Shining a light on fossil sunshine

December 15, 2016
WDG

Dr. Phil Jardine

Dr. Phil Jardine

An international team of scientists have reconstructed the longest ever record of past sunshine using pollen trapped in lake sediments collected in Ghana, Africa. The study published today in Scientific Reports enables us to understand past changes in solar input to the global system over the past 140,000 years. Previously we have had to rely upon computer models to mathematically determine past solar inputs to the Earth. “This work really is a first; being able to peer back in time to understand how the Sun has driven our global system over many of thousands of years is a very exciting prospect” said joint-lead author Dr. Phillip Jardine of The Open University.

The Sun is a key component of our natural environment, driving a multitude of processes at Earth’s surface, from photosynthesis generating energy within plants, through to global-scale circulation patterns in our oceans and atmosphere. Understanding more about how the Sun has behaved in the past, and the influence this had on Earth’s environment, will help scientists predict future climate change.

Dr. Jardine used a technique pioneered by one of his co-authors, Dr. Wesley Fraser of Oxford Brookes University, to determine past changes in solar input, specifically changes in ultraviolet (UV) radiation. Plants protect themselves from the harmful nature of ultraviolet radiation by incorporating a number of specific chemical compounds into their tissues that absorb and dissipate the energy of UV radiation. Pollen grains of flowering plants are also provided protection by these UV-absorbing chemicals, thus act as a long-term recorder of ultraviolet radiation from the Sun.

Pollen grains are readily trapped in lake sediments, where they can be preserved for millions of years. By extracting material from Lake Bosumtwi, Ghana, the pollen that was released by flowering plants thousands of years ago can be separated from the lake sediment and chemically analysed for UV-absorbing chemical compounds. It is this chemical signature within the ancient pollen grains that provides us with information about past levels of solar ultraviolet radiation.

“What we present here is a new opportunity to explore how the Earth has changed” said Dr. William Gosling (University of Amsterdam). “I am particularly excited about this because it will means that we can gain a better understanding of why vegetation changed in the past, and consequently this will allow us to anticipate better what the likely impacts of projected future climate change will be.”

This study is available now at www.nature.com/articles/srep39269

Jardine PE, Fraser WT, Lomax BH, Sephton MA, Shanahan TM, Miller CS & Gosling WD (2016) Pollen and spores as biological recorders of past ultraviolet irradiance. Scientific Reports. DOI: 10.1038/srep39269

Published open access:

Julier, A.C.M., Jardine, P.E., Coe, A.L., Gosling, W.D., Lomax, B.H. & Fraser, W.T. (2016) Chemotaxonomy as a tool for interpreting the cryptic diversity of Poaceae pollen. Review of Palaeobotany and Palynology 235, 140-147. DOI: 10.1016/j.revpalbo.2016.08.004

Ghana Fieldwork 2014; Day 02

October 17, 2014
wesfraser

The second day of our fieldwork saw us; transfer from Accra to Fumesua where FORIG is located (approximately 20 km south of Kumasi); meet up with FORIGs deputy director Dr Stephen Adu-Bredu to discuss fieldwork and outreach plans; and settle in to FORIG for the next two weeks.

The next two days will involve building pollen traps ready for deployment next and finalising the detailed day-to-day plan of work.

Ghana Fieldwork 2014; Day 01

October 17, 2014
wesfraser

The latest round of fieldwork in Ghana is underway. Adele and myself are travelling out to collect pollen traps deployed last year as part of Adeles PhD research. We will be revisiting the sites in Ankasa, Bobiri and Kogyae that Adele and Phil visited last year. This time we are also accompanied by Lottie who will be delivering workshops on outreach activity engagement and the palaeoecology represented in the sediment record of Lake Bosumtwi.

Flying into land at Accra in the twilight we passed over a storm cell, with some fantastic convective clouds illuminated by flashes of lightning within. Once out of the airport, we were taken through the hustle and bustle of Accra streets, alive with evening activity. Finally reaching our destination for the night, the FORIG guesthouse. All three members of our party readily made for bed to get a good nights sleep before tomorrows journey to Kumasi.

Organisms and environments: Frontiers in palaeoecological technique development

October 16, 2014
WDG

inquaXIX INQUA Congress
NAGOYA, JAPAN 27 July-2 August, 2015

Grass pollen from Lake Bosumwti picked for individual chemical analysis

Grass pollen from Lake Bosumwti picked for individual chemical analysis

Abstract submission is now open for the XIX International Union for Quaternary Research (INQUA) Congress. “Ecology of the past” researchers will be there and are hosting a special session, entitled Organisms and environments: Frontiers in palaeoecological technique development, at which we hope to bring together a wide range of palaeoecologists working on novel proxy development. Members of the “Ecology of the past” group will be showcasing recent findings on the environmental significance of pollen chemistry change through time; linked to the 500,000 years of solar irradiance, climate and vegetation change in tropical West Africa project (Fraser et al., 2014). Please take a look at our session and consider submitting YOUR abstract today!

For information on abstract submission click here. Closing date for abstract submission 20 December 2014.

For further information on our session click here, or “Continue reading” below…

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