VERDICT: TRUE The core claims in the TikTok post are all supported by the peer-reviewed literature and by the research institution's own communications. Only one minor detail is imprecise: the probe deployments happened in **December 2023** (published April 2024), not "in 2024." **Primary sources opened (peer-reviewed journals + university institution):** 1. Alcérreca-Huerta et al. (2024), "Recent records of thermohaline profiles and water depth in the Taam ja' Blue Hole (Chetumal Bay, Mexico)," *Frontiers in Marine Science* 11, doi:10.3389/fmars.2024.1387235 — https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1387235/full 2. Alcérreca-Huerta et al. (2023), "First insights into an exceptionally deep blue hole in the Western Caribbean: The Taam ja' Blue Hole," *Frontiers in Marine Science* 10, doi:10.3389/fmars.2023.1141160 — https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1141160/full 3. El Colegio de la Frontera Sur (ECOSUR, CONAHCYT public research center), official announcement of 29 April 2024 — https://www.ecosur.mx/agujero-azul-de-taam-ja-en-la-bahia-de-chetumal-mexico-es-el-mas-profundo-del-mundo-ecosur-conahcyt/ **Claim-linked findings:** - **Name and location — TRUE.** The 2023 paper states the hole is "named Taam ja' Blue Hole (i.e., deep water in Mayan)" in Chetumal Bay "in the southeastern coast of the Yucatán Peninsula, Mexico" (it is a fully submerged feature, mouth ~4.5–5 m below sea level). The ECOSUR announcement likewise says it was "se nombró Taam Ja' (agua profunda) en alusión a la cultura maya de la región." - **Depth "more than 420 m," bottom never reached, deepest known blue hole — TRUE.** The 2024 paper reports CTD casts on 6 and 13 December 2023 recorded 416.0 and 423.6 m below sea level, and its abstract states records "surpassed 420 mbsl with no bottom yet reached, establishing the TJBH as the deepest-known blue hole globally." ECOSUR: measurements "superan los 420 metros por debajo del nivel del mar, sin que se haya determinado la profundidad exacta del fondo." - **"Ran out of cable" — TRUE in substance (fieldwork was Dec 2023, not 2024).** The 2024 paper says the CTD "was lowered, utilizing ~500 m of cable … adhering to the maximum depth supported by the instrument," and that the ~420 m depth read shorter than the ~500 m cable because the instrument descended obliquely (~32° from vertical) — i.e., the full cable was paid out and the bottom was not reached. The caveat: the probe lowers occurred on December 6 and 13, **2023**; the study announcing them was published April 29, **2024**. - **Deep water resembles the open Caribbean, not the brackish bay above — TRUE, and the underground-link idea is correctly presented as a "hint."** The 2024 paper states: "Beyond the depth of 400 mbsl within the TJBH, the water conditions gradually converge with those of in the Caribbean Sea," with mean salinity ~36.0±0.74 PSU (Caribbean Surface Water reaches up to 36.9 PSU), while the bay water atop the entrance is warm (>25 °C) and brackish (salinity <17 PSU). This "data alignment suggests a potential subterranean connection between these water bodies and the TJBH"; the paper adds that confirming any interconnected system of caves/tunnels "is essential to decipher." ECOSUR says the deep water "se asemejaron a las que han sido reportadas en el mar Caribe a profundidades de 0-150 m, lo que sugiere la probable existencia de conexiones subterráneas entre la bahía de Chetumal y el mar Caribe." Note the connection is a hypothesis the authors themselves flag as unproven — which matches the TikTok's hedged "hints," not a confirmed fact.