Global Scale

Ocean turbulence unfolds on small scales but has far-reaching impacts. It drives vast ocean currents and sustains marine life by transporting nutrients from the deep ocean to the surface. For a long time, the immense forces of winds and tides were believed to be the sole drivers of this relentless small-scale unrest. But what if tiny living creatures also play a role?

Come for the penguins, icebergs, and adventure, stay for the science of mud. Microscopic sand grains, hitchhikers on ancient icebergs, can reveal surprising secrets if you know how to read them. Hidden mountains under miles of ice, ancient continents rent asunder, and giant glaciers meeting impassable depths. Find out what I did with thousands of sand grains and a pair of tweezers, what happens when you fire a laser at them, and what they can tell us about ice, oceans, and climate in the frozen south.

The natural world has played a critical role in the discovery and development of pharmaceutical products, with ~42 000 marine natural products (MNPs) being reported in the last 50 years. However, less than 7 % of MNPs are derived from the deep sea (below 200 m) despite it accounting for 90 % of global oceans. The physiological and biochemical characteristics that allow for environmental tolerance in extreme deep-sea environments can be linked to gene regulation and primary and secondary metabolic pathway modifications, thus offering the potential of discovering structurally diverse compounds versus the ocean’s shallow water counterpart. Based on marine chemical databases MarinLit and CMNPD, this study generates a comprehensive review of deep-sea chemical novelty and bioactivity. Building on previous reviews and databases, the addition of taxonomic, phylogenetic, environmental and trait information, allows for an initial exploration of phylogeographic relationships to deep-sea bioactivity. With currently only ~3 000 records of chemical novelty and bioactivity in the global deep-sea, this study does not reveal any significant relationships, but shows the potential value of a comprehensive database to support interdisciplinary metanalyses with the aim of guiding targeted biodiscovery in the future. Chemical diversity in the deep-sea is demonstrated with a highly isolated scaffold cluster analysis, which should encourage the focus of biodiscovery efforts in the deep-sea, that appropriately balances diverse investigation to better understand the evolution of novel compounds and a more targeted approach that can utilise phylogenetics and environment to efficiently screen compounds for pharmaceuticals. Finally, this study has highlighted the issue of sampling bias and major data gaps over geography, depth, taxonomy, phylogenetics and data quality. It should be a priority moving forward to collect and store comprehensive data according to FAIR principles. As the BBNJ agreement comes into force, its Clearing-House Mechanism may go some way in supporting deep-sea MGR data in the high seas.