The treaty, which UN members states adopted in June 2023, is set to take effect under international law in January 2026 after enough countries passed the bar for ratification on Friday.

Here are the key points:

- International waters -

The treaty covers international waters that fall outside any single country's exclusive economic zone and account for more than 60 percent of the world's oceans.

It also covers what is known as "the Area" -- shorthand for seabed and subsoil beyond the limits of national jurisdiction. That comprises just over half of the planet's seabed.

Now that the treaty is law, a decision-making body -- a Conference of the Parties (COP) -- will have to work with regional and global organizations that already oversee different aspects of the oceans, such as the International Seabed Authority.

- Marine protected areas -

Currently, almost all protected marine areas (MPAs) lie within national territorial waters.

The treaty allows for these reserves to be created in the open ocean.

Most decisions would be taken by a consensus of the COP, but an MPA can be voted into existence with a three-quarters majority, to prevent deadlock caused by a single country.

One crucial shortcoming: the text doesn't say how these conservation measures will be monitored and enforced over remote swaths of the ocean -- a task that will fall to the COP.

- Sharing the bounty? -

On the high seas, countries and entities under their jurisdiction will be allowed to collect animal, plant, or microbial matter whose genetic material might prove useful, including commercially.

Scientists, for example, have discovered molecules with the potential to treat cancer or other diseases in microbes scooped up in sediment, or produced by sponges or marine mollusks.

Benefits-sharing of those resources has been a key point of contention between wealthy and poorer nations.

The treaty establishes frameworks for the transfer of marine research technologies to developing countries and a strengthening of their research capacities, as well as open access to data.

But it will be up to the COP to decide exactly how any monetary benefits will be shared.

- Environmental impact studies -

The treaty requires signatories to assess the environmental impacts of planned activities under their control on the high seas.

It also calls for countries to assess the potential impact on international waters of activities within national waters that may substantially pollute or harm the high seas' environment.

Ultimately, states are responsible for giving the green light to any potentially harmful activity -- a role that NGOs hoped would go to the COP, to make controversial approvals more difficult.

Though they are not specifically listed in the treaty, activities that could come under regulation include transport and fishing, as well as more controversial subjects such as deep-sea mining or even geo-engineering initiatives to mitigate global warming.