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Land–Sea Ecological Rifts

A Metabolic Analysis of Nutrient Loading

Nutrient pollution caused by Surface runoff of soil and fertilizer during a rain storm (1999)

Unprotected farm fields yield topsoil as well as farm fertilizers and other potential pollutants when heavy rains occur. Photographer: Lynn Betts, U.S. Department of Agriculture, Natural Resources Conservation Service.

Brett Clark is the associate editor of MR and an associate professor of sociology at the University of Utah. Stefano B. Longo is an associate professor of sociology at North Carolina State University. They are the authors, with Rebecca Clausen, of The Tragedy of the Commodity: Oceans, Fisheries, and Aquaculture (Rutgers University Press, 2015).

Covering approximately 70 percent of the Earth’s surface, the World Ocean is “the largest ecosystem.”1 Today all areas of the ocean are affected by multiple anthropogenic effects—such as overfishing, pollution, and emission of greenhouse gases, causing warming seas as well as ocean acidification—and over 40 percent of the ocean is strongly affected by human actions. Furthermore, the magnitude of these impacts and the speed of the changes are far greater than previously understood.2 Biologist Judith S. Weis explains that “the most widespread and serious type of [marine] pollution worldwide is eutrophication due to excess nutrients.”3 The production and use of fertilizers, sewage/waste from humans and farm animals, combustion of fossil fuels, and storm water have all contributed to dramatic increases in the quantity of nutrients in waterways and oceans. Research in 2008 indicated that there were over 400 “dead zones,” areas of low oxygen, mostly near the mouths of rivers.4 Nutrient overloading thus presents a major challenge to maintaining healthy aquatic ecosystems.

Nutrients are a basic source of nourishment that all organisms need to survive. Plants require at least eighteen elements to grow normally; of these, nitrogen, phosphorus, and potassium are called macronutrients, because they are needed in larger quantities. While all essential nutrients exist in the biosphere, these three are the ones most commonly known to be deficient in commercial agricultural production systems. Beginning in the early twentieth century with the Haber-Bosch process, atmospheric nitrogen was converted into ammonia to create synthetic nitrogen fertilizer. The fixation of nitrogen, an energy-intensive process, made the nutrient far more widely available for use in agriculture. This in turn dramatically changed production systems, which no longer depended on legumes and manures to biologically supply nitrogen for other crops such as wheat, corn, and most vegetables.

In the modern era, particularly since the Second World War, the increased production and use of fertilizers served to greatly expand food production and availability. Major macronutrients are routinely applied to soils in order to maintain and increase the growth of plant life on farms, as well as private and public landscapes such as golf courses, nurseries, parks, and residences. They are used to produce fruits, vegetables, and fibers for human and non-human consumption, expand areas of recreation, and beautify communities. However, like many aspects of modern production, given the larger social dynamics and determinants that shape socioecological relationships, these technological and economic developments have generated serious negative—often unforeseen—consequences. The wide expansion and increasing rates of nitrogen and phosphorus application have caused severe damage to aquatic systems in particular. Rivers, streams, lakes, bays (estuaries), and ocean systems have been inundated with nutrient runoff, which has had far-reaching effects.

Here we examine the socioecological relationships and processes associated with the transfer of nutrients from terrestrial to marine systems. We employ a metabolic analysis to highlight the interchange of matter and energy within and between socioecological systems. In particular, we show how capitalist agrifood production contributes to distinct environmental problems, creating a metabolic rift in the soil nutrient cycle. We emphasize how the failure to mend nutrient cycles in agrifood systems has led to approaches that produce additional ruptures, such as those associated with nutrient overloading in marine systems. This analysis reveals the ways that the social relations of capitalist agriculture tend to produce interconnected ecological problems, such as those in terrestrial and aquatic systems. Further, we contend that these processes undermine the basic conditions of life on a wide-ranging scale. It is important to recognize that nutrient pollution of groundwater as well as surface waters has been a major concern since the rise of modern capitalist agriculture and the development of the global food regime.5 The failure to address the metabolic rupture in the soil nutrient cycle and the contradictions of capital are central to contemporary land-sea ecological rifts.

Marx’s Materialism and the Metabolic Rift

Karl Marx’s materialist conception of history was undergirded by his materialist conception of nature. In his studies, he merged social philosophy, political economy, and physical science. This approach allowed Marx to conduct a scientific investigation of history and to analyze the socioecological processes fundamental to life in a manner that transcended idealism, spiritualism, and teleology. In his commitment to “the earthly family,” Marx developed a sophisticated metabolic analysis.6 Drawing upon the natural scientists of his day, he noted that there is a “universal metabolism of nature,” which consists of specific cycles and processes within the broader biophysical world that support life. All human beings and societies exist within the earthly metabolism, depend on it, and interact with it. Through their productive lives and activities, he explained, humans create a social metabolism between themselves and the rest of nature, which requires the interchange of matter and energy.7

The emergence and ongoing development of capitalism has involved a dialectical process of expropriation and exploitation, which gave rise to a distinct social metabolic order. Colonialism and the enclosure movement resulted in the expropriation of common property and resources, instituted new conditions of production, and imposed alienated human relations with broader nature.8 As a system predicated on the constant pursuit of endless accumulation, capital progressively impresses its logic on the world, including basic elements of life, such as food production and consumption. Under this system, land and labor are primarily directed toward profit production, rather than meeting human needs.9

Drawing on detailed studies by agricultural chemists and agronomists of his era, Marx developed a rich metabolic assessment of capitalist agriculture, recognizing that soil fertility was influenced by the historical development of socioecological relations. Following Justus von Liebig, he noted that soil required specific levels of nutrients to retain its potential to produce good yields of crops. These crops absorb nutrients as they grow. To maintain the fertility of the soil, the nutrients must be returned to the land—Liebig’s “law of compensation.”10 Marx explained that the enclosure movement, the division between town and country that emerged with the social dynamics associated with new property rights, the drive to maximize production, and the application of industrial agricultural techniques reorganized the social metabolism, particularly in relation to the soil nutrient cycle. For example, food and fiber were increasingly shipped to distant markets in cities. The nutrients within these products frequently ended up as waste, rather than being recycled back to the land. Marx pointed out that this “disturbs the metabolic interaction between man and the earth,” causing a rift in the nutrient cycle that disrupts “the operation of the eternal natural condition for the lasting fertility of the soil.”11

In the third volume of Capital, Marx discussed how capitalist agricultural production generated a vast amount of waste associated with food and fiber consumption: “We have both the excrement produced by man’s natural metabolism and the form in which useful articles survive after use has been made of them…. The natural human waste products, remains of clothing in the form of rags, etc. are the refuse of consumption. The latter are of the greatest importance for agriculture. But there is a colossal wastage in the capitalist economy in proportion to their actual use.” He connected the metabolic rift in the soil nutrient cycle to the land and sea, pointing out that “in London, for example, they can do nothing better with the excrement produced by 4½ million people than pollute the Thames with it, at monstrous expense.”12 Also taking note of the failure to recycle soil nutrients, Frederick Engels remarked that “in London alone a greater quantity of manure than is produced by the whole kingdom of Saxony is poured away every day into the sea with an expenditure of enormous sums.”13 In Paris, as in other European cities, the sewage system at the time carried the nutrients in human refuse directly to the river.14

The metabolic rift in the soil nutrient cycle resulted in the impoverishment of rural lands and the accumulation of pollution in cities and bodies of water. In working-class neighborhoods and districts in British cities, mounting excrement and stagnant cesspools were common. These conditions contributed to the debates regarding the “Sewage Question,” on how to address ecological problems and urban sanitation concerns, including improving health and addressing potential disease epidemics.15 At the same time, there was much attention given to the need to replenish the fields with these nutrients. For example, in Les Misérables, Victor Hugo condemned the flushing of human waste into rivers, emphasizing that these nutrients were instrumental to sustaining life in general. He wrote: “They [i.e., manures] are the meadow in flower, the green grass, wild thyme, thyme and sage, they are game, they are cattle, they are the satisfied bellows of great oxen in the evening, they are perfumed hay, they are golden wheat, they are the bread on your table, they are the warm blood in veins, they are health, they are joy, they are life.”16

In Familiar Letters, Liebig underscored the connections and challenges associated with effectively recycling these necessary nutrients:

In the large towns of England the produce of English and foreign agriculture is largely consumed; elements of the soil indispensable to plants do not return to the fields,—contrivances resulting from the manners and customs of the English people, and peculiar to them, render it difficult, perhaps impossible, to collect the enormous quantity of phosphates [and nitrogen as well as other nutrients] which are daily, as solid and liquid excrements, carried into the river.17

Elaborate engineering proposals were devised to collect, treat, and transport urban wastes. Many of these plans included establishing a system that would recover nutrients and transfer this organic fertilizer back to the countryside. Nevertheless, major obstacles included the physical organization of social life associated with the separation of town and country, and the unprofitability of these operations. It was determined that it was much cheaper and faster to dispose of the “sewage into the sea,” whereby, it was also suggested, nutrients “would still be recycled, only through commercial fisheries rather than through agriculture.”18 Regardless of whether excrement was left to be amassed in cesspools or flushed to rivers and the sea, it resulted in the squandering of the earth’s wealth and created a metabolic rift.

In 1858, Punch published a satirical poem, “Mechi the Mourner,” lamenting the impoverishment of the soil and the loss of these nutrients. Though written from the vantage point of John Joseph Mechi, a wealthy British investor and farmer interested in agricultural improvements (including returning manure to the land), the poem nevertheless captured many of the concerns of the day:

The musing Mechi stood upon a turbid river’s bank;
A fat soil might that stream have made, but was not fit to drink:
The willows sighed in concert with the melancholy swain,
Whilst thus, impressed with chemic lore, he sang a mournful strain.

The phosphates they are going, they are going to the sea,
Oh, if I had them on my land, how happy I should be!
Those wasteful waves are bearing them to Ocean’s barren breast,
Those phosphates, my poor acres that so richly might have drest.

Oh watery waste!—but if thou wert a watery waste alone,
I should not grieve for riches to the raging billows thrown;
I should not wildly wring my hands and beat my brow and weep,
To see all that wealth go to swell the treasures of the deep.

Ammonia, sweetest—as thou art of all things flowing there,
Thou from those waves art flying off to scent the thankless air;
How gladly would I see thee to a proper acid wed,
And, light one, then my fallow fields should form thy bridal bed.

Ye matters odoriferous, all born of Mother Earth,
Alas! ye never will return to her who gave ye birth;
A barren mother she will be, and cease at length to teem,
Because unthinking citizens have cast you on their stream.

I know we must dispose of you, and in such wise dispose,
That you shall not too forcibly affect the tender nose.
But oh! our aqueous system has not proved a water-cure,
And ah! while we had cesspools, we had you, we had manure.19

As nutrients were being washed to sea, the rift in the soil nutrient cycle continued to spur attempts to find affordable means to enrich soil. For example, bones from European battlefields and the Sicilian catacombs were collected, ground up, and dispersed across agricultural land. Between 1840 and 1880, millions of tons of guano and nitrates from Peru and Chile were sold in Britain and other countries in the global North. During these decades, Peruvian guano was the most prized fertilizer, given the concentration of nutrients and its ability to enrich fields.20

Under the social metabolic order of capital, with its relentless drive to produce profits and alienated forms of mediation, the metabolic rift in the soil nutrient cycle has remained a persistent problem. The Haber-Bosch process, the Green Revolution, and the modern global agrifood system have only deepened these socioecological contradictions, amplifying the scope and scale of ecological rifts. In an attempt to weaken revolutionary movements and increase global capital accumulation, in the mid-twentieth century, the Green Revolution was promoted throughout the world as a technological fix to increase crop yields by further industrializing food production. As part of the technical package, high-yield varieties of cereal crops were developed and promoted.21 These crops required massive inputs of fertilizers and pesticides. Seed, fertilizer, and chemical companies, given their monopoly position, greatly boosted their profits. Further, Green Revolution agricultural inputs created greater opportunities for commodification, while naturally derived inputs, such as those in the form of manure or compost, could be accessed through non-market methods.22 Given the increasing concentration and specialization within the modern agrifood sector, and the progressive separation of animal and plant production within industrial agriculture, the use of and reliance on commodified commercial fertilizers characterizes contemporary agricultural developments.23

The intensification of capitalist agriculture has resulted in a dramatic increase in global fertilizer production. In 1950, less than 10 million metric tons of nitrogen fertilizer were produced worldwide. By 1990, the amount was approximately 80 million metric tons, a rate of increase that far outpaced population growth. The Food and Agriculture Organization of the United Nations expects that over 200 million metric tons will be produced in 2018.24 As a result, humans now introduce more fixed nitrogen into the Earth System than do natural sources, considerably influencing the nitrogen cycle. Environmental scientist Vaclav Smil notes that “this level of interference [in the nitrogen cycle] is unequaled in any other global biogeochemical cycle.”25 While the structure and organization of capitalist agriculture depletes soil nutrients, requiring constant fertilizer inputs, in the contemporary period, there is also an overapplication of fertilizer. It is estimated that only 18 percent of applied nitrogen fertilizer is taken up by commercial crops. The rest is absorbed in the soil (some of which may be used later by plants), makes its way into groundwater, streams, and rivers, and enters the atmosphere.26 These dynamics result in ecological rifts on land and at sea.

Ecological Rifts in Aquatic Systems from Nutrient Overloading

“Nutrient loading” refers to the quantity of nutrients that enter ecosystems during a specified period. While these nutrients typically exist within these ecosystems and are, in fact, essential for life, high concentrations of nutrients due to overloading become pollutants, radically altering dynamics and conditions in water systems. The major chemical compounds that are of concern in most water bodies are nitrates and phosphates. Generally, phosphates are a greater concern in fresh water systems and nitrates in marine systems, but both contribute significantly to ecosystem changes when they enter in substantial quantities and at a relatively fast pace.

The main sources of nutrients entering aquatic ecosystems are terrestrial activities, including runoff of fertilizers from agricultural production, urban runoff from public and domestic fertilizer uses (such as on golf courses or for home lawn maintenance), sewage (from direct discards and overflow), storm water, animal manure, and fossil fuel combustion. These nutrients promote plant growth on land and in aquatic ecosystems. They are interchanged between species and the larger ecosystems. The specific conditions vary according to the characteristics of the species, the biophysical world, and the socioecological relationships associated with the social and universal metabolisms.

At the base of aquatic food webs are primary producers, such as phytoplankton, that generate energy and organic materials, such as sugars, through photosynthetic processes. Although not technically plants, algae are photosynthetic organisms. By producing oxygen and serving as a source of food for various species, from molluscs to marine mammals, algae are central to life support systems on Earth. Like plants, algal growth is elevated with increased levels of nutrients such as nitrates and phosphates, and can enhance overall productivity within the food web.

Nutrient overloading contributes to the “overstimulation of algal growth [which] can severely degrade water quality and threaten human health and living resources.”27 The range, size, and consequences of the ecological impacts associated with nutrient overloading are quite severe. Weis writes that “nutrient enrichment due to excessive amounts of [nitrogen] is the primary cause of impaired coastal waterways worldwide.”28 Additionally, ongoing anthropogenic global environmental change generally exacerbates these conditions in aquatic ecosystems. For example, additional precipitation can increase runoff from agricultural fields, which will promote further growth of primary producers, creating several serious ecological problems and rifts.29 Thus, social activities have direct and indirect effects on the conditions and processes associated with nutrient loading in aquatic systems.

A central consequence of the nutrient overloading of aquatic ecosystems is eutrophication, causing an increased production of organic matter. Small increases in primary production in aquatic ecosystems may have little effect on the overall ecological conditions. However, when algal growth exceeds the typical historical range for an ecosystem, it reduces the levels of dissolved oxygen, which can create hypoxia (low oxygen levels) or even anoxia (absence of oxygen), elevating the mortality of aquatic organisms. The size of these algal blooms, under these conditions, surpasses the capacity of other species to feed upon the algae and incorporate nutrients and energy into the larger biotic community. As algal blooms die, they decompose, consuming available dissolved oxygen.30 When this aquatic rift is severe, the levels of oxygen in the surrounding waters decrease to concentrations that are deficient for supporting the development of healthy organisms that inhabit these ecosystems. Nutrient overloading is widespread. In an assessment of estuaries in the United States, Suzanne B. Bricker and her colleagues examined ninety-nine estuary systems and found that all exhibited some level of effects from eutrophication. They concluded that 78 percent of the estuaries had “eutrophic conditions rated ‘moderate’ to ‘high.'”31

Extreme levels of algal blooms and decomposition can produce “dead zones” within parts of large lakes and the ocean, decimating aquatic life as the conditions of the ecosystem are compromised. The rapid growth of dead zones is a very recent phenomenon. While such severe hypoxic and anoxic conditions can be associated with natural upwellings, the expansion of these dead zones around the world has become prevalent following the Second World War, coinciding with the massive escalation in the production of nitrogen fertilizer and other anthropogenic drivers of environmental change. Since that time, dead zones have been increasing exponentially. As stated, over 400 dead zones have been identified around the world.32 The expansion of these zones harms some of the most biologically productive regions within the Earth System.

One of the largest dead zones is located where the Mississippi River enters the Gulf of Mexico, just off the coasts of Louisiana and Texas. Depending on ecological conditions and levels of nutrient overloading, this dead zone varies in size. In 2017, it reached its largest dimensions, measuring over 8,700 square miles (approximately the size of New Jersey).33 The Mississippi River drains 40 percent of the landmass of the contiguous United States, which includes some of its most productive agricultural land in the Corn Belt. The agricultural ecosystems of these former prairies in the Mississippi River watershed have been greatly simplified, as the land has been devoted primarily to growing two crops—corn and soybeans. If a more complex rotation of crops were grown, less nitrogen would leave the land. But instead, a “leaky” system has been imposed, exacerbating nutrient problems. When corn does not follow “a multi-year productive legume crop such as alfalfa,” it quickly creates a deficiency in nitrogen. As a result, an abundant supply of nitrogen fertilizer is applied to corn fields. At harvest, elevated levels of nitrates are present. Fred Magdoff explains that “nitrate pollution of water is common in regions where this system is used because nitrate…is not well retained in soils—themselves negatively charged—and leaches easily into groundwater and tile drains, finding its way into ditches, streams, and rivers.”34 Following the winter snow and spring rains, the Mississippi River transports nutrient-rich waters to the Gulf.35

Evidence indicates that hypoxic conditions “began to appear around the turn of the last century and became more severe since the 1950s as the nitrate flux from the river to the Gulf of Mexico tripled.”36 At the end of the twentieth century, the U.S. Geological Survey estimated that of the approximately eleven million metric tons of nitrogen annually reaching the mouth of the Mississippi, over nine million metric tons were the result of agricultural fertilizers and farm animal manure.37 The social metabolic processes associated with the modern system of terrestrial agrifood production have transformed nutrient loading processes in marine ecosystems, which in turn have strained other aspects of the food system, particularly seafood production.

Such dynamics and conditions are becoming ever more common, despite variations in the combination of factors that contribute to dead zones. In marine waters off the coast of countries in Africa, Asia, and Latin America, nutrient overloading is also significantly influenced by industrial waste and wastewater. In the Chesapeake Bay, along with runoff—much of it from chicken manure accumulating on the numerous nearby factory farms—atmospheric contributions of fixed nitrogen from the combustion of fossil fuels are also an important factor. During the latter half of the twentieth century, hypoxic conditions in the Chesapeake Bay increased at “an accelerated rate,” with significant growth since the 1980s.38 Research examining the historical conditions in the Chesapeake challenge common, simplistic claims of typical or normal variation, indicating that “suggestions that current levels of hypoxia and anoxia are a natural feature of Chesapeake Bay are demonstrably false.”39 It is thus demonstrably clear that the growing number and size of dead zones is a modern phenomenon, linked to the social metabolic order of capital.

Nutrient overloading, especially as it relates to eutrophication dead zones, is causing an ecological rift that ruptures life cycles and weakens the conditions that promote reproduction of aquatic species. Low oxygen areas associated with dead zones decrease biodiversity. Organisms unable to move out of a dead zone region are stressed due to the oxygen poor conditions, which impede growth and development and reduce reproductive success. Dead zones have severe effects on benthic communities—bottom-dwelling marine organisms—such as crustaceans and molluscs, especially those with limited mobility. In many dead zones, mortality of benthic organisms is high, and fish that are able to move quickly leave the zone, creating an environment with little to no multicellular life.

As hypoxic zones expand in size, they limit the available habitat for organisms that need oxygen-rich waters to sustain their individual metabolism, and may increase their susceptibility to predation, particularly in early stages of development. For example, large predators such as tuna and marlin require environments with high levels of dissolved oxygen. Thus dead zones can increase exposure of these species, as their habitat is diminished, to fishing operations. In some cases, crabs have migrated to shallow, warm waters, trying to escape oxygen-depleted waters, only to be captured by humans, ecstatic to obtain this desired seafood.40

These consequences ripple throughout the food web and ecosystems, creating a series of socioecological concerns. As Robert J. Díaz and colleagues explain:

The most pronounced effect of dead zones is the disruption of energy flows in unwelcome ways away from upper trophic levels [i.e., high levels in the food chain]. In the absence of upper trophic levels (mostly mobile fauna that fled), energy that previously was used to sustain complex food webs is diverted to lower trophic levels (microbes). This energy shunt to microbes leads to reduced trophic complexity and ecosystem services that would otherwise be capable of supporting a higher biodiversity and production of valued top predators. A conservative global estimate of biomass lost to coastal dead zones annually is over 9,000,000 metric tons wet weight of organisms. This is a lot of potential food for higher trophic levels, including humans, basically eaten by microbes.41

Thus the universal metabolism of nature is greatly affected in a manner that reduces its potential to maintain a broad array of life, and tends toward simplified conditions.

Nutrient overloading also contributes to the growth of what are often called “harmful algal blooms.” Large algal blooms can become so dense that they choke life in these ecosystems by limiting exposure to light, which harms aquatic plants, such as seagrasses, that provide important nurseries or sources of food for other organisms. As mentioned above, blooms can cause hypoxia and kill fish and other aquatic life, but algae can also become lodged in gills and cause suffocation.42 Harmful algal blooms are often associated with “red tides,” so called as some appear as massive red-colored ocean currents. A number of microalgae produce small amounts of toxins that in typical conditions do not cause significant harm to ocean or terrestrial life. However, these large red tides can concentrate toxins to a level that can kill marine organisms and affect humans. Large fish kills have been associated with harmful algal blooms. Deaths of sea-birds and mammals—including manatees, sea lions, and dolphins—have all been linked to these harmful algal blooms. Humans are affected through the consumption of fish and shellfish that have been tainted with toxics produced from these blooms, or by breathing aerosol from wave activity, which can result in illness, and in some cases death.43

Like dead zones, the frequency, duration, and intensity of harmful algal blooms have increased in recent decades. Toxin-producing microalgae that were nonexistent or rare before 1950 have become common in the coastal waters of every continent except Antarctica.44 While this is in part due to the introduction of new species by humans into territories where they were previously absent (invasive species), these changes are driven in large part by growth in nutrient overloading into coastal waters, as well as climate change and other major ecosystem transformations.

All the consequences caused by nutrient overloading are exacerbated by other aspects of anthropogenic environmental change. Ecological rifts, such as those associated with overfishing, ocean acidification, and climate change, are generating major ecosystem changes that are magnifying these effects in marine environments.45 Increasing ocean temperatures associated with climate change “will promote the intensification and redistribution of…HABs [harmful algal blooms], around the world.”46 Additionally, anthropogenic activities have caused oxygen content in global marine systems to decline since the middle of the twentieth century, leading Denise Breitburg and her colleagues to argue that “ocean deoxygenation ranks among the most important changes occurring in marine ecosystems.”47 They indicate that nutrient overloading and climate change are the leading drivers of this ecosystem change.

A variety of social, physical, and biological processes associated with climate change act synergistically with eutrophication to exacerbate hypoxia, and therefore influence the number and scale of dead zones. These changes include lower solubility of oxygen in water, water column stratification, the increased sensitivity of estuaries to climate warming due to their shallowness, increased metabolic activity and rates of primary production, changes in the food web, sea level rise, and others. Given all these changes, the “oxygen-minimum zones in the open ocean have expanded several million square kilometers” since the mid-twentieth century.48 It is likely that the multiple complex effects of climate change on aquatic ecosystems enhanced the growth of dead zones over recent decades, and will further them “as climate change has made coastal areas more susceptible to hypoxia.”49 Throughout the twenty-first century, emerging precipitation patterns due to climate change are expected to increase eutrophication processes, even if the amount of nitrogen fertilizer used in agriculture is decreased, especially in the United States, India, and China.50

Further compounding concerns, eutrophication has been linked with ocean acidification, sometimes referred to as the other “CO2 problem.”51 Recent research examines the relationship between lowered dissolved oxygen and lowered pH, as the decomposition of organic matter associated with eutrophication not only consumes oxygen, but releases carbon dioxide.52 Anthropogenic eutrophication “could increase the susceptibility of coastal waters to ocean acidification.”53 The process would culminate in circumstances where organisms will be exposed to increased temperatures, lower oxygen, and lower pH (along with a variety of other factors), a deadly combination for many species, especially shell-forming benthic organisms.54

Overfishing of species that feed on algae also contributes to the degraded conditions in aquatic ecosystems. Organisms often referred to as filter feeders consume primary producers. These species—including molluscs, crustaceans, fish, and marine mammals—are often central links in the food chain, as many are eaten by larger predatory species. Marine areas like Chesapeake Bay, for instance, have seen a dramatic reduction in important filter feeders such as oysters and menhaden in recent history. As discussed, Chesapeake Bay has been dramatically affected by nutrient overloading from numerous terrestrial activities. At the same time, it has been losing significant numbers of organisms that consume algae. Together these factors have contributed to the deteriorated conditions in a bay that until 1975 “produced more seafood per acre than any body of water on Earth.”55

The anthropogenic drivers of environmental change, which are generating numerous ecological rifts in the conditions of life, are intimately linked to the social metabolic order of capital. This social metabolism pursues capital accumulation at any cost, shaping human social processes that are having broad effects on numerous terrestrial and aquatic ecosystems. In its basic operations, it has created metabolic rifts in the soil nutrient cycle, which are then increasingly producing ruptures in marine systems.

Rifts on Land and at Sea

Despite playing a major role in human history and helping regulate the Earth System, marine ecosystems receive little attention from the public. This is beginning to change with a proliferation of research focused on eutrophication, ocean acidification, plastic pollution, coral die-offs, and overfishing. Modern ecological problems in marine systems do not begin or end at sea. They are linked to specific social and historical processes, associated with the social metabolic order of capital.

Marx’s analysis made clear that capitalist development produces a particular social metabolism that progressively transgresses against the universal metabolism of nature, generating ecological rifts. He explained that “fertility is not so natural a quality as might be thought; it is closely bound up with the social relations of the time.”56 He detailed how capitalist agriculture robbed the soil of its nutrients, violating the law of compensation, inhibiting its restoration. He noted how the nutrients in human waste accumulated as pollution in cities and in waterways. In developing this analysis, he recognized the broad interconnections of socioecological systems and established a metabolic approach for considering ongoing developments of the capital system.

The transformation of nutrients that foster life into concentrations of waste and pollution has been ongoing for centuries. Capitalist agriculture has created a distinct metabolic rift, which remains ever present. Attempting to address this rift, synthetic fertilizers have been developed and the mining of nutrients, such as phosphate for fertilizer, has advanced in a constant effort to maintain and expand agricultural production. These changes created additional ecological contradictions, as the nutrient problem was extended to fresh water and marine systems. A seemingly never-ending supply of nitrogen fertilizer is made available by transforming fossil fuels and N2 in the atmosphere into fixed forms of nitrogen. Its application in fields, on lawns, and throughout cities has created new challenges associated with nutrient overloading in aquatic systems.

The scale and scope of nutrient overloading, combined with other anthropogenic environmental changes, imperil the longstanding ecological conditions that have characterized marine systems during the Holocene. Capitalism’s social metabolism is altering the energy and nutrient systems in marine ecosystems in a manner that is, for example, transforming the trophic-level (food web) productivity of these systems. Additionally, the complex synergistic interactions between nutrient overloading, climate change, overfishing, and ocean acidification indicate that the availability of higher trophic level species will likely continue to decline.57 The consequences of the social metabolism of capitalism are evident in the ecological rifts now manifesting in the ocean. Eutrophication and associated dead zones and harmful algal blooms are undermining the conditions that supported the reproduction of marine life. Though seemingly separate from terrestrial systems, marine ecosystems are intimately bound to the former, and provide essential life support to the Earth System as a whole. Thus, in biophysical and social terms, these land-sea processes should be analyzed jointly.58

When examining the ecosystem transformations in the modern era, we must identify the fundamental role that social organization plays in structuring human activity. For example, a system of agrifood production shaped by capitalist development is primarily geared toward accumulation of capital, which has a broad array of socioecological outcomes. It has been well understood for centuries that the metabolic rift in the soil nutrient cycle is endemic to capitalist agrifood production. Yet efforts to confront the problem have only exacerbated ecological crises on land and at sea. Further, numerous other ecological rifts have emerged, such as in the carbon cycle, leading to climate change and ocean acidification as well as less healthy soil as organic matter is converted to carbon dioxide—all of which interact to create additional, and often unforeseen, consequences.

A major contradiction within the social metabolic order of capital, as discussed here, is the way that life-supporting nutrients are principally employed to serve the interests of capital and its representatives, rather than broader human needs. Thus, with the continuing degradation of numerous ecosystems and the growing ecological crisis, it is becoming ever clearer that a reorganization of social life is necessary to address these dangerous, even existential, challenges. As István Mészáros explained, “capitalist structures and mechanisms of social control are being seriously interfered with by pressures arising from elementary imperatives of mere survival.” This is a social system where the “function of social control [has] been alienated from the social body and transferred into capital.”59 An alternative form and structure of social organization and social control is required, which prioritizes human needs, well-being, and dignity while operating sustainably within the everlasting conditions of the universal metabolism of nature. Only then can we truly address the challenges of our ecological crisis.


  1. Alex D. Rogers and Daniel D’a Laffoley, International Earth System Expert Workshop on Ocean Stresses and Impacts (Summary Report) (Oxford: International Programme on the State of the Ocean, 2011), 5.
  2. Benjamin S. Halpern et al., “A Global Map of Human Impact on Marine Ecosystems,” Science 319 (2008): 948–52; Rogers and Laffoley, International Earth System Expert Workshop.
  3. Judith S. Weis, Marine Pollution: What Everyone Needs to Know (Oxford: Oxford University Press, 2015), xvi.
  4. See Robert J. Díaz and Rutger Rosenberg, “Spreading Dead Zones and Consequences for Marine Ecosystems,” Science 321 (2008): 926–29.
  5. F. M. L. Thompson, “The Second Agricultural Revolution, 1815–1880,” Economic History Review 21, no. 1 (1968): 62–77; John Bellamy Foster, Marx’s Ecology (New York: Monthly Review Press, 2000); John Bellamy Foster, “Marx as a Food Theorist,” Monthly Review 68, no. 7 (December 2016): 1–22; Brett Clark and John Bellamy Foster, “Ecological Imperialism and the Global Metabolic Rift,” International Journal of Comparative Sociology 50, no. 3–4 (2009): 311–34.
  6. Karl Marx, “Theses on Feuerbach,” The Marx-Engels Reader (New York: Norton, 1978), 144; Foster, Marx’s Ecology.
  7. Karl Marx and Frederick Engels, Collected Works, vol. 30 (New York: International Publishers, 1975), 54–66; Karl Marx, Economic and Philosophic Manuscripts of 1844 (New York: International Publishers, 1964), 109; John Bellamy Foster, “Marx and the Rift in the Universal Metabolism of Nature,” Monthly Review 65, no. 7 (2013): 1–19; Stefano B. Longo, Rebecca Clausen, and Brett Clark, The Tragedy of the Commodity (New Brunswick: Rutgers University Press, 2015).
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  46. Christopher J. Gobler et al., “Ocean Warming Since 1982 Has Expanded the Niche of Toxic Algal Blooms in the North Atlantic and North Pacific Oceans,” Proceedings of the National Academy of Sciences of the United States of America 114 (2017): 4975–80.
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  50. Sinha, Michalak, and Balaji, “Eutrophication Will Increase During the 21st Century.”
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