Latest news with #GreatAtlanticSargassumBelt
Yahoo
24-04-2025
- Science
- Yahoo
Sargassum blob at record-challenging amount after Florida had short reprieve from seaweed
A reprieve from the unruly seaside assaults of prickly and putrid sargassum may end this summer as a record-challenging bloom of the pelagic weed swells in the tropical Atlantic. Researchers at the University of South Florida said that an estimated 13 million metric tons of seaweed in the waters between Africa and the Caribbean tops the previous March record of 12 million metric tons and that it is only expected to multiply as the peak months of June and July close in. 'We predicted back in December and January this would be a major year, but no one was certain whether it would be a record year,' said USF oceanography professor Chuanmin Hu. 'But now we already have a record March, and we have some confidence that this will be another record year.' It is a similar message to what was announced the past couple of years when the so-called Great Atlantic Sargassum Belt reached record proportions in the early months of the year. But the blooms ultimately deflated by summer leaving beaches mostly clear. The end-of-season record is a total of 22 million metric tons measured in 2022. Florida Atlantic University research professor and algae expert Brian LaPointe said drought in South America the past couple of years led to less water flowing from the Amazon River into the Atlantic, which meant fewer nutrients to feed the fields of floating macroalgae. This year, the Amazon is flowing again, LaPointe said. More: World's largest sargassum bloom, why it's probably here to stay 'I'm looking closely at the influence of the Amazon and how that correlates with drought and the downturn in biomass production,' said LaPointe, who has already come across large mats of beached sargassum in the Keys. 'We're really coming out of that drought now.' Hu said USF's Optical Oceanography lab is seeing a 'relatively large amount' of sargassum in offshore waters east of Florida. He believes the rapid-flowing Gulf Stream current will act as a barrier to it reaching beaches. But it can also sneak up through the Florida Straits, threading the gap between the Gulf Stream and the coast. Winds have been blowing primarily out of the southeast this month, and there is sargassum showing up on some Palm Beach County beaches. Cameron Koehler, who works at Nomad Surf Shop in Boynton Beach, said he taught a surf lesson Tuesday, April 22 and was surprised at the amount in the water. 'It was gnarly out there. There was quite a lot of seaweed,' Koehler said. 'I feel like it's showing up a little earlier than normal and it was pretty thick in some places.' His pupil, who was from Montana, was 'definitely not used to it.' More: Amazing video of humpback whale breaching off of Palm Beach County's coast 'He kept kicking it off his legs and feet. It's an itchy feeling,' Koehler said. Scientists began noticing the proliferation of sargassum in 2011. Hu's lab measures the sargassum by satellite and has images dating back decades. Hu said the proliferation of sargassum is tied to climate change as far as how extreme fluctuations in wet and dry years can affect the amount of nutrients reaching the ocean. Warmer sea surface temperatures make less of a difference. 'The water is already warm enough in the tropical Atlantic. Adding a degree or so would not change the story. It's pretty much the nutrients.' Hu said. The initial bump in growth in the tropical Atlantic Ocean may have happened when strong winds and ocean circulations pushed sargassum from the Sargasso Sea into the Atlantic in 2010, Hu said. That jibes with a 2020 report that included research by the National Oceanic and Atmospheric Administration that linked the increase in sargassum to a 2009-2010 change to the negative phase of the North Atlantic Oscillation, or NAO. The negative phase of the jet-stream meddling NAO means a strong shift in winds to the west and south. Those winds flushed enough sargassum out of the Sargasso Sea to establish a colony in the tropical Atlantic Ocean. There, the sargassum got more sunshine and a high dose of nutrients that also come from upwelling ocean waters, according to the report published in the journal Progress in Oceanography in March 2020. Hu said it's important to collect sargassum measurements to keep track of changes in patterns and amounts, but also to help people make travel decisions and for anglers or researchers looking for the bountiful array of life that hangs out in and under the floating mats. A $3.2 million grant from the NOAA is being used in a USF project that can zoom in closer to better see the sargassum. While it's being tested in the Keys, the plan is to extend it to waters off Palm Beach, Broward and Miami-Dade counties. 'The new system relies on satellites that provide data at a scale of about 50 meters, as compared to several kilometers in our current system,' said USF Professor Brian Barnes in a March announcement. 'Thus, instead of looking at sargassum inundation at the scale of the Florida Keys region, we are now able to see potential impacts at an individual beach scale.' Sargassum is a lifeline for fish nurseries, hungry migratory birds and sea turtle hatchlings seeking shelter in its buoyant saltwater blooms. But in mass quantities, it chokes life from canals, clogs boat propellers and is a killjoy at the beach, piling up several feet deep like a rotting bog emitting hydrogen sulfide as it decomposes. It's generally safe to swim in but can turn the water an uninviting brown and be uncomfortable when it scratches against your skin. Palm Beach County beach managers are often constrained by turtle nesting season, which began March 1. Most cities have specially licensed contractors who use tractors to clear the sargassum at least twice a week, but they are confined to areas below where turtles may nest. Kimberly Miller is a journalist for The Palm Beach Post, part of the USA Today Network of Florida. She covers real estate, weather, and the environment. Subscribe to The Dirt for a weekly real estate roundup. If you have news tips, please send them to kmiller@ Help support our local journalism, subscribe today. This article originally appeared on Palm Beach Post: Sargassum bloom could swamp Florida beaches but seaweed unpredictable
The Guardian
22-03-2025
- Science
- The Guardian
Scientists identify ‘tipping point' that caused clumps of toxic Florida seaweed
Scientists in Florida believe they have identified a 'tipping point' in atmospheric conditions in the Atlantic Ocean they say caused giant clumps of toxic seaweed to inundate beaches around the Caribbean in recent summers. Previous theories for the Great Atlantic Sargassum Belt that has killed marine animals, harmed human health and plagued the tourism industry in several countries include a surfeit of nutrients in the water, such as nitrogen and phosphorus in runoff from intensive farming and carried into the ocean in the Congo, Amazon and Mississippi rivers. While marine scientists at the University of South Florida (USF) acknowledge that as a contributory factor, they say the primary source of nutrients is a seasonal phenomenon known as vertical mixing in which shifting winds churn up the ocean and deepwater nutrient concentrations are brought to the surface. They identified atmospheric pressure changes over the Atlantic beginning around 2009 as the tipping point, with variations in circulation and wind patterns pushing more sargassum into the warmer waters of the tropics, where it grew through photosynthesis into the massive blooms that eventually ended up on the beaches of the Caribbean and the US Gulf coast. 'This was a surprising result,' said Frank Muller-Karger, distinguished professor and biological oceanographer at USF's College of Marine Science. His team of international researchers used computer modeling to replicate the transport of blooms on strong currents controlled by negative North Atlantic oscillation (NAO), and how the changing atmospheric conditions helped create the giant sargassum belt. 'We had posed the hypothesis before that it is not the rivers that feed the formation of the sargassum blooms in the tropical Atlantic. This model supports the idea that nutrients from slightly deeper layers in the ocean feed the blooms.' Muller-Karger continued, saying that 'models showed that some patches of the sargassum were swept up by the wind and currents from the Sargasso Sea toward Europe, then moved southward, and from there were injected into the tropical Atlantic. 'At first, we saw just a few patches being pushed south by the NAO. But these algae patches were met with the right conditions to grow and perpetuate blooms. This population of algae, now separated from the Sargasso Sea, forms new blooms every year thanks to having enough light, nutrients and warmer temperatures,' he said. Almost annually for more than a decade, giant clumps of goop from the 5,000-mile-wide sargassum belt have washed ashore in the Caribbean, and from Florida to Mexico, creating problems for local authorities and businesses that rely on tourism. There are also significant health concerns. The rotting sargassum releases large quantities of hydrogen sulfide, which fills the air with an acrid odor similar to rotting eggs, and can provoke asthma and other respiratory issues. Sign up to Headlines US Get the most important US headlines and highlights emailed direct to you every morning after newsletter promotion In 2023, scientists at Florida Atlantic University (FAU) warned of a 'perfect pathogen storm [with] implications for both marine life and public health', having found high levels of the flesh-eating Vibrio bacteria lurking in the decomposing vegetation. They said plastic debris in ocean pollution mixed with the sargassum to create a proliferation of the bacteria, creating an additional health risk for tourists, municipal crews clearing the seaweed and volunteers conducting beach clean-ups. 'These Vibrio are extremely aggressive and can seek out and stick to plastic within minutes,' Tracy Mincer, assistant professor of biology at FAU's Harbor Branch Oceanographic Institute and Harriet L Wilkes Honors College, said. 'We really want to make the public aware of these associated risks. In particular, caution should be exercised regarding the harvest and processing of sargassum biomass until the risks are explored more thoroughly.' The USF research, a collaboration with scientists from the University of Toulouse, Sorbonne University and the Center for Scientific Research and Higher Education, was published in Nature Communications. Their report analyzed decades of wind, currents and 3D nutrient measurements from the Atlantic to model the annual blooms.
