Pierce a blue button and what you encounter appears, surprisingly, akin to a tree. Concentric rings of chitin, the same substance that constitutes crab shells, compressed into a disc no broader than your thumbnail. Each ring chronicles growth added at the outer edge, layer by layer, as the colony drifts wherever the Pacific current dictates. No one had counted those rings before, not rigorously at least, so the duration a blue button might be riding the surface of the open ocean was unknown. The revelation, as it turns out, is that it\u2019s quite lengthy.<\/p>\n
A study released this week in *Scientific Reports* by researchers from the University of Tokyo\u2019s Misaki Marine Biological Station estimates that some blue button colonies endure at the ocean’s surface for several years, potentially as long as five. That may not seem dramatic, but for a creature previously believed to live less than a year, it alters our understanding of one of the sea’s unique ecosystems.<\/p>\n
The blue button, *Porpita porpita*, is easily overlooked and simpler to misidentify. At first sight, it resembles a small jellyfish washed ashore, jewel-blue and fragile, a few centimeters across. Upon closer inspection, it is actually a colonial organism, a compact association of tiny individuals called zooids, each assigned a specific role. Dactylozooids perform the hunting, capturing small prey along the colony’s edge. Gonozooids manage reproduction at the center. A single gastrozooid processes food for all. The entire structure floats on that chitinous disc, which acts much like a life raft, complete with sealed air chambers.<\/p>\n
Getting one into a laboratory is challenging enough. Sustaining it once obtained is an entirely different issue.<\/p>\n
Associate Professor Kohei Oguchi has been scouring the rock pools around Misaki, on the Miura Peninsula south of Tokyo, in pursuit of blue buttons for years. The organisms wash in unpredictably, deteriorate swiftly once stranded, and have thwarted nearly all attempts at culturing them. His team experimented with containers ranging from 30 centimeters to a full meter across. They evaluated temperatures between 18 and 25 degrees Celsius, varied water flow, modified sunlight exposure, offered krill, frozen shrimp, mackerel, and whitebait. Over 80 percent of specimens perished within a week regardless. What ultimately succeeded was almost embarrassingly straightforward: a 30-centimeter plastic tub of filtered seawater, changed daily, positioned near a sunny window, and a diet of freshly hatched brine shrimp nauplii. \u201cWe managed to keep 10 blue button colonies alive for up to 21 days,\u201d Oguchi stated. Three weeks of observation might not seem substantial, but for this specific creature, it was adequate.<\/p>\n
The crux was measuring float growth. Postdoctoral researcher Daiki Wakita photographed each colony at the onset and conclusion of its time in the lab, measuring float radius along eight axes with image-analysis software. Smaller colonies exhibited noticeable growth over those few weeks; the two largest, both surpassing approximately 17 millimeters in radius, demonstrated no measurable change whatsoever. This size-dependent growth slowdown is a common trend in biology, directing Wakita towards a well-known mathematical tool called the von Bertalanffy growth model, usually applied to fish and coral. Fitted to the data within a Bayesian framework, the model enabled the team to estimate the actual age of each colony upon collection.<\/p>\n
The figures were not what anyone anticipated. A colony about 4 millimeters in radius was likely around 3 months old. One at 12 millimeters, approximately a year. At 23 millimeters, the model estimated an age of about 5 years. \u201cFrom our observations of these colonies, we can now surmise that blue buttons may actually survive for several years drifting on the ocean surface,\u201d Oguchi remarked. \u201cThis duration is much greater than previously assumed, which was under a year.\u201d<\/p>\n
Written in Rings<\/p>\n
The histology revealed its own narrative. When the team scrutinized thin cross-sections of the float under a light microscope, they could observe new cuticular layers being added specifically at the margin of the disc, not expanding uniformly outward from within but accumulating at the edge, each new ring formed by a layer of secretory cells located just inside the outermost layer. \u201cThe chitinous float that supports the colony resembles the cross-section of a tree, with concentric rings,\u201d Oguchi stated. \u201cWe discovered that new layers grow from the periphery of the outer ring. This indicates that it doesn\u2019t grow from the expansion of preexisting layers, which we were uncertain about before.\u201d As each new ring is created, it extends the budding zones where new zooids can arise, meaning float growth and colony growth are functionally interconnected, the disc.<\/p>\n","protected":false},"excerpt":{"rendered":"
Pierce a blue button and what you encounter appears, surprisingly, akin to a tree. Concentric rings of chitin, the same substance that constitutes crab shells, compressed into a disc no broader than your thumbnail. Each ring chronicles growth added at the outer edge, layer by layer, as the colony drifts wherever the Pacific current dictates. […]<\/p>\n","protected":false},"author":2,"featured_media":372651,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"Default","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[179],"class_list":["post-372650","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-source-scienceblog-com"],"_links":{"self":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/posts\/372650","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=372650"}],"version-history":[{"count":0,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/posts\/372650\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=\/wp\/v2\/media\/372651"}],"wp:attachment":[{"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=372650"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=372650"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wolfscientific.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=372650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}