What is your favourite part about being a scientist and how did you get interested in science in general? When I was young, I was, as many kids, particularly interested in dinosaurs and other fossils. I liked nothing more than visiting a natural history museum marvelling at the wonders of nature‘s past. And of course, I had a proper collection of dino toys. My primary school teachers gifted me a small book about Earth history before I left, knowing very well about this passion of mine. I suppose I just didn‘t grow out of this passion (Certain movies by Spielberg might have played a part in it as well …). Thus, still aspiring to become a palaeontologist, I registered in Bonn University for the geosciences Bachelors program in 2010, which I finished in 2013. I really enjoyed my studies there, so naturally I followed up with the master‘s program that I finished in 2016.
What interests me the most in sciences is the pursue of knowledge. To enhance our knowledge by finding the natural coherence of things. Finding traces of what is yet hidden in the dark, making hypotheses, searching for more clues, trying to see and understand more and more. A great aspect in geosciences is field work. It is such a thrilling experience to visit an outcrop and reconstruct the past, which is, for me, quite a lot like detective work. Looking at all the little puzzle pieces of past ecosystems, such as fossils and sedimentological features, then trying to put it all together into a bigger picture. Since I was young I would read with excitement about the explorers of old times – Humboldt, Darwin, Shackleton, Fawcett, and the like – dreaming of going on such expeditions myself one day. Indeed, my studies brought me to many places, not seldom quite off of touristic trails, and sometimes even a slight bit dangerous. It‘s as close to the travels of these past explorers as I could have wished for.
In laymen‘s terms, what do you do? My current research is focused on ancient marine organic-walled phytoplankton. Plankton describes the organisms that float in the water column. Within the plankton we have zooplankton and phytoplankton. The former are heterotroph, which means they need to consume other organisms to gain energy, while the latter are autotroph, meaning they obtain energy through photosynthesis, just like plants on land. In today‘s oceans we find a variety of groups in the phytoplankton, such as diatoms, coccolithophores, green algae, dinoflagellates and cyanobacteria. I am working on phytoplankton from the Palaeozoic, a time interval dated roughly between 541 Million and 250 Million years ago. During this time the phytoplankton was represented mostly by what we call acritarchs. So what are acritarchs? I‘m not sure, actually. And that‘s why they are called acritarchs, as the name means „uncertain origin“. We don‘t know the biological affinity of acritarchs, and they surely belonged to a variety of groups, but most of them are interpreted to represent the remains of phytoplanktic organisms, some of which might be related to today‘s dinoflagellates.
So how can we study microscopic remains of organic-walled plankton that lived hundreds of millions of years ago? Actually, these little things are quite resistant. In order to process a rock sample for palynological analysis, we dissolve the rock in different acids. What remains are organic-walled microfossils, so called palynomorphs, such as the acritarchs, that we can study under a microscope. But what is so interesting in microscopic organisms that were floating in the ancient seas? First, they help us to define the age of sediment rocks. Many palynomorphs represent important index fossils, and thus, have a stratigraphic value. Then, since phytoplankton is often bound to certain environmental conditions, palynomorph assemblage analyses can help us reconstruct parameters, such as water temperature, depth, or distance to land, during the time of the deposition of the sediment: That is how the distribution of different taxa of phytoplankton can give us valuable information about the palaeoenvironment. Another and major aspect of phytoplankton is their photosynthetic activity. While often the continental forests are called the „lungs of the Earth“, phytoplankton are responsible for 50–80 % of the production of the oxygen in the atmosphere. Through their photosynthetic activity phytoplankton take up great amounts of CO2 from the atmosphere. Large quantities of this carbon is then stored in deeper parts of the ocean when phytoplankton die and sink to the seabed. During the early Palaeozoic the importance of phytoplankton within the carbon cycle was much bigger, since plants were yet to conquer the land. Another important aspect is the fact that phytoplankton is at the base of marine food webs. For these reasons we assume that changes in phytoplankton through time must have had an impact on both Earth‘s climate and marine ecosystems. My studies aim to find correlations between biodiversity changes of the phytoplankton and changes in different palaeo-environmental parameters, such as temperature, atmospheric O2 and CO2 concentrations, sea level, and palaeogeography.
How does your research/goals/outreach contribute to the understanding of climate change, evolution, paleontology, or to the betterment of society in general? While palaeontology is the study of past processes, it can be of great value for the present. Awareness of climate change as a major global crisis has significantly increased in the last decades. Its effects are already perceptible in many of the Earth’s ecosystems. It has become an important task to estimate future consequences of the rapidly changing climate. Palaeontological investigations provide an important tool for predicting processes in changing environments by reconstructing past intercorrelations. Inversing the famous quote of the Scottish geologist Sir Charles Lyell, “The present is the key to the past”, our knowledge of processes in Earth history may help us to estimate future developments. Several important extinction events are known, some of which are related to increases in greenhouse gases. Thus, investigating biotic changes during these crucial time intervals and comparing the results with recent developments is very important. I want to contribute with my work to our understanding of today‘s profound changes in the biosphere caused by human activities.
If you are writing about your research: What are your data and how do you obtain your data? In other words, is there a certain proxy you work with, a specific fossil group, preexisting datasets, etc.? During my Ph.D. project I mostly worked on a database of the Palaeozoic phytoplankton comprising occurrence data from published literature including stratigraphic and geographic information. We used this database to create diversity curves for the Palaeozoic phytoplankton. But I also went on sampling trips myself, which is basically taking rock samples from different stratigraphic layers. In the laboratory these samples are being processed, generally by dissolving the rock in acids and sieving the residues. Then palynological slides are being produced by distributing the sieved residues on glass slides and embedding them in a clear medium. After, the samples are analysed under the microscope. For some of my work I did morphometrics, which is measuring certain parameters of microfossil specimens in larger population in order to statistically analyse them. This can help assessing morphological variability and to review taxonomic classifications.
What advice do you have for aspiring scientists? Working in science can be frustrating at times. That‘s part of it, I suppose. Don‘t let it discourage you. Follow your passion. Other than that, „Explore. Dream. Discover.“ – H. Jackson Brown Jr.
Follow David’s updates on ResearchGate!