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A robotic float, which moves up and down the water column collecting data\n \u00a9 2022 MBARI<\/p>\n
The planet would be a whole lot hotter if it weren\u2019t for fecal pellets. Across the world\u2019s oceans, tiny organisms known as phytoplankton harvest the sun\u2019s energy, gobbling up carbon dioxide and releasing oxygen. They\u2019re eaten by little animals called zooplankton, which poop out pellets that sink to the seafloor. What is essentially a giant toilet, then, flushes carbon at the surface into the depths, where it stays locked away from the atmosphere, thus keeping the amount of CO2 up there in check.<\/p>\n
But as humans pump ever more carbon into the sky, relentlessly raising ocean temperatures, worrying signals are flashing that this commode could be changing in profound ways. Consider the northeastern Pacific, off the coast of Alaska, where two major heat waves took hold of the sea, one from 2013 to 2015 and the other from 2019 to 2020. A new study found the two events transformed the composition of phytoplankton and zooplankton, essentially clogging the toilet and preventing the downward transport of carbon into the depths.\u00a0<\/p>\n
\u201cThese long-term studies help put everything into context and also really sound the alarms,\u201d said Anya \u0160tajner, a PhD candidate in biological oceanography at the Scripps Institution of Oceanography, who wasn\u2019t involved in the research. \u201cThe ocean is changing. And not only is it going to affect the ocean \u2014 it\u2019s going to affect the life in the ocean. And eventually that\u2019s going to affect us, because we rely on the ocean for our air, our food, our climate regulation.\u201d<\/p>\n
Of course, each bit of the world\u2019s oceans has its own unique chemistry, biology, and ecology, so what happens there might not happen everywhere. But with these bursts of heat, this swath of the sea saw declines in its ability to sequester the gas that\u2019s heating the planet. That\u2019s a precarious situation, given that the oceans capture a quarter of humanity\u2019s CO2 emissions. \u201cWhile we can generalize that maybe what we saw here would happen in general across other marine heat waves in the ocean, like the carbon accumulation, I think it\u2019s important to assess that regionally as well,\u201d said Colleen Kellogg, a microbial oceanographer at Canada\u2019s Hakai Institute and co-author of the paper, which published today in the journal Nature Communications.<\/p>\n
The researchers tapped a decade of data from Biogeochemical Argo floats, which autonomously wander up and down the water column taking readings of ocean chemistry. When they reach the surface, they ping that data to a satellite. In this way, the scientists got a 10-year stream of readings without having to constantly be on a boat in the northeastern subarctic Pacific Ocean, which is not known for hospitable winters.<\/p>\n
A robotic float, which moves up and down the water column collecting data
\n \u00a9 2022 MBARI<\/p>\n
The two ocean heat waves started like those we experience on land, with the atmosphere warming things up. Indeed, the ocean has absorbed 90 percent<\/a> of the additional heat that humans have created. Accordingly, while in the 19th century just 2 percent of the ocean surface experienced bouts of extreme temperatures, that figure is now well over 50 percent.<\/a> Such events will only grow more common and more intense<\/a> unless humanity dramatically reduces its greenhouse gas emissions, and fast. As it happens, the northern Pacific has once again been smashing records of late<\/a>, perhaps in part due to regulations in 2020 cutting the amount of aerosols generated by ships, which usually cool the planet by reflecting the sun\u2019s energy back into space.<\/p>\n Like our most ferocious atmospheric blasts of heat, a lack of wind during the two events made matters even worse. Typically, after the seawater warms in the spring and summer, winter winds blow across the surface, pushing it along. This forces deeper, cooler waters to race upward to fill the void, keeping the water column more uniform, temperature-wise. This didn\u2019t happen during both heat waves, and the sea remained more stagnant, as it normally does later in the year.\u00a0<\/p>\n Because warmer water is less dense, it remains at the surface, creating a sort of cap. \u201cThen in the subsequent spring and summer, that water is even warmer, because it didn\u2019t cool the winter before,\u201d said Mariana Bif, a marine biogeochemist at the University of Miami and lead author of the paper. (Bif conducted the research while at the Monterey Bay Aquarium Research Institute.) \u201cSo the impact of marine heat waves starts in the atmosphere, and then it\u2019s transferred into the ocean.\u201d<\/p>\n The two heating events were not created equal, though. The first coincided with an El Ni\u00f1o \u2014 a band of warm water off the coast of South America \u2014 that raised temperatures in the northeast Pacific even higher. The second saw a marked decrease in salinity due to changes in ocean circulation. Because water with lower salinity is less dense, it hangs around the surface, as the saltier stuff sinks. This further strengthened the warm cap.<\/p>\n The lack of winter churning also meant the nutrients typically drawn from deeper waters were cut off, denying the phytoplankton in that cap of the elements they needed to grow. Together, the high heat and low nutrients at the surface totally changed the environment for the organisms living and processing carbon there.\u00a0<\/p>\n Read Next<\/p>\n <\/p>\n <\/a><\/p>\n The oceans just hit an ominous milestone<\/a><\/p>\n That transformed the ecosystem. Like plants on land, different types of phytoplankton need different amounts of nutrients, and in different proportions. \u201cUsually, for example, in areas where you have this great mixing and great nutrients, you have a bunch of large phytoplankton that produce a lot of carbon \u2014 a lot of biomass,\u201d Bif said.\u00a0<\/p>\n As conditions changed during the heat waves, it was the littlest of phytoplankton species that benefited. These needed less nutrients to bloom, so they proliferated as larger species declined. And because different species of zooplankton dine on differently sized phytoplankton, the smaller ones that ate the smaller species suddenly had much more sustenance. \u201cThose guys are going to make smaller fecal pellets, which would kind of float in the water more than sink,\u201d Kellogg said. \u201cSo that could be contributing to the reduction in carbon moving from the surface to the deep ocean.\u201d\u00a0<\/p>\n Because the researchers had access to that data up and down the water column, they could monitor how all that carbon was sinking during the heat waves. Or rather, how it wasn\u2019t \u2014 because the ocean\u2019s carbon toilet was malfunctioning. In the first event, carbon particles were piling up 660 feet deep, and in the second, between 660 and 1,320 feet. In these zones, zooplankton grazers continued to chew on the particles, breaking them into smaller bits that couldn\u2019t sink. In the second marine heatwave, an increase in particularly small zooplankton meant more production of tinier, non-sinking fecal pellets.\u00a0<\/p>\n Not only was the toilet not properly flushing carbon, but more and more waste was being added to these waters as the heat waves rolled on. This gave bacteria lots of organic matter to break down, adding CO2 back into the sea. Eventually, currents would bring that CO2-rich water back to the surface, where the gas can be released back into the atmosphere.<\/p>\n Now scientists will have to monitor more heat waves in other parts of the world\u2019s oceans to see if the same dynamics are at play, and how much that might be hobbling the sea\u2019s ability to sequester carbon. At the same time, phytoplankton and zooplankton are suffering through crises other than heat, like ocean acidification potentially interfering with some species\u2019 ability to grow protective shells<\/a>.\u00a0<\/p>\n If there\u2019s less phytoplankton, there will be less oxygen coming out of the oceans, and less food for the zooplankton that feed all manner of other animals in the sea, including whales. \u201cPaying attention to what\u2019s happening at the base of the food web is going to give us a lot of information,\u201d \u0160tajner said, \u201cboth about how things are going to trickle up to these larger marine animals that we care about, but also insights about our climate.\u201d<\/p>\n Luckily, with thousands of Biogeochemical Argo floats collecting data around the planet, researchers are getting an ever-clearer picture of how seas are changing, and phytoplankton along with them. \u201cThe oceans are very under-sampled, very understudied,\u201d Bif said. \u201cBut they play a central role in climate. We can\u2019t understand what we can\u2019t observe.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"The planet would be a whole lot hotter if it weren\u2019t for fecal pellets. Across the world\u2019s oceans,…\n","protected":false},"author":2,"featured_media":205605,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[192,79],"class_list":{"0":"post-205604","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-environment","9":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/205604","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=205604"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/205604\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/205605"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=205604"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=205604"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=205604"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Four](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2025\/10\/GettyImages-2217051220s.jpeg\")
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