Ocean systems, resources, and human activity

0:00- [Instructor] Shrimp is one of the most popular seafoods in the world, but did you know that producing shrimps can sometimes destroy forests? Wait, what? What do forests have to do with shrimps? And if that is true, how do we produce food without destroying our ecosystems?

0:18Let's find out. A lot of shrimp we eat is actually raised on something called shrimp farms, especially along the coasts of Southeast Asia and Latin America. And to understand where forests come in, we first need to look at a very unusual kind of forest, the mangrove forests.

0:39What's unusual here is that these are trees that actually grow in salt water right where the land meets the sea. And that's where the shrimp farms are. Shrimps are often raised in large salt ponds. And one of the easiest places to build these ponds is along tropical coastlines, where the salt water is easy to get, but that's also exactly where mangrove forests grow.

1:13So now, we see the connection. People have cleared huge areas of mangrove forests to make room for those ponds, especially in Southeast Asia and Latin America. And that's how shrimp farming has become one of the leading causes of mangrove loss around the world.

1:33And the impact is huge because these forests are incredibly important, both to oceans and to us. For example, just look at these underwater roots. Young fish and other marine animals hide here from predators while they grow. And once they do, many eventually move into the open ocean and become part of the larger food webs, which means the mangroves are almost like nurseries for the ocean.

2:07And that's not all. Mangroves also protect coastal communities. Their dense roots and vegetations absorb some of the forces of waves and storms, and that reduces flooding and erosion. And guess what? Mangroves also take in carbon dioxide during photosynthesis, and use that carbon to build their roots and trunks and leaves and other structures.

2:32In other words, mangrove forests store enormous amounts of carbon. So guess what happens when we clear these mangroves for shrimps? We're not just losing trees, we are affecting the marine food webs. And remember, more than three billion people rely on seafood as a major source of protein, so it affects us immensely.

2:56But it's not just the food, the coastal protection goes away, and some of that stored carbon can return to the atmosphere, adding to the greenhouse gases, warming up our planet. And mangroves, by the way, are just one example of how much we depend on these healthy ocean systems.

3:14For example, there are tiny organisms called phytoplankton, and they produce at least half of Earth's oxygen. And the ocean also absorbs and redistributes enormous amounts of heat, helping regulate Earth's climate. And of course, the ocean connects our economies around the world, and our activities can affect this as well.

3:40For example, when we burn fossil fuels, the green gases we release trap more heat, and the ocean, as a result, absorbs much of this extra heat, and that causes its temperature to rise. And warmer water can be especially harmful to corals. When corals become stressed by unusually warm water, they will push out the algae living inside them.

4:05This causes the corals to turn white. We call this coral bleaching. But what's important is that if this stress lasts too long, the corals can weaken and die. And that's a big deal because coral reef supports about a quarter of all marine species, which means it affects us immensely.

4:22And we also pollute ocean directly. Millions of tons of plastics enter every year. Marine animals can become tangled in it, or mistaken for food. And over large time, plastics also break down into tiny particles called microplastics, which have been found from the ocean surface all the way down to the deep sea.

4:43And so we now have the problem right in front of us. We heavily depend on healthy ocean systems, but some of our activities are damaging those very systems. So what can we do about it? So let's come back to the shrimp farming. What do we do? Should we just stop shrimp farming altogether?

5:01Nope, (chuckles) that's impractical. There are some really practical solutions. For example, in countries such as Vietnam, Indonesia, and Ecuador, communities and conservation groups are replanting mangrove forests. And some shrimp farms are also being redesigned to keep the mangroves around their ponds.

5:23This is an example of sustainable aquaculture, meaning producing seafood while trying to reduce the damage to the surrounding environment. And you and I can also make more informed choices about the seafood we buy. For farm seafood, such as shrimps, we can look for the ASC label, which stands for Aquaculture Stewardship Council.

5:45It basically means the farm has been checked by outside experts against standards for things like reducing pollution and protecting habitats, just mangroves. And for wild-caught seafood, you might see labels such as MSC. It means that the fishery has been checked to make sure it's not damaging the environment.

6:05So between restoring mangrove trees, redesigning farms, and rethinking the way we choose to eat seafood, there are real ways to keep farming shrimp without wrecking the forests. And that is the whole point. We rely on the oceans and our ecosystem, we need to use those resources, but we can always use those resources in a way that is sustainable.