Baikal team together for the Rick Battarbee Lecture Series 2014 and project meeting

Image

The team got together on Thursday 8th May for the Rick Battarbee Lecture Series at UCL where Professor Sheri Fritz (from the University of Nebraska, USA) presented a talk on diatoms and climate: ‘From Microscopic to Macroscopic: Climate Variation Through Time as Viewed Through the Lens of the Diatoms.’ Sheri Fritz discussed the work carried out on diatom-inferred salinity and climate reconstructions from continental lakes and the role of ionic concentrations within saline lakes on diatom distributions. Palaeoclimatic records from lakes in the Northern Great Plains were presented, along with research into medieval mega droughts and the formation of Nebraska diatomites during Marine Isotope Stage 3. This was an excellent talk, and the extensive diatom research was inspirational.

The following day, the baikal team (Prof Anson Mackay, Dr George Swann, Dr Suzanne McGowan, Prof Neil Rose, Dr Virginia Panizzo, Jen Adams and Sarah Roberts) gathered for the first project meeting in 2014 at UCL. The meeting began with Jen Adams, Sarah Roberts and Ginnie Panizzo discussing their research findings so far, presenting data from contemporary limnological studies and sedimentary records. Jen presented results from High Performance Liquid Chromatography (HPLC) aided algal pigment analyses and Loss-on-ignition analyses (a measure of organic content) from two catchment lakes; Black Lake and Selenga Delta Lake 1. Sarah presented work on lake-water profile and catchment nutrient concentrations (total phosphorus, silicate and nitrate concentrations), Dissolved Organic Carbon (analysed at Loughborough University), Mercury concentrations (in lake-waters and sediments analysed by Dr. Handong Yang at UCL), HPLC algal pigments and carbon isotopes (analysed at the British Geological Survey). Ginnie presented the Silicon isotope results from all the lake water profiles and catchment sites.

P1050226

The project meeting was a great opportunity to explore data interpretations amongst the group and discuss potential publications and forthcoming opportunities to present the project work at conferences- thanks all for an excellent meeting and looking forward to the next one!

Advertisements

Our first pigment analyses

Image

After all the long days of filtering water samples in our lab kunk back in March, the samples have been stored within a freezer ready for pigment analyses to begin. Filtration was carried out on the collected lake-water samples, to concentrate phytoplankton cells on a Whatman GF/F filter. All these samples have been run through the pigment analyser (High-Performance-Liquid-Chromatography system), to provide us with data on the algal community composition. This analysis can be performed as all phytoplankton groups produce pigments (chlorophylls and carotenoids) to enable cell photosynthesis, and some of these pigments can be used as important biomarkers for algal species presence and absence. The detection of these pigments provides information on the entire species assemblage within the samples, and not just a single group. This is an important aspect of the research, as phytoplankton respond very quickly to any changes within their environment, and provide excellent indicators of nutrient enrichment and climate change through species assemblage changes. Pigment records from across Lake Baikal, extending over natural timescales, will then enable the impact of recent nutrient loading on the ecosystem to be assessed.

To find out more about the application of algal biomarkers within this research, click HERE.

HPLC system: Agilent 1200 series

HPLC system: Agilent 1200 series

Before the samples are analysed on this HPLC system, sample preparation is carried out under special conditions, to enable the separation and detection of individual pigments. A mixture of organic solvents is used to extract the pigments from the cells, consisting of acetone, methanol and water. This sample preparation has to be carried out under dim light conditions, to avoid unnecessary photochemical degradation of pigments, which reduces their chemical stability. They are then stored for at least 12 hours within a freezer in the dark, to ensure pigment extraction from all the algal groups. This is important as algal species have different cell walls, and species with heavily silicified walls (such as large diatoms) require more time to fully extract their pigment composition. These samples are further filtered and HPLC-grade acetone is added as part of the final extraction step. Samples are then dried within the glass vials under nitrogen gas before analysis on the HPLC Agilent 1200 series.

Samples are placed in the autosampler within HPLC

Samples are placed in the auto-sampler tray within HPLC

Once dried, injection solvent is added and the glass vials are placed within the auto-sampler tray before being injected into the HPLC. As each sample is injected into the system, a diode-array detector then analyses the pigments. This produces a pigment chromatogram, which displays the pigment composition within the samples and individual pigments can be identified from their peak retention times and spectra.

Interpretation of these pigment chromatograms is now underway, and fortunately all the manual filtering of litres and litres of water paid off…as well as provoking some arm wrestling from all the bicep exercising…

Photo_on_14-03-2013_at_08.27

…Shortly our first pigment analyses on the sediment cores collected from the March 2013 field trip will be carried out, so more on this to follow soon…

Analysing our first water samples

Image

Part of the research that we are conducting is to analyse the silicon concentration and isotopc composition of lake waters. As we are interested in productivity, it is very important to understand silicon cycling through the year (e.g. winter versus summer conditions). This allows us to constrain down core interpretations. To find out more on why silicon is so important and what organisms use it in Lake Baikal, click here.

P1050563Having collected and filtered all water samples in the field, we are now ready to analyse the silicon concentration of the samples. This is conducted at the Brtish Geological Survey, UK. Concentration of trace metals are also given at the same time which is of great interest when looking at pollution stressors on the lake.

The next step is to measure the isotopc composition of the lake waters (δ30SDSi). In order to do this there are a number of purification steps that must be conducted, with samples being passed through a pre-cleaned resin to remove all cations (e.g. Na+, Ca2+) from the waters. This process takes rather a long time as the liquid must pass through the resin at a slow rate to ensure that there is full Si recovery of the sample.

The acid cleaning stage of the resin.

The acid cleaning stage of the resin.

However, this can only be done once the resin has been acid cleaned. Results from the ICP-MS are used at this stage in order to load onto the resin an exact volume of sample to ensure that the concentrations of all samples are high enough to precisely measure their isotopc composition.

Cationic resin preparation of samples and standards for MC-ICP_MS analyses

Cationic resin cleaning step of samples and standards for MC-ICP_MS analyses

Once samples are fully prepared they are measured once more on the ICP-MS to ensure that there is fully silicon recovery and to know the final concentration of the samples. This is important so that we know the volume of sample we need to analyse on the Multi-Collector Intercoupled Mass Spectrometer (MC-ICP-MS) and match concentrations of Si in bracketing standards.

P1050613

A lot of the action happens under the bonnet of the Multi Collector! Samples are injected into a plasma which ionises it, as the sample passes through the magnet the different masses of silicon (28, 29, 30)are separated and collected in three detectors. Based on the ratio between 30/28 we are able to understand the degree of biological uptake by diatoms that has taken place.

Making Science Count: Evaluating research impact

Image

The Truth Is Out There, so we put it in a suitcase and brought it home. From the water samples and lake sediment cores we brought back from our expedition to Lake Baikal we are building a picture of how the lake has changed over the last 100 and 1000 years. But what will happen to our results when we publish them? How likely are we to influence the work of others, whether scientists, policy-makers, or conservationists concerned with Lake Baikal? What opportunities and constraints are there for the wider dissemination of our work, and how will it be received by different people?

We’re taking the opportunity of our project to find out more about the how the process of science works, and to learn what more we could do to bring greater attention to our findings, rather than leave the impact of our work to habit, chance, and the Internet. To do this, we’re teaming up with social scientist, Stephan Price, who is going to carry out a survey of people interested in Lake Baikal and paleolimnology. We’d like to know were we fit in communities of scientists and others who take an interest in the lake and this type of research, and what the shape and character of these communities are. How are they linked up? Who is seen as important? What type of interactions do people have, and what views do people hold on our research, science and the environment?

125_0214 copy

To answer these questions, the results of the survey will be used to build a network map of the  connections we make with other people through our research, and of the connections of those connections, and so on. One thing that might limit the impact of our research, for example, could be if we are only part of a cosy community of paleolimnological scientists, with no connections beyond the clique. Publishing our work in journals, and on a blog like this can help us to get the message ‘out there’, but personal links can really help to explain the methods and the findings to people and places where it matters. If we are part of a cluster of like-minded scientists, just one weak link outside that clique could make a big difference.

Costing the Earth, Radio 4 today at 15.30

Image

Just a friendly reminder, that there is a Radio 4 episode of Costing the Earth on today at 15.30. This will outline the aims, objectives and wider context of our ongoing project. Don’t forget to tune in!

Hear all about the expedition we conducted in March as well as catching some amazing sound bites of life on the world’s deepest lake. As well as hearing from our expedition team, have the opportunity to listen to what our colleagues are up to and the type of diverse research that is conducted on the lake each year.

2013_Feb27-Mar20 Baikal Neutrino-LENA photo - 081