Top 10 Effects of an Ocean Shutdown

by Leslie Irwin, Communications Fellow, @leirwin129

This post was inspired by a ScienceOnline Oceans workshop for “sexier” blogging (#sciosexy).

Considering how many of us marine policy fellows in DC are currently affected by the government shutdown, I felt that this was appropriate. I also hope that this will spark a conversation about the importance of preserving our marine habitats and resources, and the ecosystem services they provide us. 

Over two weeks ago, the ocean failed to pass its solar energy budget, effectively halting photosynthesis and primary production. The following summarizes the top ten effects you can expect to see from a prolonged shutdown of the ocean.

These effects will have serious effects on our economies, as we rely on healthy, productive, functioning ocean systems for food (fisheries), coastal protection (reefs), and income from coastal and marine tourism.

Let’s dive in.

1.       Coral Reefs

You know those super pretty looking rock formations in coastal, tropical waters? The ones you like to go snorkeling and scuba diving on so you can snap pictures of all the colorful fish and shrimp and nudibranchs? Well you won’t be able to.

Those “rocks” of coral are actually living things. They are vast colonies of coral animals (tiny polyps) that gain their energy for growth and reproduction from a symbiotic algae, commonly known as zooxanthellae. The zooxanthellae photosynthesize to produce the energy the coral needs. But wait, they can’t anymore because of the shutdown! The coral will lose its algae partner and its pigment, and every reef in the ocean will experience coral bleaching. The coral will die and the natural process of erosion from waves and currents will take over until they’ve crumbled to the sea floor. All those colorful fish and invertebrates that rely on the reef structure for survival are out on the streets, vulnerable to predation.


Coral bleaching. NOAA

Reefs support such an interconnected web of sea life that merely taking out the zooxanthellae’s ability to photosynthesize crumbles the entire ecosystem structure. Reefs have already been threatened by mass bleaching events thanks to rising sea surface temperatures and climate change, at least this just takes out the guess work.

2.       Coastal Protection

Did you know that when major storms like hurricanes come crashing into the coasts around Florida and the Carolina’s, the barrier reefs help to dissipate some of the wave energy and reduce storm surge by the time it reaches land? Well, remember how reefs are gone? There goes your natural barrier to coastal storms and tsunamis.

3.       Shellfish

Raise your hand if you love oysters! Scallops, clams, mussels… gosh why do all these delicious sea creatures have to make their shells out of calcium carbonate?

What does that even have to do with photosynthesis?

The ocean is a natural sink for atmospheric carbon dioxide, taking up approximately 40 percent. Under normal circumstances, primary producers like phytoplankton, algae, and coral reefs take up a good portion of that carbon dioxide when they photosynthesize. Some carbon dioxide also reacts to form carbonate ions, which shellfish and other calcifying organisms take up to form their shells and skeletons. Increased carbon dioxide added to the oceans and not taken up for primary production undergoes a chemical reaction with the sea water, creating carbonic acid, rather than carbonate, effectively raising the acidity of the water.

Without photosynthesis occurring, the acidity of the oceans will only increase. Under these conditions, marine creatures with calcium carbonate shells and skeletons will start to weaken and corrode, and have a decreased ability to grow more shell.

Oceans are already experiencing this phenomenon of ocean acidification due to excess carbon emissions into the atmosphere. An ocean shutdown would significantly speed up the process.

4.       Upwelling fisheries

Upwelling occurs when deep, nutrient-rich waters are brought to the coastal surface waters by the processes of currents, the earth’s rotation, and winds— known as the Coriolis effect.

This boom in nutrients supports an explosion of primary productivity from seaweed and phytoplankton, which in turn provide a buffet for fish and many migratory species of high economic value to the region. While these regions only consist of 1% of the ocean, they provide 50% of the world’s fisheries catches.

Get rid of the primary production, and you lose those fisheries.

5.       Harmful Algal Blooms

Harmful algal blooms (HABs) occur when increased uses of fertilizers on land runoff into streams and rivers and eventually dump excess nutrients like phosphorous and nitrogen into the coastal ocean. A massive increase of algal production occurs, and HABs in particular give off biotoxins which harm fish and other marine organisms, and eventually the humans that consume them.


Harmful Algal Bloom. NOAA.

An ocean shutdown would put a stop to HABs. This is a potentially positive effect of a stall in primary production, but with everything else going belly-up, what’s the point?

6.       Sharks and whales and dolphins, oh my!

I imagine this next effect of an ocean shutdown will be met with mixed reactions.

The top predators of the oceans, including many sharks, whales, dolphins, and sea lions, will eventually run out of fish to eat, as all of the fish are dying from a lack of plankton and smaller fish that died after primary production halted. There are a good number of whales and sharks that survive by filtering massive amounts of krill and plankton (e.g. humpback whales, whale sharks) from the water column as well, so they would disappear faster.


Whaleshark. NOAA.

But you would no longer have to fear the look of the menacing black, soulless eyes of a Great White as it hunts through heavily touristed waters, even though people refuse to acknowledge that more humans are killed by hippopotamuses and car crashes than by shark attack. And since we know dolphins can be assholes, maybe they deserve it?

7.       Polar bears and penguins

Did you think that because they live on land, the polar bears and penguins would escape the consequences of an ocean shutdown? Both feed primarily on fish, and rely on steady supplies to survive. We’ve already established that the fisheries are shutdown, so penguins are going to be hurting, and polar bears are going to start moving inland and raiding peoples’ trashcans.  Those white, fuzzy bears don’t seem so cute anymore do they?



8.       Sea Floor party

This halt in primary production isn’t all bad! With all of the plankton and fish and sharks and whales dying, they have to go somewhere! As they sink to the bottom of the seafloor, there are tons of detritus feeders that are celebrating this surprising influx of dead matter. Have you ever seen the biodiversity sparked by a whale fall? Hagfish, crustaceans, polychaete worms, bacteria and more flourish under these conditions. Natural light doesn’t reach these depths, and so these organisms are not immediately reliant on photosynthesis.  Stumbling upon a whale fall is a rare occurrence, but with an ocean shutdown, there are going to be a lot more! It will be like a party on the sea floor! Dead matter for everyone!


Whale fall. NOAA.

But like most parties, they can’t go on forever. The dying organisms from the surface water will eventually run out.   Go home, hagfish, you’re drunk.

9.       Dead Zones

So remember that party? Turns out all that consumption of dead matter requires respiration. The bacteria and other animals that are feeding on the initial casualties of the ocean shutdown are using up all of the oxygen in the water, creating a giant “dead zone” of hypoxia, in which almost nothing can survive.  We see dead zones commonly occurring after a HAB, with a particularly infamous one existing in the Gulf of Mexico. Now that’s what would happen to the entire ocean, not that anything would survive the shutdown regardless.

10.   Chemotrophic takeover

But let’s not forget that there will be a winner after a (very prolonged) shutdown.

Chemosynthetic bacteria that don’t rely on photosynthesis for energy. Rather, they take up carbon dioxide or methane from the water (commonly around hydrothermal vents), and use the energy from reactions hydrogen sulfide or ammonium ions, for which oxygen is not required. These bacteria are thought to be the first to populate the oceans and produced the oxygen which eventually allowed the rest of earth’s inhabitants to evolve and thrive. Granted, this process took billions of years.


Hydrothermal vent. NOAA.

It’s amazing what the simple act of withholding the sun’s energy can do. Many people understand that terrestrial plants and crops and trees only survive with a proper amount of sunlight. We would be in serious trouble if we experienced a collapse in agriculture and loss of forests around the world. Not everyone realizes that the sun powers the ocean, and how the big fish in the sea are nothing without the tiniest photosynthetic plankton.

An ocean shutdown would be terrifying. Now is the time to focus on supporting sustainable fisheries, marine parks and reserves, reducing carbon emissions, and generally raising awareness of the services our oceans provide and promoting the science behind them!


3 thoughts on “Top 10 Effects of an Ocean Shutdown

  1. Pingback: This Week in Whales Focus: Have Some Dolphins Reached a Breaking Point? - What About Pollution | What About Pollution

  2. Pingback: Have Some Dolphins Reached a Breaking Point? - What About Pollution | What About Pollution

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