Silicon isotope records of recent environmental change and anthropogenic pollution from Lake Baikal, Siberia

Lake Baikal is the world's oldest lake lying in a rift zone in south eastern Siberia (103o43'-109o58'E and 51o28'-55o47'N) that began to form over 20 million years ago. As well as being the world's deepest and most voluminous, the lake also acts as a major water resource containing c. 20% of global surface freshwater. A key feature of Lake Baikal is the high degree of biodiversity with over 2,500 flora and fauna, the majority of which are endemic. Such high levels of endemicity have led to the lake being cited as the "most outstanding example of a freshwater ecosystem" and resulted in the site being designated a World Heritage Site in 1996. Industrial development and changes in catchment land-use since the 1950's, however, pose real and serious threats to the stability of the lake's ecosystem with pollution entering the lake from major conurbations, industrial centres, mining and agricultural practises. The lake is also responding strongly to anthropogenic climate change. Firstly, global warming is having a major impact on regional permafrost with increased melting leading to enhanced nutrient inputs to the lake. Secondly, marked increases in water column temperatures have been observed in the south basin. Thirdly, the duration of ice cover and ice thickness have declined significantly in recent decades with further declines forecast for the future. Such changes will have major implications for the food-web interactions and the wider ecosystem from the rapid growth of primary producers underneath clear ice to the lake's top consumer, Phoco sibirica (the world's only freshwater seal).

In order to ensure that future development and policy plans for the catchment are capable of sustaining Lake Baikal's unique ecosystem, there is a need for a detailed understanding as to the impact of anthropogenic influences on the lake. Efforts towards this are ongoing and led by monitoring programmes from the Limnological Research Institute in Irktusk, Russia. This project will complement and extend this work by developing the application of silicon isotope measurements in Lake Baikal to provide information on changes in biogenic nutrient utilisation. By first carrying out a calibration of the method in the modern day water column, measurements will then be taken from a series of sediment cores from around the lake to examine: 1) the impact of recent 20th Century catchment development and climate change on nutrient utilisation; 2) ascertain the response of the lake to natural climatic changes that have occurred over the last 1000 years. Results from this project will provide valuable information that will aid scientists, policy makers and other stakeholders as to the impact of recent catchment/climate changes on Lake Baikal as well as an indication of the lake's vulnerability to future climate change.

The research within this project will be of interest to a number of groups covering:

1) Policy makers and environmental groups: including both national and international as well as governmental and non-governmental organisations acting to maintain ecosystem services whilst ensuring future economic development in the region. Example bodies, range from UNESCO and the Russian government to Baikal Environment Wave (www.baikalwave.eu.org/eng.html) and the newly opened Environmental Center in Irkutsk, Russia.

2) Scientists interested in: i) examining the response of lake biology to nutrient loading and climate change; ii) the development and calibration of d30Si as a proxy in aquatic systems - opening the potential for its further use in lacustrine palaeoclimatic reconstructions in Lake Baikal and other site; iii) monitoring ecosystem health of the lake (www.geol.irk.ru/baikal/baikal.htm). This includes existing international collaborative programmes between Russia and other foreign research centres which our research builds on such as the EU funded CONTINENT project (http://continent.gfz-potsdam.de), the International Continental Drilling Programme (ICDP) Baikal Drilling Project (www.geol.sc.edu/sil/bdp.htm) and the Baikal International Centre for Ecological Research (BICER) (http://royalsociety.org/Lake-Baikal).

3) Individuals: by virtue of the lake's historic and cultural status as a site of outstanding natural beauty, as a high profile ecosystem in terms of biodiversity and conservation and as a sacred site for indigenous Buryat people.

As identified in the Pathways to Impact document, members of these three stakeholders will be identified through a series of network analyses and invited to workshop meeting in both the UK and Russia to discuss existing scientific knowledge, the outcomes of this project, current/future risks to the Lake Baikal ecosystem and to identify future objectives and research directions. From this we expect to announce a position statement as to the current and future vulnerability of the Lake Baikal ecosystem to anthropogenic changes. Further scientific impacts will be achieved through a combination of peer-reviewed papers and special sessions at major international conferences.