It all starts with the moment a ship hits the seafloor. Almost immediately, it begins to transform. Marine organisms like algae, barnacles and corals start to colonise the hull, followed by larger creatures like crabs, eels and eventually schools of fish. To divers, these wrecks can look like bustling underwater cities, but to marine scientists, they are valuable models of ecological succession.

In many cases, wrecks become vital habitats. In areas with few natural reefs, these sunken structures offer hard surfaces where life can anchor itself. Over time, they attract more and more species, effectively becoming biodiversity hotspots. This phenomenon is especially important in regions where natural reefs are under threat from climate change or pollution.

Rust never sleeps—or does it?

Wrecks are also excellent sites for studying corrosion. Saltwater, oxygen and microbes combine in a slow-motion war against steel, iron and even bronze. Researchers are especially interested in the role of bacteria in this process. Certain microorganisms can either speed up corrosion by feeding on metal or slow it down by forming protective biofilms.

Take the Titanic, for instance. Over 100 years after its sinking, scientists discovered a unique strain of rust-eating bacteria called Halomonas titanicae feasting on its iron hull. That discovery was not just a curiosity, as it offered insights into how materials break down in deep-sea conditions and how we might one day preserve sunken cultural heritage.

Archaeology in action

For underwater archaeologists, shipwrecks are time capsules that reveal the technology, trade and even daily life of past eras. But preservation is tricky. In some cases, the sea protects artefacts that would otherwise decay, such as wood, which remains intact because of oxygen-deprived conditions. In others, the ocean acts as an unforgiving force, dissolving metals, breaking down fabrics and scattering fragile cargo.

Researchers and conservators must act carefully and quickly when they find something of historical value. Some artefacts are brought to the surface for conservation, while others are left in situ, to be studied with remotely operated vehicles (ROVs) and underwater 3D mapping technologies.

Dive in—with purpose

For recreational divers, shipwrecks offer adventure with a side of awe. But every fin kick near a wreck is also a brush with the frontier of science. As more marine researchers partner with divers and citizen scientists, these sunken relics are yielding secrets about ocean ecosystems, climate impacts and even the future of sustainable marine engineering.

So the next time you descend onto a wreck, remember that you are not just exploring a ship but entering a living, changing ecosystem where nature, history and science converge. It is Titanic meets microbiome science, with you as the curious explorer in the middle of it all. ■

Ethologist Ila France Porcher, author of The Shark Sessions and The True Nature of Sharks, conducted a seven-year study of a four-species reef shark community in Tahiti and has studied sharks in Florida with shark-encounter pioneer Jim Abernethy. Her observations, which are the first of their kind, have yielded valuable details about sharks’ reproductive cycles, social biology, population structure, daily behaviour patterns, roaming tendencies and cognitive abilities. Visit: ilafranceporcher.wixsite.com/author.