Ocean Microbes Run the Planet — Here's Why That Matters

When people imagine ocean life, they picture whales and sharks and coral reefs and giant kelp

forests. But the vast majority of life in the ocean is actually invisible. In a single teaspoon

of water, there can be millions of microbial cells, including bacteria, archaea, and microscopic

phytoplankton. These organisms are too small for most people to even think about them,

but collectively, they control the chemistry of the ocean and much of the Earth's climate system.

Without them, the ocean ecosystem will collapse. This is the How to Protect the Ocean podcast,

where you get your weekday update on ocean news. If you care about staying informed about the ocean

each and every weekday Monday through Thursday, hit that follow button so you don't miss tomorrow's

story. Ocean microbes quietly power the systems that make life on Earth possible. They regulate

oxygen production, recycle nutrients, and influence how carbon moves between the ocean and the

atmosphere. In fact, many scientists now argue that microbes are the true engineers of ocean ecosystems.

Yet despite their importance, they are rarely discussed in conservation policy.

If microbes run the ocean, why do we almost never talk about them when we talk about conservation?

So here is the problem. Microbes are invisible to ocean policy and not just the naked eye.

Marine conservation often focuses on the big animals and the habitats that we can see.

Sometimes it could be ranged from marine mammals and all the way down to small invertebrates and

fish, but even then the invertebrates kind of get ignored. These are important species and ecosystems,

but they represent only a small portion of ocean life. In fact, it's actually funny when I was

a undergraduate at the University of Guelph in the marine biology and freshwater program.

One of my marine biology professors came out and said, and to be honest, pissed off the class,

and he said, hey, look, a lot of you are here for, because you want to study whales and sharks and

other, and of course, marine mammals, manatees and dolphins and all that kind of stuff, because

those are not important. I hate to say it, but you're wasting your time. He was obviously focused more

on a zoo plankton. He goes, it's the plankton that run the ocean. He goes, I know a lot of you

aren't going to like me for this, but the fact is that I'm right. This is him talking. He's like,

you have to understand the foundations of the ocean, the animals and the cells that actually run

the planet, rather, before you even learn about the ocean, about the marine mammals and the big

and the whale sharks and all that kind of fun stuff and the fish and everything that goes with it.

Because if you don't know the foundations, you don't know what runs the oceans, you're never really

going to be a true marine biologist. Now, obviously, that really kind of pissed off a lot of people

in the class. They took a lot of, it sparked, let's just say, a heated debate or a lively debate,

but it was true. If you really look at things, the fact is that we just don't understand. A lot of

people just don't know. When I tell them that every second breath is pretty much due to the ocean,

the oxygen is coming out of the ocean. We need to understand the focus, the focus on these microbes

and how important they can be. Microbes, plankton, whatever you want to categorize them,

and obviously different categories, but the unseen organisms, especially microbes. We're going to

focus this week on microbes. I got a great interview on Friday for you guys to check out as well,

and to see the applications of those microbes. So microbial organisms dominate ocean ecosystems,

both in abundance and metabolic activity. In fact, microbial life accounts for the vast majority

of living cells in the ocean. These organisms drive the biogeochemical cycles that regulate ocean

chemistry. They control how elements like carbon, nitrogen, and phosphorus move through the oceans.

And if you don't know why this is so important, especially when it comes to nitrogen and phosphorus,

obviously carbon is important for a number of different reasons. But nitrogen and phosphorus are

the key indicators, depending on the levels, that will drive nutrients and also algae. And if you

get an overabundance of nitrogen and an overabundance of phosphorus or phosphorus at the right level,

you will spark a huge algal bloom, which can cause a lot of problems for lakes and rivers and

in oceans alike. So this means that microbes determine how nutrients are recycled, how oxygen

is produced, and how carbon is stored in the deep sea. Yet when marine protected areas are designed,

microbial ecosystems are almost never considered explicitly. A lot of times when you hear

MPAs being designated, you hear, oh, we design an MPA to protect sharks or we design an MPA to protect

fish. And a lot of the times when you would expect that everything below that, so anything below

these umbrella species, would be protected as well. So that includes the microbes and everything

else that goes along with it and the genetics of all the organisms that fall within that habitat.

But they're never really the focus. Most conservation planning focuses on populations or habitat

protection, rather than microbial community health. But environmental stress can rapidly change

microbial communities. Ocean warming, pollution, and acidification can shift microbial populations

in ways that destabilize marine ecosystems. The key point is simple. If microbial systems collapse,

the rest of the ocean can follow. Now let's get into talking a little bit about the science of it all.

Our understanding of ocean microbes has grown dramatically over the past 20 years. One of the

most important projects studying this was the Terra Ocean's expeditions, which sampled microbial

life across the world's oceans. So researchers collected thousands of samples and used DNA sequencing

to map global marine microbial diversity. The results were actually staggering. Scientists

identified more than 40 million previously unknown microbial genes in the ocean alone.

The expedition also revealed that microbial communities vary depending on ocean temperature,

nutrient availability, and water circulation. Scientists also discovered how microbes drive the

marine carbon pump, a process that moves carbon from surface waters to the deep ocean.

Microscopic phytoplankton, absorbed carbon dioxide naturally during photosynthesis,

when these organisms die or are consumed, some of them carbon sinks into the deeper waters

where it can remain stored for centuries. Another major discovery relates to oxygen production.

So microscopic phytoplankton produced roughly half of the oxygen of the Earth's atmosphere,

just as I mentioned earlier. One ocean organism in particular is remarkable. The cyanobacterium

Prokola caucus is considered the most abundant photosynthetic organism on Earth. It thrives in

warm ocean waters and contributes significantly to global ocean production. Other microbes can play

equally critical roles. Nitrogen fixing bacteria, the trichodesmium converts atmospheric nitrogen

into nutrients that phytoplankton can use. Without these microbes, large regions of the oceans

would be nutrient limited and far less productive. Hedotrophic bacteria then recycle organic material

from dead organisms and waste, keeping nutrients circulating through the food web.

Together, these microbes are the foundation of marine ecosystems. Fish populations,

marine mammals, and entire fisheries ultimately depend on microbial productivity. Why are microbes

so powerful? They perform several essential ecosystem services. Firstly, they produce oxygen

through photosynthesis. Second, they capture carbon dioxide from the atmosphere and convert it

to organic matter. Third, they regulate nitrogen availability in the ocean, which determine how

productive marine ecosystems can be. And fourth, they break down organic waste and dead organisms,

recycling nutrients back into the ecosystems. Without microbial recycling, nutrients would quickly

become locked away in dead organic material. Scientists often describe microbes as the biochemical

engines of the ocean. They regulate the chemical balance that keeps marine ecosystems functioning.

If microbes are so important, why are they not considered in conservation? Why is there a

conservation blind spot with these microbes? Despite their importance, microbial ecosystems can

be highly sensitive to environmental change. And because microbes reproduce quickly, even small

changes in environmental conditions can rapidly shift communities. These shifts can have major

ecological consequences. Let's look at a few examples. Let's talk about marine heatways, for instance.

They're becoming more frequent and intense due to climate change. When ocean temperatures spike,

microbial communities often shift dramatically. For example, during marine heatwaves in the northeast

Pacific between 2013 and 2016, scientists observed large changes in microbial populations associated

with harmful algal blooms. warmer waters favor microbes to produce toxins, which then led to widespread

algal blooms that contaminated shellfish along the U.S. West Coast. These blooms force fisheries

closures and disrupted coastal economies. In other cases, warming oceans can increase populations

of disease, causing microbes that affect corals and marine animals. Let's talk nutrient pollution

and harmful algal blooms. When excess nutrients from agriculture or wastewater,

enter coastal waters, microbial communities respond rapidly. These nutrients fuel the explosive

growth of certain phytoplankton species. This process can trigger harmful algal blooms,

sometimes called red tides. Some of these blooms produce toxins that can kill fish, contaminate

shellfish and cause illness in humans. One well-known example occurred in the Gulf of Mexico.

Nutrient runoff from the Mississippi River stimulates massive microbial blooms, which eventually leads

to oxygen depletion in the warmer waters. That creates seasonal dead zones in the summer when the

wind is not mixing the water altogether. It just causes this stratification. In these dead zones,

the fish and marine animals cannot survive. These microbial-driven events can affect thousands of

square kilometers of ocean. One thing we don't talk a lot about in climate change is the role that

microbes play in ocean acidification. As atmosphere carbon dioxide increases, more CO2 dissolves in

the ocean. This causes ocean acidification. While we often hear about acidification that affects coral

reefs and shell-forming organisms, it also affects microbes. Changes in the ocean chemistry can

alter micro metabolism and nutrient cycling. For example, some studies show that acidification

can influence how microbes process nitrogen and carbon, which may alter productivity in marine

ecosystems. These changes are subtle, but potentially significant. If microbial nutrient

cycling shifts, entire food webs can be affected. This matters because microbes respond quickly

to environmental stress. That means they can act as early warning systems to ecosystem change.

But it also means microbial shifts can cascade through marine ecosystems faster than we expect.

This is why scientists increasingly argue that microbial health needs to be integrated into ocean

monitoring systems. So what would this look like for success? Recognizing microbes in ocean

conservation could involve several important steps. First, integrating microbial monitoring into

global ocean observing systems would be key. DNA sequencing technology now allows scientists

to monitor microbial communities in near real time. The technology is there. Second, including

microbial ecosystem health and marine protected area research. So MPAs often protect habitats

and fish populations, but scientists are now beginning to study how microbial communities respond

to protection. The third way is expanding global ocean DNA sequencing programs like the Tara

Ocean's project. And finally, funding long-term microbial research programs that allow scientists

to track changes over decades. Understanding microbial dynamics will be essential for predicting

the future of the ocean. Now, if you want to hear more of this science-based breakdowns

of ocean science every single weekday, follow this show so you don't miss what comes next.

Let's look at the final thoughts. I just came from the World Ocean Summit in Montreal. This

put on by the economist. It was a great summit. I got to meet a lot of people, which I loved going

to conferences for. A lot of new people from all walks of professional life and from all parts of

the world. It was really, really great. For most parts of the world, I guess. One thing that was

really talked about was the implementation of certain things and funding. And I just mentioned

that funding is really important when we're talking about long-term monitoring of microbial ecosystems.

The funding is the key and the funding is where everything lies. Without funding, we can't do

any of this. And, you know, I don't know the answers to funding. I'm not an economist. I'm not

someone who goes out and does fundraising, but I know one thing from just hearing from people

talk this past week in Montreal at the summit is it's extremely difficult to get. And with the

economy the way it is, with the world the way it is, everything shifting, everything changing.

This is a time where funding for marine protection from all scales is going to be extremely important.

The world's largest ecosystem, not the ecosystem that we see with marine mammals and sharks and

other, you know, amazing ocean species. Some of the most important parts of the ocean is the

largest ecosystem that is also invisible. Microbes shape the chemistry of the water.

Influence the stability of the climate and support the productivity of fisheries. Yet,

most people have never even heard of them. Ocean conservation often focuses on the species that we

can see, but the ocean functions because of the species we cannot. Protecting the ocean ultimately

means protecting the microbial engines that keep it alive. And tomorrow, we're going to look at the

most important roles microbes play on Earth, regulating the planet's climate. So share this episode

if you can, if you find that there's somebody will benefit from hearing this, someone who says,

hey, you know what? What's going on in the areas of the ocean that we can see, especially from

that microbial level of scale? If you find someone that knows this, share this episode with them.

I would love to hear your feedback on this episode. You can hit me up at SpeakUpForBlue.com,

forward slash feedback, that speakupforblue.com forward slash feedback. You can leave a voicemail

or you can type what you want to say, comment, question, or anything. I want to hear from you,

because this is where, you know, the whole point of this podcast is to start a conversation

on the ocean for you to continue it. So let me hear that feedback. I'd love to continue

that conversation. And until next time, thank you so much for joining me on today's episode

of the How to Protect the Ocean podcast. I'm your host, Andrew Loon. We'll talk to you tomorrow

in happy conservation.