Sample management & sharing
This section focuses on the storage of samples on-board, shipment to storage facilities, and sharing of samples. Routine management methods and processes are often similar across countries and entities, but more technologically advanced methods are highly variable.
Step 1. Storage of samples on-board
During most biological expeditions, samples are collected for shoreside analyses. There are some examples where all the necessary equipment to complete the analyses, e.g., autonomous imaging systems, are brought onboard so that no physical samples are taken home. Although technologies are changing rapidly, currently this is exceedingly rare and scientists are encouraged to bring back some number of samples to “ground-truth” their data. As such, scientists must consider the best way to preserve their samples for later analyses. Typical methods of preservation include the use of a preservative (e.g., ethanol or formaldehyde), desiccation, refrigeration, or freezing. For most biomolecular analyses such as gene sequencing (e.g., metagenomics), mRNA sequencing (so-called transcriptomics), protein sequencing (proteomics), and metabolite analyses (metabolomics), the preferred method is cryo-preservation at -80°C temperatures. As such, many research vessels have ultracold freezers onboard for use by the scientists while they are on board ship. It is common for scientists to use these for the duration of the cruise.
Step 2. Shipment of collected samples for analysis (e.g., sequencing facility, home institution, etc.)
Scientists will ship the samples back to the home institution while they are still frozen. Maintaining the cold chain is one of the biggest challenges, and the costs associated with doing so can be extraordinary. Dry ice and to a lesser extent liquid nitrogen is used to keep samples cold and ensuring that samples arrive before they thaw requires the services of a specialized courier service that maintains the cold chain. Shipping samples from ABNJ regions, e.g., from the Central Pacific Ocean to a sequencing facility in Asia, Europe, or the U.S., can cost several thousand U.S. dollars or more for a small package.
There are ways to preserve genomic DNA, environmental DNA (eDNA) and other biomolecules in ethanol, in a manner that does not require ultra-cold storage, but the analyses that can be done with such samples is more limited. In some cases, samples are sent to a facility where they are destructively sampled to recover the DNA or other molecules. The resulting data can, of course, be widely shared. However, if replicate tissues are desired for further analyses, it is up to the science party to collect and freeze additional samples in advance for dissemination or archiving.
