\n Unsurprisingly, human activity is involved in a widespread ecological change.\n <\/p>\n
Since 2011, a monstrous structure has taken shape in the Atlantic Ocean almost every year, sprawling from the West African coast to the Gulf of Mexico. It\u2019s the Great Atlantic Sargassum Belt\u2014a gargantuan bloom of a brown free-floating seaweed. In May, the seaweed belt hit a record biomass of 37.5 million tons.<\/p>\n
In a study<\/a> published last month in the journal Harmful Algae, researchers from Florida Atlantic University\u2019s (FAU) Harbor Branch Oceanographic Institute outline the rapidly growing seaweed\u2019s development during the last four decades.<\/p>\n \u201cThe expansion of sargassum isn\u2019t just an ecological curiosity\u2014it has real impacts on coastal communities. The massive blooms can clog beaches, affect fisheries and tourism, and pose health risks,\u201d Brian Lapointe, lead author of the study and a marine scientist at FAU Harbor Branch, said in a university statement<\/a>.<\/p>\n \u201cUnderstanding why sargassum is growing so much is crucial for managing these impacts,\u201d he added. \u201cOur review helps to connect the dots between land-based nutrient pollution, ocean circulation, and the unprecedented expansion of sargassum across an entire ocean basin.\u201d<\/p>\n Something massive this way comes <\/p>\n Scientists previously believed that sargassum was mostly limited to the Sargasso Sea\u2019s nutrient-poor waters. More recent research, however, has revealed the organism to be quite the traveler, tracing sargassum\u2019s movement from nutrient-rich coastal areas, such as the western Gulf of Mexico, to the open ocean, hitching a ride on the Loop Current<\/a> (one of the fastest currents in the Atlantic) and the Gulf Stream. In the open ocean, nutrients<\/a> are usually concentrated at great depth.<\/p>\n In 2004 and 2005, satellite imagery revealed massive sargassum windrows\u2014long bands of floating sargassum\u2014in the western Gulf of Mexico, a region where rivers, including the Mississippi and Atchafalaya, are increasingly dumping nutrients. \u201cThese nutrient-rich waters fueled high biomass events along the Gulf Coast, resulting in mass strandings, costly beach cleanups and even the emergency shutdown of a Florida nuclear power plant in 1991,\u201d Lapointe explained.<\/p>\n In fact, research since the 1980s revealed that the seaweed grows faster and is more productive in shallow nutrient-rich waters than nutrient-poor open ocean waters. In other words, more nutrients mean more sargassum. In certain conditions, the biomass of Sargassum natans and Sargassum fluitans can increase twofold in just 11 days.<\/p>\n Human-driven changes in nutrients <\/p>\n Phosphorus and nitrogen are crucial nutrients for sargassum. From the 1980s to the 2020s, while the seaweed\u2019s nitrogen content rose by over 50%, its phosphorus declined.<\/p>\n \u201cThese changes reflect a shift away from natural oceanic nutrient sources like upwelling and vertical mixing, and toward land-based inputs such as agricultural runoff, wastewater discharge and atmospheric deposition,\u201d Lapointe explained. In other words, human activity. Carbon levels in sargassum are creeping upwards, demonstrating how outside nutrients are changing its makeup and affecting ocean plant life, he added.<\/p>\n The researchers suggest that nutrients from the Amazon River play a huge role in the Great Atlantic Sargassum Belt, too, with floods and droughts in the Amazon basin seemingly associated with changes in the sargassum\u2019s biomass. The team also highlights, however, that sargassum windrows are able to also grow in nutrient-poor waters by recycling nutrients in marine animal poop, among other methods.<\/p>\n \u201cOur review takes a deep dive into the changing story of sargassum\u2014how it\u2019s growing, what\u2019s fueling that growth, and why we\u2019re seeing such a dramatic increase in biomass across the North Atlantic,\u201d Lapointe explained. \u201cBy examining shifts in its nutrient composition\u2014particularly nitrogen, phosphorus and carbon\u2014and how those elements vary over time and space, we\u2019re beginning to understand the larger environmental forces at play.\u201d<\/p>\n The study is just one more example of how human activity is driving deeply rooted ecological changes, with the extent of its farthest-reaching consequences still terrifyingly unknown.<\/p>\n","protected":false},"excerpt":{"rendered":"Unsurprisingly, human activity is involved in a widespread ecological change. Since 2011, a monstrous structure has taken shape…\n","protected":false},"author":3,"featured_media":197687,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[3808,159,9985,67,132,68],"class_list":{"0":"post-197686","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-atlantic-ocean","9":"tag-science","10":"tag-seaweed","11":"tag-united-states","12":"tag-unitedstates","13":"tag-us"},"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/197686","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=197686"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/197686\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/197687"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=197686"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=197686"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=197686"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}