{"id":43,"date":"2026-06-18T17:29:47","date_gmt":"2026-06-18T16:29:47","guid":{"rendered":"https:\/\/www.oceanblogs.org\/m219\/?p=43"},"modified":"2026-06-18T17:35:53","modified_gmt":"2026-06-18T16:35:53","slug":"keeping-the-record-alive-long-term-ocean-observations-in-the-tropical-atlantic","status":"publish","type":"post","link":"https:\/\/www.oceanblogs.org\/m219\/2026\/06\/18\/keeping-the-record-alive-long-term-ocean-observations-in-the-tropical-atlantic\/","title":{"rendered":"Keeping the Record Alive: Long-Term Ocean Observations in the Tropical Atlantic"},"content":{"rendered":"\n

By Naomi Krauzig (GEOMAR)<\/p>\n\n\n\n

One of the most rewarding aspects of M219 has been contributing to the maintenance of the long-term GEOMAR mooring arrays<\/a> that quietly monitor the tropical Atlantic year after year.<\/p>\n\n\n\n

While CTD\/LADCP casts and other shipboard measurements provide invaluable snapshots of the ocean, these anchored instruments provide something that cannot be obtained otherwise: continuous observations spanning minutes, days, seasons, years, and even decades. As an observational oceanographer, it is difficult not to appreciate the value of these datasets. They form the foundation for understanding ocean variability in regions that are critical for Atlantic climate variability and allow us to detect and quantify long-term changes that would otherwise remain hidden within the ocean’s natural variability.<\/p>\n\n\n\n

Our first major operations took place off the Brazilian coast at 11\u00b0S, where the K1 to K4 moorings form part of a long-term observing system monitoring the western boundary current system and the Atlantic Meridional Overturning Circulation (AMOC). Within just a few days, the four deep-sea moorings were successfully recovered, assessed, serviced, and redeployed.<\/p>\n\n\n\n

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Bottom topography off northeastern Brazil showing the locations of the K1-K4 moorings and CTD\/LADCP stations (white dots) along 11o<\/sup>S (left) and photograph during the recovery of the K2 mooring (right). Photo: Naomi Krauzig.<\/em><\/p>\n\n\n\n

Every recovery felt a bit like opening a treasure chest. After spending a year or more beneath the ocean surface, these instruments returned carrying an invaluable record of currents, temperature, salinity, oxygen, and other key ocean properties. It was incredibly rewarding to see how well they had performed. Nearly all instruments operated successfully throughout the entire deployment period, delivering high-quality datasets with remarkably few gaps.<\/p>\n\n\n\n

From Brazil, we continued north to the equator at 23\u00b0W, home to another key long-term mooring at exactly 0\u00b0N. Since 2006, this mooring has been monitoring the Equatorial Undercurrent and the deep equatorial circulation from the surface to nearly 4,000 m depth. Its successful recovery and redeployment mean that this unique 20-year time series will continue, helping us better understand how the tropical Atlantic influences climate, oxygen and nutrient transport, and marine ecosystems across the basin.<\/p>\n\n\n\n

Our final mooring destination brought us to the Cape Verde Ocean Observatory (CVOO<\/a>), one of the flagship long-term ocean observatories in the eastern tropical Atlantic. Here, physical, biogeochemical, and ecological observations come together to track how the ocean stores heat and carbon and how marine ecosystems respond to environmental change. Like the moorings at 11\u00b0S and the equator, the value of CVOO lies not in a single measurement, but in the continuity of the multi-decadal record.<\/p>\n\n\n\n

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Snapshots from mooring recoveries during M219. Several moorings carry a multidisciplinary suite of instruments and require careful coordination to ensure a successful recovery. Photos: Naomi Krauzig<\/em><\/p>\n\n\n\n

For me, one of the most memorable aspects was seeing how many people contributed to the success of the mooring operations. Careful planning laid the foundation, while having a dedicated person keeping track of every step ensured that everything ran smoothly (kudos to Anna Christina Hans, aka Tina!). On deck, crew, technicians, and scientists worked together like a well-oiled machine, stepping in where needed and solving problems on the fly.<\/p>\n\n\n\n

The teamwork extended all the way back home to GEOMAR. Thanks to Rebecca Hummels’ mooring toolbox, data from several instruments could already be processed and checked while parts of the moorings were still in the water, providing an early look at the quality of the observations. On top of that, mooring experts were available around the clock to provide information, advice, and troubleshooting whenever needed. I believe the high success rate of the recoveries and redeployments is a testament to the experience, teamwork, and dedication of everyone involved.<\/p>\n\n\n\n

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Redeployment of the K4 mooring showing the positive atmosphere and team spirit, despite long working hours and the demanding nature of the operations. Photo: Naomi Krauzig.<\/em><\/figcaption><\/figure>\n\n\n\n

With the major milestone of the successful mooring work behind us, another exciting operation was still ahead. Waiting in Mindelo was a brand-new surface buoy, ready to begin its own contribution to these invaluable long-term observations. Stay tuned to learn more about that deployment in a future blog post.<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

By Naomi Krauzig (GEOMAR) One of the most rewarding aspects of M219 has been contributing to the maintenance of the long-term GEOMAR mooring arrays that quietly monitor the tropical Atlantic year after year. While CTD\/LADCP casts and other shipboard measurements provide invaluable snapshots of the ocean, these anchored instruments provide something that cannot be obtained […]<\/p>\n","protected":false},"author":272,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-43","post","type-post","status-publish","format-standard","hentry","category-at-sea"],"_links":{"self":[{"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/posts\/43","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/users\/272"}],"replies":[{"embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/comments?post=43"}],"version-history":[{"count":3,"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/posts\/43\/revisions"}],"predecessor-version":[{"id":55,"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/posts\/43\/revisions\/55"}],"wp:attachment":[{"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/media?parent=43"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/categories?post=43"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.oceanblogs.org\/m219\/wp-json\/wp\/v2\/tags?post=43"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}