Nutrient pollution is existential---it collapses oceans and outweighs climate change---US runoff reduction buys time to confront extinction

One notable aspect of the Planetary Boundaries Project is that—at least for the moment—climate change is not the planetary boundary that we are at most risk of having already crossed. Instead, there are two other boundaries currently far more worrisome than climate change itself— biosphere integrity, or the global loss of biodiversity, and biogeochemical flows, or nutrient pollution. U.S. ocean law can both feasibly and profitably focus on these two issues—couched in terms of food security and public health, respectively—to reduce existing stressors to its marine ecosystems while simultaneously improving the well-being of its residents.

1. Seize the moment regarding marine food security.

Marine fish, shellfish, and algae are a significant component of global food security. According to the United Nations Food & Agriculture Organization (FAO), “Global food fish consumption increased at an average annual rate of 3.1 percent from 1961 to 2017, a rate almost twice that of annual world population growth (1.6 percent) for the same period, and higher than that of all other animal protein foods (meat, dairy, milk, etc.), which increased by 2.1 percent per year.”406 However, wild-caught marine fisheries leveled off in the 1990s,407 and less than two-thirds of fish stocks are being fished sustainably.408 In contrast, marine aquaculture plays an increasing role in the world’s food security, producing in 2018 30.8 million metric tons of fish and shellfish and over 32 million metric tons of aquatic algae, primarily kelp.409

Marine food security and marine biodiversity are interlinked. Overfishing and the related phenomenon of fishing down the food web threaten both ecosystem resilience and marine biodiversity.410 Indeed, there is considerable evidence that industrialized commercial global overfishing produced some of the first pervasive stresses to marine ecosystems, creating legacy problems that still stymie effective marine management.411 At the same time, marine biodiversity loss is a food security issue. As the discussion in Part II suggests, the changes occurring in the ocean and their impacts on marine food webs and ecosystems have direct consequences for human food security. From a global perspective, the IPCC concluded in 2019 that, already, “[c]hanges in the ocean have impacted marine ecosystems and ecosystem services with regionally diverse outcomes, challenging their governance (high confidence).”412 While, at the moment, these changes are both enhancing and undermining food security, depending on the exact community involved, the impacts on ecosystem services already “have negative consequences for health and well-being (medium confidence), and for Indigenous peoples and local communities dependent on fisheries (high confidence).”413

Future changes to the ocean, including species migration and food web simplification, pose greater threats to global food security, fisheries governance, and even national security—including for the United States.414 Moreover, the decreasing supplies of wild seafood are also likely to be less safe because of elevated concentrations of mercury and other toxics in marine plants and animals and increasing contamination, especially of shellfish, by both Vibrio pathogens (the family of bacteria that include cholera and the flesh-eating Vibrio vulnificus) and harmful algal blooms like red tides.415 “These risks are projected to be particularly large for human communities with high consumption of seafood, including coastal Indigenous communities (medium confidence), and for economic sectors such as fisheries, aquaculture, and tourism (high confidence).”416

Overfishing has long been considered the primary threat to marine biodiversity and ecosystem function,417 and, as discussed in Part II, even the United States continues to struggle with managing fish stocks sustainably. However, range shifts primarily induced by climate change are challenging that belief, and they are already complicating fisheries regulation. A 2018 study of 686 marine species indicated that species along the Pacific Coast of North America could shift ranges as much as 1500 kilometers (more than 930 miles), while those on the Atlantic Coast could shift more than 600 kilometers (more than 370 miles).418 As the researchers noted, “In the United States, fisheries are managed regionally, including species that are managed by individual states and federally managed fisheries that are governed by regional councils with representatives from neighboring states,”419 and their projected range shifts are more than sufficient to move commercially important fish stocks across regulatory jurisdictions within the United States, from the United States to Canada, from Mexico to the United States, and, on the Pacific Coast, from Canada to the United States (Alaska).420 Other management challenges include “shifts in fishing locations, conflict over regional allocation of fisheries quota, displaced fishermen, and changes in stock boundaries.”421

Given the future increasing risks both to and from U.S. fisheries, a renewed focus on marine food security from a systems perspective, with the goal of greatly reducing the stresses that marine food production imposes on marine ecosystems, is an appropriate starting point for incorporating a systems valuation of the ocean in U.S. ocean law. Indeed, this timing and new focus are even more appropriate given the likely shifts in how the United States will secure its marine food supply in the near future. Even before climate change complicates the subject, marine fisheries are at their limits globally,422 and, as noted, marine aquaculture is quickly making up the marine food security gap.423 While the United States is currently a relatively minor marine aquaculture producer on the global scale,424 the aquaculture industry is poised to expand rapidly over the next few decades, especially in federal waters.425

Like overfishing, many types of marine aquaculture can stress marine ecosystems.426 However, neither all aquaculture operations nor all aquacultured species have the same impacts to ecosystems, and some forms of marine aquaculture can actually improve marine ecosystem function and reduce other stressors. For instance, marine aquaculture can enhance the stocks of imperiled or previously imperiled species.427 More expansively, shellfish and kelp aquaculture are often two of the least polluting forms of human food production, marine or terrestrial.428 As the FAO has emphasized, mollusks like clams and oysters are filter feeders, meaning that aquacultured mollusks do not need to be fed.429 Similarly, seaweeds grow through photosynthesis.430 As a result, “[m]arine bivalves, filter-feeding organisms that extract organic matter from water for growth, and seaweeds, which grow by photosynthesis by absorbing dissolved nutrients, are sometimes described as extractive species.”431 Thus, not only does aquaculture of these species impose little pollution burden on the marine environment, but these species can actually reduce nutrient pollution in marine environments while providing tasty human food, regardless of whether the pollution comes from fed finfish aquaculture432 or other sources, such as fertilizer runoff from upstream agriculture.433 In addition, shellfish aquaculture and kelp aquaculture can improve water quality,434 and kelp aquaculture is being promoted for its carbon sequestration amenities.435

There are also benefits to growing kelp and shellfish together. Seaweed aquaculture can help buffer areas of the ocean from the effects of ocean acidification.436 This buffering phenomenon has already been observed in connection with natural seagrass beds and kelp forests,437 but recent studies in Japan, Korea, and China indicate that kelp farms produce the same effects—namely, a higher pH level (less acidic water) for the waters within the seaweed farm compared to adjacent waters away from the farm.438 “These findings demonstrate that the net primary production of seaweed farms acts as an important sink of CO2,” and “co-culture of bivalves and seaweed aquaculture in multitrophic aquaculture systems can protect the bivalves from ocean acidification, while also mitigating the impacts associated to nutrient release from the bivalves.”439

We are at a moment in the United States when fisheries managers know that they will need to adapt to climate change impacts. Various state and federal agencies know that they need to decide more comprehensively how to regulate marine aquaculture. Federal agencies are already testing the limits of their jurisdiction to regulate this expanding industry through their fragmented regulatory authorities,440 and Congress has considered a new federal statute to govern it,441 potentially creating another siloed compartment of federal ocean regulation. No approach offered thus far from within the United States’ fragmented governance has considered marine aquaculture as simultaneously a food security, fisheries job transition, public health, marine biodiversity, climate adaptation, and climate resilience enterprise. The state and federal governments’ inabilities to adopt a systems view of the ocean is hampering the very urgent regulatory need to distinguish among the various types of marine biodiversity and to promote the enterprises and species that accomplish multiple marine management goals442—including, possibly, helping to ensure that the plant does not cross its biodiversity, nutrient pollution, or ocean acidification boundaries. A complex systems approach to ocean law in this area should emphasize increased security of the country’s marine food supply, in terms of both quantity443 and food safety,444 while minimizing existing and potential new stressors to the marine environment, such as by reducing wild fishing limits and quotas and favoring aquaculture operations that grow native species of kelp, shellfish, and finfish that do not require feeding or antibiotic regimes.

2. Dealing with nutrient pollution.

Nutrient pollution is a known problem in U.S. environmental law and policy—including, explicitly, a marine problem. Water flowing over and from farms, in the forms of both irrigation return flows and runoff from rain or snowmelt, carries excess fertilizer to the ocean.445 Nutrients also reach the water through atmospheric deposition, such as from the burning of fossil fuels.446 Once there, nutrients induce large blooms of marine plants—phytoplankton and algae. Algae are marine plants, many of which are beneficial to marine food webs.447 Marine algae include both the large marine seaweeds and kelp and the nearly microscopic algal forms of marine phytoplankton.448 The small phytoplankton forms of algae can create an “algal bloom,” which “is a rapid increase in the population of algae in an aquatic system. . . . Typically only one or a few phytoplankton species are involved and some blooms may be recognized by discoloration of the water resulting from the high density of pigmented cells.”449 This discoloration can give algal blooms common names, such as “red tides.”450 Increasing nutrient concentrations are the usual cause of algal blooms451 because, like terrestrial plants, marine phytoplankton respond to nitrogen and phosphorus compounds as fertilizers.

Algal blooms impact both marine ecosystems and human health. At the ecosystem level, as the blooms die off, their decomposition consumes all the oxygen in the water column, leading to hypoxic conditions that make large areas of the ocean uninhabitable by marine animals.452 In the United States, the largest of these so-called “dead zones” occurs seasonally in the northern Gulf of Mexico at the mouth of the Mississippi River and can reach the size of Massachusetts or New Jersey—over 7000 square miles.453

Dead zones are now common throughout the world’s coastal regions.454 The number of dead zones in the world’s seas—including around the United States—has doubled every decade since 1960 as a result of increasing marine pollution, and a 2008 study identified more than 400 dead zones throughout the world.455 Perhaps most disturbingly, dead zones are missing biomass compared to what would be expected, suggesting that the oxygen deprivation that algal blooms cause can have long-term effects on a region’s biodiversity and productivity.456

Nutrient pollution is also a recognized public health issue, with both human and financial costs. In the ocean, the most direct health cost of the failure to adequately control nutrient pollution is harmful algal blooms, or HABs. A HAB is a bloom of a species of phytoplankton that produces toxic or harmful effects.457 With respect to human health, the most important HABs are those that “produce toxins that can kill fish, mammals and birds, and may cause human illness or even death in extreme cases.”458 For example, sea lions in California have died when blooms of certain marine algae produce domoic acid.459 Public health officials have identified several HAB-related human illnesses,460 caused when humans eat contaminated seafood (generally shellfish) and are poisoned by the accumulated toxins.461 Climate change is acting in concert with excess nutrient pollution to make harmful algal blooms worse.462

The Planetary Boundaries Project recognized nutrient pollution as a global problem that is pushing the Earth dangerously close to a transformative threshold. However, it is also a U.S. problem. As the U.S. EPA states, “Harmful algal blooms are a major environmental problem in all 50 states. Red tides, blue-green algae, and cyanobacteria are examples of harmful algal blooms that can have severe impacts on human health, aquatic ecosystems, and the economy.”463 Harmful algal blooms are neither new nor completely unnatural—hundreds of years ago, early west coast settlers were occasional poisoned by toxins in the seafood they consumed—but their economic significance to the United States has increased.464 Moreover, while there are important variations among the different types of HABs that recur in the United States, overall “HABs are affecting more regions with more toxins and impacts than was the case decades ago.”465 Some of this increase results from better monitoring, but nutrient pollution remains an important factor in the increasing number and expanding locations of HAB events,466 particularly “in certain estuaries, embayments, and sounds . . . [where t]he emerging cyanobacterial problem in the freshwater-to-marine continuum is one example of nutrient pollution-driven enhancement of HAB incidence.”467 Notably, 7% of the United States’ continental coastal waters have experienced overgrowth of algae as a result of nutrient pollution.468

As the EPA has noted, aquatic nutrient pollution in the United States comes from a number of sources, including “fertilizer, animal manure, sewage treatment plant discharge, detergents, stormwater runoff, cars and power plants, failing septic tanks and pet waste.”469 The Federal Water Pollution Control Act, better known from its 1977 amendments as the Clean Water Act,470 extends its water quality protections to the ocean,471 and nutrients are pollutants that the act regulates.472 Some of the sources of nutrient pollution that the EPA lists are already subject to Clean Water Act regulation, especially sewage treatment plants473 and concentrated animal feeding operations.474 Many, however, are not. The Clean Air Act is the primary authority for regulating car and power plant emissions. The EPA, however, has long worked to reduce nitrogen emissions from both sources for air quality reasons, and the migration (however slow) away from fossil fuels toward renewable energy sources will further reduce these sources’ contributions to nutrient pollution of the ocean.475 Instead, a systems approach to the ocean should inspire a redoubling of efforts under the Clean Water Act to bring agricultural point and nonpoint source nutrient pollution under control.

Agriculture’s exceptionalism is a longstanding feature of Clean Water Act regulation, reflecting a mythologized icon of the small family farm.476 The Act accordingly exempts “agricultural stormwater discharges and return flows from irrigated aquaculture” from being considered point sources.477 Routine farming activities and the construction of farm stock ponds, irrigation ditches, and farm roads are likewise exempt from the Section 404 “dredge and fill” permit program,478 and water features converted to dry farmland before December 23, 1985, are often exempt from regulation as “prior converted cropland.”479

Nevertheless, several new realities suggest that the Clean Water Act can and should play a larger role in how farms are run, especially to reduce the nutrient pollution that reaches the ocean. First, the reality of farming in the United States has changed. As the U.S. Department of Agriculture recognizes, “[a]gricultural production in the 21st century . . . is concentrated on a smaller number of large, specialized farms in rural areas where less than a fourth of the U.S. population lives.”480 Industrialized agriculture does not warrant the same kinds of exemptions from water quality regulation that small family farms do. Second, both the EPA and state governments have increasingly recognized the importance of agricultural nutrient pollution, and many states have already enacted laws and regulatory programs to address this problem.481 Third, the EPA has used the Clean Water Act’s Total Maximum Daily Load (TMDL) authorities482 to create new tools to connect agricultural water pollution— including nutrient pollution—to larger water quality goals. The first of these, directly related to ocean water quality, is the Chesapeake Bay regional TMDL that the EPA established in late December 2010.483 This TMDL established regional limits on nitrogen, phosphorus, and sediment pollution, allocated among 92 segments of the tidally influenced portion of the Chesapeake Bay watershed and affected water quality programs in Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and the District of Columbia.484 The second is the EPA’s renewed interest in water quality trading. The EPA first released its water quality trading policy in 2003, emphasizing its use for nutrient and sediment pollution.485 However, in 2019 and 2020, it released a number of new documents to encourage water quality trading486—including new partnerships with the U.S. Department of Agriculture specifically aimed at nutrient pollution.487 In addition, a map published by the EPA reveals increased use of water quality trading in the United States, especially in Minnesota and the Chesapeake Bay states.488

Thus, despite agriculture’s exceptionalism under the Clean Water Act, it is possible to use the Act’s existing tools to reduce nutrient pollution in the United States, to the benefit of both our own coastal environments and global Planetary Boundaries. Indeed, the National Academy of Sciences has already recommended a TMDL or TMDL-like mechanism to address the Gulf of Mexico dead zone.489 Framing the nutrient pollution issue in terms of enhancing public health,490 quality of life,491 and marine food security492 should aid the political palatability of increased nutrient protection measures. Overall, reducing the nutrient stressors to the ocean will give this complex system more resilience to cope with other stressors, such as climate change and ocean acidification, preserving the many values it provides human beings.

VI. CONCLUSION

Americans must adapt to a changing ocean. While this task would be much easier if there were an effective global regime to stabilize or reduce the anthropogenic greenhouse gas concentrations in the atmosphere, no such regime is yet in place. Nevertheless, the United States, and other coastal governments, should resist the temptation to view climate change mitigation as the only regulatory pathway worth pursuing in terms of influencing, and reducing the magnitude of, the changes occurring in the complex system of systems that is the world ocean.

There is no doubt that a systems view of the ocean should humble human attempts at comprehensive governance and management. The emergent properties of complex systems, the potential for ecosystems to cross critical thresholds and transform, and the panarchy model of multiscalar influence thoroughly undermine any human aspiration to even grossly maintain marine ecosystems in the states we prefer while simultaneously harvesting all the ecosystem goods that we desire. In short, we are not fully in charge. As the IPCC emphasizes, climate change’s impacts to the ocean challenges the capacity of all governance systems to respond, both regarding human health and well-being and in terms of communities’ abilities to adapt effectively.493 Moreover, it laments, “[g]overnance arrangements (e.g., marine protected areas, spatial plans and water management systems) are, in many contexts, too fragmented across administrative boundaries and sectors to provide integrated responses to the increasing and cascading risks from climate-related changes in the ocean.”494

However, it is equally clear that human actions and activities matter. That fact is the very point of the Anthropocene. Reconciling those realities reveals the panarchy governance paradox that a complex systems view of the ocean underscores: law can accomplish more to aid ecosystems and social-ecological systems in adapting to a changing ocean by categorizing humans as stressors rather than managers and by prioritizing the reduction of the stressing activities.

It is easy to criticize the starting points proposed in this Article as incomplete—they are. Nevertheless, they represent a realistic beginning response to the profound governance challenges that a changing ocean poses. Valuing the ocean as a complex system will not, in itself, fix the United States’ ocean governance fragmentation problem. However, a systems perspective does provide insight into how the United States’ fragmented ocean laws can still rationally and meaningfully prioritize the increased resilience of the ocean’s many social-ecological systems, possibly helping the entire world avoid crossing a transformative threshold at the same time. From this perspective, nutrient pollution and marine food security emerge as the first two logical priorities. States and the EPA can address nutrient pollution far more aggressively than they currently do pursuant to their existing Clean Water Act authorities. Given changing industry realities, the expanding marine aquaculture industry and commercial fishing industry in the United States both require additional attention. A systems approach underscores how both these industries are linked to Americans’ overall food security, allowing for a more comprehensive marine food policy (a “Blue Food” policy495) that simultaneously minimizes the impact of food security on changing marine ecosystems.

Our future depends on how the ocean responds as a system to the multiple stresses humans are inflicting upon it. To emphasize two components of the trillions of dollars of ecosystem services at stake, the ocean’s continuing ability to dampen the impacts of anthropogenic greenhouse gas emissions has been keeping the planet habitable, while its smallest communities of phytoplankton continue to provide half the oxygen we breathe. Complex systems theory and resilience thinking teach that reducing anthropogenic stressors on the ocean can lower the chances that either local ecosystems or the entire planet irreversibly cross thresholds into far less productive and hospitable states of being. The Planetary Boundaries Project, in turn, identifies key stressors to focus on— and they are not all climate change.

Revaluing the ocean as a complex adaptive system thus paradoxically illuminates paths to effective marine governance action in the face of nearly overwhelming and unpredictable future change. Reducing marine nutrient pollution and rethinking the ocean’s role in food security in the U.S. will not eliminate all the Anthropocene’s challenges. But they might—just might—help buy humanity some additional time to figure out more comprehensive solutions while simultaneously enhancing the adaptive capacities of our own ocean places and the Americans who depend upon them.