This Tide Bite is a bit different from most, in focusing less on a student or researcher’s work at FHL and more on how the ‘convening power’ of FHL can lead to wonderful brainstorming opportunities. We see this with small groups coming to the Whiteley Center to write a grant proposal, researchers from different universities chatting on the dock and starting an interdisciplinary project, and students talking to visiting scientists and ending up going to graduate school in a research lab of one of those new contacts. In this essay, Chuck describes a creative and potentially profound idea that arose from a workshop at FHL – one that could improve food security for the world’s population as it continues to grow.
Algal Solutions: An Anthropocene Diet
by Dr. Charles H. Greene, FHL Associate Director for Research and Strategic Planning
Chuck Greene received his PhD in Oceanography from the University of Washington in 1985 and spent a year as a postdoctoral fellow at the Woods Hole Oceanographic Institution. Subsequently, he joined the faculty at Cornell where he served as Director of the Ocean Resources & Ecosystems Program. Currently, Chuck is Associate Director for Research and Strategic Planning at Friday Harbor Laboratories. His research interests have ranged from the ecological dynamics of marine animal populations to the impacts of global climate change on ocean ecosystems. He is a Fellow of the Oceanography Society and a Sustaining Fellow of the Association for the Sciences of Limnology and Oceanography.
Foreword
My wife, Drew Harvell, and I met at Friday Harbor Laboratories (FHL) during graduate school and were married on the deck of the dining hall. While we spent several decades as professors at Cornell University, we always came back home to FHL during the summers to conduct research and to teach. Our kids spent the summers of their childhoods at FHL adventuring in the intertidal and running with the pack of other kids on the bunny lawn. When they became teenagers, I began to worry about the future my generation was leaving to them and future generations. This led me to shift the focus of my research in a direction that I hoped would lead society towards a more sustainable future. During the coming years, I am planning to lead efforts at FHL and on San Juan Island to advance sustainability science both globally and locally. This edition of Tide Bites is intended to give you a taste of what’s to come.
Global Challenges
Our home planet has been so fundamentally altered by humanity that many scientists consider us to be living in the new geological epoch of the Anthropocene. From the beginning of the fossil-fueled industrial revolution to the end of the 20th century, the human population grew at an exponential rate. Only during recent decades has that growth begun to level off. It is projected that the population will peak at approximately 10-billion people by the middle of the 21st century (Figure 1).
From an ecological perspective, fossil fuels have enabled the human population to reach a level that cannot be sustained without some significant changes in our behavior. After nearly a half-century of inaction, progress is now being made in reducing society’s carbon footprint. Renewable energy sources are rapidly replacing fossil fuels in power generation and transportation, the two largest sectors responsible for society’s greenhouse gas emissions. The next largest contributor to greenhouse gas emissions is the agriculture, forestry, and land-use sector.
Subsidized by fossil fuels, terrestrial agriculture spread over much of the planet’s arable land and provided the backbone for the 20th century’s food production system. Fossil fuels became essential to producing nitrogen fertilizers and to powering the internal combustion engines that enabled more efficient machines to replace draught animals in plowing our fields and harvesting our crops. Such machines also enabled us to divert and dam many of the world’s great rivers to provide the freshwater necessary to irrigate such a massive agricultural enterprise.
However even with these advances, the global food production system is now unable to meet society’s nutritional demands, with a quarter of the world’s population malnourished. In addition to its carbon footprint, the land and freshwater requirements of terrestrial agriculture take a heavy toll on the environmental quality and diversity of Earth’s biosphere. How will it be possible to increase global food production to meet society’s projected nutritional requirements by 2050 and still insure a sustainable future (Zurek et al. 2022)?
Seeking Ocean Solutions
In October 2021, the Ocean Visions Marine Circular Bioeconomy (MCB) Task Force conducted a workshop hosted by Friday Harbor Laboratories to explore marine aquaculture’s potential for sustainably intensifying global food production (Greene et al. 2022a). Sponsored by the Advanced Research Projects Agency–Energy (ARPA-E), the MCB Task Force approached the problem initially by asking three questions:
- Given the population increase projected for 2050, how much additional FOOD would be required to meet society’s increased nutritional requirements (i.e., the food gap)?
- Given the increased nutritional requirements projected for 2050, how much additional LAND would be required by agriculture to close this food gap (i.e., the land gap)?
- Given the greenhouse gas emissions associated with existing agricultural practices, how much do we project these emissions will increase under a business-as-usual scenario, and how much do we need to reduce these projected emissions to achieve the Intergovernmental Panel on Climate Change’s (IPCC) stabilized temperature increase targets of 1.5°C and 2.0°C (i.e., the climate mitigation gap)?
The answers to these questions are summarized in Figure 1, and they raise one of the most daunting challenges of our times:
Can we create a global food production system that meets society’s projected nutritional requirements while simultaneously reducing its carbon and land footprints to levels consistent with our sustainability goals?
In response to this challenge, scientists initially explored the terrestrial option to see if agriculture could be intensified sustainably to close the food gap. They found that such an intensification, especially with regard to meat and dairy, will be highly constrained due to agriculture’s negative impacts on climate, land use, freshwater use, and biodiversity (World Resources Institute, 2019). Barring an unforeseen revolution in agriculture, this terrestrial option does not appear viable.
If we look toward the ocean for what are often referred to as blue foods solutions, the most obvious options also fall short (Costello et al. 2020). Most wild-capture fisheries are already fully exploited or overexploited. Although the aquaculture markets for finfish, shellfish, and seaweed are currently expanding, a significant intensification of aquaculture around the world would increase nutrient pollution as well as the spread of diseases and parasites among wild populations. It would also increase conflicts with fishermen, ocean energy providers and other competing stakeholders, exhausting available space in the coastal ocean long before closing the projected food gap.
So if these obvious terrestrial and marine options do not look promising, where does that leave us? The answer to this question is both surprising and exciting. To secure an adequate food supply by the second half of the 21st century, the MCB Task Force recommends that society should consider shifting its attention to a largely overlooked source of food from the sea: marine microalgae. Furthermore, it appears that the best option is to grow these marine microalgae in land-based aquaculture facilities (Figure 2).
Transforming Marine Aquaculture Down the Food Chain
Shifting the focus of marine aquaculture down the food chain to microalgae presents many important nutritional and environmental sustainability advantages (Greene et al. 2022b). As a taxonomically diverse group composed of thousands of different, mostly unstudied species, marine microalgae offer a potentially large, untapped source of high-quality protein: many species possess protein contents exceeding 50% of their dry mass. Relative to terrestrial plants, marine microalgae provide a better source of essential amino acids and other micronutrients such as vitamins, antioxidants, omega-3 polyunsaturated fatty acids and minerals. Similar to soy, microalgae-derived protein powders can be incorporated into meat and dairy substitutes as well as pastas and baked goods. Due to the marvels of modern food science, these algae-based products can look, taste, smell, and have the texture of the food products they are replacing. They can also be nutritionally superior.
A land-based marine microalgae aquaculture industry can offer many environmental sustainability advantages when compared to agriculture. Marine microalgae growth rates are often an order of magnitude greater than those of the most productive terrestrial crops. Thus marine microalgae grown in onshore aquaculture facilities have the potential to produce an equivalent amount of food from less than one-tenth the land area. This land footprint advantage provides marine microalgae with an opportunity to close the global nutritional gap in ways that would be impossible to achieve with terrestrial agriculture.
Because marine microalgae do not require soil or irrigation, their cultivation does not need to compete with agriculture and other stakeholders for arable land and freshwater. The cultivation of these marine microalgae is so efficient in its use of nutrients – only losing those nutrients that are harvested in the desired products – the problems associated with excess fertilizer runoff and subsequent eutrophication of aquatic and marine ecosystems can be minimized.
A global analysis of coastal areas suitable for growing marine microalgae reveals that this novel sector of the global food production system has the potential to provide the world’s total protein demand projected for 2050, up to 286 Mt yr-1 (Greene et al. 2022b). This finding is rather remarkable since all of the production is confined to a relatively narrow margin of land close to the coast where seawater is readily accessible (Figure 3). In addition, not all geographical areas of the world are created equal when it comes to the incoming solar radiation necessary for growing marine microalgae. A closer look reveals that much of this new sector’s potential lies in the Global South. While Eurasia and North America have long served as the world’s breadbaskets, marine microalgae-based aquaculture provides an opportunity to better balance food production between the two hemispheres.
Financial considerations must be taken into account when considering a large-scale expansion of marine microalgae-based aquaculture in the Global South. On the positive side, land and labor costs are relatively inexpensive in the Global South, and these will provide further incentives for development. Perhaps the most important financial incentive is the Green Climate Fund. Introduced at the 2011 United Nations Climate Change Conference in Durban, South Africa, the Green Climate Fund was conceived as a mechanism for wealthier countries to assist developing countries in their efforts to mitigate and adapt to the impacts of climate change. Implementation of the Green Climate Fund has been slow because there are few incentives for wealthier countries to contribute to it, especially with regard to adaptation measures. However, marine microalgae-based aquaculture can offer mutually-beneficial investment opportunities for both wealthy and developing countries by providing climate mitigation while simultaneously enhancing global food and water security.
Media responses highlighting this research can be found at the following websites:
References
Costello C., Cao L., Gelcich S., Cisneros-Mata M.A., Free C.M., Froehlich H.E., Golden C.D., Ishimura G., Maier J., Macadam-Somer I., Mangin T., Melnychuk M.C., Miyahara M., de Moor C.L., Naylor R., Nøstbakken L., Ojea E., O’Reilly E., Parma A.M., Plantinga A.J., Thilsted S.H., and J. Lubchenco. 2020. The future of food from the sea. Nature: 588, 95-100.
Greene C.H., and C.M. Scott-Buechler. 2022b. Algal solutions: Transforming marine aquaculture from the bottom up for a sustainable future. PLoS Biology: 20(10), e3001824.
Greene C.H., Scott-Buechler C.M., Hausner A.L.P., Johnson Z.I., Lei X.G., and M.E. Huntley. 2022a. Transforming the future of marine aquaculture: A circular economy approach. Oceanography: 35(2), 26-34.
Hannah R., Roser M., and P. Rosado. 2020. CO2 and greenhouse gas emissions. OurWorldInData.org. https://ourworldindata.org/emissions-by-sector.
World Resources Institute. 2019. Creating a sustainable future: a menu of solutions to feed nearly 10 billion people by 2050. World Resources Report. Washington, DC, USA. 558pp.
Zurek M., Hebinck A., and O. Selomane. 2022. Climate change and the urgency to transform food systems. Science 376: 1416-1421.