MHF-7743 Sediment Core
Field Report — MAR-38N, 3,847m

The retrieval of sediment core MHF-7743 — the source of Abyssolide-9™ — from the MAR-38N hydrothermal vent field at 3,847 metres depth required specialised equipment and operational protocols developed specifically for the 2018 Azores Deep Survey by the MHF Foundation for Marine Biochemistry.

The expedition deployed a VICTOR-class ROV (Remotely Operated Vehicle), on secondment from GEOMAR Helmholtz Centre for Ocean Research Kiel. The VICTOR platform was selected for its certified operational depth rating of 6,000 metres and its modular payload bay, which accommodated the custom titanium sealed core barrel designed by the MHF Foundation engineering team.

The titanium core barrel was a non-standard modification: a pressure-equalising valve system allowed ambient seawater to fill the barrel during descent, then sealed hermetically at the moment of core insertion, trapping a pressurised sample at approximately 380 atmospheres. This prevented the decompression-induced cell lysis that had compromised previous deep-sea microbial samples on prior Foundation expeditions.

On-board screening of the freshly retrieved core under UV illumination produced the anomalous bioluminescent signal — a persistent blue autofluorescence at approximately 480nm — that triggered the expedited isolation protocol. Dr. Vera Solenne extracted a 2g sub-sample immediately for shipboard characterisation. A second 2g sub-sample was sealed under inert argon gas in cryo-storage at −80°C for post-expedition laboratory integrity verification. The remaining core was maintained sealed in its titanium barrel for transit to Geneva.

The shipboard LC-MS screening — conducted over 18 hours using the vessel's portable mass spectrometry unit — returned a dominant peak at m/z 848.3 (corresponding to [M+H]⁺ of a compound at 847.3 Da), an observation Dr. Solenne described in her field notes as “consistent with a cyclic peptide of bathypelagic origin — possibly the most significant single data point of this expedition and, if the structure holds on NMR, potentially of this programme.”