Three thousand feet down there is no color left.<\/p>\n
The lights swing across flat grey mud, and a rusted drum comes up out of it.<\/p>\n
Around the drum the seabed has gone chalk white in a ring, hard edged against the mud beyond.<\/p>\n
Outside the ring there are burrows and tracks. Inside it there is almost nothing<\/strong>.<\/p>\n Everyone had come looking for a pesticide.<\/p>\n What was actually killing that circle of seabed sits in a different corner<\/strong> of the chemistry.<\/p>\n Open ocean water runs around pH 8.1, a mild alkalinity that everything down there is built for.<\/p>\n Pore water inside the halos measures close to 12<\/strong>, roughly household bleach.<\/p>\n That is not a poison in the usual sense. It is a solvent for the machinery of a cell, and almost nothing carries the biochemistry to hold itself together in it.<\/p>\n The ring itself is a mineral, not a stain.<\/p>\n Caustic alkaline waste leaking out of a drum meets the magnesium dissolved in seawater and throws down brucite<\/strong>, a magnesium hydroxide that cements the mud into a crust like set mortar.<\/p>\n That crust then dissolves slowly, which keeps the pore water around it strongly basic and drives out pale carbonate that draws the outline wider.<\/p>\n The drum is not just leaking. It is building the thing that keeps it leaking.<\/p>\n Deep sediment normally carries a dense and varied bacterial community.<\/p>\n Inside a halo the diversity collapses. Ten organisms account for about 71 percent<\/strong> of everything present.<\/p>\n They are alkaliphiles, and their nearest relatives are not marine sediment bacteria at all. They belong with organisms found at hydrothermal and serpentinite systems, places where the rock chemistry itself produces water this basic.<\/p>\n A ring of that on the seabed off a major city is a habitat that has no business existing there.<\/p>\n It also has one practical use. Because a halo shows up plainly on video, a survey can flag which drums<\/strong> are leaking caustic without putting a core into every one of them.<\/p>\n Two expeditions in 2021 did the job between them.<\/p>\n One mapped the ground, running side scan sonar over more than 36,000 acres of basin between the coast and Catalina and returning about 27,000 targets identified with confidence as barrels.<\/p>\n The other went down with a remotely operated vehicle and took sediment cores at 0, 1, 3 and 5 meters out from five barrels<\/strong>, three of them ringed and two not.<\/p>\n The cores were sliced into layers and run for pH, minerals, DDT and microbial DNA.<\/p>\n A hard concretion lifted from between a halo and its drum turned out to be brucite, which is what pinned the chemistry down.<\/p>\n The results were published in September of 2025<\/strong> by a Scripps team led by Johanna Gutleben with Paul Jensen as senior author.<\/p>\n DDT and its breakdown products are all over that basin, averaging 233 nanograms per gram of dry sediment and peaking above 1,400.<\/p>\n But the concentrations show no relationship<\/strong> to how close a sample sits to a barrel.<\/p>\n Gutleben put the reason plainly. One of the main waste streams from making DDT was acid, and they did not put that into barrels.<\/p>\n It went into the water directly. The alkaline signal, by contrast, is sharp and local<\/strong>, tied to specific drums.<\/p>\n Jensen adds a second qualification worth having. The highest DDT concentrations sit buried an inch or two below the surface, which he describes as kind of contained<\/a>.<\/p>\n What is not contained is the caustic, and the same basin has already shown how long deep sea disturbance<\/a> outlasts the act that caused it.<\/p>\n Nobody knows how many of those drums held alkaline waste.<\/p>\n The one third figure counts white halos seen on video, and whether it holds across the whole dumping ground is an open question.<\/p>\n Nor is 27,000 a total. It is what sonar could identify with confidence out of more than a hundred thousand objects on that seabed.<\/p>\n Sorting it out means far more sampling, and the halos at least make it possible to aim, the same way replayed video<\/a> has been used to find what a first pass missed.<\/p>\n Fourteen dump sites<\/strong> took industrial waste off Southern California from the 1930s until ocean dumping was closed off in 1972.<\/p>\n On brucite dissolution rates, the authors reckon the effects will take several thousand years<\/strong> to work through.<\/p>\n Jensen’s line on it is that fifty plus years later you are still seeing<\/a> this, and he calls it shocking. What a drum draws around itself, it keeps drawing.<\/p>\n","protected":false},"excerpt":{"rendered":" Three thousand feet down there is no color left. The lights swing across flat grey mud, and a rusted drum comes up out of it. Around the drum the seabed has gone chalk white in a ring, hard edged against the mud beyond. Outside the ring there are burrows and tracks. Inside it there is almost … Read more<\/a><\/p>\n","protected":false},"author":28,"featured_media":34903,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"among roughly 27","rank_math_title":"Sonar mapped 27,000 barrels on the seafloor off Los Angeles, and the white halos ringing a third of them sit in sediment as caustic as household bleach rather than the pesticide anyone was looking for","rank_math_description":"Researchers probed 5 mystery barrels on the seafloor off Los Angeles and found caustic alkaline waste, not DDT, creating dead zones as harsh as bleach.","footnotes":""},"categories":[83],"tags":[],"class_list":["post-34899","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earth"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/34899","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/comments?post=34899"}],"version-history":[{"count":0,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/34899\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/34903"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=34899"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=34899"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=34899"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}What a pH of 12 does to a patch of seabed<\/h2>\n
What can live in a circle like that<\/h2>\n
How the work was actually done<\/h2>\n
Why the pesticide turned out to be the wrong lead<\/h2>\n
What is still open<\/h2>\n