‘Going back in time’

After completing the second of the two terms of five years leading the Institute as director, Henk Brinkhuis’ career comes full circle, turning back to his old loves: marine palynology and scientific ocean drilling.

Two-and-a-half billion years of climate information

“My scientific specialization is in the study of ancient ocean mud, especially its organic content” - In other words: marine palynology and organic biogeochemistry, combining marine geology with paleoecology, paleoclimate and paleoceanography’. Marine palynology entails the study of microscopic, acid-resistant organic remains of ancient plants and animals found in marine sediments. ‘My favourite group are the organic-walled dinoflagellate cysts” Typically, these are single celled algae inhabiting both fresh water and marine environments. One interesting thing is that some of them produce an organic-walled resting stage, called cyst. These may be considered as ‘bioplastic’, considering their resistance to degradation of organic material. By studying these cysts, and their Paleozoic and even older precursors, the so-called acritarchs, we can look back in time no less than two-and-a-half billion years. These microfossils are typically used for dating and assessing the paleoenvironment. Particularly when taken together with all the other palynological elements in each sample, including remains of other organisms, from sea and washed in from land, marine palynology becomes a powerful tool for recognizing and reconstructing ancient climate change. Moreover, such information, when tied to geochemical studies including stable isotope analysis from the same samples, can indeed be used to learn from the past, and predict the climatic future of our planet.

Scientific ocean drilling – the ’International ocean discovery program’ - IODP

“Earlier in 2021, I was appointed chair of the so-called Forum of the international Ocean Discovery Program, starting per October 1”. The IODP Forum is a venue for exchanging ideas and views on the scientific progress of the International Ocean Discovery Program. Specifically, the Forum is the custodian of the IODP Science Plan 2013-2023 and provides advice to the IODP Facility Boards on Platform Provider activity. The IODP Forum meets at least annually and membership is open to all countries, consortia, or entities that provide funds to IODP platform operations. Henk refers to this program as ‘the best international science program ever’ and compares it to the spirit of that famous classic TV series ‘StarTrek’ where all of mankind work together, even with beings from other worlds, to solve problems. With the present climate crisis in mind, we are particularly interested in reconstructing the warm periods in history. For example, the Paleocene-Eocene Thermal Maximum was a period, relatively ‘nearby’, only 56 million years ago, when the average temperature on Earth rapidly rose six degrees, in an already warmer world. There were even Palm trees growing on the continents around the North Pole! From a present point of view, with huge amounts of anthropogenic CO₂ in the atmosphere, it is important to find out: how did the planet counter this warm period 56 million years ago, with its large amounts of CO₂?” How did Mother Earth go from Hothouse to Icehouse. That is the main question on Henk’s mind.

Floating carbon-catcher

“There is increasing evidence that massive growth of the tiny free-floating freshwater fern Azolla has played a major role in taking carbon out of the atmosphere by the end of the very warm Early Eocene, some 50 million years ago. This phenomenon that lasted around 800,000 years, started right at the first, but definite, long term cooling trend, towards the modern ‘icehouse’. Azolla grows extremely fast, making it a pest to modern day ecologists, but back then, covering more than 30 million km2 of Nordic seas, it may have acted as the biggest floating carbon-catcher in history, its mats sinking in anoxic oblivion of the ancient oceans, bringing down all that Carbon to the (long term) geological Carbon cycle.”

Keep on Drilling

“I hope to further contribute to the detailed knowledge of the long-term carbon cycle, that can be understood through studies of dinoflagellates, isotopes and other tracers that we find in ocean sediments. This also means we must keep participating in international efforts of scientific ocean drilling in the future, also post 2024, when the current Ocean Discovery Program ends. The US is planning on renewing their scientific drilling vessel, while Europe is pushing for its Marine Science Program that Japan, China, Korea, India, Australia and New Zealand are part of as well.”

Photos taken during the IODP 302 ACEX expedition on the North Pole.

Current positions (selection)

•    Professor in Marine Palynology and Paleoecology, Utrecht University
•    Chair IODP forum
•    Member of various scientific advisory boards, nationally and internationally
•    Member of the KNAW

Education

1985-1992 - University Utrecht, PhD Geology, Palaeoceanography, Marine Palynology, Micropaleontology
1978-1985 - University Utrecht, MSc, Geology