Time Machine Biology
Dr Moriaki Yasuhara has spent twelve years in Hong Kong looking at the effects of human activity and natural events on the local environment. That might sound like a long time, but it’s the blink of an eye to a paleoecologist.
Dr Moriaki Yasuhara has spent twelve years in Hong Kong looking at the effects of human activity and natural events on the local environment. That might sound like a long time, but it’s the blink of an eye to a paleoecologist.
Join us on Croucher News as we meet Dr Yasuhara from the University of Hong Kong, to find out more about his work - and learn about time machine biology.
To begin with, we asked about the term paleoecologist. Yasuhara explained that this was a branch of paleontology, which is the study of fossils and prehistoric life.
“Paleoecology applies the skills and techniques of paleontology; put simply, it uses fossils to study the ecology of a place over a period of time, perhaps millions of years or just a few thousand, hundred, or dozens years, often beyond our normal human timescales and memory,” he told us.
To take their samples, Yasuhara and his team extract continuous sediment cores that preserve a record of environmental change over time. This involves using a hollow tube or drill to extract a cylindrical sample of sediment from the ocean floor. “Sediment gradually accumulates over time, so deeper sediment below the ocean floor represents older time and surface sediment on the ocean floor is ‘now’. By studying the sediment core from the bottom to the top, we can study the continuous history of a certain time period. This could be hundreds, thousands, or even millions of years, depending on the length of the core, ” he said.
The fossils used for this kind of study are tiny, small enough to be included in small amounts of sediment available from sediment cores. In fact, they’re so small that they are usually referred to as “microfossils”. Their study requires the use of light or electron microscopy. One example of microfossils used by Yasuhara and his team are ostracods, crustaceans which preserve well within the fossil record, making them excellent indicators for this kind of research. Live specimens are still to be found, so their occurrence can be measured for hundreds of millions of years right up to now.
“Sometimes I refer to my work as time machine biology. What I mean is that by using sediment cores and the microfossils fund there as a proxy, we are able to have an idea of the diversity and abundance of the broader marine community at different times. We’re also able to gauge past environments such as temperature and oxygen levels in the ocean at that time using geochemical and other methods. So, in effect, we’re able to travel back to that period in terms of our data to see deep-time marine ecosystem and biodiversity at that time.” Yasuhara also told us that being able to see trends over a long period of time also gives us a chance to have some idea of what might happen in the future. That would be much more difficult if you only had contemporary observation data.
Yasuhara’s research has shed light on the unique challenges faced by Hong Kong’s marine ecosystem. The region is heavily influenced by the Asian monsoon, which can have a significant impact on local climate patterns and marine life. At the same time, pollution from industrial and urban sources poses a threat to water quality and marine biodiversity in Hong Kong’s coastal areas.
“Hong Kong is at the northern tip of the so-called Coral Triangle,” explained Yasuhara. “This is an extraordinary area which has the greatest biodiversity of any part of the ocean, anywhere,” he said.
“So, as we study the effects of natural events and human activity on the ecosystem of Hong Kong already happened over decades and centuries using ‘time machine biology’ or paleoecology, this suggests what might be in store for yet less developed parts of the tropics, particularly in the rest of the Coral Triangle. This is useful to know in terms of developing ways to minimise the impact on biodiversity in those less developed areas.”
We asked Yasuhara how he got into this niche area of paleoecology in the first place. He explained that he initially liked living creatures when he was a kid. “I used to walk along the shore looking for crabs or shells. When I started to think about my future more seriously in my high school or undergraduate time, I somehow found creatures from deep time, that is, fossils, could be as interesting as contemporary ones, if not more so. That’s what led me into paleoecology,” he said.
He has found Hong Kong a good place to do his research, not only because of the unique local ecology, but also because of the support he gets from his colleagues and the university. And Yasuhara finds that Hong Kong’s also a great place to find enthusiastic PhD students to work with.
And when we asked him about the future of his work and its wider impact, he told us that in Hong Kong there was support for this area of research. “In the wider community, there’s a lot of interest in what has happened to the local marine ecosystem and biodiversity over the last 100 years or so, mainly through the results of human activity. This can be effectively studied via fossils and time machine biology, and that leads to funding opportunities. People want to know what’s going on, so that the right measures can be put into place to mitigate the impact of human activity. I also get invited to give lectures in other places in the city, and I find that there’s a real eagerness to know more,” he told us. “I find that encouraging.”