Could underwater farms help fight climate change? - Ayana Elizabeth Johnson and Megan Davis
- 184,681 Views
- 2,386 Questions Answered
- TEDEd Animation
Seaweeds, aka sea vegetables, are super nutritious – rich in protein, iodine and other minerals. We should eat more of it! We can also feed seaweed to livestock. Fun fact: Cows fed certain seaweed species belch 58% less methane. That’s a big deal because methane is at least 34 times more potent a greenhouse gas than carbon dioxide. Plus, with the wonder of photosynthesis, growing seaweeds absorbs tons of carbon, making it a valuable climate solution. To learn more about the incredible potential of seaweed aquaculture check out this World Bank report. For more on seaweed and cow burps, click here!
Oysters are filter feeders that live off nutrients in the water, and therefore clean the water around them as they eat. A 2018 study suggests that eating shellfish actually has a lower carbon footprint than sticking to a purely vegan diet, because it’s such an efficient way to produce protein – no feed or fertilizer needed. Also, oysters are known as “ecosystem engineers” because they can form enormous reefs that creative habitat for many other species. In New York City, oysters are being used to restore water quality and create habitat in the harbour. Learn more about oyster restoration in the New York harbor. For more on shellfish, check out the benefits of a shellfish diet. To learn more about shellfish more generally, check out Seafood in the Future: Bivalves are Better.
Regenerative Ocean Farming
Regenerative ocean farming (aka restorative ocean farming) is a way to grow food (seaweed and shellfish) while simultaneously restoring ocean ecosystems. While farming on land requires water, fertilizer, and feed, none of this is required for seaweed and shellfish aquaculture, since they live just off of sunlight and nutrients in the water. Plus, industrial agriculture uses an immense amount of fertilizer (there’s a huge need for a shift to regenerative practices on land as well), much of which runs down rivers to the sea causing nutrient pollution – ocean farms can help absorb that excess and rebalance sea water. Seaweed is also an excellent fertilizer, so it can be harvested and used back on land, thus closing the loop. To learn more about the connections between farming on land and at sea, and how regenerative practices are a key solution to the climate crisis, read: Soil and Seaweed: Farming Our Way to a Climate Solution.
The non-profit organization GreenWave has been pioneering the development of this sector, and training new ocean farmers.
Fishmeal and Overfishing
Overfishing is threatening fish populations around the world, so much so that global catch has been declining since 1996. At the same time, aquaculture has been growing rapidly and now supplies over half of seafood we eat. Intuitively, farming fish might seem better than catching wild fish, but… it’s complicated. Aquaculture can still put lots of pressure on wild fisheries. Each year around 20 million metric tonnes of wild caught fish is turned into fishmeal and fish oil. Fishmeal is basically a mish mash of fish parts – like the seafood equivalent of sausage. Most of this is fed to animals on land, but some is used to feed farmed fish. So, as fish aquaculture grows, so does indirect pressure on wild fisheries. Not only does this practice contribute to overfishing, it is also inefficient. The aquaculture industry is working hard to develop alternatives to fishmeal like plant proteins and insects, but maybe we should just eat the small fish (like sardines and anchovies) instead of catching wild fish to feed farmed animals. For more on overfishing, check out this United Nations report on State of World Fisheries and Aquaculture, and this TED-Ed on Will the Ocean Ever Run Out of Fish?
Create and share a new lesson based on this one.