Ocean Carbon Changes the Micro-Fabric of Life

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When the waters south of Miami turned Jacuzzi hot this summer, reaching 101.1 degrees Fahrenheit in Manatee Bay, scientists were saddened by the impact on parrotfish, grunts, spiny lobsters and coral reefs. But what about the invisible world of the marine microbiome that we can’t see—one of bacteria, fungi, algae and viruses?

Before you say “ewww,” you should know that these creatures are small, where on Earth there are more stars in the universe, connecting all living things on our planet. Scientists have found them deep in sea caves, volcanic craters, icebergs, caves and mines. They provide more oxygen to the atmosphere and help organisms digest food and regulate the immune system. When organisms—including humans—die, microbes decompose, releasing carbon, nitrogen, and phosphates that create new life. About 38 trillion bacteria live in and on you right now. Without bacteria and everything they do, you wouldn’t last long.

Even humans will not thrive on this planet where our indiscriminate use of fossil fuels and industrial chemicals continues to turn the delicate balance of microbes that maintain our biological systems and habitats into dysfunctional ones. Billions of years of evolution have moved Earth from a carbon-rich atmosphere to one rich in oxygen. Over those eons, microbes have largely accomplished this terraforming by feeding on carbon and producing the oxygen we breathe as a by-product, a process that humans seem hell-bent on reversing unless we take immediate action to save the world much less by drastically reducing carbon emissions. and indiscriminate use of other chemicals.

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People put down the Earth’s microbiome in terms of what happens when you eat fast food burgers and potato chips 24/7. You get bellyache, or worse, partly because processed food and high fructose syrup change the composition of bacteria in our intestines, reducing the influence of “good” bacteria and increasing “bad” bacteria. Likewise, carbon and other pollutants are altering the Earth’s microbiome and undermining the planetwide ecological systems most people are aware of.

For example, tiny marine organisms called phytoplankton not only produce much of the oxygen on Earth, but they also absorb about 30 percent of the carbon produced by humans each year. Called the ocean’s biological carbon pump, or simply the biological pump, the system that supports phytoplankton is threatened as ocean temperatures rise and phytoplankton are drowned in carbon. “We’re lucky because we have oceans to release a lot of CO₂,” says Chris Dupont, an oceanographer and biologist at the J. Craig Venter in La Jolla, California.

Rising CO levels₂ makes seawater more acidic. This damages bacteria that are sensitive to changes in pH. Pollution from phosphates and nitrogen in terrestrial fertilizers flows from rivers to the sea and causes dead zones where the water is hypoxic, containing less than two parts per million of oxygen, a place where few (or no) fish or other marine life can survive. survive. The dead zone below the Mississippi River in the Gulf of Mexico has reached the size of New Jersey and, while it fluctuates in size seasonally and from year to year, overall it has been growing larger. Worldwide, the number of dead zones has doubled in the decade since the 1960s and now number in the hundreds, from the Baltic Sea to the coasts of Latin America and Africa and the Great Lakes. The largest dead area on earth is the 63,700-square-mile Gulf of Oman, almost the size of Florida.

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Ocean warming and uncontrolled chemical use cause coral reefs to excrete bacteria and tiny algae called zooxanthellae that live in their tissues and provide them with essential nutrients. Zooxanthellae help remove waste and protect against bacteria and are responsible for the coral’s bright colors. Their loss contributes to the dead, stark whiteness of the rock. More heat in the North Atlantic is also promoting increased levels of a type of toxic bacteria called toxemia Vibrio, which causes intestinal diseases, including cholera, in humans, according to a 2016 study. Vibrio is injuredthe so-called flesh-eating bacteria, and Karenia brevis, a type of toxic algae that can kill fish and cause respiratory and other problems in manatees, sea turtles and humans, are among other dangerous pathogens on the rise in areas of the North Atlantic coast. These bacteria are often associated with “red tides” that swell along Florida and other coasts as algae thrive in warm water and gorge on nutrients from fertilizer.

Scientists can only guess what the temperature of the hot tub in Florida is doing to the microbes that live there. “One hundred degrees Fahrenheit water will change the microbiome, but we don’t really know the consequences,” marine biologist Jack Gilbert of the University of California, San Diego, told me. “Microbes are highly variable, but as these changes become more common, we will see changes in the dynamics of populations and their metabolic activity that can have consequences throughout the food chain.”

As the world moves to reduce the human activities that contribute to climate change, it is important that the effect on the smallest creatures on earth is considered and the concerns of photo-loving species such as Adélie penguins, wild tulips, piper plovers – and the aforementioned parrotfish and spiny lobster . That is the point made in the new book, The Journey of Doctor II: Studies in the Marine Microbiome, which I co-authored with geneticist Craig Venter. The book describes two decades of work scouring the world’s oceans for microbes from a 100-foot boat.

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Dupont says: “It is difficult to get the attention of politicians and others about what is happening. But scientists are trying. For example, in 2019, a group of 34 microbiologists published a paper titled “Scientific Warning to Humanity: Microorganisms and Climate Change.” The authors put “humanity on notice that the impact of climate change will depend heavily on the responses of microorganisms, which are necessary to achieve a sustainable future for the environment.”

As we think more about climate change, it becomes clear that nature is responding to the ongoing chemical assault by “reversing in unexpected ways”—a warning given in 1962 when marine biologist Rachel Carson wrote. Silent Spring. Six decades later we see what he meant by extremely hot seas, heat, wildfires, floods, crop loss and hurricanes. Now we can add that nature is going backwards with the smallest creatures on earth, as humanity changes the little life that supports us on the planet, more and more, it does not.

This is an opinion and analysis article, and the opinions expressed by the author or authors are not necessarily those American science.