Coral fossils dating back to the Paleozoic Era

Oceans under the microscope: mapping the future with fossils

20 July 2017

Our oceans are changing fast. Find out how Museum collections are helping scientists to understand the future of marine life.

Around 95% of the Earth's oceans are still unexplored - in fact, we know less about the deep sea than we do about space.

But although vast swathes of the oceans remain mysterious to us, these watery worlds sustain life on Earth.

To keep these precious resources healthy, it is vital that they are fully understood.

Data from the Museum's collections can reveal both how oceans have changed and the future risks to life underwater. They can also offer insights for better ocean conservation.

The fossilised shells and bones of long-dead creatures are more than just dusty, old specimens - they could hold the key to protecting animals of the present that are facing a very uncertain future.

A fossilised section of sea floor dating back 340 million years.

A fossilised section of sea floor dating back 430 million years. Scientists can use specimens like this in the collections to examine how animals lived and died millions of years ago.

 

Prof Richard Twitchett, a palaeontologist at the Museum, explains how Museum collections can help us understand the risks facing the most vulnerable species in the ocean. 

Why do we need to study the ocean?

Oceans are the cradle of life on Earth, where the first living species evolved millions of years ago. They sustain ecosystems that feed us, support industry, protect shorelines and nurture life on land.

By studying them now, we can build a picture of how they have changed as a result of climate change, pollution and human activity, and reveal the extent of the threat to these delicate ecosystems.

Predicting the consequences of human activity relies on understanding how ocean systems work, what they were like before humans evolved and how the creatures that live in them will respond to change.

There are countless ways in which researchers are trying to do that, and under the Museum roof, experts are using fossils dating back 250 million years.

A drawer full of specimens

The Museum's vast marine fossil collections are a frozen archive that can inform our predictions of the future

 

Looking into the future

The Museum's collections contain more than eight million marine fossils from periods spanning millions of years.

They represent hundreds of different ancient species, including fish, mammals, crustaceans, ammonites and corals. This wealth of data can help scientists understand what can happen to the oceans over long periods of time.

Prof Twitchett is investigating how marine ecosystems of the past responded to major upheavals such as global warming or mass extinctions.

He says, 'Understanding the ocean's past is crucial to predicting its future. People are concerned about climate change because carbon dioxide levels haven't been this high for many millions of years. We wouldn't know that without studying the past.

'There have been several very large warming crises on Earth within the last 250 million years, where the oceans got warmer and there has been more carbon dioxide in the atmosphere. Changes in sea temperatures are not a new phenomenon.

A selection of brachiopods

Brachiopods are one of the oldest animals found in the fossil record, and were most abundant in the Palaeozoic Era, about 541 to 252 million years ago. Information about how the temperature of the seas has changed through time is locked away in their fossilised shells. 

 

'None of the historic warming events are direct parallels to the present, because everything's different now: the species, position of the continents, carbon cycle, starting conditions and starting temperatures.

'But the benefit of history is that we can study these events alongside each other, and we can see certain things repeatedly happening to the animals in the water, like changes in body size.

'When you spot those patterns, the data becomes incredibly powerful. It suggests those changes could happen again.'

Life in the hot tub

With this data, scientists can try to develop a clearer vision of what might happen to animals living in the sea when conditions change dramatically.

In past periods of warmer ocean temperatures, it has been common for oxygen levels in the water to drop.

Warm water holds less oxygen, and this combined with increased pollution could see the size of the ocean's dead zones expanding. These are the parts of the ocean where there is too little oxygen to support large animals.

Fossils are also a key to establishing baseline data. Historic collections tell us exactly where different animals and plants lived before plastics, pollution, overfishing and the major rise in carbon dioxide. They show us how distributions of species have changed in response to stress, such as human activity.

Anemones in a hydrothermal vent in the Cayman Trough

Anemones at a hydrothermal vent in the Cayman Trough, 5000 metres below the surface of the Caribbean Sea

 

By matching knowledge about living animals to data about the past, scientists hope to inform decisions about which areas of the oceans are most critical to save.

Twitchett says, 'The more data we have, the easier it will be to make accurate predictions about the future. We are trying to understand how good the current predictions are and how serious the situation is.

'The Museum's collections are such a valuable resource. There is key information about past periods of climate change locked away in the fossils. They are a frozen, untapped archive that we are working on as well as preserving for future generations of scientists to learn from.'

Discovery on the ocean floor

Dr Adrian Glover, a deep-sea biologist and researcher at the Museum, is mapping biodiversity in areas that are poorly known but are now new frontiers for deep-sea industry.

Some of his work delves into the deepest parts of the oceans, studying worms and other invertebrates that live on the muddy sediments and hydrothermal vents of the sea floor.

Glover says, 'Human activity is reaching into new areas of our oceans. We have to understand these areas to be able to assess the risks and provide sustainable conservation strategies.

'Half of this planet is deep sea, and the deep sea is the least studied part of the ocean.'

Glover is investigating the lives of deep-sea creatures including this worm, Bathykurila guaymasensis

Glover is investigating the ecology and evolution of deep-sea creatures including this worm, Bathykurila guaymasensis, discovered at a depth of 1,600 metres

 

Tiny links in the food chain

Glover and other researchers are collecting genetic data about these worms and other deep-sea animals, including molluscs, starfish, sea urchins, fish, crustaceans and sponges.

These smaller creatures might seem insignificant - but if they were to disappear from the ocean, we'd notice. Worms and molluscs become food for larger animals, which vast swathes of humanity rely on.

The team are joining deep-sea research expeditions in the Pacific Ocean, where they are discovering new, undocumented species.

Glover explains, 'Currently, industry is starting to explore environments we have never sampled before. We need to establish a baseline of biodiversity before you can measure any change.

'Understanding what is living underwater, in both shallow seas and deep-ocean vents, will enable us to manage the oceans more sustainably.

'We'll be able to better predict the impact of warmer seas, ocean acidification and increased plastic in the marine food chain.

'Above all, we owe it to humanity to at least try to document and understand our diverse deep-sea wilderness areas before we change them.'

Dive in

Read more about life beneath the waves.

Get involved

Be a digital volunteer for the Museum. Help us to record data from microscopic marine fossils.