Warming Oceans: When The Oceans Suffer, We Will Too

Did you hear about the unusual fishes that have been appearing off the coast of New England? Folks in New England have been catching fishes they’ve never seen before. Except they’re not new species or alien fishes, but warm-water fishes. Thanks to the warming oceans, these fishes followed the warm water into a territory it has never appeared before.

It’s a tell-tale sign that the oceans are warming up – a direct effect of climate change.

Carbon, climate change, and warming oceans

You may already know this, but I think the relationship between our warming oceans and climate change bears repeating.

If it wasn’t for our precious oceans, the earth’s temperature would’ve risen to a high of 50 degrees Celsius. Over the years. humans have released a huge amount of greenhouse gases such as methane and carbon dioxide from our various activities.

• Learn about the carbon cycle to better understand climate change

These gases trap heat in our atmosphere. But the ocean has absorbed over 90% of the heat that’s trapped by these gases. This trapped heat causes the oceans to warm and reduces the amount of oxygen that dissolves in the water.

According to a study done by the International Center for Climate and Environmental Sciences at the Institute of Atmospheric Physics, the ocean has absorbed the equivalent of energy released by 3.6 billion Hiroshima-size atom bomb explosions over the past 25 years.

To make things worse, the excess carbon dioxide in the air dissolves in the water too, causing the oceans to acidify. The ocean absorbs approximately 30% of the carbon dioxide that’s in the atmosphere.

Needless to say, the heat, in combination with changing oxygen levels and increased acidity is harmful to marine life.

Impacts of the Warming Oceans

Humans can plant more trees and hide in air-conditioned homes in a hotter world, but what can we do when the ocean warms?

Disrupts fishes’ reproduction

Have you ever seen the eggs of fishes? They’re tiny and don’t have a shell. The most common way for fishes to reproduce is oviparity, which means the female will lay the eggs, and the eggs will be externally fertilized a male.

A new study found that heat tolerance in mating fishes and the eggs of fishes are significantly lower than those in fishes outside of the mating season.

This is because less oxygen dissolves in warmer water. Fish embryos, or fish eggs, can’t take in oxygen because they haven’t developed gills. The oxygen they require to survive is provided in the egg and sperm cells the mating parents produce. This makes them a lot more sensitive to rising sea temperatures.

Most of them won’t be able to evolve fast enough to overcome the effects of warming oceans. By the way, it’s not just oceans that warms, rivers and lakes will too. Where can a fish escape to in a warmer lake?

If global warming goes unchecked, the reproduction of 60% of the world’s fishes will be affected by 2100.

If we keep global warming at 1.5 degrees Celsius, 10% of fishes’ reproduction will still be affected, but that’s a very significant improvement!

• Find out why it’s so important to keep global warming under 1.5 degrees Celsius

Reduces phytoplankton population

Plankton forms the base of the marine food web. They’re an important source of food for tiny marine creatures, and phytoplankton is also crucial for removing carbon dioxide from the atmosphere.

As mentioned earlier, some of the carbon dioxide in the air is absorbed by the ocean. Through photosynthesis, phytoplankton in the ocean removes more than 100,000 million tonnes of carbon dioxide daily and produces oxygen in exchange.

NASA has found that warming oceans have caused a decline in the growth of phytoplankton. They explain that it’s likely because surface water becomes warmer, it becomes harder for these warmer water to mix with deeper, nutrient-rich water.

Phytoplankton lives closer to the surface, this means that lesser nutrients are available for them, hence affecting their productivity.

When phytoplankton population decreases, small marine creatures find themselves with lesser food, and that’ll affect their growth too.

Since phytoplankton grows better in cooler waters, they also migrate in search of cooler waters. Wherever phytoplankton goes, the marine creatures that rely on phytoplankton for food follow if they can.

When they can’t, they may dwindle in population, or die.

• Read about the fantastic phytoplankton here

Displaces marine life and reduces diversity

Warm water fishes appearing in the New England waters doesn’t sound that scary. After all, fishes do swim and oceans don’t have walls. However, when one thinks of the ocean as a whole, it’s not difficult to see the implications of it.

For instance, when warm water fishes migrate to cooler waters, what happens to cold-water fishes that were originally living there? They’d have to move too. A lot of them will be migrating higher up north in search of cooler waters, but what happens to the fishes at the Northernmost parts of the ocean? Where do they go?

Worst still, what happens to fishes in the ocean near the equator? What happens to the entire food web in the ocean near the equator?

As the oceans continue to warm, it’s inevitable that we’ll lose entire species of marine animals that can’t keep up with the changing ocean temperature and chemistry.

Already massive coral bleaching events have been happening all around the world.

Coral bleaching

Corals have been around for more than 210 million years. They are an important source of food and shelter for a quarter of marine life and are like nurseries for many young fishes.

The structures they form also protects the shoreline against severe storm and reduces damages from flooding.

Coral reefs are made up of little colorless animals called polyps. Their colors come from the microalgae that they house. Together, they share a symbiotic relationship.

Coral provides shelter for the microalgae, and the microalgae provide the coral with food. They’re self-sustaining and can live for a very long time in a stable environment.

However, corals are sensitive to temperature increase. Increases of just 1-2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) can trigger massive bleaching events.

Coral bleaching occurs when stressed corals expel the microalgae inside them. As mentioned, corals are made up of colorless polyp. When they expel microalgae, they lose the color. The white color that’s left is the color of its skeleton.

Without the microalgae, the coral loses its food source and will start to starve and become susceptible to diseases. The coral will die within days to weeks if water temperatures doesn’t return to normal.

50% of the world’s coral reefs have died. And it’s estimated that more than 90% will die by 2050. My youngest nephew will only be 36 years old. Our youths will suffer the brunt of climate change.

The loss of coral reefs will affect the population of marine life. In turn, humans will find themselves missing a huge amount of protein.

If you want to learn more about corals, check out this Netflix documentary called Chasing Corals. It’s good, but heartbreaking. Be warned.

Depletion of a vital source of protein and the livelihood of millions

According to the World Wildlife Fund, around 3 billion people around the world depend on seafood as a primary source of protein. That’s nearly 40% of the world’s population. Millions depend on fisheries and aquaculture for their livelihood.

For years, fishermen in subtropical Europe have been experiencing lower catches as the fishes they’re used to catching, like sardines, mackerels, and anchovies, migrate northward in search of cooler waters.

This phenomenon is only going to continue unless we put in more effort to curb global warming and protect the oceans. All the impacts mentioned so far all lead to a decrease in the population and diversity of marine life. This is a crisis waiting to unfold. That is if it isn’t already unfolding.

Worsens adverse weather events

When seawater warms, they expand and result in sea level rises. Warmer oceans also create more intense hurricanes and El Niño events, bringing more floods, and droughts. Coupled with the destruction of coral reefs, coastal communities are in for a hard time in the future.

What we can do

Our ocean is under attack. Aside from sea temperature rises, the ocean and all its inhabitants have to deal with overfishing, plastic pollution, micro-plastic invasion, chemical pollution, and ocean acidification.

Like it or not, the ordeals the ocean faces today are a result of human activity. We all had a part in it, we all can do our part to make things right, no matter how difficult it may seem.

We can do the following:

• Support ocean and coastal conservation and restoration efforts
• Support renewable energy and move away from fossil fuels – it’s crucial to reduce our carbon emission
• Reduce our individual carbon footprint and be conscious of actions that can pollute waterways and eventually the ocean. Every bit counts
• Spread awareness of the problem, talk about it with friends and family!
• Support Marine Council Stewardship-certified fisheries
• Choose sustainable seafood. Here’s a consumer guide for the US, and a consumer guide for other countries
• Reduce plastic use

Fighting climate change and supporting ocean conservation and restoration aren’t just for the sake of marine animals. We’re doing it for us too. We need the ocean more than we realize.

There isn’t much time left. We need to act now and act boldly.