Phytoplankton (workpackage 3.1)
Workpackage 3.1 is dedicated to lake assessment using lake phytoplankton. Particular emphasis is placed on the development of new biological metrics to assess the impact of eutrophication on phytoplankton communities. The uncertainty of assessment results is being addressed using replicate sample data from an excessive field campaign in summer 2009. The specific objectives of WP 3.1 are:
- to develop and validate metrics for phytoplankton composition and algal blooms in relation to eutrophication pressure, for application in all regions of Europe,
- to quantify the main sources of uncertainty in phytoplankton metrics (chlorophyll, composition and bloom metrics),
- to produce tools and practical guidance for phytoplankton sampling and analysis to harmonise methods across the EU and reduce uncertainty in phytoplankton classifications and
- to examine combination rules for the use of chlorophyll, composition and bloom metrics in ecological status assessments, specifically in relation to eutrophication pressure.
Existing phytoplankton data have been collated from 1,734 lakes in 19 European countries to develop and validate metrics for the impact of eutrophication on phytoplankton composition and algal blooms. To quantify the main sources of uncertainty, a field campaign was carried out in 31 lakes across Europe (sample sites). In each lake, phytoplankton were sampled from 3 locations with replicates from each location counted by 2 different analysts. Three different methods have been used to analyse the phytoplankton community: traditional counts, HPLC (high-performance liquid chromatography) of algal pigments and fluoroprobe of different algal groups.
Outcome and products
Common metrics are being developed for different regions of Europe for both phytoplankton composition and algal blooms. These metrics are being developed, alongside the use of Chlorophyll a, as a measure of phytoplankton abundance, to represent the ecological status of a lake with respect to eutrophication pressures. Our philosophy is that we want this to be more than just a proxy measure of phosphorus concentrations, but more widely represent changes in community structure and functioning associated with nutrient pressures. Potential candidate metrics of a phytoplankton multimetric index are:
- Composition, size structure and changes in functional groups
- Evenness of the community and health risks associated with cyanobacterial blooms
Relevance for end-users
The development of common metrics is being carried out in close collaboration with GIGs and should be complete by September 2010 in time to help take forward the Intercalibration process. This will provide a common measure that will allow easier comparison of the varied phytoplankton metrics that have been developed around Europe. The work on uncertainty will inform guidance to national agencies and future CEN standards on phytoplankton sampling. Ultimately we aim to deliver tools that will deliver more robust assessments of the ecological health of European lakes.
Dr Laurence Carvalho, Centre for Ecology & Hydrology, UK.