Salmon? Whitefish? Arctic char? Wading through responsible seafood choices can be convoluted. Seafood has long been a contentious issue with environmentalist groups, who argue that some stocks are irresponsibly managed and overfished, upsetting fragile ecosystems.

Consulting guides like the Monterey Bay Aquarium’s Seafood Watch can be helpful. To create them, researchers meticulously assess the latest seafood standards based on information from fisheries and aquaculture specialists—it’s an involved process to decide, for example, that albacore tuna is a “Best Choice,” but yellowfin tuna is in the “Avoid” category. But there are issues with seafood guides: They must frequently be updated, and they vary by season and your location in the United States. And though not all farmed seafood is bad seafood, if not correctly managed, some methods of aquaculture pollute local waterways by discharging fish waste.

Embracing seaweed

So is there an easy way to eat from the sea without contributing to excess carbon emissions? Yes! Embracing seaweed may be the answer to mitigating climate change, and a growing number of natural products brands are innovating to make this healthful ingredient more sustainable and accessible.

When understanding climate change, researchers often refer to what are called “carbon sinks”—areas on the planet that have capacity to absorb carbon from the atmosphere and store it in plants, the soil and the ocean. The ocean already sequesters an enormous amount of carbon—about 25 percent of the carbon dioxide people have put into the atmosphere (through burning rainforests, transportation and manufacturing) has been diffused in the ocean—mostly in deep-water areas (around 3,000 meters).

But there is a huge disadvantage to ocean carbon sequestration: acidification. When the ocean absorbs carbon, chemical reactions lower the pH of the water. Since the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units, a whopping 30 percent increase in acidity, says the National Oceanic and Atmospheric Administration. This has drastic biological impacts on mollusks, coral, oysters, clams and sea urchins—animals that billions of people around the world rely on for food.

Storing carbon from the ocean

Carbon in the air? Not great. Carbon in the ocean? Not much better. But carbon in plants? That’s where seaweed can come in.

“Studies of late show that marine plants and aquatic systems are much more a part of the carbon sink picture than we thought,” says Davida Mitchell, general manager of Blue Evolution foods, a vertically integrated food company that grows and distributes seaweed-containing products. Although there is much research still to be done, a pioneering study published in the journal Ecology suggests that seaweed can capture and store carbon from the ocean.

Blue Evolution is currently collecting data in its own seaweed farms, which are grown both in shoreline tanks and in open-ocean pens, depending on the species. Mitchell says the on-shore operations pump in coastal seawater to grow the seaweed and return it to the ocean—hopefully cleaner than when it went in. The company is trying to discern whether its seaweed can scrub seawater of its excess carbon, which would, in theory, raise the water’s pH to healthier levels.

But remember: Like conventional versus organic agriculture on land, not all seaweed farmers are alike. Even though seaweed doesn’t require fertilizers or pesticides to grow (just sunlight and water!), some farmers may overcrowd waterways, taxing the ocean and increasing disease potential. Similar to land-based food production, seaweed, too, is best cultivated with biodiversity and respect for the farm in mind—in this case, the ocean rather than the soil.