What viruses make up a red tide bloom?
In the study recently published in the American Society for Microbiology's journal mSphere, researchers said an examination of water samples from off of Southwest Florida found several viruses percolating in red tide blooms.
The viruses are largely not harmful to humans in the traditional sense, but they can help researchers gain insights into the development of blooms that can plague coastlines for weeks, months, or even years at a time.
"We know that viruses play an important role in the dynamics of harmful algal blooms, but we haven't known what viruses might be associated with Karenia brevis blooms," Jean Lim, the study's lead author and researcher at the USF College of Marine Science, said in a statement. "Now that we've identified several viruses in red tide blooms, we can work to determine which viruses might have an influence on these events."
The study's findings were heavily based on water samples collected off Southwest Florida during what was considered a severe bloom in 2021.
The red tide event was the worst in recent memory along Florida's Gulf Coast, with widespread reports of fish die-offs and respiratory irritations, from Sarasota to Naples.
The extensive bloom even impacted the manatee population, resulting in hundreds of deaths of the giant sea cows.
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Using a technique called viral metagenomics, researchers identified multiple viral species, including one previously unknown virus, among the algae.
Most of the viruses belonged to the order Picornavirales and the family Marnaviridae, which are considered important in regulating marine ecosystems.
By better understanding the viruses, researchers may hold a potential key to controlling the growth of blooms and triggering their decline.
"There may be a correlation between viral abundances and bloom dynamics," Lim stated. "For example, an increase in the number of viruses found in a sample might suggest that a red tide bloom is about to begin or is near its end. Researchers could use information about viral abundances to help predict bloom cycles."
Additionally, by understanding what makes a bloom grow, there theoretically could be advanced alerts before an event impacts a coastal region.
Traditionally, marine experts have relied on satellite images and ocean circulation models to track the movement of blooms, but by understanding the viral dynamics, researchers may be able to identify certain patterns and predict the onset or decline of a red tide event.
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In 2024, satellites detected significant levels of chlorophyll in the Gulf, which can sometimes signal the onset of a red tide event.
The bloom gradually began to affect coastal regions across Southwest Florida in early 2025, prompting health alerts for several communities.
Rather unexpectedly, during the spring, samples started to show fewer traces of Karenia brevis, suggesting that the bloom might be in its waning stages.
The recent event is one that university researchers may be able to develop a timeline for once viruses and their impacts on microscopic algae are better understood.
According to the Florida Fish and Wildlife Conservation Commission, blooms are most commonly found in the Sunshine State during late summer and fall, but they can occur year-round and be detrimental to marine life and the tourism industry.Original article source: What viruses make up a red tide bloom?
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Atlantic
4 days ago
- Atlantic
The Sea Slug Defying Biological Orthodoxy
This week, a friend sent me our horoscope—we're both Gemini—from Seven Days, a beloved Vermont weekly, because, improbably, it was about the sea slug I'd been telling her about just days before. 'The sea slug Elysia chlorotica is a small, unassuming creature that performs a remarkable feat: It eats algae and steals its chloroplasts, then incorporates them into its own body,' the horoscope explained. Years ago I had incorporated this fact into my own view of the world, and it had changed my understanding of the rules of biology. This particular slug starts life a brownish color with a few red dots. Then it begins to eat from the hairlike strands of the green algae Vaucheria litorea: It uses specialized teeth to puncture the alga's wall, and then it slurps out its cells like one might slurp bubble tea, each bright-green cellular boba moving up the algal straw. The next part remains partially unexplained by science. The slug digests the rest of the cell but keeps the chloroplasts—the plant organelles responsible for photosynthesis—and distributes these green orbs through its branched gut. Somehow, the slug is able to run the chloroplasts itself and, after sucking up enough of them, turns a brilliant green. It appears to get all the food it needs for the rest of its life by way of photosynthesis, transforming light, water, and air into sugar, like a leaf. The horoscope took this all as a metaphor: Something I'd 'absorbed from another' is 'integrating into your deeper systems,' it advised. 'This isn't theft, but creative borrowing.' And in that single line, the horoscope writer managed to explain symbiosis—not a metaphor at all, but an evolutionary mechanism that may be more prevalent across biology than once thought. Elysia chlorotica is a bewitching example of symbiosis. It is flat, heart-shaped, and pointed at the tail, and angles itself toward the sun. Its broad surface is grooved by a web of veins, like a leaf's is. Ignore its goatish head, and you might assume this slug was a leaf, if a particularly gelatinous one. Sidney Pierce, a marine biologist retired from the University of South Florida, remembers his surprise when a grad student brought a specimen into his office in the Marine Biological Laboratory at Woods Hole, on Cape Cod, more than two decades ago. Photosynthesis requires specialized equipment and chemistry, which animals simply do not have—'yet here was an animal that's figured out how to do it,' he told me. He spent the next 20-odd years trying to find the mechanism. 'Unfortunately, I didn't get all the way to the end,' he said. No one has, as my colleague Katherine J. Wu has written. The algae and the slug may have managed some kind of gene transfer, and over time, produced a new way of living, thanks not to slow, stepwise evolution—the random mutation within a body—but by the wholesale transfer of a piece of code. A biological skill leaked out of one creature into another. All of us are likely leakier than we might assume. After all, every cell with a nucleus, meaning all animal and plant cells, has a multigenetic heritage. Mitochondria—the organelles in our cells responsible for generating energy—are likely the product of an ancient symbiosis with a distant ancestor and a microbe, and have their own separate DNA. So we are walking around with the genetic material of some other ancient life form suffused in every cell. And the earliest ancestor of all plants was likely the product of a fusion between a microbe and a cyanobacterium; plants' photosynthesizing organelles, too, have distinct DNA. Lynn Margulis, the biologist who made the modern case for this idea, was doubted for years until new genetic techniques proved her correct. Her conviction about the symbiotic origins of mitochondria and chloroplasts was a monumental contribution to cell biology. But Margulis took her theory further; in her view, symbiosis was the driving force of evolution, and many entities were likely composites. Evolution, then, could be traced not only through random mutation, but by combination. 'Life did not take over the globe by combat, but by networking. Life forms multiplied and complexified by co-opting others, not just by killing one another,' she wrote, with her son, in 1986. This remains pure conjecture, and an exaggeration of the role of symbiosis beyond what mainstream evolutionary theory would support; random mutation is still considered the main driver of speciation. Yet more scientists now wonder if symbiosis may have played a larger role in the heritage of many species than we presently understand. Phillip Cleves, a geneticist at the Carnegie Institution for Science who studies the symbiotic relationship between corals and their algae symbionts, told me how, as an undergraduate, he was blown away by the fact that corals' alliance with algae made possible ecosystems—coral reefs—that support a quarter of all known marine life. The algae cells live, whole, inside coral cells, and photosynthesize as normal, sustaining the coral in nutrient-poor tropical waters. 'I realize now that that type of interaction between organisms is pervasive across the tree of life,' he said. It's probable that the ancestors of all eukaryotes were more influenced by bacteria in their environments than modern evolutionary theory has accounted for. 'All animals and plants likely require interactions with microbes, often in strong, persistent symbiotic associations,' Margaret McFall-Ngai, a leading researcher of the role of microbes in animal development, wrote in 2024. These interactions, she argued, are so fundamental to life that the animal immune system should perhaps be thought of as a sort of management system for our many microbial symbionts. Although biology has been slow to recognize symbiosis's significance, she thinks this line of research should now take center stage, and could alter how all stripes of biologists think about their work. Cleves, too, sees himself as working to build a new field of science, by training people on how to ask genetic questions about symbiotic relationships in nature: When I called him, he was preparing to teach a four-week course at the Marine Biological Laboratory in Woods Hole on exactly that. Genomic research has only relatively recently been cheap enough to apply it routinely and broadly to all sorts of creatures, but now scientists can more easily ask: How do animals' interactions with microbes shape the evolution of individual species? And how does that change dynamics in an ecosystem more broadly? Elysia chlorotica is also a lesson in how easily the boundaries between an organism and its environment can be traversed. 'Every time an organism eats, a whole wad of DNA from whatever it's eating passes through the animal. So DNA gets transferred all the time from species to species,' Pierce told me. Most times it doesn't stick, but on the rare occasions when it does, it can reroute the fate of a species. 'I think it happens more than it's recognized, but a lot of times it's hard to recognize because you don't know what you're looking for. But in these slugs, it's pretty obvious,' he said. They're bright green. Still, attempts to understand what is happening inside Elysia chlorotica have mostly fallen short. Scientists such as Pierce presume that, over time, elements of the algal genome have been transferred to the slug, allowing it to run photosynthesis, yet they have struggled to find evidence. 'It's very hard to find a gene if you don't know what you're looking for,' Pierce said—plus, slug DNA is too muddled to parse a lot of the time. Slugs are full of mucus, which can ruin samples, and because the chloroplasts are embedded inside the slug cells, many samples of slug DNA end up picking up chloroplast DNA too. After years of trying, and at least one false start by a different lab, Pierce and his colleagues did manage to find a gene in the slug that was involved with chloroplast repair, hinting that a genetic transfer had occurred, and offering a clue as to how the animal manages to keep the plant organelles alive. But another research team showed that related species of photosynthesizing slugs can survive for months deprived of sunlight and actual food: They may simply be hardy. Why, then, if not to make nutrients, might the slugs be photosynthesizing? Perhaps for camouflage. Or perhaps they're stashing chloroplasts, which themselves contain useful fats and proteins, as food reserves. (Pierce, for one, is skeptical of those explanations.) Whatever benefit Elysia chlorotica derives from the chloroplasts, there couldn't be a leakier creature. It crosses the divide between plant and animal, one species and another, and individual and environment. I first read about the slug in a book titled Organism and Environment by Sonia Sultan, an evolutionary ecologist at Wesleyan University, in which she forwards the argument that we should be paying more attention to how the environment influences the way creatures develop, and how those changes are passed generationally, ultimately influencing the trajectory of species. While Elysia chlorotica is an extreme example of this, a version of it happens to us, and our bodies, all the time. Encounters with the bacteria around us reshape our microbiomes, which in turn affect many aspects of our health. Encounters with pollution can reroute the trajectory of our health and even, in some cases, the health of our offspring. Researchers think access to healthy foods—a factor of our environments—can modify how our genes are expressed, improving our lives in ways that scientists are just beginning to understand. We are constantly taking our environment in, and it is constantly transforming us.
Miami Herald
11-07-2025
- Miami Herald
‘Splash in the water' turns out to be ‘species of mystery' in Malaysia. See it
As darkness settled over a nature reserve of Malaysia, a 'rare' creature emerged and moved along the riverbank. A nearby trail camera captured its presence in the country's first such sighting 'in over a decade.' But no one realized the significance of the photos — until now. Conservationists and forestry officials set up trail cameras at Tangkulap Forest Reserve last year as part of a project to survey flat-headed cats, an endangered species of wildcats, the organization Panthera said in a July 1 blog post. During the survey, the trail cameras photographed whatever animals wandered past. Later, researchers sifted through these images and found some 'unidentified otter photos,' which they labeled 'by-catch' and put in the 'general archives,' Thye Lim, Panthera's Malaysia project coordinator, told McClatchy News. The otter photos sat around, largely untouched, until earlier this year, when Panthera researchers revisited the data as part of a 'collaboration with the Malaysian Otter Network,' Lim said. To their surprise and excitement, the otter experts noticed a set of photos from February 2024 showing a Eurasian otter — the country's first sighting of the species in 11 years, the organization told McClatchy News via email. Eurasian otters are widespread from Asia to Europe, but 'its presence in Southeast Asia is largely unknown and extremely rare, and it's considered highly endangered' in Malaysia, Panthera said. 'The Eurasian otter has long been a species of mystery in Sabah,' Lim said. Photos show the otter moving along a riverbank at night. Panthera praised the Eurasian otter sighting, saying its 'splash in the water has made waves in the conservation world.' 'It is exciting to hear about this recent discovery of the Eurasian otter in Sabah,' Mohd Azlan Jayasilan bin Abdul Gulam Azad, a specialist with Malaysian Otter Network, said in the blog post. 'Studying otters is challenging and often underrepresented in many natural history-related research efforts in Malaysia.' 'This rare discovery marks a historic moment,' Panthera wrote in a July 2 Facebook post. Tangkulap Forest Reserve is now 'the only location in Malaysia where all four of the country's otter species coexist,' Panthera said. Still, 'pollution, habitat fragmentation and overfishing remain significant threats to their survival.' Tangkulap Forest Reserve is in the Malaysian state of Sabah on the island of Borneo, which is shared between Malaysia, Brunei and Indonesia.
Axios
11-07-2025
- Axios
Rivers can fuel hurricanes, new USF study finds
A new study from the University of South Florida finds that freshwater from nearby rivers can help supercharge hurricanes. Why it matters: The findings add to growing evidence that river plumes can exacerbate coastal storms, underscoring the need to incorporate them into hurricane forecasts. The big picture: Hurricane Idalia surged from Category 1 to Category 4 in less than 24 hours as it neared Florida's Big Bend in August 2023, a phenomenon known as rapid intensification. Hurricanes Helene and Milton did the same. Each time, the abrupt spike made it harder for forecasters to assess the storms' impact. Zoom in: Researchers studied a large plume of freshwater that stretched from the Mississippi River to the Florida Keys, and found that where it met saltwater, ideal conditions for rapid intensification were created. The freshwater from rivers along the Gulf Coast created a thick surface layer that did not mix with the cooler saltwater below, keeping the surface water warm and potentially fueling storms. What they're saying: "Our study demonstrates the value of considering the influence of river plumes on storm intensification," said Chuanmin Hu, a professor of oceanography at USF and one of the study's authors.
