What are microfossils and why should we care? Sometimes it can be difficult to make the case for a group of fossils which at their largest usually reach just 1mm (although some are actually much larger than this), but microfossils have and continue to play an incredibly important role in many areas of natural science research.
These sand grain sized time capsules are the remains of a diverse range of plants and animals, either whole organisms or component parts such as seeds, teeth or scales that have been preserved throughout Earth’s history.
While some microfossils are terrestrial, most are derived from marine environments, with the majority being organisms like plankton that form the basis of the food chain in marine ecosystems, and act as key carbon sinks for the planet. Due to their shells, or ‘tests’, these organisms are well preserved within the fossil record, providing numerous opportunities to understand more about life on Earth in the past, present and future (not all of the objects in the micropalaeontology collections are fossils though – there are also modern specimens of spores and pollen, more on them later).
The micropalaeontology collections span the length and breadth of the planet, have been collected from as far back as the 1800s, including as part of historically important early expeditions, and represent over 500 million years of life. These tiny specimens can help us with mighty scientific questions, and here’s just a few examples…
1. Track climate change
Microfossils provide a snapshot of climate conditions at a specific moment in time. Researchers can look at the geochemical composition (heavy and light oxygen) of the shells of these organisms to find out what the environmental conditions were like when they were alive, and the shell was formed (explained further in this short video). By tracking how these geochemical characteristics change throughout the fossil record we can see how the Earth’s climate has changed over time and compare this to modern day observations.
This can also enable scientists to make predictions about how climate change may affect organisms now and in the future. As plankton form the base of the food chain they are usually one of the first organisms to respond to environmental changes such as changing salinity or temperature. This means they are an early indicator of shifts in the ecosystem and can therefore be used to predict more widespread impacts of climate change within the marine environment.
2. Innovative pill coverings
What’s the link between microfossils and medicine? A recent article from scientists at the Museum and colleagues at the European Synchrotron Radiation Facility, analysed the structure of historic and modern conifer pollen. It found that the wall structure of conifer pollen is the only known natural occurrence of a nanofoam, a type of nanomaterial that plays a key role in nanotechnologies across healthcare, electronics and more.
The occurrence of this structure in nature shows how the exceptionally strong cell wall of these pollen has enabled them to survive mass extinctions, but it also has a range of possible applications for the modern world. This includes the development of coverings for targeted release pills currently being researched by the pharmaceutical industry or even as anodes in rechargeable batteries.
3. Crime scene investigation
The classic ‘whodunit’ doesn’t usually include a micropalaeontologist, but maybe it will be more common in the future… A growing field of research and industry is taking the identification of microfossils to the court room as a key form of forensic evidence.
Because microfossils are small and abundant, they can tell us a lot about where a person may or may not have been. Whether this is pollen or spores on a jacket or sand on a shoe, by identifying the microfossils contained in the sample we can match a person to a place, or an item to a person. One of the most high-profile uses of micropalaeontology in a criminal case to date was as part of the Soham murder investigation where microfossils successfully linked the suspects’ car to the crime scene.
4. Monitor ocean acidification
Museum research has shown clear links between microfossils and one of the key effects of climate change, ocean acidification. Samples collected 150 years ago during the HMS Challenger expedition have enabled scientists to track how acidification from climate change is impacting the world’s oceans.
As carbon dioxide concentration rises in the Earth’s atmosphere due to human activity an increasing amount of the gas is dissolved into the oceans, making the water more acidic. Microfossils present in plankton tows collected on the Challenger expedition were compared to modern plankton samples from the same locations to identify any effects of rising ocean acidity. Results showed significant reductions in shell thickness in all modern species, indicating that these organisms are finding it more difficult to build shells than their ancient ancestors and highlighting a potential early sign of the impacts of climate change on the marine ecosystem.
5. Reconstruct our past
Discovering these charismatic large specimens is just the first step in finding out what life was like when these animals were alive. Often rock samples collected from digs provide a host of additional information about the environment the specimens once called home, which is key to scientific understanding.
Depending on the species of microfossils preserved in the surrounding rock we can understand more about the climate, the type of habitat, other plants and animals that were around, as well as potentially any major geological or meteorological events that could have taken place e.g. a volcanic eruption or flooding. In the past, microfossils provided evidence that a Mantellisaurus found in Surrey, UK, died 121-127 million years ago, in a temporary pond, that was surrounded by ferns and conifers – all from a few microscopic specimens. They are a key part of the puzzle and story, giving evidence and clues to past environments, species assemblages or drivers of extinction and evolution.
The micropalaeontology collections are one of the Natural History Museum collections that will eventually be rehomed at our new science and digitisation centre. To find out more about the project and to sign-up for email updates , including information on collections closures when available, visit the website.