Historically, there has been great success in maintaining and improving the quality of surface waters by developing an understanding of the links between anthropogenic pressures (e.g. water abstraction, agriculture, and effluent discharges) and the chemical status of waters, although there remain many challenges in reliably designing and implementing the necessary programs of measures. Our present understanding of the link between chemical properties and ecological state, while good in some instances, is generally not adequate to support management intervention against ecological objectives. In this report we review and identify information gaps in our knowledge on relations between pressures, chemical and ecological status for the major pressures types and biological quality elements. We also give an overview of the chemical parameters that are used to determine the ecological status of water body types and of the biological indicators currently applied and/or potentially applicable as classification parameters for inland and coastal waters.
This gap-analysis is needed to 1) identify the key areas of further work within the REBECCA project and 2) to identify the areas where further experimental or monitoring work would be needed (beyond the scope of REBECCA), due to lack of data or quantitative understanding of the functional relationships between chemical status and biological quality indicators. This report should help in focusing the on-going WFD intercalibration process in 2005-6. In particular it should provide insights on which biological and pressure parameters should be selected and which data there would be available to illustrate the degradation of the biological quality with respect of pressure gradients.
Regarding data availability to Rebecca project, major gaps were identified as follow:
• Data from the Mediterranean and alpine lake types
• Data from large part of the Mediterranean coastal & transitional types (with exception of Italy)
• Data on concentrations of toxic chemical substances in combination with biological quality element indicator data
• Macrophyte and benthic invertebrate data from many lake & coastal types
• Fish data from lakes (and transitional waters – not included in REBECCA) Apart from these data gaps, there are common “knowledge gaps” in relation to tasks required by the WFD that exist for all surface water categories:
• Development of reference conditions
• Development of type-specific classifications
• Criteria for setting class boundaries
• Criteria for setting ecological thresholds
• Supporting element classifications related to biological impact
• Relationships between nitrogen conditions and ecological responses
• Estimations of uncertainty in classifications
• Uncertainty in measured data
• Responses to combined pressures
Additionally, a summary of specific knowledge gaps for each combination of pressure and quality element is given in the following pages for inland and marine water ecosystems.