Ozone boost for wild berries



22 August 2012

Increasing levels of atmospheric CO2 and ultra violet radiation (UV) may provide unexpected benefits to wild berry species according to a study in the Swedish sub-arctic conducted by scientists at IBERS.

Such berries are an important food harvest for the people of Northern Europe during late summer and autumn. They also represent a vital source of nutrition to birds at high latitudes.   

In findings from a 20 year experiment just published in the journal Ambio, the team discovered that when plants were exposed to a combination of enhanced UV and elevated CO2, the antioxidant content of bilberries (Vaccinium myrtillus) increased, together with the quantities of berries produced. UV radiation also increased levels of seed fertility.

Enhanced levels of UV remain an environmental concern at high latitudes since the discovery of the ozone ‘hole’ in 1985. Atmospheric concentrations of CO2 continue to rise contributing to future climate warming.

However, this study suggests potential nutritional benefits for consumers of wild bilberries. This could also enhance seed dispersal of the species, because some birds preferentially feed on berries with higher antioxidant content.

The scientists, led by Dr Dylan Gwynn-Jones, believe that enhanced UV radiation produces ‘stress responses’ in wild bilberries, which drives the plants to put more energy into reproduction. Elevated CO2 may actually promote this process as more carbon is available from photosynthesis.
The researchers caution that although their study indicates some indirect short-term benefits for wild bilberries and related species in the study (crowberry and lingonberry), these changing environmental factors may affect the functioning of Northern ecosystems.

The research is funded by the National Environmental Research Council (NERC), http://www.nerc.ac.uk and supported by the Swedish Polar Research Secretariat http://www.polar.se/en/.

The paper Enhanced UV-B and Elevated CO2 Impacts Sub-Arctic Shrub Berry Abundance, Quality and Seed Germination is published in the academic journalAmbio and is available online at http://dx.doi.org/10.1007/s13280-012-0311-4.

The Authors of the paper are Dylan Gwynn-Jones, Alan Jones, Alice Waterhouse, Ana Winters, David Comont, John Scullion, Rosie Gardias, Bente J. Graee, John A. Lee, Terry V. Callaghan (2012)

The study
The investigation was conducted as part of a twenty year programme of experimentation in the Arctic circle of northern Sweden, taking place at the internationally renowned Abisko Scientific Research Station. This centre of excellence is administered by the Swedish Polar Research Secretariat and has developed leading lines of research on Arctic ecosystems over recent decades, including investigating the effects of climate change. The experimental area interfaces the boreal forest biome and Arctic tundra and is a plant community described scientifically as ‘sub-Arctic birch-heath’. The experimental treatments and controls for this study were instigated in 1993 over 16 replicated plots that cover approximately a 25 x 25m area. To test the effects of elevated CO2, open top chambers (0.73m2) fumigate the vegetation during each growing season at CO2 levels predicted for the year 2050 (600ppm). Enhanced UV-B radiation from an array of fluorescent lamps is also applied, which simulates 15% depletion in stratospheric ozone. Berries were sampled from the experimental plots in August 2006 and July-August 2009. Those used for biochemical analysis were immediately stabilised by freeze drying, a process that extracts water from biological tissue using a vacuum and preserves its chemistry. The stabilised samples were analysed in the UK at the Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, to detect concentrations of flavonoid compounds, using high pressure liquid chromatography (HPLC). These compounds make up the suite of chemicals known as ‘antioxidants’ with known benefits to health.

Ozone depletion
1) The 2011 Arctic ozone thinning episode (as reported in Nature) produced an 80% loss of stratospheric ozone in the Arctic region - which was the largest ever recorded in the northern hemisphere (our experimental treatment, which simulates a 15% loss appears relatively conservative by comparison) http://www.nature.com/nature/journal/v478/n7370/full/nature10556.html  

2) Ozone depletion is at its worst in late winter-spring, hence UV exposure will also be highest at this time. Late snow cover offers some degree of protection for vegetation from this, especially at high latitudes in the Arctic. The ozone layer 'repairs' during the course of the summer due to stratospheric mixing, meaning that the direct exposure of ripening berries in the wild to elevated UV is likely to be more moderate at this time of the year.

About the journal Ambio

addresses the scientific, social, economic, and cultural factors that influence the condition of the human environment. AMBIO was founded in 1972, the year of the first UN Conference on the Environment. For more than 40 years AMBIO has brought international perspective to important developments in environmental research, policy and related activities, for an international readership of specialists, generalists, students, decision-makers and interested laymen. The broad scope of coverage extends to ecology, environmental economics, geology, geochemistry, geophysics, paleontology, hydrology, water resources, oceanography, earth sciences, meteorology, and physical geography.

Funding and support
The research is funded by the National Environmental Research Council (NERC), http://www.nerc.ac.uk

NERC is the UK's main agency for funding and managing world-class research, training and knowledge exchange in the environmental sciences. It coordinates some of the world's most exciting research projects, tackling major issues such as climate change, food security, environmental influences on human health, the genetic make-up of life on earth, and much more. NERC receives around £300m a year from the government's science budget, which it uses to fund research and training in universities and its own research centres.

The experiment is co-supported by the NERC and the Swedish Polar Research Secretariat SPRS promote and co-ordinates Swedish polar research, including research in the Arctic and Antarctic regions. Abisko Scientific Research Station is part of this network and is situated about 200 km north of the Arctic Circle in Sweden (68º21’N, 18º49’E).