The aim of this challenge was to produce gridded data layers of the average seasonal eutrophication over a 10 year period in the North Sea basin.
The approach taken for this challenge used the method of the OSPAR Contracting Parties for measuring eutrophication. In brief this entailed the collection of information on various eutrophication parameters that are then given an assessment level and analysed for trends over time to determine eutrophication patterns. The assessment of eutrophication is not carried out at a whole basin level but rather on smaller geographical scales which are then aggregated to provide a whole basin view.
The data gathered for the challenge included:
- Riverine inputs and direct discharges;
- Area specific nutrient concentrations;
- Area specific N/P ratio;
- Chlorophyll a concentrations;
- Phytoplankton indicator species and macrophytes (including macroalgae) presence;
- Oxygen availability;
- Changes to the zoobenthos and fish populations, including kills due to changes in environmental conditions;
- Area specific organic carbon/organic matter;
- Presence of algal toxins.
As whole basin data for an assessment of eutrophication does not exist the challenge relied on accessing information that had been collected and provided by EU member states. The main issue with this approach is the variability in monitoring data held by different nations as there are different programmes and standards of reporting meaning that collation of the data was difficult for this challenge.
The temporal and spatial coverage for some of the required data was insufficient to provide an assessment of seasonal eutrophication over a 10 year period. It was also the case that where data were available over a reasonable time period the access was sometimes restricted to a particular number of years meaning the information was less useful. There were also odd data gaps for some of the key parameters used to assess eutrophication, with macrophyte/macroalgae data only available for the Kattegat and little to no information on fish kills for any of the countries that are monitoring eutrophication. There was also some bias identified in the datasets as locations within heavily modified water bodies close to e.g. fish farms were monitored with a greater regularity than areas which were less modified or considered natural, even if they had been identified as suffering from eutrophication.
One of the main issues also identified was in regards to the metadata provided with several of the datasets. This was either insufficient or lacking meaning that the data downloaded for use in the challenge was unusable as the temporal or spatial scale was unknown or the quality of the data could not be determined.
The challenge set in this case was not met due to the lack of temporal and spatial data available for the required parameters. Therefore no series of seasonal eutrophication over a 10 year period could be produced.
For more information please see the Final Project Report.