reefs. Harvesting of the corals themselves using dynamite for fishing, pollution sedimentation, human activities driving corals also to depletion to threat of extinction for many coral species because of climate change and direct impacts on the coral reefs all over the world. This map is showing what we’ve mentioned many, many times, and that is, the run-off of nitrogen and phosphorus, leading to eutrophication and to hypoxia, to dead zones. Depleted of oxygen along the coasts of the rivers. Look at the entire eastern coast of the United States and the Gulf of Mexico coast of the southern United States, especially where the Mississippi river enters the Gulf of Mexico, the massive amount of dead zones there. Similarly, we see that in the North Sea. We see it around China and Korea and Japan. We’re there’s a tremendous amount of eutrophication taking place. And this map, we’ve seen before, is the step by step acidification of the oceans as the high concentrations of CO2 dissolve in the oceans. Create H2C03, carbonic acid, that acid attacks the shellfish, the calcareous species in the ocean, threatening whole classes of marine life. We’ve got huge problems we have some tools to address these. But I think the fair summary is that our oceans are at profound and still growing threat because of the pressures of human activity. We depend on the oceans in countless ways for our well being, for our survival. If we don’t take care and face up to these multiple assaults. We will face a growing crisis in, the not so distant future.

Biodiversity Under Threat

Ecosystems provide vital services for human well being, provisioning and regulation among them. Biodiversity, the variation of life within species, across species, and across ecosystems.

Determines to an important extent, how well ecosystems perform. And therefore, how well they provide vital services for humanity. There was a long standing hunch that a greater degree of biodiversity. More genetic variation within species a richer web of species in a food chain or in a given ecosystem, would raise the performance of ecosystems. And over the last 20 years, ecologists have been making valiant efforts to understand the linkage of biodiversity to ecosystem functioning. Their conclusion is a very strong one. And that is that biodiversity, biological diversity, raises the performance of ecosystems in valuable ways. And when biodiversity is under threat, at any level of organization, less genetic variation within a species, less variation of the range of species, less favorable interaction across ecosystems. When biodiversity is a threat, ecosystem functions are degraded.

Let me give just a few examples of what has been found as reported recently in some overviews of this linkage, from biodiversity to ecosystem functions. Consider provisioning, for example. The way that ecosystems provide food or fiber for human needs. One thing that’s found is that crop yields are higher in farm systems that have a higher biodiversity. This is a very big deal, because a lot of the industrial food production is monoculture. One kind of crop grown massively on a farm, rather than a high biodiverse farming system. And even within, that one crop, whether it’s rice, or wheat, or maize or, some other crop, it’s one seed variety perhaps, industrially manufactured.

And so what’s happening is that the biodiversity of our farm systems is shrinking. And one of the findings is that this is making our farm systems less productive. Yields actually go down. And maybe farmers don’t know this individually, or they haven’t had the experience, or they’ve become part of an industrial food chain that has discouraged a highly biodiverse farm system, but the results are farms in threat. And farms that are monoculture are also far more vulnerable to the invasion of pests and pathogens. One of the things that biodiversity does is protect an ecosystem from an invasion. In invasive species like a weed variety, or in invasion of a pest that attacks a certain kind of plant.  If there are multiple kinds of plants in the ecosystem, maybe there’s some loss, but the parasite or the pest is controlled. But if there’s one monocle through it can tear through the entire area without limit essentially. So the resistance to invasions, to parasites, to pests is also reduced. Another finding quite similar is in marine ecosystems.

If there is a reduction of biodiversity of the fish species. And that’s happening all over the world as fishermen clear a particular fisheries area of the most favorite species, or particular easy to catch species, or the fewer numbers at the higher trophic levels of the ecosystem, meaning the kinds of fish that it, that eat other fish, that are piscivorous that are fish eating fish and higher up on the food chain. In other words, the phenomenon has now been verified by ecologists across many different kinds of ecosystems and many different kinds of reductions of biodiversity. also, when it comes to implications for climate regulation, reducing ecosystem performance by lo, a loss of biodiversity also can reduce storage of carbon in cycles, or in plant life.And therefore, essentially, releasing carbon dioxide into the atmosphere because there’s less biological sequestration of the carbon within the ecosystem. So the regulatory functions of ecosystems in climate as well, are degraded when biodiversity is lost. Now, that’s all pretty bad news, and the reason it’s bad news is that in ecosystem after ecosystem, biodiversity is at massive threat. It’s already being reduced, degraded, hugely threatened. Why? For so many reasons that it’s going to be extraordinarily difficult to bring under control. A summary perhaps that’s useful is to look at a map of the world that was prepared by my colleagues at the Earth Institute a number of years ago, called the Human Footprint Map. What my colleagues did was to take a number of indicators. For example, population density, land use change, infrastructure coverage railroads, roads, other human changes. Aggregate them, weight them in an index, and then for each small part of the world, the kilometer by kilometer ask, how big is the human influence, the human footprint in this part of the world. And they came up with a map that looks like this. The darker the red, the stronger is the human footprint. If an area is all green, that’s a part of the world very little touched by human influence.

Well, what you see in this map is the sweep of humanity. Humanity is basically everywhere where it’s habitable. And so you look at the United States there’s no dark green area essentially in the continental United States. The eastern half of the U.S. is much darker red than the western half because it’s much more densely settled. In part because it’s it is more humid, there is more food production and the western part of the United States by and large is arid and more mountainous, with much less population density. But even there, the human activity, land use change, pasture land, farm land, urban settlements, roads, rail, are pervasive. So where are the dark green areas? well, in Africa, the desert, the Sahara desert. Yes, very, very low human impact, but very, very few people living in the Sahara. For the boreal regions of the Eurasian landmass. Up in the tundra. where there are still forests and very little population because it’s frozen much of the year or year round. And there’s not agriculture in these very high latitudes. And so there’s relatively low human impact. But look at India. Look at China other than the Tibetan Plateau at 20,000 feet or more above sea level. Look at South America aside from still parts of the Amazon rainforest.

What you see is the pervasive human footprint. Humanity is everywhere. And just like the underlying index that is the basis of this map, humanity is everywhere in many, many  different ways. It’s there in infrastructure, it’s in farming. It’s in changes to basic chemical cycling, as we’ve talked about so much in water use, or nitrogen cycling, or phosphorus cycling, as a result of agricultural activities. Now, a related idea was led by a great ecologist, Peter Vitousek. now, more than 15 years ago, when he and his colleagues asked the question about human domination of the ecosystems. How much are we taking in that provisioning. We need food. We need pasture land. We need areas to to, to put our asphalt down for our cities and our roads, and our parking lots. How much of the global ecosystems is humanity appropriating? What is the human domination? Their conceptual framework for that is shown here in this complicated flow chart. They start at the top with human population both its size and the resource use. Then, the human enterprises, they called it, what humanity does in agriculture and industry and recreation in international trade. Then they talked about the several ways that human activity appropriates or dominates ecosystems. Land transformation, for example, farming or land clearing for pasture land and for use of forests could be the change of the cycling of key nutrients and chemicals and the ecosystem as we talked about like nitrogen or the water cycle or the carbon cycle with its enormous effects on climate. Or changes directly in the biosphere. As we harvest crops, as we hunt species, as we fish for fish. Or as we rearrange the biogeography of species by saying, why don’t we take that species from Australia and put it here, without having a deep understanding of what happens when one species invades another ecosystem where its predator or control mechanisms might not apply. And all of this, if you go down the flow chart, changes the climate system, for example, through the greenhouse gases of carbon dioxide, methane, and nitrous oxide. And leads to a loss of biological diversity, which is our main focus right now. So what Professor Vitousek and his colleagues did was to try to assess how big is the human domination of ecosystems by several fascinating metrics. How much land has humanity transformed? How much have we changed the carbon cycle? What have we done to water use and so forth? Their conclusion revealed the massive extent of human impacts across all of these dimensions. Land area, 40, 50 percent of the total net primary production through photosynthesis on the planet is for us. That’s a pretty voracious species. We are grabbing and have grabbed land area. Whether it’s the pastures, the forests, the arable land. And said okay to the other species, we’ll take that, thank you. That will be our pasture, that will be our farmland, and the extent of the human reach on land transformation is perhaps half of the total net primary productivity on the planet. CO2, we know we’ve changed the carbon cycle fundamentally, and already raised the level of carbon dioxide in the atmosphere from 280 parts per million, pre-industrial revolution, to 400 parts per million and rising. Now, water use. Tens of thousands of dams put on the world’s rivers. Massive taking of groundwater for irrigation especially. Harvesting the the flow that comes from glacier melt. And that very dangerously for us is going to come to an end as those glaciers retreat and then finally disappear under the force of global warming. Water use in crisis in many, many parts of the world because we have appropriated so much. Of the the, the available fresh water cycling. Nitrogen, we know we have come to dominate the nitrogen cycle. Turning N2 in the atmosphere into so called reactive nitrogen like ammonia or nitrates and nitrates that can be taken up by living organisms, is, both a natural process as we’ve discussed but also an industrial process, the Haber-Bosch process. That famous process that enabled humanity to grow so much more food that it made it possible for the population of the planet, to rise from not quite two billion people at the start of the twentieth century, to six billion people by the end, and now 7.2 billion people. We have threatened species so much that we realize that we need to classify and measure the species, that are endangered. We need to understand the extent of these dangers. and, the International Union for the Conversation of Nature, the IUCN, is the global score keeper of endangered species. It’s extremely important to understand what they’re measuring, and how they’re measuring it. And that is shown first on this diagram which helps us to understand the classification system used by the IUCN. Now the first thing to say is that there are an unknown number of total species on the planet and theories vary roughly between ten million species of all kinds. Plants, animals, microbial life. To possibly up to a 100 million species. We’ve not classified, large proportions of those species. So IUCN, still is in the process of classification, as is the world scientific community. Of those that are classified, then there are categorizations of species that are not threatened by human activity, they’re so in, in so many places and in such large numbers that humanity does not pose threats. To those that have already been driven to extinction. And you can see here the classification that are of, of the various gradations of threat. Species that are extinct because of human activity. Species that are extinct in the wild but perhaps still live in small numbers in captivity. Critically endangered species, endangered species, vulnerable species, near threatened species, and those of least concern. So, the IUCN keeps its so-called Red List which gives the numbers of species in these very threatened categories. And you’re looking at the tables for critically endangered, endangered, and vulnerable species. And when one looks at the numbers, it’s of course, very, very frightening because even in a very short period of time, the numbers classified as critically endangered, for example are soaring. Partly this is through new classifications and adding species that have not been classified before. But it’s also very much that human activity is driving species to the state of being critically endangered and to extinction. The IUCN Red List is invaluable and of course, it is profoundly troubling. We know that major classifications of animals and plants are being pushed to the extreme, the critical danger levels and some to extinction. And just to mention, a few that are most dramatic amphibious species the world over are declining hugely in numbers. And this is taking place ac, across the range of amphibians and it’s taking place all over the world. Recent studies for the United States have shown an enormous drop-off. And one of the frightening things for the loss of amphibians in the United States is those that had the highest proportionate drop-off in frequency of sightings are the ones that were classified by IUCN as the most endangered. And so the declines of amphibious species are not taking place in the most abundant and safest but in the most endangered. Another major collapse, of of species are pollinator species which are so vital for our plants and our fruits and our food provisioning. The honey bee, in the United States, has been experiencing a dramatic, troubling and still poorly understood decline in numbers. And in some cases, a collapse of bee colonies that has come to be called the colony collapse disorder. And it is so striking with the fall of numbers. But even more striking perhaps, that we don’t quite understand why, where, what’s happening to this radical die off of bees across the United States. There are many potential culprits, Could be a parasite, a parasitic mite has been implicated, but then again multiple viruses have been implicated. Bacterial diseases. A drop of, nutrition, of, the honey bees, coming from changes of landscape and crop varieties. And many, many scientists think that it’s the increased use of pesticides that is a major cause of this. Another absolutely shocking, and dramatic, and troubling loss of species abundance and threat of extinction are the great apes. Our closest relatives on earth where humanity shares the genetic code and the evolutionary history just as close as can be. 95% or more of the genetic code shared with great apes, with the gorillas, chimpanzees, orangutans bonobos and the dramatic decline of numbers of these great apes and of their habitat in the last 25 years is absolutely shocking. I had the occasion recently to visit one group of eastern mountain gorillas in Rwanda in Volcano National Park, which is doing a valiant effort to preserve the habitat of the mountain gorillas. It’s of course an incredible experience to be together with the gorilla group and to see them in the wild. And it was absolutely rather shocking to see how fragile is the remaining habitat for these endangered gorilla groups. Because the farm land, under tremendous population pressure is pushing right up against the the cloud forests, the bamboo forests, that are the habitat of the mountain gorillas. There is a stone wall which separates the farm land from the the bamboo forest. One doesn’t go far inside the bamboo forest to meet with the groups of the gorillas. You see how close humanity and the gorillas are living together and by the way, that means that humanity can pass pathogens, diseases, human diseases to gorillas. We share so much of our biology, of our genetics of our immune systems, that the diseases easily flow in both directions and disease itself can be transmitted to these gorilla groups. Well, it was breathtaking to be together with the mountain gorilla family and and a mountain group in the wild. But it was absolutely shocking to see how humanity has pressed against the remaining habitat for this species. The, the one of the closest relatives that we have and how fragile is that distance now that that is their margin of survival on the planet. These pressures are coming in all directions. They are causing huge risks to biodiversity. The risks to biodiversity are causing huge losses of ecosystem functions, and we have to understand now what we can do about it.

What is Biodiversity?

We’ve been examining what happens, when a growing world economy collides against planetary boundaries. We have a world output now, of 80 to $90 trillion, 7.2 billion people. We know that the numbers are continuing to rise. We know that the world economy is continuing to grow at three to 4% per year, meaning a doubling, every 20 years or so. We know, that there are already huge pressures on the world’s ecosystems, on the climate, on the oceans. And we have not yet found a way of course, to reconcile that continuing growth, with environmental sustainability.

We’ve studied a few ways that this, collision or this trespass of planetary boundaries is occurring, climate change being the most dramatic. Pollution of the air and water and the dangers to our cities being another. I want to go into greater depth now, on the question of the viability of other species, the biodiversity on the planet. I’ve mentioned several times, that humanity is putting so much pressure on the Earth, that we’re actually causing a dramatic increase in the rate of species extinction. Maybe 100 to a 1000 times, greater rate of species extinction, than was occurring before the the industrial revolution. That loss of species and many other phenomena associated with it, such as the decline of genetic diversity within species. The decline of abundance of species, even when they’re not being pushed to extinction, but just to smaller and smaller numbers. That combined effect is so large, that it is causing what could be the sixth great extinction on the planet, as I’ve discussed, and it is causing huge threats to humanity. As always, whether it’s with climate change, or dangers to our cities, or challenges of health and education, first we need to understand, what’s happening? Why is it happening? What are the mechanisms? We have to do a differential diagnosis of the losses to biodiversity, and to the rising rates of species extinction. Then we have to analyze, what we can do about it, what’s the prescription, what are the possible approaches? Now, there’s one overriding truth to this sixth wave of extinctions and to the threats to biodiversity. And that is, that the threats are coming from many, many different angles, as is true in almost everything we’re studying. We’re dealing with a complex system, where there’s not a linear effect from a single cause to a single outcome, and then onto another effect. There are multiple stressors, multiple drivers of environmental change, multiple causes of species extinction or decline of abundance and genetic diversity. We need to understand the complexity of this system because no single approach is going to be sufficient to reversing the trends that are underway. Heading off this sixth great extinction that is a threat, to not only millions of other species, but to one that we also have a especially strong vested interest in, and that’s Homo sapiens, that’s us. And so we need to get into the very complex nature of this threat. You’re looking at an example of biodiversity, the incredible diversity of species and interactions in this marine environment that you’re viewing right now. And of course, what you see are multiple species of animals and plant life. Many species are microscopic, and you don’t see them. You see the interactions of the fish, corals, and we know the microscopic plankton for example in the oceans, with the non-living part of the system in front of you, the fluxes of energy, of sunlight of nutrients that are arriving in this ecosystem from a variety of sources. What is an ecosystem? It is exactly that collection, of plants and animals and microbial life, interacting with the abiotic or nonliving part of the local system, with the energy and nutrient fluxes.

The key is that this is a set of living organisms together with the non-living environment. Interacting in a system and of course, what ecologists do in studying ecosystems, is study the fluxes and dynamics of the system. How does nutrient flow take place within a food web and within the processes of metabolism. Of, oxidation, respiration, photosynthesis, and other basic processes of, the metabolism of the living organisms, within the system. How does the diversity of the, species and the diversity of the individual organisms within a species, affect the behavior of that whole ecosystem? So when we have an ecosystem, we’re also interested in another core concept. And that is the biological diversity or biodiversity of that ecosystem. And of the biodiversity across ecosystems, as ecosystems, marine, and terrestrial, interact with each other, to produce outcomes, at an even higher level, of aggregation and organization. So what is bio-diversity? Bio-diversity is the variability of life, and it is variability that occurs at all different levels of organization. We care about the variability of life within a species, each of us is different from from other people. We have different genetic codes. We carry different effects of our our environment. We know that the relationship of environment and genetics, is extremely complicated. We found out that it’s even more complicated than we thought, through the emerging field of epi-genetics, which tells us that the environment affects, how our genes code or don’t code, in ways that actually can transmit across generations. Even not in the DNA itself, but in the way that that DNA is expressed in cells from a parental generation to offspring. So, we care about the variation, within a species. We care about the interaction across species. All of the various relationships of predator and prey, and mutualism, and parasitism, and the ways that species interact, and live together and are part of, larger food chains and nutrient fluxes. And a part of the way that, the disease is pathogens, transmit within an ecosystem. And we care about the biological diversity across ecosystems. Because the interaction of ecosystems, of dry land ecosystems, or desert ecosystems, interacting with the humid ecosystems, with alpine or marine ecosystems, is also absolutely crucial for understanding, how any of those individual ecosystems functions, but also understanding the global functioning of the, the earth as a whole. What happens in the oceans or what happens in the polar regions or what happens in the rain forests, affects global dynamics of heat dissipation, of the water cycle, and through multiple processes, affects ecosystems all over the world. So there are distant relationships between changes in the pole-ward regions, for example. And what happens even in the tropics or, or places that are thousands and thousands of kilometers, distant. So, biological diversity or biodiversity, requires us to understand the variation of life, at all different levels of organization, and to understand how that variability affects the performance of ecosystems, in ways that matter.

One of the most important studies that was done, in recent decades in fact, on the functioning of ecosystems, was a major global effort which reported in the year 2005, called the Millennium Ecosystem Assessment[1]. It took a global view of the major ecosystems in the world, and tried to give a conceptual framing, of how they’re functioning, how they’re interacting and what they mean for humanity. And one of the important schematic ideas that came out of the millennium ecosystem assessment is, this chart that you’re looking at right now.

The idea of this chart is to define, how ecosystems affect human well-being. That’s not the only thing we care about ecosystems, but it’s a pretty important part. And you see on the left, various categories of ecosystem services, so-called. Ecosystem services are the benefits, that ecosystems give to humanity, and to other species, I would like to add. And those benefits come in a variety of forms. Partly, ecosystems directly provide for human needs. Provisioning services, growing food, providing fresh water. providing, wood and fiber for building structures, for our clothing. Providing biomass for our fuels. So, provisioning is one direct and obvious category. A bit less, direct, but absolutely profound, is the idea of regulatory ecosystem services. Ecosystems control basic climate patterns, disease patterns cycling of crucial nutrients, in ways that are of fundamental importance to humanity. Even if they’re not directly the provisions of things, that we eat or directly consume. So for example, ecosystems in their functioning, have huge effects on climate regulation. If, the pole-ward Nordic and Arctic ecosystems are heavily changed by climate warming, then we’re also going to get powerful feedbacks that could be of tremendous adverse consequence. For example, the melting of the great ice sheets. Or the decline of ice covering the seas, changing the reflectance of the planet and providing a massive feedback, amplifying climate change, coming from greenhouse gasses. Or, the melting of ice in the Tundra, releasing massive amounts potentially, of methane or carbon dioxide, in a feedback mechanism. So, ecosystems provide regulatory services, either helping to sustain a climate in a safe zone, or if these ecosystems get perturbed, amplifying adverse changes that are coming from other factors, such as greenhouse gas concentrations. Flood regulation is the second kind of ecosystem service. Coastal areas are often protected by the mangrove swamps just off the coast or by other topographical features of ecosystems, and if those get perturbed, if those are lost by human-induced changes, that can lead to great dangers. The coastal areas around New Orleans, for example, were degraded by the ways that human activity led to changes of the dynamics of the Mississippi River, as it flows into the Gulf of Mexico. And the loss of those coastal barriers meant, that when Hurricane Katrina slammed the Gulf of Mexico, this added tremendous force and damage, to New Orleans and to the rest of the coastline. And so, the loss of coastal regulatory protection because of human activity, clearing mangrove swamps or changing river flow dynamics, had a hugely consequential and adverse effect for humanity. Ecosystems regulate disease and pests, and when ecosystems are degraded, pests or invasive species,that is species that have been brought in by accident or even inadvertently, from outside a particular place and maybe don’t have natural predators within that new environment, can spread, can take over, can be essentially like wild weeds or spreading parasites, with devastating consequences to food production, for example, or to human health. The ecosystems for instance, the wetlands which are a major part of the water cycle help to provide fresh water help to replenish ground water. Vital for household use or for crop production. When ecosystems are deranged, we can lose water services needed to grow food and needed for human health. Ecosystems have a third category called supportive ecosystem services you see here. Nutrient cycling or the way that soils are formed, through the interaction of biotic and abiotic processes. And soil formation then, is a crucial underpinning of course, of our agricultural productivity. And finally, the millennium ecosystem assessment identified cultural features, which are our values, our aesthetics. One of the, greatest scientists, of our age, E.O. Wilson, the great biologist at Harvard University, one of the leaders in understanding biodiversity and one of the leaders in understanding human nature, in, in our world, has given the idea that, humanity has a deeply ingrained love of bio-diversity. That we even inherited as part of our, our, our mental baggage during human evolution. A trait that he calls biofelia or love of of a diverse of a biology and the, the bioda, and our biodiversity. And Professor Wilson has given extensive compelling evidence from the range of anthropological studies for example, of how humanity feels at home, in certain natural environments. And how the degradation or derangement of those natural environments can deeply upset our cultures, our mental well being our sense of aesthetics, our overall quality of life. Well, those ecosystem services, translate into many dimensions of human well-being, our physical security, the materials that we need for life, our human, physical and mental health. Our ability to interact fruitfully in society, in other words, there are contributors to our social capital, and to the preservation of social relations and as the millennium ecosystem assessment emphasized, they contribute to our freedom, our capability to accomplish our life’s tasks. So, ecosystem services are central, they are a threat because they are such core, dimensions to our human well being, we now have to turn to the question of, how biodiversity contributes to the functioning of ecosystems, and what happens when biodiversity is put at great threat, by human activity. That’s our next subject

[1] http://www.millenniumassessment.org/en/index.html