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Earth & Marine Sciences - Nurturing Nori

Nori tank

UMaine marine biologists study the reproduction of red algae to cultivate the sea vegetables’ nutritional and economic benefits

Ankle deep in a thick mat of rockweed, the brisk January air still heavy with the aroma of low tide, Nic Blouin is checking temperature sensors among the rocky crags and crevasses of Acadia National Park’s scenic Schoodic Point. A doctoral student in the University of Maine’s School of Marine Sciences, Blouin’s research is focused on the reproductive biology of the red alga Porphyra umbilicalis, known as nori to the sea vegetable gourmand. While his research speaks to some of the most basic questions in marine biology, Blouin is doing much more than simply peeking into the sex life of marine algae. He’s working to change how Americans look at food.

“You can use this one in a lot of different dishes: bruschetta, spanakopita, roasted potatoes,” Blouin says of a reddish-brown blade of rather nondescript algae. “I like to dry it and use it as a seasoning.”

Working with UMaine marine sciences professor Susan Brawley, Blouin is taking a multifaceted approach to studying nori, combining cutting-edge laboratory research with hands-on field trials that he hopes will jump-start a new economic engine in Maine: sea vegetable aquaculture.

The idea of using Maine’s marine macroalgae as food is nothing new. The harvest of Irish moss for use as a thickening agent was once an important source of supplemental income for Maine fishermen, and several of the state’s native algae have been marketed in various forms for decades. One Maine company, Maine Coast Sea Vegetables, has been in operation since the 1970s. But on a larger scale, Maine’s potential as a provider of sea vegetables has remained largely untapped, due at least in part to the average American’s lack of familiarity with the ocean garden.

“(Sea vegetable) aquaculture is a $6 billion industry worldwide. Nori alone is nearly $2 billion of that, and that comes entirely from Asia. Nori and other algae are high in protein. They’re also a source of vitamins and omega-3 fatty acids. They’re a very healthful food; we’re just not used to eating them. Because there are so few people working on this in the U.S., and because there is so little known about its basic biology, you have to spread yourself around a little bit,” says Blouin, whose lab and field commitments combine to create a very demanding schedule. “I have projects going on both sides–in basic research and in economic development.”

Nic Blouin

On Schoodic Point, Ph.D. student Nic Blouin uses remote sensors anchored to the rocks to better understand how changes in water temperature affect nori reproduction.

As part of his thesis, Blouin worked to develop reliable techniques for cultivating P. umbilicalis commercially. With funding from Maine Sea Grant, Maine Technology Institute and the U.S. Environmental Protection Agency, Blouin developed methods for using dried material briefly reimmersed in seawater to create a special brew of reproductive spores for seeding the polyethylene nets used for growing the nori.

After being thoroughly soaked with the reproductive “tea,” the nets were set out in a custom-made, 24-foot-long raceway, where the growing conditions are optimized for the young plants. By managing temperature, circulation, drying intervals and nutrient inputs, Blouin gathered the initial data that could provide the foundation for large-scale cultivation of native nori in Maine waters.

“A lot of what we are doing with P. umbilicalis involves adaptations of other technologies, bringing them together in one uniform way,” says Blouin. “The idea is to streamline the process so that we can transfer that technology to future (sea vegetable) farmers.”

A native of the North Atlantic, P. umbilicalis has a potential advantage over Pacific species of nori, such as P. yezoensis, used in Asia’s large-scale aquaculture operations. Porphyra umbilicalis reproduces exclusively asexually along the Northeast coast. Currently, commercial nori farmers spend more than half of the yearlong growing season coddling the tiny, inedible filamentous phase of the alga’s complicated life cycle. In China, Japan and South Korea, gigantic warehouses shelter shallow tanks filled with billions of clamshells, each tinted with the pink stain of nori in its filamentous state. P. umbilicalis produces asexual spores that begin as tiny versions of the adult blade, effectively pressing fast-forward on the algae’s life cycle.

By utilizing the asexual P. umbilicalis, Maine nori farmers could bypass the expensive, time-consuming filamentous phase, speeding production, eliminating seasonality and reducing overhead costs.

The cultivation of nori and other marine algae could prove to be the perfect complement for other forms of aquacultural enterprise. Preliminary studies conducted by Blouin near salmon pens in Cobscook Bay suggest that net-grown nori could be incorporated into multicrop aquaculture. Dubbed Integrated Multi-Trophic Aquaculture (IMTA), this approach to ocean farming is critical to the development of stable and sustainable food production in the Earth’s oceans.

In Cobscook Bay, Blouin is measuring the degree to which nori nets and finfish aquaculture might complement one another. Effective IMTA methods promise not only additional economic returns, but substantial environmental benefits as well, potentially minimizing nutrient inputs while maintaining marine ecosystems.

Blouin’s doctoral research now focuses on unraveling the mysteries of reproduction in this red alga at the genetic level. Mortar and pestle in hand, he grinds samples of P. umbilicalis and extracts the genetic material using targeted viruses, creating a library of nori RNA. Then he identifies and sequences unique genes to determine the genetic controls for sexual and asexual reproduction in the genus.

Identifying the genetic triggers for asexual reproduction in P. umbilicalis may provide important insights into similar mechanisms in other species, offering researchers better understanding of the evolution of sex and greater control over the cultivation of sea vegetable varieties chosen for size, speed of growth, flavor or other traits.

“There’s no seasonality: P. umbilicalis is present year-round in the Northeast,” says Blouin. “If we can build an understanding of what triggers its asexual versus sexual reproduction, we may be able to get at those triggers in related species. We might be able to trigger asexual reproduction in P. amplissima, another local species that can grow a blade that is almost a meter long. It’s another Porphyra species that would make a great candidate for aquaculture.”

Blouin and Brawley see tremendous potential in expanding sea vegetable aquaculture in North America. From speaking at conferences and forums to helping organize the highly successful Sea Vegetable Celebration Day on the UMaine campus, Blouin and Brawley are not only in the lab, they are in the trenches, bringing sea vegetable aquaculture innovation to the surface. So far, average Americans have been slow to embrace the idea of getting veggies from the sea, but they’re coming around.

“Aquaculture has been undersupported in this country, especially sea vegetable aquaculture. In contrast, Asian governments have invested huge amounts in support of aquaculture,” says Brawley. “We have an opportunity now, because of the growth of finfish aquaculture, to develop ways to combine the two–a good thing, both commercially and for the environment.”

From sushi bars to snack foods, products containing farmed sea vegetables are slowly growing in popularity in the U.S. For now, Blouin and Brawley plan to continue down the path they started, doing basic research and market development to find new ways to make sea vegetable aquaculture a viable enterprise in the U.S.

by David Munson

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